Cosmopolitan C Library

This function first tries to trigger your SIGABRT handler. If the signal handler returns, then signal(SIGABRT, SIG_DFL) is called before SIGABRT is raised again.

@noreturn

@asyncsignalsafe

@see libc/calls/abort.c

abs

Returns absolute value of 𝑥.

This function is a footgun since your argument may be narrrowed. Consider using labs(), llabs(), or better yet a macro like this:

#define ABS(X) ((X) >= 0 ? (X) : -(X))

Note that passing x as INT_MIN is undefined behavior, which depends on whether or not your c library as well as the objects that call it were built using the -fwrapv or -ftrapv flags.

@param

int x

@return

int

@see libc/intrin/abs.c

accept

Creates client socket file descriptor for incoming connection.

@param

int fd: is the server socket file descriptor
struct sockaddr* opt_out_addr: will receive the remote address
unsigned int* opt_inout_addrsize: provides and receives addr's byte length

@return

int: client fd which needs close(), or -1 w/ errno

@cancelationpoint

@asyncsignalsafe

@restartable (unless SO_RCVTIMEO)

@see libc/sock/accept.c

accept4

Creates client socket file descriptor for incoming connection.

@param

int fd: is the server socket file descriptor
struct sa* opt_out_addr: will receive the remote address
unsigned int* opt_inout_addrsize: provides and receives out_addr's byte length
int flags: can have SOCK_{CLOEXEC,NONBLOCK}, which may apply to both the newly created socket and the server one

@return

int: client fd which needs close(), or -1 w/ errno

@cancelationpoint

@asyncsignalsafe

@restartable (unless SO_RCVTIMEO)

@see libc/sock/accept4.c

access

Checks if effective user can access path in particular ways.

This is equivalent to saying:

faccessat(AT_FDCWD, path, mode, 0);

@param

const char* path: is a filename or directory
int mode: can be R_OK, W_OK, X_OK, F_OK

@return

int: 0 if ok, or -1 w/ errno

@see faccessat() for further documentation

@asyncsignalsafe

@see libc/calls/access.c

acos

Returns arc cosine of 𝑥.

@param

double x

@return

double: value in range [0,M_PI]; NAN if 𝑥 ∈ {NAN,+INFINITY,-INFINITY}; NAN if 𝑥 ∉ [-1,1]

@see libc/tinymath/acos.c

acosh

Returns inverse hyperbolic cosine of 𝑥.

@param

double x

@return

double

@define acosh(x) = log(x + sqrt(x*x-1))

@see libc/tinymath/acosh.c

acoshf

Returns inverse hyperbolic cosine of 𝑥.

@param

float x

@return

float

@define acosh(x) = log(x + sqrt(x*x-1))

@see libc/tinymath/acoshf.c

acosl

Returns arc cosine of 𝑥.

@param

long double x

@return

long double

@define atan2(fabs(sqrt((1-𝑥)*(1+𝑥))),𝑥)

@domain -1 ≤ 𝑥 ≤ 1

@see libc/tinymath/acosl.c

AcquireToken

Atomically decrements signed byte index if it's positive.

Multiple threads are able to call this method, to determine if enough tokens exist to perform an operation. Return values greater than zero mean a token was atomically acquired. Values less than, or equal zero means the bucket is empty. There must exist 1 << c signed bytes (or buckets) in the b array.

Since this design uses signed bytes, your returned number may be used to control how much burstiness is allowed. For example:

int t = AcquireToken(tok.b, ip, 22);
if (t < 64) {
  if (t > 8) write(client, "HTTP/1.1 429 \r\n\r\n", 17);
  close(client);
  return;
}

Could be used to send rejections to clients that exceed their tokens, whereas clients who've grossly exceeded their tokens, could simply be dropped.

@param

_Atomic char* b: is array of token buckets
unsigned int x: is ipv4 address
int c: is cidr

@return

int

@see net/http/tokenbucket.c

addmntent

@param

struct FILE* f
struct mnt* mnt

@return

int

@see third_party/musl/mntent.c

aligned_alloc

Same as memalign(a, n) but requires IS2POW(a).

@param

unsigned long a
unsigned long n: number of bytes needed

@return

void*: memory address, or NULL w/ errno

@throw EINVAL if !IS2POW(a)

@see pvalloc()

@see libc/mem/aligned_alloc.c

alphasort

@param

struct dirent** a
struct dirent** b

@return

int

@see libc/stdio/alphasort.c

AppendResourceReport

Generates process resource usage report.

@param

char** b
struct rusage* ru
const char* nl

@return

void

@see libc/log/appendresourcereport.c

appends

Appends string to buffer, e.g.

char *b = 0;
appends(&b, "hello");
free(b);

The resulting buffer is guaranteed to be NUL-terminated, i.e. !b[appendz(b).i] will be the case.

@param

char** b
const char* s

@return

long: bytes appended (always strlen(s)) or -1 if ENOMEM

@see appendz(b).i to get buffer length

@note 2x faster than appendf()

@see libc/stdio/appends.c

AppendStrList

@param

struct StrList* sl

@return

int

@see libc/stdio/appendstrlist.c

arm_optimized_routines_notice

@type

const char[62]

@see libc/intrin/armopt.c

asin

Returns arc sine of 𝑥.

@param

double x

@return

double: value in range [-M_PI/2,M_PI/2]; NAN if 𝑥 ∈ {NAN,+INFINITY,-INFINITY}; NAN if 𝑥 ∉ [-1,1]

@see libc/tinymath/asin.c

asinhf

Returns inverse hyperbolic sine of 𝑥.

@param

float x

@return

float

@define asinh(x) = sign(x)*log(|x|+sqrt(x*x+1)) ~= x - x^3/6 + o(x^5)

@see libc/tinymath/asinhf.c

asinl

Returns arc sine of 𝑥.

@param

long double x

@return

long double

@define atan2(𝑥,sqrt((1-𝑥)*(1+𝑥)))

@domain -1 ≤ 𝑥 ≤ 1

@see libc/tinymath/asinl.c

asprintf

Formats string, allocating needed memory.

@param

char** strp
const char* fmt
...

@return

int: bytes written (excluding NUL) or -1 w/ errno

@see xasprintf() for a better API

@see libc/stdio/asprintf.c

__assert_fail

Handles assert() failure.

@param

const char* expr
const char* file
int line

@return

void

@see libc/calls/assertfail.c

atanh

Returns inverse hyperbolic tangent of 𝑥.

@param

double x

@return

double

@define x ? log1p(2 * x / (1 - x)) / 2 : x

@see libc/tinymath/atanh.c

atanhf

Returns inverse hyperbolic tangent of 𝑥.

@param

float x

@return

float

@define x ? log1p(2 * x / (1 - x)) / 2 : x

@see libc/tinymath/atanhf.c

atanhl

Returns inverse hyperbolic tangent of 𝑥.

@param

long double x

@return

long double

@define x ? log1p(2 * x / (1 - x)) / 2 : x

@see libc/tinymath/atanhl.c

atexit

Adds global destructor.

Destructors are called in reverse order. They won't be called if the program aborts or _exit() is called. Invocations of this function are usually generated by the C++ compiler.

@param

void(*)() f

@return

int: 0 on success or nonzero if out of space

@see libc/intrin/atexit.c

atof

Converts string to double.

@param

const char* s

@return

double

@see libc/stdio/atof.c

atoi

Turns string into int.

Decimal is the only radix supported. Leading whitespace (as specified by the isspace() function) is skipped over. Unlike strtol(), the atoi function has undefined behavior on error and it never changes errno

@param

const char* nptr: is a non-null nul-terminated string

@return

int: the decoded signed saturated integer

@see libc/fmt/atoi.c

atol

Turns string into long.

@param

const char* nptr: is a non-null nul-terminated string

@return

long: the decoded signed saturated integer

@see libc/fmt/atol.c

basename

Returns pointer to last filename component in path, e.g.

path     │ dirname() │ basename()
─────────────────────────────────
0        │ .         │ .
.        │ .         │ .
..       │ .         │ ..
/        │ /         │ /
usr      │ .         │ usr
/usr/    │ /         │ usr
/usr/lib │ /usr      │ lib

Both / and \ are are considered valid component separators on all platforms. Trailing slashes are ignored. We don't grant special consideration to things like foo/., c:/, \\?\Volume, etc.

@param

char* path: is UTF-8 and may be mutated, but not expanded in length

@return

char*: pointer to path, or inside path, or to a special r/o string

@see dirname()

@see SUSv2

@see libc/fmt/basename.c

bcmp

Tests inequality of first 𝑛 bytes of 𝑝 and 𝑞.

@param

void* a
void* b
unsigned long n

@return

int: 0 if a and b have equal contents, otherwise nonzero

@see timingsafe_bcmp()

@asyncsignalsafe

@see libc/str/bcmp.c

bcopy

Moves memory the BSD way.

Please use memmove() instead. Note the order of arguments.

@param

void* src
void* dest
unsigned long n

@return

void

@see libc/intrin/bcopy.c

bind

Assigns local address and port number to socket, e.g.

struct sockaddr_in in = {AF_INET, htons(12345), {htonl(0x7f000001)}};
int fd = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP);
bind(fd, (struct sockaddr *)&in, sizeof(in));

On Windows, Cosmopolitan's implementation of bind() takes care of always setting the WIN32-specific SO_EXCLUSIVEADDRUSE option on inet stream sockets in order to safeguard your servers from tests

@param

int fd: is the file descriptor returned by socket()
struct sa* addr: is usually the binary-encoded ip:port on which to listen
unsigned int addrsize: is the byte-length of addr's true polymorphic form

@return

int: 0 on success or -1 w/ errno

@error ENETDOWN, EPFNOSUPPORT, etc.

@asyncsignalsafe

@see libc/sock/bind.c

bingblit

@param

int ys
int xs
UNKNOWN M
int yn
int xn

@return

short*

@see libc/x/bingblit.c

bsearch

Searches sorted array for exact item in logarithmic time.

@param

void* key
void* base
unsigned long nmemb
unsigned long size
int(*)() cmp

@return

void*

@see bsearch_r()

@see libc/mem/bsearch.c

bsearch_r

Searches sorted array for exact item in logarithmic time.

@param

void* key
void* base
unsigned long nmemb
unsigned long size
int(*)() cmp
void* arg

@return

void*

@see bsearch()

@see libc/mem/bsearch_r.c

bsf

Returns position of first bit set.

                      ctz(𝑥)         31^clz(𝑥)   clz(𝑥)
  uint32 𝑥   bsf(𝑥) tzcnt(𝑥)   ffs(𝑥)   bsr(𝑥) lzcnt(𝑥)
0x00000000      wut       32        0      wut       32
0x00000001        0        0        1        0       31
0x80000001        0        0        1       31        0
0x80000000       31       31       32       31        0
0x00000010        4        4        5        4       27
0x08000010        4        4        5       27        4
0x08000000       27       27       28       27        4
0xffffffff        0        0        1       31        0

@param

int x: is a 32-bit integer

@return

int: number in range 0..31 or undefined if 𝑥 is 0

@see libc/intrin/bsf.c

bsfl

Returns position of first bit set.

                      ctz(𝑥)         31^clz(𝑥)   clz(𝑥)
  uint32 𝑥   bsf(𝑥) tzcnt(𝑥)   ffs(𝑥)   bsr(𝑥) lzcnt(𝑥)
0x00000000      wut       32        0      wut       32
0x00000001        0        0        1        0       31
0x80000001        0        0        1       31        0
0x80000000       31       31       32       31        0
0x00000010        4        4        5        4       27
0x08000010        4        4        5       27        4
0x08000000       27       27       28       27        4
0xffffffff        0        0        1       31        0

@param

long x

@return

int: number in range 0..63 or undefined if 𝑥 is 0

@see libc/intrin/bsf.c

bsr

Returns binary logarithm of 𝑥.

                      ctz(𝑥)         31^clz(𝑥)   clz(𝑥)
  uint32 𝑥   bsf(𝑥) tzcnt(𝑥)   ffs(𝑥)   bsr(𝑥) lzcnt(𝑥)
0x00000000      wut       32        0      wut       32
0x00000001        0        0        1        0       31
0x80000001        0        0        1       31        0
0x80000000       31       31       32       31        0
0x00000010        4        4        5        4       27
0x08000010        4        4        5       27        4
0x08000000       27       27       28       27        4
0xffffffff        0        0        1       31        0

@param

int x: is a 32-bit integer

@return

int: number in range 0..31 or undefined if 𝑥 is 0

@see libc/intrin/bsr.c

bsrl

Returns binary logarithm of 𝑥.

                      ctz(𝑥)         31^clz(𝑥)   clz(𝑥)
  uint32 𝑥   bsf(𝑥) tzcnt(𝑥)   ffs(𝑥)   bsr(𝑥) lzcnt(𝑥)
0x00000000      wut       32        0      wut       32
0x00000001        0        0        1        0       31
0x80000001        0        0        1       31        0
0x80000000       31       31       32       31        0
0x00000010        4        4        5        4       27
0x08000010        4        4        5       27        4
0x08000000       27       27       28       27        4
0xffffffff        0        0        1       31        0

@param

long x: is a 64-bit integer

@return

int: number in range 0..63 or undefined if 𝑥 is 0

@see libc/intrin/bsrl.c

bswap_16

@param

unsigned short x

@return

unsigned short

@see libc/intrin/bswap.c

bswap_32

@param

unsigned int x

@return

unsigned int

@see libc/intrin/bswap.c

bswap_64

@param

unsigned long x

@return

unsigned long

@see libc/intrin/bswap.c

btowc

@param

int c

@return

unsigned int

@see libc/str/btowc.c

bulk_free

Frees and clears (sets to NULL) each non-null pointer in given array.

This is twice as fast as freeing them one-by-one. If footers are used, pointers that have been allocated in different mspaces are not freed or cleared, and the count of all such pointers is returned. For large arrays of pointers with poor locality, it may be worthwhile to sort this array before calling bulk_free.

@param

void** p
unsigned long n

@return

unsigned long

@see libc/mem/bulk_free.c

bzero

Sets memory to zero.

bzero n=0                          661 picoseconds
bzero n=1                          661 ps/byte          1,476 mb/s
bzero n=2                          330 ps/byte          2,952 mb/s
bzero n=3                          220 ps/byte          4,428 mb/s
bzero n=4                          165 ps/byte          5,904 mb/s
bzero n=7                           94 ps/byte         10,333 mb/s
bzero n=8                           41 ps/byte         23,618 mb/s
bzero n=15                          44 ps/byte         22,142 mb/s
bzero n=16                          20 ps/byte         47,236 mb/s
bzero n=31                          21 ps/byte         45,760 mb/s
bzero n=32                          20 ps/byte         47,236 mb/s
bzero n=63                          10 ps/byte         92,997 mb/s
bzero n=64                          15 ps/byte         62,982 mb/s
bzero n=127                         15 ps/byte         62,490 mb/s
bzero n=128                         10 ps/byte         94,473 mb/s
bzero n=255                         14 ps/byte         68,439 mb/s
bzero n=256                          9 ps/byte            105 gb/s
bzero n=511                         15 ps/byte         62,859 mb/s
bzero n=512                         11 ps/byte         83,976 mb/s
bzero n=1023                        15 ps/byte         61,636 mb/s
bzero n=1024                        10 ps/byte         88,916 mb/s
bzero n=2047                         9 ps/byte            105 gb/s
bzero n=2048                         8 ps/byte            109 gb/s
bzero n=4095                         8 ps/byte            115 gb/s
bzero n=4096                         8 ps/byte            118 gb/s
bzero n=8191                         7 ps/byte            129 gb/s
bzero n=8192                         7 ps/byte            130 gb/s
bzero n=16383                        6 ps/byte            136 gb/s
bzero n=16384                        6 ps/byte            137 gb/s
bzero n=32767                        6 ps/byte            140 gb/s
bzero n=32768                        6 ps/byte            141 gb/s
bzero n=65535                       15 ps/byte         64,257 mb/s
bzero n=65536                       15 ps/byte         64,279 mb/s
bzero n=131071                      15 ps/byte         63,166 mb/s
bzero n=131072                      15 ps/byte         63,115 mb/s
bzero n=262143                      15 ps/byte         62,052 mb/s
bzero n=262144                      15 ps/byte         62,097 mb/s
bzero n=524287                      15 ps/byte         61,699 mb/s
bzero n=524288                      15 ps/byte         61,674 mb/s
bzero n=1048575                     16 ps/byte         60,179 mb/s
bzero n=1048576                     15 ps/byte         61,330 mb/s
bzero n=2097151                     15 ps/byte         61,071 mb/s
bzero n=2097152                     15 ps/byte         61,065 mb/s
bzero n=4194303                     16 ps/byte         60,942 mb/s
bzero n=4194304                     16 ps/byte         60,947 mb/s
bzero n=8388607                     16 ps/byte         60,872 mb/s
bzero n=8388608                     16 ps/byte         60,879 mb/s

@param

void* p: is memory address
unsigned long n: is byte length

@return

void: p

@asyncsignalsafe

@see libc/intrin/bzero.c

c16rtomb

@param

char* s
unsigned short c16
unsigned int* ps

@return

unsigned long

@see libc/str/c16rtomb.c

c32rtomb

@param

char* s
unsigned int c
unsigned int* t

@return

unsigned long

@see libc/str/c32rtomb.c

cachestat

Query the page cache statistics of a file.

@param

int fd: The open file descriptor to retrieve statistics from.
struct cachestat_range* cstat_range: The byte range in fd to query. When len > 0, the range is [off..off + len]. When len == 0, the range is from off to the end of fd.
struct cachestat* cstat: The structure where page cache statistics are stored.
unsigned int flags: Currently unused, and must be set to 0.

@return

int: 0 on success, or -1 w/ errno.

@raise EFAULT if cstat_range or cstat points to invalid memory

@raise EINVAL if flags is nonzero

@raise EBADF if fd is negative or not open

@raise EOPNOTSUPP if fd refers to a hugetlbfs file

@raise ENOSYS if not Linux 6.5

@see libc/calls/cachestat.c

calloc

Allocates n * itemsize bytes, initialized to zero.

@param

unsigned long n: is number of items
unsigned long itemsize: is size of each item

@return

void*: rax is memory address, or NULL w/ errno

@note overreliance on memalign is a sure way to fragment space

@see dlcalloc()

@see libc/mem/calloc.c

CategorizeIp

Classifies IP address.

@param

unsigned int x

@return

int: integer e.g. kIpLoopback, kIpPrivate, etc.

@see GetIpCategoryName()

@see net/http/categorizeip.c

cbrt

Returns cube root of 𝑥.

@param

double x

@return

double

@see libc/tinymath/cbrt.c

cbrtf

Returns cube root of 𝑥.

@param

float x

@return

float

@see libc/tinymath/cbrtf.c

cbrtl

Returns cube root of 𝑥.

@param

long double x

@return

long double

@see libc/tinymath/cbrtl.c

cfgetispeed

Returns input baud rate.

@param

struct termios* t

@return

unsigned int

@asyncsignalsafe

@see libc/calls/cfspeed.c

cfgetospeed

Returns output baud rate.

@param

struct termios* t

@return

unsigned int

@asyncsignalsafe

@see libc/calls/cfspeed.c

cfmakeraw

@param

struct termios* t

@return

void

@see libc/calls/cfmakeraw.c

cfsetispeed

Sets input baud rate.

@param

struct termios* t
unsigned int speed: can be B0, B50, B38400, B4000000, etc.

@return

int: 0 on success, or -1 w/ errno

@raise EINVAL if speed isn't valid

@asyncsignalsafe

@see libc/calls/cfspeed.c

cfsetospeed

Sets output baud rate.

@param

struct termios* t
unsigned int speed: can be B0, B50, B38400, B4000000, etc.

@return

int: 0 on success, or -1 w/ errno

@raise EINVAL if speed isn't valid

@asyncsignalsafe

@see libc/calls/cfspeed.c

cfsetspeed

Sets input and output baud rate.

@param

struct termios* t
unsigned int speed: can be B0, B50, B38400, B4000000, etc.

@return

int: 0 on success, or -1 w/ errno

@raise EINVAL if speed isn't valid

@asyncsignalsafe

@see libc/calls/cfspeed.c

chmod

Changes permissions on file, e.g.:

CHECK_NE(-1, chmod("foo/bar.txt", 0644));
CHECK_NE(-1, chmod("o/default/program", 0755));
CHECK_NE(-1, chmod("privatefolder/", 0700));

The esoteric bits generally available on System Five are:

CHECK_NE(-1, chmod("/opt/", 01000));          // sticky bit
CHECK_NE(-1, chmod("/usr/bin/sudo", 04755));  // setuid bit
CHECK_NE(-1, chmod("/usr/bin/wall", 02755));  // setgid bit

@param

const char* pathname: must exist
unsigned int mode: contains octal flags (base 8)

@return

int

@errors ENOENT, ENOTDIR, ENOSYS

@asyncsignalsafe

@see fchmod()

@see libc/calls/chmod.c

chomp

Mutates line to remove line-ending characters.

@param

char* line: is NULL-propagating

@return

char*

@see getline

@see libc/str/chomp.c

chomp16

Mutates line to remove line-ending characters.

@param

unsigned short* line: is NULL-propagating

@return

unsigned short*

@see getline

@see libc/str/chomp16.c

chown

Changes owner and/or group of pathname.

@param

const char* pathname
unsigned int uid: is user id, or -1u to not change
unsigned int gid: is group id, or -1u to not change

@return

int: 0 on success, or -1 w/ errno

@see fchown() if pathname is already open()'d

@see lchown() which does not dereference symbolic links

@see /etc/passwd for user ids

@see /etc/group for group ids

@asyncsignalsafe

@see libc/calls/chown.c

chromium_notice

@type

const char[63]

@see libc/intrin/chromium.c

chroot

Changes root directory.

Please consider using unveil() instead of chroot(). If you use this system call then consider using both chdir() and closefrom() before calling this function. Otherwise there's a small risk that fchdir() could be used to escape the chroot() environment. Cosmopolitan Libc focuses on static binaries which make chroot() infinitely easier to use since you don't need to construct an entire userspace each time however unveil() is still better to use on modern Linux and OpenBSD because it doesn't require root privileges.

@param

const char* path: shall become the new root directory

@return

int: 0 on success, or -1 w/ errno

@raise EACCES if we don't have permission to search a component of path

@raise ENOTDIR if a directory component in path exists as non-directory

@raise ENAMETOOLONG if symlink-resolved path length exceeds PATH_MAX

@raise ENAMETOOLONG if component in path exists longer than NAME_MAX

@raise EPERM if not root or pledge() is in play

@raise EIO if a low-level i/o error occurred

@raise EFAULT if path is bad memory

@raise ENOENT if path doesn't exist

@raise ENOSYS on Windows

@see libc/calls/chroot.c

clearerr

Clears eof and error state indicators on stream.

@param

struct FILE* f: is file object stream pointer

@return

void

@see clearerr_unlocked()

@see libc/stdio/clearerr.c

clearerr_unlocked

Clears eof and error state indicators on stream.

@param

struct FILE* f: is file object stream pointer

@return

void

@see clearerr()

@see libc/stdio/clearerr_unlocked.c

__clk_tck

Returns system clock ticks per second.

The returned value is memoized. This function is intended to be used via the CLK_TCK macro wrapper.

The returned value is always greater than zero. It's usually 100 hertz which means each clock tick is 10 milliseconds long.

@return

int

@see libc/calls/clktck.c

clock

Returns sum of CPU time consumed by current process since birth.

This function provides a basic idea of how computationally expensive your program is, in terms of both the userspace and kernel processor resources it's hitherto consumed. Here's an example of how you might display this information:

printf("consumed %g seconds of cpu time\n",
       (double)clock() / CLOCKS_PER_SEC);

This function offers at best microsecond accuracy on all supported platforms. Please note the reported values might be a bit chunkier depending on the kernel scheduler sampling interval see CLK_TCK.

@return

long: units of CPU time consumed, where each unit's time length should be 1./CLOCKS_PER_SEC seconds; Cosmopolitan currently returns the unit count in microseconds, i.e. CLOCKS_PER_SEC is hard-coded as 1000000. On failure this returns -1 / errno.

@raise ENOSYS should be returned currently if run on Bare Metal

@see clock_gettime() which polyfills this on Linux and BSDs

@see getrusage() which polyfills this on XNU and NT

@see libc/proc/clock.c

clock_getres

Returns granularity of clock.

@param

int clock
struct timespec* ts

@return

int: 0 on success, or -1 w/ errno

@error EPERM if pledge() is in play without stdio promise

@error EINVAL if clock isn't supported on this system

@error EFAULT if ts points to bad memory

@see libc/calls/clock_getres.c

clock_gettime

Returns nanosecond time.

@param

int clock: supports the following values across OSes: - CLOCK_REALTIME - CLOCK_MONOTONIC - CLOCK_REALTIME_COARSE - CLOCK_MONOTONIC_COARSE - CLOCK_THREAD_CPUTIME_ID - CLOCK_PROCESS_CPUTIME_ID
struct timespec* ts: is where the result is stored (or null to do clock check)

@return

int: 0 on success, or -1 w/ errno

@raise EFAULT if ts points to invalid memory

@error EINVAL if clock isn't supported on this system

@error EPERM if pledge() is in play without stdio promise

@error ESRCH on NetBSD if PID/TID OR'd into clock wasn't found

@see strftime(), gettimeofday()

@asyncsignalsafe

@vforksafe

@see libc/calls/clock_gettime.c

clock_nanosleep

Sleeps for particular amount of time.

Here's how you could sleep for one second:

clock_nanosleep(0, 0, &(struct timespec){1}, 0);

Your sleep will be interrupted automatically if you do something like press ctrl-c during the wait. That's an EINTR error and it lets you immediately react to status changes. This is always the case, even if you're using SA_RESTART since this is a @norestart system call.

void OnCtrlC(int sig) {} // EINTR only happens after delivery
signal(SIGINT, OnCtrlC); // do delivery rather than kill proc
printf("save me from sleeping forever by pressing ctrl-c\n");
clock_nanosleep(0, 0, &(struct timespec){INT_MAX}, 0);
printf("you're my hero\n");

If you want to perform an uninterruptible sleep without having to use sigprocmask() to block all signals then this function provides a good solution to that problem. For example:

struct timespec rel, now, abs;
clock_gettime(CLOCK_REALTIME, &now);
rel = timespec_frommillis(100);
abs = timespec_add(now, rel);
while (clock_nanosleep(CLOCK_REALTIME, TIMER_ABSTIME, &abs, 0));

will accurately spin on EINTR errors. That way you're not impeding signal delivery and you're not loosing precision on the wait timeout. This function has first-class support on Linux, FreeBSD, and NetBSD; on OpenBSD it's good; on XNU it's bad; and on Windows it's ugly.

@param

int clock

may be

CLOCK_REALTIME
CLOCK_MONOTONIC

int flags

can be 0 for relative and TIMER_ABSTIME for absolute

struct timespec* req

can be a relative or absolute time, depending on flags

struct timespec* rem

shall be updated with the remainder of unslept time when (1) it's non-null; (2) flags is 0; and (3) -1 w/ EINTR is returned; if this function returns 0 then rem is undefined; if flags is TIMER_ABSTIME then rem is ignored

@return

int: 0 on success, or errno on error

@raise EINTR when a signal got delivered while we were waiting

@raise ECANCELED if thread was cancelled in masked mode

@raise ENOTSUP if clock is known but we can't use it here

@raise EFAULT if req or null or bad memory was passed

@raise EINVAL if clock is unknown to current platform

@raise EINVAL if flags has an unrecognized value

@raise EINVAL if req->tv_nsec ∉ [0,1000000000)

@raise ENOSYS on bare metal

@cancelationpoint

@returnserrno

@norestart

@see libc/calls/clock_nanosleep.c

clock_settime

Changes time.

@param

int clockid
struct timespec* ts

@return

int

@see libc/calls/clock_settime.c

close_range

Closes inclusive range of file descriptors, e.g.

// close all non-stdio file descriptors
if (close_range(3, -1, 0) == -1) {
  for (int i = 3; i < 256; ++i) {
    close(i);
  }
}

The following flags are available:

CLOSE_RANGE_UNSHARE (Linux-only)
CLOSE_RANGE_CLOEXEC (Linux-only)

This is only supported on Linux 5.9+ and FreeBSD 13+. Consider using closefrom() which will work on OpenBSD too.

@param

unsigned int first
unsigned int last
unsigned int flags

@return

int: 0 on success, or -1 w/ errno

@error EINVAL if flags are bad or first is greater than last

@error EMFILE if a weird race condition happens on Linux

@error ENOSYS if not Linux 5.9+ or FreeBSD 13+

@error ENOMEM on Linux maybe

@see closefrom()

@see libc/calls/close_range.c

closefrom

Closes extra file descriptors, e.g.

if (closefrom(3))
  for (int i = 3; i < 256; ++i)
    close(i);

@param

int first

@return

int: 0 on success, or -1 w/ errno

@raise EBADF if first is negative

@raise ENOSYS if not Linux 5.9+, FreeBSD 8+, OpenBSD, or NetBSD

@raise EBADF on OpenBSD if first is greater than highest fd

@raise EINVAL if flags are bad or first is greater than last

@raise EMFILE if a weird race condition happens on Linux

@raise EINTR possibly on OpenBSD

@raise ENOMEM on Linux maybe

@see libc/calls/closefrom.c

CloseSymbolTable

Frees symbol table.

@param

struct SymbolTable** table

@return

int: 0 on success or -1 on system error

@see libc/runtime/closesymboltable.c

commandv

Resolves full pathname of executable.

@param

const char* name
char* pathbuf
unsigned long pathbufsz

@return

char*: execve()'able path, or NULL w/ errno

@errno ENOENT, EACCES, ENOMEM

@see free(), execvpe()

@asyncsignalsafe

@vforksafe

@see libc/calls/commandv.c

commandvenv

Finds full executable path in overridable way.

This is a higher level version of the commandv() function. Programs that spawn subprocesses can use this function to determine the path at startup. Here's an example how you could use it:

if ((strace = commandvenv("STRACE", "strace"))) {
  strace = strdup(strace);
} else {
  fprintf(stderr, "error: please install strace\n");
  exit(1);
}

@param

const char* var: is environment variable which may be used to override PATH search, and it can force a NULL result if it's empty
const char* cmd: is name of program, which is returned asap if it's an absolute path

@return

const char*: pointer to exe path string, or NULL if it couldn't be found or the environment variable was empty; noting that the caller should copy this string before saving it

@see libc/log/commandvenv.c

CompareSlices

@param

const char* a
unsigned long n
const char* b
unsigned long m

@return

int

@see libc/str/compareslices.c

CompareSlicesCase

@param

const char* a
unsigned long n
const char* b
unsigned long m

@return

int

@see libc/str/compareslicescase.c

confstr

@param

int name
char* buf
unsigned long len

@return

unsigned long

@see libc/stdio/confstr.c

connect

Connects socket to remote end.

ProTip: Connectionless sockets, e.g. UDP, can be connected too. The benefit is not needing to specify the remote address on each send. It also means getsockname() can be called to retrieve routing details.

@param

int fd
struct sa* addr
unsigned int addrsize

@return

int: 0 on success or -1 w/ errno

@cancelationpoint

@asyncsignalsafe

@restartable (unless SO_RCVTIMEO)

@see libc/sock/connect.c

copy_file_range

Transfers data between files.

If this system call is available (Linux c. 2018 or FreeBSD c. 2021) and the file system supports it (e.g. ext4) and the source and dest files are on the same file system, then this system call shall make copies go about 2x faster.

This implementation requires Linux 5.9+ even though the system call was introduced in Linux 4.5. That's to ensure ENOSYS works reliably due to a faulty backport, that happened in RHEL7. FreeBSD detection on the other hand will work fine.

@param

int infd: is source file, which should be on same file system
long* opt_in_out_inoffset: may be specified for pread() behavior
int outfd: should be a writable file, but not O_APPEND
long* opt_in_out_outoffset: may be specified for pwrite() behavior
unsigned long uptobytes: is maximum number of bytes to transfer
unsigned int flags: is reserved for future use and must be zero

@return

long: number of bytes transferred, or -1 w/ errno

@raise EXDEV if source and destination are on different filesystems

@raise EBADF if infd or outfd aren't open files or append-only

@raise EPERM if fdout refers to an immutable file on Linux

@raise ECANCELED if thread was cancelled in masked mode

@raise EINVAL if ranges overlap or flags is non-zero

@raise EFBIG if setrlimit(RLIMIT_FSIZE) is exceeded

@raise EFAULT if one of the pointers memory is bad

@raise ERANGE if overflow happens computing ranges

@raise ENOSPC if file system has run out of space

@raise ETXTBSY if source or dest is a swap file

@raise EINTR if a signal was delivered instead

@raise EISDIR if source or dest is a directory

@raise ENOSYS if not Linux 5.9+ or FreeBSD 13+

@raise EIO if a low-level i/o error happens

@see sendfile() for seekable → socket

@see splice() for fd ↔ pipe

@cancelationpoint

@see libc/calls/copy_file_range.c

copysign

Returns 𝑥 with same sign as 𝑦.

@param

double x
double y

@return

double

@see libc/tinymath/copysign.c

copysignf

Returns 𝑥 with same sign as 𝑦.

@param

float x
float y

@return

float

@see libc/tinymath/copysignf.c

copysignl

Returns 𝑥 with same sign as 𝑦.

@param

long double x
long double y

@return

long double

@see libc/tinymath/copysignl.c

cos

Returns cosine of 𝑥.

@param

double x

@return

double

@see libc/tinymath/cos.c

cosf

Returns cosine of y.

This is a fast cosf implementation. The worst-case ULP is 0.5607, and the maximum relative error is 0.5303 * 2^-23. A single-step range reduction is used for small values. Large inputs have their range reduced using fast integer arithmetic.

@param

float y

@return

float

@raise EDOM and FE_INVALID if y is an infinity

@see libc/tinymath/cosf.c

cosh

Returns hyperbolic cosine of 𝑥.

cosh(x) = (exp(x) + 1/exp(x))/2
        = 1 + 0.5*(exp(x)-1)*(exp(x)-1)/exp(x)
        = 1 + x*x/2 + o(x^4)

@param

double x

@return

double

@see libc/tinymath/cosh.c

coshf

Returns hyperbolic cosine of 𝑥.

cosh(x) = (exp(x) + 1/exp(x))/2
        = 1 + 0.5*(exp(x)-1)*(exp(x)-1)/exp(x)
        = 1 + x*x/2 + o(x^4)

@param

float x

@return

float

@see libc/tinymath/coshf.c

cosl

Returns cosine of 𝑥.

@param

long double x

@return

long double

@see libc/tinymath/cosl.c

cosmo

Cosmopolitan runtime.

@param

edi: is argc
rsi: is argv
rdx: is environ
rcx: is auxv

@noreturn

@see libc/runtime/cosmo.S

cosmo2flock

@param

unsigned long memory

@return

void

@see libc/calls/metaflock.c

cosmo_once

Ensures initialization function is called exactly once.

This is the same as pthread_once except that it always uses a tiny spinlock implementation and won't make any system calls. It's needed since this function is an upstream dependency of both pthread_once() and nsync_once(). Most code should favor calling those functions.

@param

_Atomic unsigned int* once
void(*)() init

@return

int: 0 on success, or errno on error

@see libc/intrin/cosmo_once.c

_countbits

Returns population count of array.

@param

void* a: is byte sequence
unsigned long n

@return

unsigned long: number of bits set to one

@note 30gbps on Nehalem (Intel 2008+) otherwise 3gbps

@see libc/intrin/countbits.c

CountTokens

Returns current number of tokens in bucket.

@param

_Atomic char* b: is array of token buckets
unsigned int x: is ipv4 address
int c: is cidr

@return

int

@see net/http/tokenbucket.c

CPU_AND

@param

struct cpuset_t* d
struct cpuset_t* x
struct cpuset_t* y

@return

void

@see libc/calls/struct/cpuset.h

CPU_COUNT

@param

struct cpuset_t* set

@return

int

@see libc/calls/struct/cpuset.h

CPU_COUNT_S

@param

unsigned long size
struct cpuset_t* set

@return

int

@see libc/calls/struct/cpuset.h

CPU_EQUAL

@param

struct cpuset_t* x
struct cpuset_t* y

@return

int

@see libc/calls/struct/cpuset.h

CPU_OR

@param

struct cpuset_t* d
struct cpuset_t* x
struct cpuset_t* y

@return

void

@see libc/calls/struct/cpuset.h

CPU_XOR

@param

struct cpuset_t* d
struct cpuset_t* x
struct cpuset_t* y

@return

void

@see libc/calls/struct/cpuset.h

CPU_ZERO

@param

struct cpuset_t* set

@return

void

@see libc/calls/struct/cpuset.h

crc32c

Computes 32-bit Castagnoli Cyclic Redundancy Check.

x^32+x^26+x^23+x^22+x^16+x^12+x^11+x^10+x^8+x^7+x^5+x^4+x^2+x+1
0b00011110110111000110111101000001

@param

unsigned int init: is the initial hash value
void* data: points to the data
unsigned long size: is the byte size of data

@return

unsigned int: eax is the new hash value

@note Used by ISCSI, TensorFlow, etc.

@see libc/str/crc32c.c

crc32init

@param

unsigned int* table
unsigned int polynomial

@return

void

@see libc/nexgen32e/crc32init.c

creat

Creates file.

This is equivalent to saying:

int fd = openat(AT_FDCWD, file, O_CREAT | O_WRONLY | O_TRUNC, mode);

@param

const char* file: specifies filesystem path to create
unsigned int mode: is octal bits, e.g. 0644 usually

@return

int: file descriptor, or -1 w/ errno

@see openat() for further documentation

@cancelationpoint

@asyncsignalsafe

@restartable

@vforksafe

@see libc/calls/creat.c

critbit0_allprefixed

Invokes callback for all items with prefix.

@param

struct critbit0* t
const char* prefix
long(*)() callback
void* arg

@return

long: 0 unless iteration was halted by CALLBACK returning nonzero, in which case that value is returned

@note h/t djb and agl

@see libc/mem/critbit0_allprefixed.c

critbit0_clear

Removes all items from 𝑡.

@param

struct critbit0* t: tree

@return

void

@note h/t djb and agl

@see libc/mem/critbit0_clear.c

critbit0_contains

Returns non-zero iff 𝑢 ∈ 𝑡.

@param

struct critbit0* t: tree
const char* u: NUL-terminated string

@return

_Bool

@note h/t djb and agl

@see libc/mem/critbit0_contains.c

critbit0_delete

Removes 𝑢 from 𝑡.

@param

struct critbit0* t: tree
const char* u: NUL-terminated string

@return

_Bool: true if 𝑡 was mutated

@note h/t djb and agl

@see libc/mem/critbit0_delete.c

critbit0_emplace

Inserts 𝑢 into 𝑡 without copying.

@param

struct critbit0* t
void* u
unsigned long ulen

@return

int: 1 if 𝑡 was mutated, 0 if present, or -1 w/ errno

@note h/t djb and agl

@see libc/mem/critbit0_emplace.c

critbit0_get

Returns first item in 𝑡 with prefix 𝑢.

@param

struct critbit0* t: tree
const char* u: NUL-terminated string

@return

char*: item or NULL if not found

@note h/t djb and agl

@see libc/mem/critbit0_get.c

critbit0_insert

Inserts 𝑢 into 𝑡.

@param

struct critbit0* t: tree
const char* u: NUL-terminated string

@return

int: 1 if 𝑡 was mutated, 0 if present, or -1 w/ errno

@note h/t djb and agl

@see libc/mem/critbit0_insert.c

crypt

Encrypts password the old fashioned way.

The method of encryption depends on the first three chars of salt:

$1$ is MD5
$2$ is Blowfish
$5$ is SHA-256
$6$ is SHA-512
Otherwise DES

@param

const char* key
const char* salt

@return

char*: static memory with encrypted password

@see third_party/argon2/

@see third_party/musl/crypt.c

crypt_r

Encrypts password the old fashioned way.

The method of encryption depends on the first three chars of salt:

$1$ is MD5
$2$ is Blowfish
$5$ is SHA-256
$6$ is SHA-512
Otherwise DES

@param

const char* key
const char* salt
struct crypt_data* data

@return

char*: static memory with encrypted password

@see third_party/argon2/

@see third_party/musl/crypt_r.c

ctermid

Generates path of controlling terminal.

This function always returns /dev/tty since that's supported by all supported platforms, and polyfilled on Windows.

@param

char* s: may optionally specify an outut buffer L_ctermid in size

@return

char*: pointer to s (or image memory if s was null) which contains path of controlling terminal, or empty string if if this program is a win32 app running in gui mode

@see libc/stdio/ctermid.c

ctime

Represents time as string.

@param

const long* timep

@return

char*

@threadunsafe

@see libc/time/ctime.c

ctime_r

@param

const long* timep
char* buf

@return

char*

@see libc/time/ctime_r.c

__cxa_atexit

Adds global destructor.

Destructors are called in reverse order. They won't be called if the program aborts or _exit() is called. Invocations of this function are usually generated by the C++ compiler. Behavior is limitless if some other module has linked calloc().

@param

void* fp: is void(*)(T)
void* arg: is passed to callback
void* pred: can be non-null for things like dso modules

@return

int: 0 on success or nonzero w/ errno

@note folks have forked libc in past just to unbloat atexit()

@see libc/intrin/cxaatexit.c

__cxa_demangle

@param

const char* mangled_name
char* buf
unsigned long* n
int* status

@return

char*

A pointer to the start of the NUL-terminated demangled name, or a null pointer if the demangling fails. The caller is responsible for deallocating this memory using @c free.

The demangling is performed using the C++ ABI mangling rules, with GNU extensions. For example, this function is used in __gnu_cxx::__verbose_terminate_handler.

See https://gcc.gnu.org/onlinedocs/libstdc++/manual/ext_demangling.html for other examples of use.

@brief Demangling routine. ABI-mandated entry point in the C++ runtime library for demangling.

@note The same demangling functionality is available via libiberty (@c <libiberty/demangle.h> and @c libiberty.a) in GCC 3.1 and later, but that requires explicit installation (@c --enable-install-libiberty) and uses a different API, although the ABI is unchanged.

@see libc/stdio/demangle.c

__cxa_demangle_gnu3

@param

const char* org

@return

char*: New allocated demangled string or NULL if failed.

@brief Decode the input string by IA-64 C++ ABI style.

GNU GCC v3 use IA-64 standard ABI.

@todo

Testing and more test case. 2. Code cleaning.

@see libc/stdio/demangle.c

__cxa_finalize

Triggers global destructors.

They're called in LIFO order. If a destructor adds more destructors, then those destructors will be called immediately following, before iteration continues.

@param

void* pred: can be null to match all

@return

void

@see libc/intrin/cxafinalize.c

__cxa_printexits

Prints global destructors.

@param

struct FILE* f
void* pred: can be null to match all

@return

void

@see libc/log/cxaprintexits.c

_Cz_adler32

Updates running Adler-32 checksum with the bytes buf[0..len-1] and return the updated checksum. If buf is Z_NULL, this function returns the required initial value for the checksum.

@return

unsigned long

@see third_party/zlib/zlib.h

_Cz_adler32_combine

Combine two Adler-32 checksums into one. For two sequences of bytes, seq1 and seq2 with lengths len1 and len2, Adler-32 checksums were calculated for each, adler1 and adler2. adler32_combine() returns the Adler-32 checksum of seq1 and seq2 concatenated, requiring only adler1, adler2, and len2. Note that the off_t type (like off_t) is a signed integer. If len2 is negative, the result has no meaning or utility.

@return

unsigned long

@see third_party/zlib/zlib.h

_Cz_adler32_z

Same as adler32(), but with a size_t length.

@return

unsigned long

@see third_party/zlib/zlib.h

_Cz_compress

Compresses source buffer into the destination buffer. sourceLen is the byte length of the source buffer. Upon entry, destLen is the total size of the destination buffer, which must be at least the value returned by compressBound(sourceLen). Upon exit, destLen is the actual size of the compressed data. compress() is equivalent to compress2() with a level parameter of Z_DEFAULT_COMPRESSION.

@return

int: Z_OK if success, Z_MEM_ERROR if there was not enough memory, Z_BUF_ERROR if there was not enough room in the output buffer.

@see third_party/zlib/zlib.h

_Cz_compress2

Compresses source buffer into the destination buffer. The level parameter has the same meaning as in deflateInit. sourceLen is the byte length of the source buffer. Upon entry, destLen is the total size of the destination buffer, which must be at least the value returned by compressBound(sourceLen). Upon exit, destLen is the actual size of the compressed data.

@return

int: Z_OK if success, Z_MEM_ERROR if there was not enough memory, Z_BUF_ERROR if there was not enough room in the output buffer, Z_STREAM_ERROR if the level parameter is invalid.

@see third_party/zlib/zlib.h

_Cz_compressBound

Returns an upper bound on the compressed size after compress() or compress2() on sourceLen bytes. It would be used before a compress() or compress2() call to allocate the destination buffer.

@return

unsigned long

@see third_party/zlib/zlib.h

_Cz_crc32

Update a running CRC-32 with the bytes buf[0..len-1] and return the updated CRC-32. If buf is Z_NULL, this function returns the required initial value for the crc. Pre- and post-conditioning (one's complement) is performed within this function so it shouldn't be done by the application.

Usage example:

uLong crc = crc32(0L, Z_NULL, 0);
while (read_buffer(buffer, length) != EOF) {
  crc = crc32(crc, buffer, length);
}
if (crc != original_crc) error();

@return

unsigned long

@see third_party/zlib/zlib.h

_Cz_crc32_combine

Combine two CRC-32 check values into one. For two sequences of bytes, seq1 and seq2 with lengths len1 and len2, CRC-32 check values were calculated for each, crc1 and crc2. crc32_combine() returns the CRC-32 check value of seq1 and seq2 concatenated, requiring only crc1, crc2, and len2.

@return

unsigned long

@see third_party/zlib/zlib.h

_Cz_crc32_z

Same as crc32(), but with a size_t length.

@return

unsigned int

@see third_party/zlib/zlib.h

_Cz_deflate

deflate compresses as much data as possible, and stops when the input buffer becomes empty or the output buffer becomes full. It may introduce some output latency (reading input without producing any output) except when forced to flush.

The detailed semantics are as follows. deflate performs one or both of the following actions:

Compress more input starting at next_in and update next_in and

avail_in accordingly. If not all input can be processed (because there is not enough room in the output buffer), next_in and avail_in are updated and processing will resume at this point for the next call of deflate().

Generate more output starting at next_out and update next_out and

avail_out accordingly. This action is forced if the parameter flush is non zero. Forcing flush frequently degrades the compression ratio, so this parameter should be set only when necessary. Some output may be provided even if flush is zero.

Before the call of deflate(), the application should ensure that at least one of the actions is possible, by providing more input and/or consuming more output, and updating avail_in or avail_out accordingly; avail_out should never be zero before the call. The application can consume the compressed output when it wants, for example when the output buffer is full (avail_out == 0), or after each call of deflate(). If deflate returns Z_OK and with zero avail_out, it must be called again after making room in the output buffer because there might be more output pending. See deflatePending(), which can be used if desired to determine whether or not there is more ouput in that case.

Normally the parameter flush is set to Z_NO_FLUSH, which allows deflate to decide how much data to accumulate before producing output, in order to maximize compression.

If the parameter flush is set to Z_SYNC_FLUSH, all pending output is flushed to the output buffer and the output is aligned on a byte boundary, so that the decompressor can get all input data available so far. (In particular avail_in is zero after the call if enough output space has been provided before the call.) Flushing may degrade compression for some compression algorithms and so it should be used only when necessary. This completes the current deflate block and follows it with an empty stored block that is three bits plus filler bits to the next byte, followed by four bytes (00 00 ff ff).

If flush is set to Z_PARTIAL_FLUSH, all pending output is flushed to the output buffer, but the output is not aligned to a byte boundary. All of the input data so far will be available to the decompressor, as for Z_SYNC_FLUSH. This completes the current deflate block and follows it with an empty fixed codes block that is 10 bits long. This assures that enough bytes are output in order for the decompressor to finish the block before the empty fixed codes block.

If flush is set to Z_BLOCK, a deflate block is completed and emitted, as for Z_SYNC_FLUSH, but the output is not aligned on a byte boundary, and up to seven bits of the current block are held to be written as the next byte after the next deflate block is completed. In this case, the decompressor may not be provided enough bits at this point in order to complete decompression of the data provided so far to the compressor. It may need to wait for the next block to be emitted. This is for advanced applications that need to control the emission of deflate blocks.

If flush is set to Z_FULL_FLUSH, all output is flushed as with Z_SYNC_FLUSH, and the compression state is reset so that decompression can restart from this point if previous compressed data has been damaged or if random access is desired. Using Z_FULL_FLUSH too often can seriously degrade compression.

If deflate returns with avail_out == 0, this function must be called again with the same value of the flush parameter and more output space (updated avail_out), until the flush is complete (deflate returns with non-zero avail_out). In the case of a Z_FULL_FLUSH or Z_SYNC_FLUSH, make sure that avail_out is greater than six to avoid repeated flush markers due to avail_out == 0 on return.

If the parameter flush is set to Z_FINISH, pending input is processed, pending output is flushed and deflate returns with Z_STREAM_END if there was enough output space. If deflate returns with Z_OK or Z_BUF_ERROR, this function must be called again with Z_FINISH and more output space (updated avail_out) but no more input data, until it returns with Z_STREAM_END or an error. After deflate has returned Z_STREAM_END, the only possible operations on the stream are deflateReset or deflateEnd.

Z_FINISH can be used in the first deflate call after deflateInit if all the compression is to be done in a single step. In order to complete in one call, avail_out must be at least the value returned by deflateBound (see below). Then deflate is guaranteed to return Z_STREAM_END. If not enough output space is provided, deflate will not return Z_STREAM_END, and it must be called again as described above.

deflate() sets strm->adler to the Adler-32 checksum of all input read so far (that is, total_in bytes). If a gzip stream is being generated, then strm->adler will be the CRC-32 checksum of the input read so far. (See deflateInit2 below.)

deflate() may update strm->data_type if it can make a good guess about the input data type (Z_BINARY or Z_TEXT). If in doubt, the data is considered binary. This field is only for information purposes and does not affect the compression algorithm in any manner.

@return

int: Z_OK if some progress has been made (more input processed or more output produced), Z_STREAM_END if all input has been consumed and all output has been produced (only when flush is set to Z_FINISH), Z_STREAM_ERROR if the stream state was inconsistent (for example if next_in or next_out was Z_NULL or the state was inadvertently written over by the application), or Z_BUF_ERROR if no progress is possible (for example avail_in or avail_out was zero). Note that Z_BUF_ERROR is not fatal, and deflate() can be called again with more input and more output space to continue compressing.

@see third_party/zlib/zlib.h

_Cz_deflateBound

deflateBound() returns an upper bound on the compressed size after deflation of sourceLen bytes. It must be called after deflateInit() or deflateInit2(), and after deflateSetHeader(), if used. This would be used to allocate an output buffer for deflation in a single pass, and so would be called before deflate(). If that first deflate() call is provided the sourceLen input bytes, an output buffer allocated to the size returned by deflateBound(), and the flush value Z_FINISH, then deflate() is guaranteed to return Z_STREAM_END. Note that it is possible for the compressed size to be larger than the value returned by deflateBound() if flush options other than Z_FINISH or Z_NO_FLUSH are used.

@return

unsigned long

@see third_party/zlib/zlib.h

_Cz_deflateCopy

Sets destination stream as a complete copy of the source stream.

This function can be useful when several compression strategies will be tried, for example when there are several ways of pre-processing the input data with a filter. The streams that will be discarded should then be freed by calling deflateEnd. Note that deflateCopy duplicates the internal compression state which can be quite large, so this strategy is slow and can consume lots of memory.

@return

int: Z_OK if success, Z_MEM_ERROR if there was not enough memory, Z_STREAM_ERROR if the source stream state was inconsistent (such as zalloc being Z_NULL). msg is left unchanged in both source and destination.

@see third_party/zlib/zlib.h

_Cz_deflateEnd

All dynamically allocated data structures for this stream are freed. This function discards any unprocessed input and does not flush any pending output.

@return

int: Z_OK if success, Z_STREAM_ERROR if the stream state was inconsistent, Z_DATA_ERROR if the stream was freed prematurely (some input or output was discarded). In the error case, msg may be set but then points to a static string (which must not be deallocated).

@see third_party/zlib/zlib.h

_Cz_deflateGetDictionary

Returns the sliding dictionary being maintained by deflate. dictLength is set to the number of bytes in the dictionary, and that many bytes are copied to dictionary. dictionary must have enough space, where 32768 bytes is always enough. If deflateGetDictionary() is called with dictionary equal to Z_NULL, then only the dictionary length is returned, and nothing is copied. Similary, if dictLength is Z_NULL, then it is not set.

deflateGetDictionary() may return a length less than the window size, even when more than the window size in input has been provided. It may return up to 258 bytes less in that case, due to how zlib's implementation of deflate manages the sliding window and lookahead for matches, where matches can be up to 258 bytes long. If the application needs the last window-size bytes of input, then that would need to be saved by the application outside of zlib.

@return

int: Z_OK on success, or Z_STREAM_ERROR if the stream state is inconsistent.

@see third_party/zlib/zlib.h

_Cz_deflateInit

Initializes the internal stream state for compression. The fields zalloc, zfree and opaque must be initialized before by the caller. If zalloc and zfree are set to Z_NULL, deflateInit updates them to use default allocation functions.

The compression level must be Z_DEFAULT_COMPRESSION, or between 0 and 9: 1 gives best speed, 9 gives best compression, 0 gives no compression at all (the input data is simply copied a block at a time). Z_DEFAULT_COMPRESSION requests a default compromise between speed and compression (currently equivalent to level 6).

@return

int: Z_OK if success, Z_MEM_ERROR if there was not enough memory, or Z_STREAM_ERROR if level is not a valid compression level. msg is set to null if there is no error message. deflateInit does not perform any compression: this will be done by deflate().

@see third_party/zlib/zlib.h

_Cz_deflateInit2

This is another version of deflateInit with more compression options. The fields next_in, zalloc, zfree and opaque must be initialized before by the caller.

The method parameter is the compression method. It must be Z_DEFLATED in this version of the library.

The windowBits parameter is the base two logarithm of the window size (the size of the history buffer). It should be in the range 8..15 for this version of the library. Larger values of this parameter result in better compression at the expense of memory usage. The default value is 15 if deflateInit is used instead.

For the current implementation of deflate(), a windowBits value of 8 (a window size of 256 bytes) is not supported. As a result, a request for 8 will result in 9 (a 512-byte window). In that case, providing 8 to inflateInit2() will result in an error when the zlib header with 9 is checked against the initialization of inflate(). The remedy is to not use 8 with deflateInit2() with this initialization, or at least in that case use 9 with inflateInit2().

windowBits can also be -8..-15 for raw deflate. In this case, -windowBits determines the window size. deflate() will then generate raw deflate data with no zlib header or trailer, and will not compute a check value.

windowBits can also be greater than 15 for optional gzip encoding. Add 16 to windowBits to write a simple gzip header and trailer around the compressed data instead of a zlib wrapper. The gzip header will have no file name, no extra data, no comment, no modification time (set to zero), no header crc, and the operating system will be set to the appropriate value, if the operating system was determined at compile time. If a gzip stream is being written, strm->adler is a CRC-32 instead of an Adler-32.

For raw deflate or gzip encoding, a request for a 256-byte window is rejected as invalid, since only the zlib header provides a means of transmitting the window size to the decompressor.

The memLevel parameter specifies how much memory should be allocated for the internal compression state. memLevel=1 uses minimum memory but is slow and reduces compression ratio; memLevel=9 uses maximum memory for optimal speed. The default value is 8. See zconf.h for total memory usage as a function of windowBits and memLevel.

The strategy parameter is used to tune the compression algorithm. Use the value Z_DEFAULT_STRATEGY for normal data, Z_FILTERED for data produced by a filter (or predictor), Z_HUFFMAN_ONLY to force Huffman encoding only (no string match), or Z_RLE to limit match distances to one (run-length encoding). Filtered data consists mostly of small values with a somewhat random distribution. In this case, the compression algorithm is tuned to compress them better. The effect of Z_FILTERED is to force more Huffman coding and less string matching; it is somewhat intermediate between Z_DEFAULT_STRATEGY and Z_HUFFMAN_ONLY. Z_RLE is designed to be almost as fast as Z_HUFFMAN_ONLY, but give better compression for PNG image data. The strategy parameter only affects the compression ratio but not the correctness of the compressed output even if it is not set appropriately. Z_FIXED prevents the use of dynamic Huffman codes, allowing for a simpler decoder for special applications.

@return

int: Z_OK if success, Z_MEM_ERROR if there was not enough memory, or Z_STREAM_ERROR if any parameter is invalid (such as an invalid method). msg is set to null if there is no error message. deflateInit2 does not perform any compression: this will be done by deflate().

@see third_party/zlib/zlib.h

_Cz_deflateParams

Dynamically update the compression level and compression strategy. The interpretation of level and strategy is as in deflateInit2(). This can be used to switch between compression and straight copy of the input data, or to switch to a different kind of input data requiring a different strategy. If the compression approach (which is a function of the level) or the strategy is changed, and if any input has been consumed in a previous deflate() call, then the input available so far is compressed with the old level and strategy using deflate(strm, Z_BLOCK). There are three approaches for the compression levels 0, 1..3, and 4..9 respectively. The new level and strategy will take effect at the next call of deflate().

If a deflate(strm, Z_BLOCK) is performed by deflateParams(), and it does not have enough output space to complete, then the parameter change will not take effect. In this case, deflateParams() can be called again with the same parameters and more output space to try again.

In order to assure a change in the parameters on the first try, the deflate stream should be flushed using deflate() with Z_BLOCK or other flush request until strm.avail_out is not zero, before calling deflateParams(). Then no more input data should be provided before the deflateParams() call. If this is done, the old level and strategy will be applied to the data compressed before deflateParams(), and the new level and strategy will be applied to the the data compressed after deflateParams().

deflateParams returns Z_OK on success, Z_STREAM_ERROR if the source stream state was inconsistent or if a parameter was invalid, or Z_BUF_ERROR if there was not enough output space to complete the compression of the available input data before a change in the strategy or approach. Note that in the case of a Z_BUF_ERROR, the parameters are not changed. A return value of Z_BUF_ERROR is not fatal, in which case deflateParams() can be retried with more output space.

@return

int

@see third_party/zlib/zlib.h

_Cz_deflatePending

deflatePending() returns the number of bytes and bits of output that have been generated, but not yet provided in the available output. The bytes not provided would be due to the available output space having being consumed. The number of bits of output not provided are between 0 and 7, where they await more bits to join them in order to fill out a full byte. If pending or bits are Z_NULL, then those values are not set.

@return

int: Z_OK if success, or Z_STREAM_ERROR if the source stream state was inconsistent.

@see third_party/zlib/zlib.h

_Cz_deflatePrime

deflatePrime() inserts bits in the deflate output stream. The intent is that this function is used to start off the deflate output with the bits leftover from a previous deflate stream when appending to it. As such, this function can only be used for raw deflate, and must be used before the first deflate() call after a deflateInit2() or deflateReset(). bits must be less than or equal to 16, and that many of the least significant bits of value will be inserted in the output.

@return

int: Z_OK if success, Z_BUF_ERROR if there was not enough room in the internal buffer to insert the bits, or Z_STREAM_ERROR if the source stream state was inconsistent.

@see third_party/zlib/zlib.h

_Cz_deflateReset

This function is equivalent to deflateEnd followed by deflateInit, but does not free and reallocate the internal compression state. The stream will leave the compression level and any other attributes that may have been set unchanged.

deflateReset returns Z_OK if success, or Z_STREAM_ERROR if the source stream state was inconsistent (such as zalloc or state being Z_NULL).

@return

int

@see third_party/zlib/zlib.h

_Cz_deflateSetDictionary

Initializes the compression dictionary from the given byte sequence without producing any compressed output. When using the zlib format, this function must be called immediately after deflateInit, deflateInit2 or deflateReset, and before any call of deflate. When doing raw deflate, this function must be called either before any call of deflate, or immediately after the completion of a deflate block, i.e. after all input has been consumed and all output has been delivered when using any of the flush options Z_BLOCK, Z_PARTIAL_FLUSH, Z_SYNC_FLUSH, or Z_FULL_FLUSH. The compressor and decompressor must use exactly the same dictionary (see inflateSetDictionary).

The dictionary should consist of strings (byte sequences) that are likely to be encountered later in the data to be compressed, with the most commonly used strings preferably put towards the end of the dictionary. Using a dictionary is most useful when the data to be compressed is short and can be predicted with good accuracy; the data can then be compressed better than with the default empty dictionary.

Depending on the size of the compression data structures selected by deflateInit or deflateInit2, a part of the dictionary may in effect be discarded, for example if the dictionary is larger than the window size provided in deflateInit or deflateInit2. Thus the strings most likely to be useful should be put at the end of the dictionary, not at the front. In addition, the current implementation of deflate will use at most the window size minus 262 bytes of the provided dictionary.

Upon return of this function, strm->adler is set to the Adler-32 value of the dictionary; the decompressor may later use this value to determine which dictionary has been used by the compressor. (The Adler-32 value applies to the whole dictionary even if only a subset of the dictionary is actually used by the compressor.) If a raw deflate was requested, then the Adler-32 value is not computed and strm->adler is not set.

@return

int: Z_OK if success, or Z_STREAM_ERROR if a parameter is invalid (e.g. dictionary being Z_NULL) or the stream state is inconsistent (for example if deflate has already been called for this stream or if not at a block boundary for raw deflate). deflateSetDictionary does not perform any compression: this will be done by deflate().

@see third_party/zlib/zlib.h

_Cz_deflateSetHeader

Provides gzip header information for when a gzip stream is requested by deflateInit2(). deflateSetHeader() may be called after deflateInit2() or deflateReset() and before the first call of deflate(). The text, time, os, extra field, name, and comment information in the provided gz_header structure are written to the gzip header (xflag is ignored -- the extra flags are set according to the compression level). The caller must assure that, if not Z_NULL, name and comment are terminated with a zero byte, and that if extra is not Z_NULL, that extra_len bytes are available there. If hcrc is true, a gzip header crc is included. Note that the current versions of the command-line version of gzip (up through version 1.3.x) do not support header crc's, and will report that it is a "multi-part gzip file" and give up.

If deflateSetHeader is not used, the default gzip header has text false, the time set to zero, and os set to 255, with no extra, name, or comment fields. The gzip header is returned to the default state by deflateReset().

deflateSetHeader returns Z_OK if success, or Z_STREAM_ERROR if the source stream state was inconsistent.

@return

int

@see third_party/zlib/zlib.h

_Cz_deflateTune

Fine tune deflate's internal compression parameters. This should only be used by someone who understands the algorithm used by zlib's deflate for searching for the best matching string, and even then only by the most fanatic optimizer trying to squeeze out the last compressed bit for their specific input data. Read the deflate.c source code for the meaning of the max_lazy, good_length, nice_length, and max_chain parameters.

deflateTune() can be called after deflateInit() or deflateInit2(), and returns Z_OK on success, or Z_STREAM_ERROR for an invalid deflate stream.

@return

int

@see third_party/zlib/zlib.h

_Cz_gzbuffer

Sets internal buffer size used by this library's functions. The default buffer size is 8192 bytes. This function must be called after gzopen() or gzdopen(), and before any other calls that read or write the file. The buffer memory allocation is always deferred to the first read or write. Three times that size in buffer space is allocated. A larger buffer size of, for example, 64K or 128K bytes will noticeably increase the speed of decompression (reading).

The new buffer size also affects the maximum length for gzprintf().

@return

int: Z_OK on success, or -1 on failure, such as being called too late.

@see third_party/zlib/zlib.h

_Cz_gzclearerr

Clears the error and end-of-file flags for file. This is analogous to the clearerr() function in stdio. This is useful for continuing to read a gzip file that is being written concurrently.

@return

void

@see third_party/zlib/zlib.h

_Cz_gzclose

Flushes all pending output if necessary, closes the compressed file and deallocates the (de)compression state. Note that once file is closed, you cannot call gzerror with file, since its structures have been deallocated. gzclose must not be called more than once on the same file, just as free must not be called more than once on the same allocation.

@return

int: Z_STREAM_ERROR if file is not valid, Z_ERRNO on a file operation error, Z_MEM_ERROR if out of memory, Z_BUF_ERROR if the last read ended in the middle of a gzip stream, or Z_OK on success.

@see third_party/zlib/zlib.h

_Cz_gzclose_r

Same as gzclose(), but gzclose_r() is only for use when reading, and gzclose_w() is only for use when writing or appending. The advantage to using these instead of gzclose() is that they avoid linking in zlib compression or decompression code that is not used when only reading or only writing respectively. If gzclose() is used, then both compression and decompression code will be included the application when linking to a static zlib library.

@return

int

@see third_party/zlib/zlib.h

_Cz_gzdirect

Returns true (1) if file is being copied directly while reading, or false (0) if file is a gzip stream being decompressed.

If the input file is empty, gzdirect() will return true, since the input does not contain a gzip stream.

If gzdirect() is used immediately after gzopen() or gzdopen() it will cause buffers to be allocated to allow reading the file to determine if it is a gzip file. Therefore if gzbuffer() is used, it should be called before gzdirect().

When writing, gzdirect() returns true (1) if transparent writing was requested ("wT" for the gzopen() mode), or false (0) otherwise. (Note: gzdirect() is not needed when writing. Transparent writing must be explicitly requested, so the application already knows the answer. When linking statically, using gzdirect() will include all of the zlib code for gzip file reading and decompression, which may not be desired.)

@return

int

@see third_party/zlib/zlib.h

_Cz_gzdopen

Associates gzFile with the file descriptor.

File descriptors are obtained from calls like open, dup, creat, pipe or fileno (if the file has been previously opened with fopen). The mode parameter is as in gzopen.

The next call of gzclose on the returned gzFile will also close the file descriptor fd, just like fclose(fdopen(fd, mode)) closes the file descriptor fd. If you want to keep fd open, use fd = dup(fd_keep); gz = gzdopen(fd, mode);. The duplicated descriptor should be saved to avoid a leak, since gzdopen does not close fd if it fails. If you are using fileno() to get the file descriptor from a FILE *, then you will have to use dup() to avoid double-close()ing the file descriptor. Both gzclose() and fclose() will close the associated file descriptor, so they need to have different file descriptors.

@return

struct gzFile_s*: Z_OK if there was insufficient memory to allocate the gzFile state, if an invalid mode was specified (an 'r', 'w', or 'a' was not provided, or '+' was provided), or if fd is -1. The file descriptor is not used until the next gz* read, write, seek, or close operation, so gzdopen will not detect if fd is invalid (unless fd is -1).

@see third_party/zlib/zlib.h

_Cz_gzeof

Returns true (1) if the end-of-file indicator has been set while reading, false (0) otherwise. Note that the end-of-file indicator is set only if the read tried to go past the end of the input, but came up short. Therefore, just like feof(), gzeof() may return false even if there is no more data to read, in the event that the last read request was for the exact number of bytes remaining in the input file. This will happen if the input file size is an exact multiple of the buffer size.

If gzeof() returns true, then the read functions will return no more data, unless the end-of-file indicator is reset by gzclearerr() and the input file has grown since the previous end of file was detected.

@return

int

@see third_party/zlib/zlib.h

_Cz_gzerror

Returns the error message for the last error which occurred on the given compressed file. errnum is set to zlib error number. If an error occurred in the file system and not in the compression library, errnum is set to Z_ERRNO and the application may consult errno to get the exact error code.

The application must not modify the returned string. Future calls to this function may invalidate the previously returned string. If file is closed, then the string previously returned by gzerror will no longer be available.

gzerror() should be used to distinguish errors from end-of-file for those functions above that do not distinguish those cases in their return values.

@return

const char*

@see third_party/zlib/zlib.h

_Cz_gzflush

Flushes all pending output into the compressed file. The parameter flush is as in the deflate() function. The return value is the zlib error number (see function gzerror below). gzflush is only permitted when writing.

If the flush parameter is Z_FINISH, the remaining data is written and the gzip stream is completed in the output. If gzwrite() is called again, a new gzip stream will be started in the output. gzread() is able to read such concatenated gzip streams.

gzflush should be called only when strictly necessary because it will degrade compression if called too often.

@return

int

@see third_party/zlib/zlib.h

_Cz_gzfread

Read up to nitems items of size size from file to buf, otherwise operating as gzread() does. This duplicates the interface of stdio's fread(), with size_t request and return types. If the library defines size_t, then size_t is identical to size_t. If not, then size_t is an unsigned integer type that can contain a pointer.

gzfread() returns the number of full items read of size size, or zero if the end of the file was reached and a full item could not be read, or if there was an error. gzerror() must be consulted if zero is returned in order to determine if there was an error. If the multiplication of size and nitems overflows, i.e. the product does not fit in a size_t, then nothing is read, zero is returned, and the error state is set to Z_STREAM_ERROR.

In the event that the end of file is reached and only a partial item is available at the end, i.e. the remaining uncompressed data length is not a multiple of size, then the final partial item is nevetheless read into buf and the end-of-file flag is set. The length of the partial item read is not provided, but could be inferred from the result of gztell(). This behavior is the same as the behavior of fread() implementations in common libraries, but it prevents the direct use of gzfread() to read a concurrently written file, reseting and retrying on end-of-file, when size is not 1.

@return

unsigned long

@see third_party/zlib/zlib.h

_Cz_gzfwrite

Writes nitems items of size size from buf to file, duplicating the interface of stdio's fwrite(), with size_t request and return types. If the library defines size_t, then size_t is identical to size_t. If not, then size_t is an unsigned integer type that can contain a pointer.

gzfwrite() returns the number of full items written of size size, or zero if there was an error. If the multiplication of size and nitems overflows, i.e. the product does not fit in a size_t, then nothing is written, zero is returned, and the error state is set to Z_STREAM_ERROR.

@return

unsigned long

@see third_party/zlib/zlib.h

_Cz_gzgetc

Reads one byte from the compressed file. gzgetc returns this byte or -1 in case of end of file or error. This is implemented as a macro for speed. As such, it does not do all of the checking the other functions do. I.e. it does not check to see if file is NULL, nor whether the structure file points to has been clobbered or not.

@return

int

@see third_party/zlib/zlib.h

_Cz_gzgets

Reads bytes from the compressed file until len-1 characters are read, or a newline character is read and transferred to buf, or an end-of-file condition is encountered. If any characters are read or if len == 1, the string is terminated with a null character. If no characters are read due to an end-of-file or len < 1, then the buffer is left untouched.

@return

char*: buf which is a null-terminated string, or it returns NULL for end-of-file or in case of error. If there was an error, the contents at buf are indeterminate.

@see third_party/zlib/zlib.h

_Cz_gzoffset

Returns current offset in the file being read or written. This offset includes the count of bytes that precede the gzip stream, for example when appending or when using gzdopen() for reading. When reading, the offset does not include as yet unused buffered input. This information can be used for a progress indicator. On error, gzoffset() returns -1.

@return

long

@see third_party/zlib/zlib.h

_Cz_gzopen

Opens a gzip (.gz) file for reading or writing.

The mode parameter is as in fopen ("rb" or "wb") but can also include a compression level ("wb9") or a strategy: 'f' for filtered data as in "wb6f", 'h' for Huffman-only compression as in "wb1h", 'R' for run-length encoding as in "wb1R", or 'F' for fixed code compression as in "wb9F". (See the description of deflateInit2 for more information about the strategy parameter.) 'T' will request transparent writing or appending with no compression and not using the gzip format.

"a" can be used instead of "w" to request that the gzip stream that will be written be appended to the file. "+" will result in an error, since reading and writing to the same gzip file is not supported. The addition of "x" when writing will create the file exclusively, which fails if the file already exists. On systems that support it, the addition of "e" when reading or writing will set the flag to close the file on an execve() call.

These functions, as well as gzip, will read and decode a sequence of gzip streams in a file. The append function of gzopen() can be used to create such a file. (Also see gzflush() for another way to do this.) When appending, gzopen does not test whether the file begins with a gzip stream, nor does it look for the end of the gzip streams to begin appending. gzopen will simply append a gzip stream to the existing file.

gzopen can be used to read a file which is not in gzip format; in this case gzread will directly read from the file without decompression. When reading, this will be detected automatically by looking for the magic two- byte gzip header.

@return

struct gzFile_s*: Z_OK if the file could not be opened, if there was insufficient memory to allocate the gzFile state, or if an invalid mode was specified (an 'r', 'w', or 'a' was not provided, or '+' was provided). errno can be checked to determine if the reason gzopen failed was that the file could not be opened.

@see third_party/zlib/zlib.h

_Cz_gzprintf

Converts, formats, and writes the arguments to the compressed file under control of the format string, as in fprintf. gzprintf returns the number of uncompressed bytes actually written, or a negative zlib error code in case of error. The number of uncompressed bytes written is limited to 8191, or one less than the buffer size given to gzbuffer(). The caller should assure that this limit is not exceeded. If it is exceeded, then gzprintf() will return an error (0) with nothing written. In this case, there may also be a buffer overflow with unpredictable consequences, which is possible only if zlib was compiled with the insecure functions sprintf() or vsprintf() because the secure snprintf() or vsnprintf() functions were not available. This can be determined using zlibCompileFlags().

@param

...

@return

int

@see third_party/zlib/zlib.h

_Cz_gzputc

Writes character converted to an unsigned char into compressed file.

@return

int: value that was written, or -1 on error

@see third_party/zlib/zlib.h

_Cz_gzputs

Writes the given null-terminated string to the compressed file, excluding the terminating null character.

@return

int: Z_OK number of characters written, or -1 in case of error.

@see third_party/zlib/zlib.h

_Cz_gzread

Reads given number of uncompressed bytes from the compressed file. If the input file is not in gzip format, gzread copies the given number of bytes into the buffer directly from the file.

After reaching the end of a gzip stream in the input, gzread will continue to read, looking for another gzip stream. Any number of gzip streams may be concatenated in the input file, and will all be decompressed by gzread(). If something other than a gzip stream is encountered after a gzip stream, that remaining trailing garbage is ignored (and no error is returned).

gzread can be used to read a gzip file that is being concurrently written. Upon reaching the end of the input, gzread will return with the available data. If the error code returned by gzerror is Z_OK or Z_BUF_ERROR, then gzclearerr can be used to clear the end of file indicator in order to permit gzread to be tried again. Z_OK indicates that a gzip stream was completed on the last gzread. Z_BUF_ERROR indicates that the input file ended in the middle of a gzip stream. Note that gzread does not return -1 in the event of an incomplete gzip stream. This error is deferred until gzclose(), which will return Z_BUF_ERROR if the last gzread ended in the middle of a gzip stream. Alternatively, gzerror can be used before gzclose to detect this case.

@return

int: Z_OK number of uncompressed bytes actually read, less than len for end of file, or -1 for error. If len is too large to fit in an int, then nothing is read, -1 is returned, and the error state is set to Z_STREAM_ERROR.

@see third_party/zlib/zlib.h

_Cz_gzrewind

Rewinds file.

This function is supported only for reading.

@return

int

@note gzrewind(file) is equivalent to (int)gzseek(file, 0L, SEEK_SET)

@see third_party/zlib/zlib.h

_Cz_gzseek

Sets starting position for the next gzread or gzwrite on the given compressed file. The offset represents a number of bytes in the uncompressed data stream. The whence parameter is defined as in lseek(2); the value SEEK_END is not supported.

If the file is opened for reading, this function is emulated but can be extremely slow. If the file is opened for writing, only forward seeks are supported; gzseek then compresses a sequence of zeroes up to the new starting position.

@return

long: resulting offset location as measured in bytes from the beginning of the uncompressed stream, or -1 in case of error, in particular if the file is opened for writing and the new starting position would be before the current position.

@see third_party/zlib/zlib.h

_Cz_gzsetparams

Dynamically update the compression level or strategy. See the description of deflateInit2 for the meaning of these parameters. Previously provided data is flushed before the parameter change.

@return

int: Z_OK if success, Z_STREAM_ERROR if the file was not opened for writing, Z_ERRNO if there is an error writing the flushed data, or Z_MEM_ERROR if there is a memory allocation error.

@see third_party/zlib/zlib.h

_Cz_gztell

Returns starting position for the next gzread or gzwrite on the given compressed file. This position represents a number of bytes in the uncompressed data stream, and is zero when starting, even if appending or reading a gzip stream from the middle of a file using gzdopen().

@return

long

@note gztell(file) is equivalent to gzseek(file, 0L, SEEK_CUR)

@see third_party/zlib/zlib.h

_Cz_gzungetc

Pushes one character back onto the stream to be read as the first character on the next read. At least one character of push-back is allowed. gzungetc() returns the character pushed, or -1 on failure. gzungetc() will fail if c is -1, and may fail if a character has been pushed but not read yet. If gzungetc is used immediately after gzopen or gzdopen, at least the output buffer size of pushed characters is allowed. (See gzbuffer above.) The pushed character will be discarded if the stream is repositioned with gzseek() or gzrewind().

@return

int

@see third_party/zlib/zlib.h

_Cz_gzwrite

Writes given number of uncompressed bytes into the compressed file. gzwrite returns the number of uncompressed bytes written or 0 in case of error.

@return

int

@see third_party/zlib/zlib.h

_Cz_inflate

inflate decompresses as much data as possible, and stops when the input buffer becomes empty or the output buffer becomes full. It may introduce some output latency (reading input without producing any output) except when forced to flush.

The detailed semantics are as follows. inflate performs one or both of the following actions:

Decompress more input starting at next_in and update next_in and avail_in accordingly. If not all input can be processed (because there is not enough room in the output buffer), then next_in and avail_in are updated accordingly, and processing will resume at this point for the next call of inflate().
Generate more output starting at next_out and update next_out and avail_out accordingly. inflate() provides as much output as possible, until there is no more input data or no more space in the output buffer (see below about the flush parameter).

Before the call of inflate(), the application should ensure that at least one of the actions is possible, by providing more input and/or consuming more output, and updating the next_* and avail_* values accordingly. If the caller of inflate() does not provide both available input and available output space, it is possible that there will be no progress made. The application can consume the uncompressed output when it wants, for example when the output buffer is full (avail_out == 0), or after each call of inflate(). If inflate returns Z_OK and with zero avail_out, it must be called again after making room in the output buffer because there might be more output pending.

The flush parameter of inflate() can be Z_NO_FLUSH, Z_SYNC_FLUSH, Z_FINISH, Z_BLOCK, or Z_TREES. Z_SYNC_FLUSH requests that inflate() flush as much output as possible to the output buffer. Z_BLOCK requests that inflate() stop if and when it gets to the next deflate block boundary. When decoding the zlib or gzip format, this will cause inflate() to return immediately after the header and before the first block. When doing a raw inflate, inflate() will go ahead and process the first block, and will return when it gets to the end of that block, or when it runs out of data.

The Z_BLOCK option assists in appending to or combining deflate streams. To assist in this, on return inflate() always sets strm->data_type to the number of unused bits in the last byte taken from strm->next_in, plus 64 if inflate() is currently decoding the last block in the deflate stream, plus 128 if inflate() returned immediately after decoding an end-of-block code or decoding the complete header up to just before the first byte of the deflate stream. The end-of-block will not be indicated until all of the uncompressed data from that block has been written to strm->next_out. The number of unused bits may in general be greater than seven, except when bit 7 of data_type is set, in which case the number of unused bits will be less than eight. data_type is set as noted here every time inflate() returns for all flush options, and so can be used to determine the amount of currently consumed input in bits.

The Z_TREES option behaves as Z_BLOCK does, but it also returns when the end of each deflate block header is reached, before any actual data in that block is decoded. This allows the caller to determine the length of the deflate block header for later use in random access within a deflate block. 256 is added to the value of strm->data_type when inflate() returns immediately after reaching the end of the deflate block header.

inflate() should normally be called until it returns Z_STREAM_END or an error. However if all decompression is to be performed in a single step (a single call of inflate), the parameter flush should be set to Z_FINISH. In this case all pending input is processed and all pending output is flushed; avail_out must be large enough to hold all of the uncompressed data for the operation to complete. (The size of the uncompressed data may have been saved by the compressor for this purpose.) The use of Z_FINISH is not required to perform an inflation in one step. However it may be used to inform inflate that a faster approach can be used for the single inflate() call. Z_FINISH also informs inflate to not maintain a sliding window if the stream completes, which reduces inflate's memory footprint. If the stream does not complete, either because not all of the stream is provided or not enough output space is provided, then a sliding window will be allocated and inflate() can be called again to continue the operation as if Z_NO_FLUSH had been used.

In this implementation, inflate() always flushes as much output as possible to the output buffer, and always uses the faster approach on the first call. So the effects of the flush parameter in this implementation are on the return value of inflate() as noted below, when inflate() returns early when Z_BLOCK or Z_TREES is used, and when inflate() avoids the allocation of memory for a sliding window when Z_FINISH is used.

If a preset dictionary is needed after this call (see inflateSetDictionary below), inflate sets strm->adler to the Adler-32 checksum of the dictionary chosen by the compressor and returns Z_NEED_DICT; otherwise it sets strm->adler to the Adler-32 checksum of all output produced so far (that is, total_out bytes) and returns Z_OK, Z_STREAM_END or an error code as described below. At the end of the stream, inflate() checks that its computed Adler-32 checksum is equal to that saved by the compressor and returns Z_STREAM_END only if the checksum is correct.

inflate() can decompress and check either zlib-wrapped or gzip-wrapped deflate data. The header type is detected automatically, if requested when initializing with inflateInit2(). Any information contained in the gzip header is not retained unless inflateGetHeader() is used. When processing gzip-wrapped deflate data, strm->adler32 is set to the CRC-32 of the output produced so far. The CRC-32 is checked against the gzip trailer, as is the uncompressed length, modulo 2^32.

@return

int: Z_OK if some progress has been made (more input processed or more output produced), Z_STREAM_END if the end of the compressed data has been reached and all uncompressed output has been produced, Z_NEED_DICT if a preset dictionary is needed at this point, Z_DATA_ERROR if the input data was corrupted (input stream not conforming to the zlib format or incorrect check value, in which case strm->msg points to a string with a more specific error), Z_STREAM_ERROR if the stream structure was inconsistent (for example next_in or next_out was Z_NULL, or the state was inadvertently written over by the application), Z_MEM_ERROR if there was not enough memory, Z_BUF_ERROR if no progress was possible or if there was not enough room in the output buffer when Z_FINISH is used. Note that Z_BUF_ERROR is not fatal, and inflate() can be called again with more input and more output space to continue decompressing. If Z_DATA_ERROR is returned, the application may then call inflateSync() to look for a good compression block if a partial recovery of the data is to be attempted.

@see third_party/zlib/zlib.h

_Cz_inflateBack

inflateBack() does a raw inflate with a single call using a call-back interface for input and output. This is potentially more efficient than inflate() for file i/o applications, in that it avoids copying between the output and the sliding window by simply making the window itself the output buffer. inflate() can be faster on modern CPUs when used with large buffers. inflateBack() trusts the application to not change the output buffer passed by the output function, at least until inflateBack() returns.

inflateBackInit() must be called first to allocate the internal state and to initialize the state with the user-provided window buffer. inflateBack() may then be used multiple times to inflate a complete, raw deflate stream with each call. inflateBackEnd() is then called to free the allocated state.

A raw deflate stream is one with no zlib or gzip header or trailer. This routine would normally be used in a utility that reads zip or gzip files and writes out uncompressed files. The utility would decode the header and process the trailer on its own, hence this routine expects only the raw deflate stream to decompress. This is different from the default behavior of inflate(), which expects a zlib header and trailer around the deflate stream.

inflateBack() uses two subroutines supplied by the caller that are then called by inflateBack() for input and output. inflateBack() calls those routines until it reads a complete deflate stream and writes out all of the uncompressed data, or until it encounters an error. The function's parameters and return types are defined above in the in_func and out_func typedefs. inflateBack() will call in(in_desc, &buf) which should return the number of bytes of provided input, and a pointer to that input in buf. If there is no input available, in() must return zero -- buf is ignored in that case -- and inflateBack() will return a buffer error. inflateBack() will call out(out_desc, buf, len) to write the uncompressed data buf[0..len-1]. out() should return zero on success, or non-zero on failure. If out() returns non-zero, inflateBack() will return with an error. Neither in() nor out() are permitted to change the contents of the window provided to inflateBackInit(), which is also the buffer that out() uses to write from. The length written by out() will be at most the window size. Any non-zero amount of input may be provided by in().

For convenience, inflateBack() can be provided input on the first call by setting strm->next_in and strm->avail_in. If that input is exhausted, then in() will be called. Therefore strm->next_in must be initialized before calling inflateBack(). If strm->next_in is Z_NULL, then in() will be called immediately for input. If strm->next_in is not Z_NULL, then strm->avail_in must also be initialized, and then if strm->avail_in is not zero, input will initially be taken from strm->next_in[0 .. strm->avail_in - 1].

The in_desc and out_desc parameters of inflateBack() is passed as the first parameter of in() and out() respectively when they are called. These descriptors can be optionally used to pass any information that the caller- supplied in() and out() functions need to do their job.

On return, inflateBack() will set strm->next_in and strm->avail_in to pass back any unused input that was provided by the last in() call. The return values of inflateBack() can be Z_STREAM_END on success, Z_BUF_ERROR if in() or out() returned an error, Z_DATA_ERROR if there was a format error in the deflate stream (in which case strm->msg is set to indicate the nature of the error), or Z_STREAM_ERROR if the stream was not properly initialized. In the case of Z_BUF_ERROR, an input or output error can be distinguished using strm->next_in which will be Z_NULL only if in() returned an error. If strm->next_in is not Z_NULL, then the Z_BUF_ERROR was due to out() returning non-zero. (in() will always be called before out(), so strm->next_in is assured to be defined if out() returns non-zero.) Note that inflateBack() cannot return Z_OK.

@return

int

@see third_party/zlib/zlib.h

_Cz_inflateBackEnd

All memory allocated by inflateBackInit() is freed.

@return

int: Z_OK on success, or Z_STREAM_ERROR if the stream state was inconsistent.

@see third_party/zlib/zlib.h

_Cz_inflateCopy

Sets the destination stream as a complete copy of the source stream.

This function can be useful when randomly accessing a large stream. The first pass through the stream can periodically record the inflate state, allowing restarting inflate at those points when randomly accessing the stream.

@return

int: Z_OK if success, Z_MEM_ERROR if there was not enough memory, Z_STREAM_ERROR if the source stream state was inconsistent (such as zalloc being Z_NULL). msg is left unchanged in both source and destination.

@see third_party/zlib/zlib.h

_Cz_inflateEnd

All dynamically allocated data structures for this stream are freed. This function discards any unprocessed input and does not flush any pending output.

@return

int: Z_OK or Z_STREAM_ERROR if stream state inconsistent

@see third_party/zlib/zlib.h

_Cz_inflateGetDictionary

Returns the sliding dictionary being maintained by inflate. dictLength is set to the number of bytes in the dictionary, and that many bytes are copied to dictionary. dictionary must have enough space, where 32768 bytes is always enough. If inflateGetDictionary() is called with dictionary equal to Z_NULL, then only the dictionary length is returned, and nothing is copied. Similary, if dictLength is Z_NULL, then it is not set.

@return

int: Z_OK on success, or Z_STREAM_ERROR if the stream state is inconsistent.

@see third_party/zlib/zlib.h

_Cz_inflateGetHeader

inflateGetHeader() requests that gzip header information be stored in the provided gz_header structure. inflateGetHeader() may be called after inflateInit2() or inflateReset(), and before the first call of inflate(). As inflate() processes the gzip stream, head->done is zero until the header is completed, at which time head->done is set to one. If a zlib stream is being decoded, then head->done is set to -1 to indicate that there will be no gzip header information forthcoming. Note that Z_BLOCK or Z_TREES can be used to force inflate() to return immediately after header processing is complete and before any actual data is decompressed.

The text, time, xflags, and os fields are filled in with the gzip header contents. hcrc is set to true if there is a header CRC. (The header CRC was valid if done is set to one.) If extra is not Z_NULL, then extra_max contains the maximum number of bytes to write to extra. Once done is true, extra_len contains the actual extra field length, and extra contains the extra field, or that field truncated if extra_max is less than extra_len. If name is not Z_NULL, then up to name_max characters are written there, terminated with a zero unless the length is greater than name_max. If comment is not Z_NULL, then up to comm_max characters are written there, terminated with a zero unless the length is greater than comm_max. When any of extra, name, or comment are not Z_NULL and the respective field is not present in the header, then that field is set to Z_NULL to signal its absence. This allows the use of deflateSetHeader() with the returned structure to duplicate the header. However if those fields are set to allocated memory, then the application will need to save those pointers elsewhere so that they can be eventually freed.

If inflateGetHeader is not used, then the header information is simply discarded. The header is always checked for validity, including the header CRC if present. inflateReset() will reset the process to discard the header information. The application would need to call inflateGetHeader() again to retrieve the header from the next gzip stream.

@return

int: Z_OK if success, or Z_STREAM_ERROR if the source stream state was inconsistent.

@see third_party/zlib/zlib.h

_Cz_inflateInit

Initializes the internal stream state for decompression. The fields next_in, avail_in, zalloc, zfree and opaque must be initialized before by the caller. In the current version of inflate, the provided input is not read or consumed. The allocation of a sliding window will be deferred to the first call of inflate (if the decompression does not complete on the first call). If zalloc and zfree are set to Z_NULL, inflateInit updates them to use default allocation functions.

@return

int: Z_OK if success, Z_MEM_ERROR if there was not enough memory, or Z_STREAM_ERROR if the parameters are invalid, such as a null pointer to the structure. msg is set to null if there is no error message. inflateInit does not perform any decompression. Actual decompression will be done by inflate(). So next_in, and avail_in, next_out, and avail_out are unused and unchanged. The current implementation of inflateInit() does not process any header information -- that is deferred until inflate() is called.

@see third_party/zlib/zlib.h

_Cz_inflateInit2

This is another version of inflateInit with an extra parameter. The fields next_in, avail_in, zalloc, zfree and opaque must be initialized before by the caller.

The windowBits parameter is the base two logarithm of the maximum window size (the size of the history buffer). It should be in the range 8..15 for this version of the library. The default value is 15 if inflateInit is used instead. windowBits must be greater than or equal to the windowBits value provided to deflateInit2() while compressing, or it must be equal to 15 if deflateInit2() was not used. If a compressed stream with a larger window size is given as input, inflate() will return with the error code Z_DATA_ERROR instead of trying to allocate a larger window.

windowBits can also be zero to request that inflate use the window size in the zlib header of the compressed stream.

windowBits can also be -8..-15 for raw inflate. In this case, -windowBits determines the window size. inflate() will then process raw deflate data, not looking for a zlib or gzip header, not generating a check value, and not looking for any check values for comparison at the end of the stream. This is for use with other formats that use the deflate compressed data format such as zip. Those formats provide their own check values. If a custom format is developed using the raw deflate format for compressed data, it is recommended that a check value such as an Adler-32 or a CRC-32 be applied to the uncompressed data as is done in the zlib, gzip, and zip formats. For most applications, the zlib format should be used as is. Note that comments above on the use in deflateInit2() applies to the magnitude of windowBits.

windowBits can also be greater than 15 for optional gzip decoding. Add 32 to windowBits to enable zlib and gzip decoding with automatic header detection, or add 16 to decode only the gzip format (the zlib format will return a Z_DATA_ERROR). If a gzip stream is being decoded, strm->adler is a CRC-32 instead of an Adler-32. Unlike the gunzip utility and gzread() (see below), inflate() will not automatically decode concatenated gzip streams. inflate() will return Z_STREAM_END at the end of the gzip stream. The state would need to be reset to continue decoding a subsequent gzip stream.

@return

int: Z_OK if success, Z_MEM_ERROR if there was not enough memory, or Z_STREAM_ERROR if the parameters are invalid, such as a null pointer to the structure. msg is set to null if there is no error message. inflateInit2 does not perform any decompression apart from possibly reading the zlib header if present: actual decompression will be done by inflate(). (So next_in and avail_in may be modified, but next_out and avail_out are unused and unchanged.) The current implementation of inflateInit2() does not process any header information -- that is deferred until inflate() is called.

@see third_party/zlib/zlib.h

_Cz_inflateMark

Returns two values, one in the lower 16 bits of the return value, and the other in the remaining upper bits, obtained by shifting the return value down 16 bits. If the upper value is -1 and the lower value is zero, then inflate() is currently decoding information outside of a block. If the upper value is -1 and the lower value is non-zero, then inflate is in the middle of a stored block, with the lower value equaling the number of bytes from the input remaining to copy. If the upper value is not -1, then it is the number of bits back from the current bit position in the input of the code (literal or length/distance pair) currently being processed. In that case the lower value is the number of bytes already emitted for that code.

A code is being processed if inflate is waiting for more input to complete decoding of the code, or if it has completed decoding but is waiting for more output space to write the literal or match data.

inflateMark() is used to mark locations in the input data for random access, which may be at bit positions, and to note those cases where the output of a code may span boundaries of random access blocks. The current location in the input stream can be determined from avail_in and data_type as noted in the description for the Z_BLOCK flush parameter for inflate.

@return

long: the value noted above, or -65536 if the provided source stream state was inconsistent.

@see third_party/zlib/zlib.h

_Cz_inflatePrime

This function inserts bits in the inflate input stream. The intent is that this function is used to start inflating at a bit position in the middle of a byte. The provided bits will be used before any bytes are used from next_in. This function should only be used with raw inflate, and should be used before the first inflate() call after inflateInit2() or inflateReset(). bits must be less than or equal to 16, and that many of the least significant bits of value will be inserted in the input.

If bits is negative, then the input stream bit buffer is emptied. Then inflatePrime() can be called again to put bits in the buffer. This is used to clear out bits leftover after feeding inflate a block description prior to feeding inflate codes.

@return

int: Z_OK if success, or Z_STREAM_ERROR if the source stream state was inconsistent.

@see third_party/zlib/zlib.h

_Cz_inflateReset

This function is equivalent to inflateEnd followed by inflateInit, but does not free and reallocate the internal decompression state. The stream will keep attributes that may have been set by inflateInit2.

@return

int: Z_OK if success, or Z_STREAM_ERROR if the source stream state was inconsistent (such as zalloc or state being Z_NULL).

@see third_party/zlib/zlib.h

_Cz_inflateReset2

This function is the same as inflateReset, but it also permits changing the wrap and window size requests. The windowBits parameter is interpreted the same as it is for inflateInit2. If the window size is changed, then the memory allocated for the window is freed, and the window will be reallocated by inflate() if needed.

@return

int: Z_OK if success, or Z_STREAM_ERROR if the source stream state was inconsistent (such as zalloc or state being Z_NULL), or if the windowBits parameter is invalid.

@see third_party/zlib/zlib.h

_Cz_inflateSetDictionary

Initializes the decompression dictionary from the given uncompressed byte sequence. This function must be called immediately after a call of inflate, if that call returned Z_NEED_DICT. The dictionary chosen by the compressor can be determined from the Adler-32 value returned by that call of inflate. The compressor and decompressor must use exactly the same dictionary (see deflateSetDictionary). For raw inflate, this function can be called at any time to set the dictionary. If the provided dictionary is smaller than the window and there is already data in the window, then the provided dictionary will amend what's there. The application must insure that the dictionary that was used for compression is provided.

@return

int: Z_OK if success, Z_STREAM_ERROR if a parameter is invalid (e.g. dictionary being Z_NULL) or the stream state is inconsistent, Z_DATA_ERROR if the given dictionary doesn't match the expected one (incorrect Adler-32 value). inflateSetDictionary does not perform any decompression: this will be done by subsequent calls of inflate().

@see third_party/zlib/zlib.h

_Cz_inflateSync

Skips invalid compressed data until a possible full flush point (see above for the description of deflate with Z_FULL_FLUSH) can be found, or until all available input is skipped. No output is provided.

inflateSync searches for a 00 00 FF FF pattern in the compressed data. All full flush points have this pattern, but not all occurrences of this pattern are full flush points.

@return

int: Z_OK if a possible full flush point has been found, Z_BUF_ERROR if no more input was provided, Z_DATA_ERROR if no flush point has been found, or Z_STREAM_ERROR if the stream structure was inconsistent. In the success case, the application may save the current current value of total_in which indicates where valid compressed data was found. In the error case, the application may repeatedly call inflateSync, providing more input each time, until success or end of the input data.

@see third_party/zlib/zlib.h

_Cz_uncompress

Decompresses the source buffer into the destination buffer. sourceLen is the byte length of the source buffer. Upon entry, destLen is the total size of the destination buffer, which must be large enough to hold the entire uncompressed data. (The size of the uncompressed data must have been saved previously by the compressor and transmitted to the decompressor by some mechanism outside the scope of this compression library.) Upon exit, destLen is the actual size of the uncompressed data.

@return

int: Z_OK if success, Z_MEM_ERROR if there was not enough memory, Z_BUF_ERROR if there was not enough room in the output buffer, or Z_DATA_ERROR if the input data was corrupted or incomplete. In the case where there is not enough room, uncompress() will fill the output buffer with the uncompressed data up to that point.

@see third_party/zlib/zlib.h

_Cz_uncompress2

Same as uncompress, except that sourceLen is a pointer, where the length of the source is *sourceLen. On return, *sourceLen is the number of source bytes consumed.

@return

int

@see third_party/zlib/zlib.h

_Cz_zlibVersion

The application can compare zlibVersion and ZLIB_VERSION for consistency. If the first character differs, the library code actually used is not compatible with the zlib.h header file used by the application. This check is automatically made by deflateInit and inflateInit.

@return

const char*

@see third_party/zlib/zlib.h

daylight

@type

int

@see libc/time/timezone.c

DecodeBase64

Decodes base64 ascii representation to binary.

This supports the following alphabets:

ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/
ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789-_

@param

const char* data: is input value
unsigned long size: if -1 implies strlen
unsigned long* out_size: if non-NULL receives output length

@return

char*: allocated NUL-terminated buffer, or NULL w/ errno

@see net/http/decodebase64.c

DecodeLatin1

Decodes ISO-8859-1 to UTF-8.

@param

const char* p: is input value
unsigned long n: if -1 implies strlen
unsigned long* z: if non-NULL receives output length

@return

char*: allocated NUL-terminated buffer, or NULL w/ errno

@see net/http/decodelatin1.c

demangle_notice

@type

const char[140]

@see libc/stdio/demangle.c

difftime

@param

long time1
long time0

@return

double

@see libc/time/difftime.c

dirname

Returns directory portion of path, e.g.

path     │ dirname() │ basename()
─────────────────────────────────
.        │ .         │ .
..       │ .         │ ..
/        │ /         │ /
usr      │ .         │ usr
/usr/    │ /         │ usr
/usr/lib │ /usr      │ lib

@param

char* path: is UTF-8 and may be mutated, but not expanded in length

@return

char*: pointer to path, or inside path, or to a special r/o string

@see basename()

@see SUSv2

@see libc/fmt/dirname.c

div

Divides integers yielding numerator and denominator.

@param

int num
int den

@return

struct retval

@see libc/fmt/div.c

__divmodti4

Divides 128-bit signed integers w/ remainder.

@param

__int128 a: is numerator
__int128 b: is denominator
unsigned __int128* opt_out_rem: receives euclidean division remainder if not null

@return

__int128: quotient or result of division

@note rounds towards zero

@see libc/intrin/divmodti4.c

__divti3

Divides 128-bit signed integers.

@param

__int128 a: is numerator
__int128 b: is denominator

@return

__int128: quotient or result of division

@note rounds towards zero

@see libc/intrin/divti3.c

djbsort

D.J. Bernstein's outrageously fast integer sorting algorithm.

@param

int* a
unsigned long n

@return

void

@see libc/str/djbsort.c

djbsort_avx2

D.J. Bernstein's outrageously fast integer sorting algorithm.

@param

rdi: is int32 array
rsi: is number of elements in rdi

@return

@note public domain

@see en.wikipedia.org/wiki/Sorting_network

@see libc/nexgen32e/djbsort-avx2.S

dl_iterate_phdr

@param

int(*)() callback
void* data

@return

int

@see libc/calls/dl_iterate_phdr.c

dlmalloc_requires_more_vespene_gas

Acquires more system memory for dlmalloc.

@param

unsigned long size

@return

void*: memory map address on success, or null w/ errno

@see third_party/dlmalloc/vespene.c

dn_comp

@param

const char* src
unsigned char* dst
int space
unsigned char** dnptrs
unsigned char** lastdnptr

@return

int

@see third_party/musl/dn_comp.c

dn_skipname

@param

const unsigned char* s
const unsigned char* end

@return

int

@see third_party/musl/dn_skipname.c

dprintf

Formats string directly to file descriptor.

@param

int fd
const char* fmt
...

@return

int

@see libc/stdio/dprintf.c

drand48

@return

double

@see third_party/musl/rand48.c

dup

Duplicates file descriptor.

The O_CLOEXEC flag shall be cleared from the resulting file descriptor; see dup3() to preserve it.

One use case for duplicating file descriptors is to be able to reassign an open()'d file or pipe() to the stdio of an executed subprocess. On Windows, in order for this to work, the subprocess needs to be a Cosmopolitan program that has socket() linked.

Only small programs should duplicate sockets. That's because this implementation uses DuplicateHandle() on Windows, which Microsoft says might cause its resources to leak internally. Thus it likely isn't a good idea to design a server that does it a lot and lives a long time, without contributing a patch to this implementation.

@param

int fd: remains open afterwards

@return

int: some arbitrary new number for fd

@raise EPERM if pledge() is in play without stdio

@raise ENOTSUP if fd is a zip file descriptor

@raise EBADF if fd is negative or not open

@asyncsignalsafe

@vforksafe

@see libc/calls/dup.c

E2BIG

Argument list too errno_t.

@type

const int

@see libc/errno.h

EACCES

Permission denied.

@type

const int

@see libc/errno.h

eaccess

Performs access() check using effective user/group id.

@param

const char* filename
int amode

@return

int

@see libc/calls/eaccess.c

EADDRINUSE

Address already in use.

@type

const int

@see libc/errno.h

EADDRNOTAVAIL

Address not available.

@type

const int

@see libc/errno.h

EAFNOSUPPORT

Address family not supported.

@type

const int

@see libc/errno.h

EAGAIN

Resource temporarily unavailable (e.g. SO_RCVTIMEO expired, too many processes, too much memory locked, read or write with O_NONBLOCK needs polling, etc.).

@type

const int

@see libc/errno.h

EALREADY

Connection already in progress.

@type

const int

@see libc/errno.h

EBADF

Bad file descriptor.

@type

const int

@see libc/errno.h

EBADMSG

Bad message.

@type

const int

@see libc/errno.h

EBUSY

Device or resource busy.

@type

const int

@see libc/errno.h

ECANCELED

Operation canceled.

@type

const int

@see libc/errno.h

ECHILD

No child process.

@type

const int

@see libc/errno.h

ECONNABORTED

Connection reset before accept.

@type

const int

@see libc/errno.h

ECONNREFUSED

Connection refused error.

@type

const int

@see libc/errno.h

ECONNRESET

Connection reset by client.

@type

const int

@see libc/errno.h

EDEADLK

Resource deadlock avoided.

@type

const int

@see libc/errno.h

EDESTADDRREQ

Destination address required.

@type

const int

@see libc/errno.h

EDOM

Mathematics argument out of domain of function.

@type

const int

@see libc/errno.h

EDQUOT

Disk quota exceeded.

@type

const int

@see libc/errno.h

EEXIST

File exists.

@type

const int

@see libc/errno.h

EFAULT

Pointer passed to system call that would otherwise segfault.

@type

const int

@see libc/errno.h

EFBIG

File too large.

@type

const int

@see libc/errno.h

_EfiPostboot

Start the Cosmopolitan runtime after exiting UEFI Boot Services.

@param

rdi: is mm
rsi: is new pml4t
rdx: is argc
rcx: is argv

@return

@see libc/runtime/efimain.greg.c

@see libc/runtime/efipostboot.S

EFTYPE

Inappropriate file type or format.

@type

const int

@see libc/errno.h

EHOSTDOWN

Host down error.

@type

const int

@see libc/errno.h

EHOSTUNREACH

Host unreachable error.

@type

const int

@see libc/errno.h

EIDRM

Identifier removed.

@type

const int

@see libc/errno.h

EILSEQ

Unicode decoding error.

@type

const int

@see libc/errno.h

EINPROGRESS

Operation already in progress.

@type

const int

@see libc/errno.h

EINTR

The greatest of all errnos.

@type

const int

@see libc/errno.h

EINVAL

Invalid argument.

@type

const int

@see libc/errno.h

EIO

Unix consensus.

@type

const int

@see libc/errno.h

EISCONN

Socket is connected.

@type

const int

@see libc/errno.h

EISDIR

Is a a directory.

@type

const int

@see libc/errno.h

ElevateSeDebugPrivilege

@return

int

@see libc/calls/sedebug.c

ELOOP

Too many levels of symbolic links.

@type

const int

@see libc/errno.h

EMEDIUMTYPE

Wrong medium type.

@type

const int

@see libc/errno.h

EMFILE

Too many open files.

@type

const int

@see libc/errno.h

EMLINK

Too many links.

@type

const int

@see libc/errno.h

EMSGSIZE

Message too errno_t.

@type

const int

@see libc/errno.h

EMULTIHOP

Multihop attempted.

@type

const int

@see libc/errno.h

ENAMETOOLONG

Filename too errno_t.

@type

const int

@see libc/errno.h

EncodeBase64

Encodes binary to base64 ascii representation.

@param

const char* data: is input value
unsigned long size: if -1 implies strlen
unsigned long* out_size: if non-NULL receives output length

@return

char*: allocated NUL-terminated buffer, or NULL w/ errno

@see net/http/encodebase64.c

EncodeHttpHeaderValue

Encodes HTTP header value.

This operation involves the following:

Trim whitespace.
Turn UTF-8 into ISO-8859-1.
Make sure no C0 or C1 control codes are present (except tab).

If the input value isn't thompson-pike encoded then this implementation will fall back to latin1 in most cases.

@param

const char* data: is input value
unsigned long size: if -1 implies strlen
unsigned long* out_size: if non-NULL receives output length on success

@return

char*: allocated NUL-terminated string, or NULL w/ errno

@see net/http/encodehttpheadervalue.c

EncodeLatin1

Encodes UTF-8 to ISO-8859-1.

@param

const char* p: is input value
unsigned long n: if -1 implies strlen
unsigned long* z: if non-NULL receives output length
int f: can kControlC0, kControlC1, kControlWs to forbid

@return

char*: allocated NUL-terminated buffer, or NULL w/ errno

@error EILSEQ means UTF-8 found we can't or won't re-encode

@error ENOMEM means malloc() failed

@see net/http/encodelatin1.c

EncodeUrl

Encodes URL.

@param

struct Url* h
unsigned long* z: if not null receives string length of result

@return

char*: nul-terminated url string needing free

@see ParseUrl()

@see net/http/encodeurl.c

encrypt

@param

char* block
int edflag

@return

void

@see third_party/musl/encrypt.c

endgrent

Closes group database.

@return

void

@threadunsafe

@see third_party/musl/grp.c

endhostent

@return

void

@see third_party/musl/ent.c

endmntent

@param

struct FILE* f

@return

int

@see third_party/musl/mntent.c

endprotoent

@return

void

@see third_party/musl/proto.c

endpwent

Closes global handle to password database.

@return

void

@see getpwent()

@threadunsafe

@see third_party/musl/pwd.c

endservent

@return

void

@see third_party/musl/serv.c

endswith

Returns true if s has suffix.

@param

const char* s: is a NUL-terminated string
const char* suffix: is also NUL-terminated

@return

int

@see libc/str/endswith.c

endswith16

Returns true if s has suffix.

@param

const unsigned short* s: is a NUL-terminated string
const unsigned short* suffix: is also NUL-terminated

@return

int

@see libc/str/endswith16.c

endutxent

@return

void

@see libc/runtime/utmp.c

ENETDOWN

Network is down.

@type

const int

@see libc/errno.h

ENETRESET

Connection reset by network.

@type

const int

@see libc/errno.h

ENETUNREACH

Host is unreachable.

@type

const int

@see libc/errno.h

ENFILE

Too many open files in system.

@type

const int

@see libc/errno.h

ENOBUFS

No buffer space available.

@type

const int

@see libc/errno.h

ENODATA

No data.

@type

const int

@see libc/errno.h

ENODEV

No such device.

@type

const int

@see libc/errno.h

ENOENT

No such file or directory.

@type

const int

@see libc/errno.h

ENOEXEC

Exec format error.

@type

const int

@see libc/errno.h

ENOLCK

No locks available.

@type

const int

@see libc/errno.h

ENOLINK

Link severed.

@type

const int

@see libc/errno.h

ENOMEDIUM

No medium found.

@type

const int

@see libc/errno.h

ENOMEM

We require more vespene gas.

@type

const int

@see libc/errno.h

ENOMSG

No message error.

@type

const int

@see libc/errno.h

ENONET

No network.

@type

const int

@see libc/errno.h

ENOPROTOOPT

Protocol not available.

@type

const int

@see libc/errno.h

ENOSPC

No space left on device.

@type

const int

@see libc/errno.h

ENOSR

Out of streams resources.

@type

const int

@see libc/errno.h

ENOSTR

No string.

@type

const int

@see libc/errno.h

ENOSYS

System call unavailable.

@type

const int

@note kNtErrorInvalidFunction on NT

@see libc/errno.h

ENOTBLK

Block device required.

@type

const int

@see libc/errno.h

ENOTCONN

Socket is not connected.

@type

const int

@see libc/errno.h

ENOTDIR

Not a directory.

@type

const int

@see libc/errno.h

ENOTEMPTY

Directory not empty.

@type

const int

@see libc/errno.h

ENOTRECOVERABLE

State not recoverable.

@type

const int

@see libc/errno.h

ENOTSOCK

Not a socket.

@type

const int

@see libc/errno.h

ENOTSUP

Operation not supported.

@type

const int

@see libc/errno.h

ENOTTY

Inappropriate i/o control operation.

@type

const int

@see libc/errno.h

ENXIO

No such device or address.

@type

const int

@see libc/errno.h

EOPNOTSUPP

Socket operation not supported.

@type

const int

@see libc/errno.h

EOVERFLOW

Overflow error.

@type

const int

@see libc/errno.h

EOWNERDEAD

Owner died.

@type

const int

@see libc/errno.h

EPERM

Operation not permitted.

@type

const int

@note kNtErrorInvalidAccess on NT

@see libc/errno.h

EPFNOSUPPORT

Protocol family not supported.

@type

const int

@see libc/errno.h

EPIPE

Broken pipe.

@type

const int

@see libc/errno.h

EPROTO

Protocol error.

@type

const int

@see libc/errno.h

EPROTONOSUPPORT

Protocol not supported.

@type

const int

@see libc/errno.h

EPROTOTYPE

Protocol wrong type for socket.

@type

const int

@see libc/errno.h

erand48

@param

unsigned short* s

@return

double

@see third_party/musl/rand48.c

ERANGE

Result too large.

@type

const int

@see libc/errno.h

EREMOTE

Remote error.

@type

const int

@see libc/errno.h

ERESTART

Please restart syscall.

@type

const int

@see libc/errno.h

erf

Returns error function of x.

Highest measured error is 1.01 ULPs at 0x1.39956ac43382fp+0.

@param

double x

@return

double

@raise ERANGE on underflow

@see libc/tinymath/erf.c

erff

@param

float x

@return

float

@see libc/tinymath/erff.c

EROFS

Read-only filesystem.

@type

const int

@see libc/errno.h

__errno

Global variable for last error.

The system call wrappers update this with WIN32 error codes. Unlike traditional libraries, Cosmopolitan error codes are defined as variables. By convention, system calls and other functions do not update this variable when nothing's broken.

@type

int

@see libc/sysv/consts.sh

@see libc/sysv/errfuns.h

@see __errno_location() stable abi

@see libc/sysv/errno.c

__errno_location

Returns address of errno variable.

@return

int*

@see libc/sysv/errno.c

EscapeFragment

Escapes URL fragment.

@param

const char* p: is input value
unsigned long n: if -1 implies strlen
unsigned long* z: if non-NULL receives output length

@return

char*: allocated NUL-terminated buffer, or NULL w/ errno

@see net/http/escapefragment.c

EscapeHost

Escapes URL host or registry name.

@param

const char* p: is input value
unsigned long n: if -1 implies strlen
unsigned long* z: if non-NULL receives output length

@return

char*: allocated NUL-terminated buffer, or NULL w/ errno

@see net/http/escapehost.c

EscapeHtml

Escapes HTML entities.

@param

const char* p: is input value
unsigned long n: if -1 implies strlen
unsigned long* z: if non-NULL receives output length

@return

char*: allocated NUL-terminated buffer, or NULL w/ errno

@see net/http/escapehtml.c

EscapeIp

Escapes URL IP-literal.

This is the same as EscapeHost except colon is permitted.

@param

const char* p: is input value
unsigned long n: if -1 implies strlen
unsigned long* z: if non-NULL receives output length

@return

char*: allocated NUL-terminated buffer, or NULL w/ errno

@see net/http/escapeip.c

EscapeJsStringLiteral

Escapes UTF-8 data for JavaScript or JSON string literal.

HTML entities and forward slash are escaped too for added safety. Single quote (') is \uxxxx-encoded for consistency, as it's allowed in JavaScript, but not in JSON strings.

We assume the UTF-8 is well-formed and can be represented as UTF-16. Things that can't be decoded will fall back to binary. Things that can't be encoded will use invalid codepoint markers. This function is agnostic to numbers that have been used with malicious intent in the past under buggy software. Noncanonical encodings such as overlong NUL are canonicalized as NUL. Therefore it isn't necessary to say EscapeJsStringLiteral(Underlong(𝑥)) since EscapeJsStringLiteral(𝑥) will do the same thing.

@param

char** r: is realloc'able output buffer reused between calls
unsigned long* y: is used to track byte length of *r
const char* p: is input value
unsigned long n: if -1 implies strlen
unsigned long* z

@return

char*: *r on success, or null w/ errno

@see net/http/escapejsstringliteral.c

EscapeParam

Escapes query/form name/parameter.

@param

const char* p: is input value
unsigned long n: if -1 implies strlen
unsigned long* z: if non-NULL receives output length

@return

char*: allocated NUL-terminated buffer, or NULL w/ errno

@see net/http/escapeparam.c

EscapePass

Escapes URL password.

@param

const char* p: is input value
unsigned long n: if -1 implies strlen
unsigned long* z: if non-NULL receives output length

@return

char*: allocated NUL-terminated buffer, or NULL w/ errno

@see net/http/escapepass.c

EscapePath

Escapes URL path.

This is the same as EscapePathSegment() except slash is allowed.

@param

const char* p: is input value
unsigned long n: if -1 implies strlen
unsigned long* z: if non-NULL receives output length

@return

char*: allocated NUL-terminated buffer, or NULL w/ errno

@see net/http/escapepath.c

EscapeSegment

Escapes URL path segment.

Please note this will URI encode the slash character. That's because segments are the labels between the slashes in a path.

@param

const char* p: is input value
unsigned long n: if -1 implies strlen
unsigned long* z: if non-NULL receives output length

@return

char*: allocated NUL-terminated buffer, or NULL w/ errno

@see net/http/escapesegment.c

EscapeUrl

Escapes URL component using generic table.

This function is agnostic to the underlying charset. Always using UTF-8 is a good idea.

@param

const char* p: is input value
unsigned long n: if -1 implies strlen
unsigned long* z: if non-NULL receives output length
const char* T

@return

char*: allocated NUL-terminated buffer, or NULL w/ errno

@see kEscapeAuthority

@see kEscapeIpLiteral

@see kEscapePath

@see kEscapePathSegment

@see kEscapeParam

@see kEscapeFragment

@see net/http/escapeurl.c

EscapeUrlView

Escapes URL component using generic table w/ stpcpy() api.

@param

char* p
struct fragment* v
const char* T

@return

char*

@see net/http/escapeurlview.c

EscapeUser

Escapes URL user name.

@param

const char* p: is input value
unsigned long n: if -1 implies strlen
unsigned long* z: if non-NULL receives output length

@return

char*: allocated NUL-terminated buffer, or NULL w/ errno

@see net/http/escapeuser.c

ESHUTDOWN

Cannot send after transport endpoint shutdown.

@type

const int

@see libc/errno.h

ESOCKTNOSUPPORT

Socket type not supported.

@type

const int

@see libc/errno.h

ESPIPE

Invalid seek.

@type

const int

@see libc/errno.h

ESRCH

No such process.

@type

const int

@see libc/errno.h

ESTALE

Stale error.

@type

const int

@see libc/errno.h

ETIME

Timer expired.

@type

const int

@see libc/errno.h

ETIMEDOUT

Connection timed out.

@type

const int

@see libc/errno.h

ETOOMANYREFS

Too many references: cannot splice.

@type

const int

@see libc/errno.h

ETXTBSY

Won't open executable that's executing in write mode.

@type

const int

@see libc/errno.h

euidaccess

Performs access() check using effective user/group id.

@param

const char* filename
int amode

@return

int

@see libc/calls/euidaccess.c

EUSERS

Too many users.

@type

const int

@see libc/errno.h

EXDEV

Improper link.

@type

const int

@see libc/errno.h

execlp

Executes program, with PATH search and current environment.

The current process is replaced with the executed one.

@param

const char* prog: is program to launch (may be PATH searched)
const char* arg
...

@return

int: doesn't return on success, otherwise -1 w/ errno

@asyncsignalsafe

@vforksafe

@see libc/proc/execlp.c

execve

Replaces current process with program.

On Windows, argv and envp can't contain binary strings. They need to be valid UTF-8 in order to round-trip the WIN32 API, without being corrupted.

On Windows, only file descriptors 0, 1 and 2 can be passed to a child process in such a way that allows them to be automatically discovered when the child process initializes. Cosmpolitan currently treats your other file descriptors as implicitly O_CLOEXEC.

@param

const char* prog
char** argv
char** envp

@return

int: doesn't return, or -1 w/ errno

@raise ETXTBSY if another process has prog open in write mode

@raise ENOEXEC if file is executable but not a valid format

@raise ENOMEM if remaining stack memory is insufficient

@raise EACCES if execute permission was denied

@asyncsignalsafe

@vforksafe

@see libc/proc/execve.c

execvpe

Executes program, with path environment search.

This function is a wrapper of the execve() system call that does path resolution. The PATH environment variable is taken from your global environ rather than the envp argument.

@param

const char* prog: is the program to launch
char** argv: is [file,argv₁..argvₙ₋₁,NULL]
char** envp: is ["key=val",...,NULL]

@return

int: doesn't return on success, otherwise -1 w/ errno

@asyncsignalsafe

@vforksafe

@see libc/proc/execvpe.c

exit

Exits process with grace.

This calls functions registered by atexit() before terminating the current process, and any associated threads. It also calls all the legacy linker registered destructors in reversed order

This implementation allows exit() to be called recursively via atexit() handlers.

@param

int exitcode: is masked with 255

@noreturn

@see _Exit()

@see libc/runtime/exit.c

exp10

Returns 10ˣ.

The largest observed error is ~0.513 ULP.

@param

double x

@return

double

@see libc/tinymath/exp10.c

exp10f

Returns 10ˣ.

@param

float x

@return

float

@see libc/tinymath/exp10f.c

exp2l

Returns 2^𝑥.

@param

long double x

@return

long double

@see libc/tinymath/exp2l.c

expm1

Returns 𝑒^𝑥-𝟷.

@param

double x

@return

double

@see libc/tinymath/expm1.c

fabs

Returns absolute value of floating point number.

@param

double x

@return

double

@see libc/tinymath/fabs.c

fabsf

Returns absolute value of floating point number.

@param

float x

@return

float

@see libc/tinymath/fabsf.c

fabsl

Returns absolute value of floating point number.

@param

long double x

@return

long double

@see libc/tinymath/fabsl.c

faccessat

Checks if effective user can access path in particular ways.

@param

int dirfd: is normally AT_FDCWD but if it's an open directory and file is a relative path, then file is opened relative to dirfd
const char* path: is a filename or directory
int amode: can be R_OK, W_OK, X_OK, or F_OK
int flags: can have AT_EACCESS and/or AT_SYMLINK_NOFOLLOW

@return

int: 0 if ok, or -1 and sets errno

@raise EINVAL if amode or flags had invalid values

@raise EPERM if pledge() is in play without rpath promise

@raise EACCES if access for requested amode would be denied

@raise ENOTDIR if a directory component in path exists as non-directory

@raise ENOENT if component of path doesn't exist or path is empty

@raise ENOTSUP if path is a zip file and dirfd isn't AT_FDCWD

@note on Linux flags is only supported on Linux 5.8+

@asyncsignalsafe

@see libc/calls/faccessat.c

fadvise

Drops hints to O/S about intended I/O behavior.

It makes a huge difference. For example, when copying a large file, it can stop the system from persisting GBs of useless memory content.

@param

int fd
unsigned long offset
unsigned long len: 0 means until end of file
int advice: can be MADV_SEQUENTIAL, MADV_RANDOM, etc.

@return

int: 0 on success, or -1 w/ errno

@raise EBADF if fd isn't a valid file descriptor

@raise ESPIPE if fd refers to a pipe

@raise EINVAL if advice was invalid

@raise ENOSYS on XNU and OpenBSD

@see libc/calls/fadvise.c

__fbufsize

Returns capacity of stdio stream buffer.

@param

struct FILE* f

@return

unsigned long

@see libc/stdio/fbufsize.c

fchdir

Sets current directory based on file descriptor.

This does *not* update the PWD environment variable.

@param

int dirfd

@return

int

@raise EACCES if search permission was denied on directory

@raise ENOTDIR if dirfd doesn't refer to a directory

@raise EBADF if dirfd isn't a valid file descriptor

@raise ENOTSUP if dirfd refers to /zip/... file

@see open(path, O_DIRECTORY)

@asyncsignalsafe

@see libc/calls/fchdir.c

fchmod

Changes file permissions via open()'d file descriptor.

@param

int fd
unsigned int mode: contains octal flags (base 8)

@return

int

@raise EROFS if fd is a /zip/... file

@asyncsignalsafe

@see chmod()

@see libc/calls/fchmod.c

fchmodat

Changes permissions on file, e.g.:

CHECK_NE(-1, fchmodat(AT_FDCWD, "foo/bar.txt", 0644));
CHECK_NE(-1, fchmodat(AT_FDCWD, "o/default/program", 0755));
CHECK_NE(-1, fchmodat(AT_FDCWD, "privatefolder/", 0700));

@param

int dirfd
const char* path: must exist
unsigned int mode: contains octal flags (base 8)
int flags: can have AT_SYMLINK_NOFOLLOW

@return

int

@raise EROFS if dirfd or path use zip file system

@raise EOPNOTSUP on Linux if path is a symbolic link, AT_SYMLINK_NOFOLLOW is set in flags, and filesystem does not support setting the mode of symbolic links.

@errors ENOENT, ENOTDIR, ENOSYS

@asyncsignalsafe

@see fchmod()

@see libc/calls/fchmodat.c

fchown

Changes owner and/or group of file, via open()'d descriptor.

@param

int fd
unsigned int uid: is user id, or -1u to not change
unsigned int gid: is group id, or -1u to not change

@return

int: 0 on success, or -1 w/ errno

@see /etc/passwd for user ids

@see /etc/group for group ids

@raises ENOSYS on Windows

@see libc/calls/fchown.c

fchownat

Changes owner and/or group of path.

@param

int dirfd: is open()'d relative-to directory, or AT_FDCWD, etc.
const char* path
unsigned int uid: is user id, or -1 to not change
unsigned int gid: is group id, or -1 to not change
int flags: can have AT_SYMLINK_NOFOLLOW, etc.

@return

int: 0 on success, or -1 w/ errno

@raise EROFS if dirfd or path use zip file system

@see chown(), lchown() for shorthand notation

@see /etc/passwd for user ids

@see /etc/group for group ids

@asyncsignalsafe

@see libc/calls/fchownat.c

fclose

Closes standard i/o stream and its underlying thing.

@param

struct FILE* f: is the file object

@return

int: 0 on success or -1 on error, which can be a trick for differentiating between EOF and real errors during previous i/o calls, without needing to call ferror()

@see libc/stdio/fclose.c

fcntl

Does things with file descriptor, e.g.

CHECK_NE(-1, fcntl(fd, F_SETFD, FD_CLOEXEC));

This function lets you duplicate file descriptors without running into an edge case where they take over stdio handles:

CHECK_GE((newfd = fcntl(oldfd, F_DUPFD,         3)), 3);
CHECK_GE((newfd = fcntl(oldfd, F_DUPFD_CLOEXEC, 3)), 3);

This function implements file record locking, which lets independent processes (and on Linux 3.15+, threads too!) lock arbitrary ranges associated with a file. See test/libc/calls/lock_test.c and other locking related tests in that folder.

On Windows, the Cosmopolitan Libc polyfill for POSIX advisory locks only implements enough of its nuances to support SQLite's needs. Some possibilities, e.g. punching holes in lock, will raise ENOTSUP.

@param

int fd

is the file descriptor

int cmd

can be one of:

F_GETFD gets FD_CLOEXEC status of fd
F_SETFD sets FD_CLOEXEC status of argfile descriptor
F_GETFLreturns file descriptor status flags
F_SETFLsets file descriptor status flags -O_NONBLOCKmay be changed -O_APPENDmay be changed -O_DIRECTmay be changed -O_SEQUENTIALmay be changed (no-op on non-Windows) -O_RANDOMmay be changed (no-op on non-Windows) - Other bits (O_ACCMODE, O_CREAT, etc.) are ignored
F_DUPFD is like dup() but argis a minimum result, e.g. 3
F_DUPFD_CLOEXEC ditto but sets O_CLOEXECon returned fd
F_SETLK for record locking where arg is struct flock *
F_SETLKWditto but waits for lock (SQLite avoids this)
F_GETLKto retrieve information about a record lock
F_OFD_SETLKfor better non-blocking lock (Linux 3.15+ only)
F_OFD_SETLKWfor better blocking lock (Linux 3.15+ only)
F_OFD_GETLKfor better lock querying (Linux 3.15+ only)
F_FULLFSYNCon MacOS for fsync() with release barrier
F_BARRIERFSYNCon MacOS for fsync() with even more barriers
F_SETNOSIGPIPE on MacOS and NetBSD to control SIGPIPE
F_GETNOSIGPIPE on MacOS and NetBSD to control SIGPIPE
F_GETPATH on MacOS and NetBSD where arg is char[PATH_MAX]
F_MAXFDon NetBSD to get max open file descriptor
F_NOCACHEon MacOS to toggle data caching
F_GETPIPE_SZon Linux to get pipe size
F_SETPIPE_SZon Linux to set pipe size
F_NOTIFY raise SIGIO upon fd events in arg(Linux only) -DN_ACCESSfor file access -DN_MODIFYfor file modifications -DN_CREATEfor file creations -DN_DELETEfor file deletions -DN_RENAMEfor file renames -DN_ATTRIBfor file attribute changes -DN_MULTISHOT bitwise or for realtime signals (non-coalesced)

...

@return

int: 0 on success, or -1 w/ errno

@raise EBADF if fd isn't a valid open file descriptor

@raise EINVAL if cmd is unknown or unsupported by os

@raise EINVAL if cmd is invalid or unsupported by os

@raise EPERM if pledge() is in play w/o stdio or flock promise

@raise ENOLCK if F_SETLKW would have exceeded RLIMIT_LOCKS

@raise EPERM if cmd is F_SETOWN and we weren't authorized

@raise ESRCH if cmd is F_SETOWN and process group not found

@raise ENOTSUP on Windows if locking operation isn't supported yet

@raise EDEADLK if cmd was F_SETLKW and waiting would deadlock

@raise EMFILE if cmd is F_DUPFD or F_DUPFD_CLOEXEC and RLIMIT_NOFILE would be exceeded

@cancelationpoint when cmd is F_SETLKW or F_OFD_SETLKW

@asyncsignalsafe

@restartable

@see libc/calls/fcntl.c

fdexists

Returns true if file descriptor exists.

This function is equivalent to:

fcntl(fd, F_GETFL) != -1

Except it won't clobber errno and has minimal linkage.

@param

int fd

@return

int

@see libc/calls/fdexists.c

fdim

Returns positive difference.

@param

double x
double y

@return

double

@see libc/tinymath/fdim.c

fdimf

Returns positive difference.

@param

float x
float y

@return

float

@see libc/tinymath/fdimf.c

fdiml

Returns positive difference.

@param

long double x
long double y

@return

long double

@see libc/tinymath/fdiml.c

fdlibm_notice

@type

const char[92]

@see libc/intrin/fdlibm.c

fdopen

Allocates stream object for already-opened file descriptor.

@param

int fd: existing file descriptor or -1 for plain old buffer
const char* mode: is passed to fopenflags()

@return

struct FILE*: new stream or NULL w/ errno

@error ENOMEM

@see libc/stdio/fdopen.c

feclearexcept

Clears floating point exception status, e.g.

feclearexcept(FE_ALL_EXCEPT);

@param

excepts

may bitwise-or the following:

FE_INVALID
FE_DIVBYZERO
FE_OVERFLOW
FE_UNDERFLOW
FE_INEXACT
FE_ALL_EXCEPT (all of the above)

@return

: 0 on success, or nonzero on error

@see libc/intrin/fenv.S

feholdexcept

Saves floating-point environment and clears current exceptions.

@param

void** envp

@return

int

@see libc/intrin/feholdexcept.c

feof

Returns true if stream is in end-of-file state.

@param

struct FILE* f: is file object stream pointer

@return

int

@see feof_unlocked()

@see libc/stdio/feof.c

feof_unlocked

Returns true if stream is in end-of-file state.

@param

struct FILE* f: is file object stream pointer

@return

int

@see feof()

@see libc/stdio/feof_unlocked.c

ferror

Returns nonzero if stream is in error state.

@param

struct FILE* f: is file stream pointer

@return

int: non-zero if and only if it's an error state

@see ferror_unlocked(), feof()

@note EOF doesn't count

@see libc/stdio/ferror.c

ferror_unlocked

Returns nonzero if stream is in error state.

@param

struct FILE* f: is file stream pointer

@return

int: non-zero w/ errno only if f is in error state

@note EOF doesn't count

@see ferror(), feof()

@see libc/stdio/ferror_unlocked.c

fesetround

Sets rounding mode.

This configures the x87 FPU as well as SSE.

@param

int r

@return

int: 0 on success, or -1 on error

@see libc/intrin/fesetround.c

fetestexcept

@param

excepts

may bitwise-or the following:

FE_INVALID
FE_DIVBYZERO
FE_OVERFLOW
FE_UNDERFLOW
FE_INEXACT
FE_ALL_EXCEPT (all of the above)

@return

: mask of which exception status codes are currently set, or zero if there aren't any floating point exceptions

@see libc/intrin/fenv.S

feupdateenv

Restores floating point environment and raises exceptions.

@param

void** envp

@return

int

@see libc/intrin/feupdateenv.c

fflush

Blocks until data from stream buffer is written out.

@param

struct FILE* f: is the stream handle, or 0 for all streams

@return

int: is 0 on success or -1 on error

@see libc/stdio/fflush.c

ffs

Finds lowest set bit in word.

@param

int x

@return

int

@see libc/intrin/ffs.c

ffsl

Finds lowest set bit in word.

@param

long x

@return

int

@see libc/intrin/ffs.c

fgetc

Reads byte from stream.

@param

struct FILE* f: is non-null file object stream pointer

@return

int: byte in range 0..255, or -1 w/ errno

@see fgetc_unlocked()

@see libc/stdio/fgetc.c

fgetc_unlocked

Reads byte from stream.

@param

struct FILE* f: is file object stream pointer

@return

int: byte in range 0..255, or -1 w/ errno

@see fgetc()

@see libc/stdio/fgetc_unlocked.c

fgetln

Retrieves line from stream, e.g.

char *line;
while ((line = chomp(fgetln(stdin, 0)))) {
  printf("%s\n", line);
}

The returned memory is owned by the stream. It'll be reused when fgetln() is called again. It's free()'d upon fclose() / fflush()

When reading from the console on Windows in ICANON mode, the returned line will end with \r\n rather than \n.

@param

struct FILE* stream: specifies non-null open input stream
unsigned long* len: optionally receives byte length of line

@return

char*: nul-terminated line string, including the \n character unless a line happened before EOF without \n, otherwise it returns NULL and feof() and ferror() can examine the state

@see getdelim()

@see libc/stdio/fgetln.c

fgetpos

@param

struct FILE* stream
unsigned long* pos

@return

int

@see libc/stdio/fgetpos.c

fgets

Reads line from stream.

This function is similar to getline() except it'll truncate lines exceeding size. The line ending marker is included and may be removed using chomp().

When reading from the console on Windows in ICANON mode, the returned line will end with \r\n rather than \n.

@param

char* s: is output buffer
int size: is capacity of s
struct FILE* f: is non-null file object stream pointer

@return

char*: s on success, NULL on error, or NULL if EOF happens when zero characters have been read

@see fgets_unlocked()

@see libc/stdio/fgets.c

fgets_unlocked

Reads line from stream.

This function is similar to getline() except it'll truncate lines exceeding size. The line ending marker is included and may be removed using chomp().

@param

char* s: is output buffer
int size: is capacity of s
struct FILE* f: is non-null file object stream pointer

@return

char*: s on success, NULL on error, or NULL if EOF happens when zero characters have been read

@see libc/stdio/fgets_unlocked.c

fgetwc

Reads UTF-8 character from stream.

@param

struct FILE* f: is non-null file object stream pointer

@return

unsigned int: wide character or -1 on EOF or error

@see fgetwc_unlocked()

@see libc/stdio/fgetwc.c

fgetwc_unlocked

Reads UTF-8 character from stream.

@param

struct FILE* f

@return

unsigned int: wide character or -1 on EOF or error

@see libc/stdio/fgetwc_unlocked.c

fgetws

Reads UTF-8 content from stream into UTF-32 buffer.

This function is similar to getline() except it'll truncate lines exceeding size. The line ending marker is included and may be removed using chomp().

@param

int* s: is is nul-terminated string that's non-null
int size: is byte length of s
struct FILE* f: is file stream object pointer

@return

int*

@see fgetws()

@see libc/stdio/fgetws.c

fgetws_unlocked

Reads UTF-8 content from stream into UTF-32 buffer.

This function is similar to getline() except it'll truncate lines exceeding size. The line ending marker is included and may be removed using chomp().

@param

int* s: is is nul-terminated string that's non-null
int size: is byte length of s
struct FILE* f: is file stream object pointer

@return

int*

@see fgetws()

@see libc/stdio/fgetws_unlocked.c

fileno

Returns file descriptor associated with stream.

@param

struct FILE* f: is file stream object pointer

@return

int: fd on success or -1 w/ errno;

@see libc/stdio/fileno.c

fileno_unlocked

Returns file descriptor associated with stream.

@param

struct FILE* f: is file stream object pointer

@return

int: fd on success or -1 w/ errno;

@see libc/stdio/fileno_unlocked.c

FindComBinary

Returns path of binary without debug information, or null.

@return

const char*: path to non-debug binary, or -1 w/ errno

@see libc/runtime/findcombinary.c

FindContentType

Returns Content-Type for file extension.

@param

const char* p
unsigned long n

@return

const char*

@see net/http/findcontenttype.c

FindDebugBinary

Returns path of binary with the debug information, or null.

@return

const char*: path to debug binary, or NULL

@see libc/calls/finddebugbinary.c

FindElfSectionByName

Returns ELF section header for section with name.

@param

struct Elf64_Ehdr* elf: points to the start of the executable image data
unsigned long mapsize: is the number of bytes past elf we can access
char* shdrstrtab
const char* name

@return

struct Elf64_Shdr*: pointer to section header within image, or null

@see libc/elf/findelfsectionbyname.c

finite

Returns nonzero if 𝑥 isn't INFINITY or NAN.

@param

double x

@return

int

@see libc/tinymath/finite.c

finitef

Returns nonzero if 𝑥 isn't INFINITY or NAN.

@param

float x

@return

int

@see libc/tinymath/finitef.c

finitel

Returns nonzero if 𝑥 isn't INFINITY or NAN.

@param

long double x

@return

int

@see libc/tinymath/finitel.c

__flbf

Returns nonzero if stream is line buffered.

@param

struct FILE* f

@return

int

@see libc/stdio/flbf.c

flock

Acquires lock on file.

Please note multiple file descriptors means multiple locks.

@param

int fd
int op: can have LOCK_{SH,EX,NB,UN} for shared, exclusive, non-blocking, and unlocking

@return

int: 0 on success, or -1 w/ errno

@cancelationpoint

@restartable

@see libc/calls/flock.c

flock2cosmo

@param

unsigned long memory

@return

void

@see libc/calls/metaflock.c

flockfile

Acquires reentrant lock on stdio object, blocking if needed.

@param

struct FILE* f

@return

void

@see libc/stdio/flockfile.c

_flushlbf

Flushes all line-buffered streams.

@return

void

@see libc/stdio/flushlbf.c

fma

Performs fused multiply add.

@param

double x
double y
double z

@return

double: 𝑥 * 𝑦 + 𝑧 rounded as one ternary operation

@see libc/tinymath/fma.c

fmaf

Performs fused multiply add.

@param

float x
float y
float z

@return

float: 𝑥 * 𝑦 + 𝑧 with a single rounding error

@see libc/tinymath/fmaf.c

fmax

Returns maximum of two doubles.

If one argument is NAN then the other is returned. This function is designed to do the right thing with signed zeroes.

@param

double x
double y

@return

double

@see libc/intrin/fmax.c

fmaxf

Returns maximum of two floats.

If one argument is NAN then the other is returned. This function is designed to do the right thing with signed zeroes.

@param

float x
float y

@return

float

@see libc/intrin/fmaxf.c

fmaxl

Returns maximum of two long doubles.

If one argument is NAN then the other is returned. This function is designed to do the right thing with signed zeroes.

@param

long double x
long double y

@return

long double

@see libc/intrin/fmaxl.c

fmemopen

Opens buffer as stream.

@param

void* buf: becomes owned by this function, and is allocated if NULL
unsigned long size
const char* mode

@return

struct FILE*: new stream or NULL w/ errno

@raise ENOMEM if buf is NULL and we failed to allocate it

@raise ENOMEM if buf is NULL and malloc() wasn't linked

@raise EINVAL if buf is NULL when + isn't in mode

@see libc/stdio/fmemopen.c

fmin

Returns minimum of two doubles.

If one argument is NAN then the other is returned. This function is designed to do the right thing with signed zeroes.

@param

double x
double y

@return

double

@see libc/tinymath/fmin.c

fminl

Returns minimum of two long doubles.

If one argument is NAN then the other is returned. This function is designed to do the right thing with signed zeroes.

@param

long double x
long double y

@return

long double

@see libc/tinymath/fminl.c

fmod

Does (𝑥 rem 𝑦) w/ round()-style rounding.

@param

double x
double y

@return

double: remainder ∈ (-|𝑦|,|𝑦|) in %xmm0

@define 𝑥-trunc(𝑥/𝑦)*𝑦

@see libc/tinymath/fmod.c

fmodf

@param

float x
float y

@return

float

@see libc/tinymath/fmodf.c

fmodl

Does (𝑥 rem 𝑦) w/ round()-style rounding.

@param

long double x
long double y

@return

long double: remainder ∈ (-|𝑦|,|𝑦|) in %xmm0

@define 𝑥-trunc(𝑥/𝑦)*𝑦

@see libc/tinymath/fmodl.c

fnmatch

Matches filename.

* for wildcard
? for single character
[abc] to match character within set
[!abc] to match character not within set
\*\?\[\] for escaping above special syntax

@param

const char* pat
const char* str
int flags

@return

int

@see glob()

@see third_party/musl/fnmatch.c

FoldHeader

Collapses repeating headers onto a single line.

@param

struct HttpMessage* msg
const char* b
int h
unsigned long* z

@return

char*

@see net/http/foldheader.c

fopen

Opens file as stream object.

@param

const char* pathname: is a utf-8 ideally relative filename
const char* mode: is the string mode/flag DSL see fopenflags()

@return

struct FILE*: new object to be free'd by fclose() or NULL w/ errno

@note microsoft unilaterally deprecated this function lool

@see libc/stdio/fopen.c

fopenflags

Turns stdio flags description string into bitmask.

@param

const char* mode

@return

int

@see libc/stdio/fopenflags.c

forkpty

@param

int* pm
char* name
struct termios* tio
struct winsize* ws

@return

int

@see third_party/musl/forkpty.c

FormatBinary64

Converts unsigned 64-bit integer to binary string.

@param

char* p: needs at least 67 bytes
unsigned long x
char z: is 0 for DIGITS, 1 for 0bDIGITS, 2 for 0bDIGITS if ≠0

@return

char*: pointer to nul byte

@see libc/fmt/formatbinary64.c

FormatFlex64

Formats integer using decimal or hexadecimal.

This formats as int64 signed decimal. However it's a:

positive number
with population count of 1
and a magnitude of at least 256

Then we switch to hex notation to make the number more readable.

@param

char* p
long x
char z

@return

char*

@see libc/fmt/formatflex64.c

FormatHex64

Converts unsigned 64-bit integer to hex string.

@param

char* p: needs at least 19 bytes
unsigned long x
char z: is 0 for DIGITS, 1 for 0xDIGITS, 2 for 0xDIGITS if ≠0

@return

char*: pointer to nul byte

@see libc/intrin/formathex64.c

FormatInt32

Converts signed 32-bit integer to string.

@param

char* p: needs at least 12 bytes
int x

@return

char*: pointer to nul byte

@see libc/intrin/formatint32.c

FormatInt64

Converts signed 64-bit integer to string.

@param

char* p: needs at least 21 bytes
long x

@return

char*: pointer to nul byte

@see libc/intrin/formatint64.c

FormatInt64Thousands

Converts 64-bit integer to string w/ commas.

@param

char* p: needs at least 27 bytes
long x

@return

char*: pointer to nul byte

@see libc/fmt/formatint64thousands.c

FormatOctal32

Converts unsigned 32-bit integer to octal string.

@param

char* p: needs at least 12 bytes
unsigned int x
int z: ensures it starts with zero

@return

char*: pointer to nul byte

@see libc/intrin/formatoctal32.c

FormatOctal64

Converts unsigned 64-bit integer to octal string.

@param

char* p: needs at least 24 bytes
unsigned long x
int z: ensures it starts with zero

@return

char*: pointer to nul byte

@see libc/fmt/formatoctal64.c

FormatUint32

Converts unsigned 32-bit integer to string.

@param

char* p: needs at least 12 bytes
unsigned int x

@return

char*: pointer to nul byte

@see libc/intrin/formatint32.c

FormatUint64

Converts unsigned 64-bit integer to string.

@param

char* p: needs at least 21 bytes
unsigned long x

@return

char*: pointer to nul byte

@see libc/intrin/formatint64.c

FormatUint64Thousands

Converts unsigned 64-bit integer to string w/ commas.

@param

char* p: needs at least 27 bytes
unsigned long x

@return

char*: pointer to nul byte

@see libc/fmt/formatint64thousands.c

fpathconf

@param

int fd
int name

@return

long

@see libc/runtime/fpathconf.c

__fpending

Returns number of pending output bytes.

@param

struct FILE* f

@return

unsigned long

@see libc/stdio/fpending.c

fprintf

Formats and writes text to stream.

@param

struct FILE* f
const char* fmt
...

@return

int

@see printf() for further documentation

@see libc/stdio/fprintf.c

fprintf_unlocked

Formats and writes text to stream.

@param

struct FILE* f
const char* fmt
...

@return

int

@see printf() for further documentation

@see libc/stdio/fprintf_unlocked.c

__fpurge

Discards contents of stream buffer.

@param

struct FILE* f

@return

void

@see libc/stdio/__fpurge.c

fpurge

Discards contents of stream buffer.

@param

struct FILE* f

@return

int

@see libc/stdio/fpurge.c

fputc

Writes byte to stream.

@param

int c: is byte to buffer or write, which is masked
struct FILE* f

@return

int: c as unsigned char if written or -1 w/ errno

@see libc/stdio/fputc.c

fputc_unlocked

Writes byte to stream.

@param

int c: is byte to buffer or write, which is masked
struct FILE* f

@return

int: c as unsigned char if written or -1 w/ errno

@see libc/stdio/fputc_unlocked.c

fputs

Writes string to stream.

Writing stops at the NUL-terminator, which isn't included in output. This function blocks until the full string is written, unless an unrecoverable error happens.

@param

const char* s: is a NUL-terminated string that's non-NULL
struct FILE* f: is an open stream

@return

int: bytes written, or -1 w/ errno

@see libc/stdio/fputs.c

fputs_unlocked

Writes string to stream.

Writing stops at the NUL-terminator, which isn't included in output. This function blocks until the full string is written, unless an unrecoverable error happens.

@param

const char* s: is a NUL-terminated string that's non-NULL
struct FILE* f: is an open stream

@return

int: bytes written, or -1 w/ errno

@see libc/stdio/fputs_unlocked.c

fputwc

Writes wide character to stream.

@param

int wc: has wide character
struct FILE* f: is file object stream pointer

@return

unsigned int: wide character if written or -1 w/ errno

@see libc/stdio/fputwc.c

fputwc_unlocked

Writes wide character to stream.

@param

int wc: has wide character
struct FILE* f: is file object stream pointer

@return

unsigned int: wide character if written or -1 w/ errno

@see libc/stdio/fputwc_unlocked.c

fputws

Writes wide character string to stream.

Writing stops at the NUL-terminator, which isn't included in output. This function blocks until the full string is written, unless an unrecoverable error happens.

@param

const int* s: is a NUL-terminated string that's non-NULL
struct FILE* f: is an open stream

@return

int: strlen(s), or -1 w/ errno

@see libc/stdio/fputws.c

fputws_unlocked

Writes wide character string to stream.

Writing stops at the NUL-terminator, which isn't included in output. This function blocks until the full string is written, unless an unrecoverable error happens.

@param

const int* s: is a NUL-terminated string that's non-NULL
struct FILE* f: is an open stream

@return

int: strlen(s), or -1 w/ errno

@see libc/stdio/fputws_unlocked.c

fread

Reads data from stream.

@param

void* buf
unsigned long stride: specifies the size of individual items
unsigned long count: is the number of strides to fetch
struct FILE* f

@return

unsigned long: count on success, [0,count) on eof, or 0 on error or count==0

@see libc/stdio/fread.c

fread_unlocked

Reads data from stream.

@param

void* buf
unsigned long stride: specifies the size of individual items
unsigned long count: is the number of strides to fetch
struct FILE* f

@return

unsigned long: count on success, [0,count) on eof, or 0 on error or count==0

@see libc/stdio/fread_unlocked.c

__freadable

Returns nonzero if stream allows reading.

@param

struct FILE* f

@return

int

@see libc/stdio/freadable.c

__freading

Returns nonzero if stream is read only.

@param

struct FILE* f

@return

int

@see libc/stdio/freading.c

free

Free memory returned by malloc() & co.

Releases the chunk of memory pointed to by p, that had been previously allocated using malloc or a related routine such as realloc. It has no effect if p is null.

@param

void* p: is allocation address, which may be NULL

@return

void

@see dlfree()

@see libc/mem/free.c

freeaddrinfo

@param

struct ai* p

@return

void

@see third_party/musl/freeaddrinfo.c

freebsd_complex_notice

@type

const char[105]

@see libc/intrin/fbclibm.c

freebsd_libm_notice

@type

const char[187]

@see libc/intrin/fblibm.c

freeifaddrs

Frees network interface address list.

@param

struct ifaddrs* ifp

@return

void

@see libc/sock/ifaddrs.c

freelocale

@param

struct __locale_struct* l

@return

void

@see libc/str/freelocale.c

FreeStrList

@param

struct StrList* sl

@return

void

@see libc/stdio/freestrlist.c

freopen

Overwrites existing stream.

This function can be used in two ways. The first is sort of a mutating assignment. The second behavior, if pathname is NULL, is just changing the mode of an already open file descriptor.

@param

const char* pathname: is the file to open or NULL
const char* mode: is the mode string flags, see fopenflags()
struct FILE* stream: is the existing allocated stream memory, which is flushed and closed if already open

@return

struct FILE*: stream object if successful, or NULL w/ errno

@see libc/stdio/freopen.c

frexp

Splits number normalized fraction and exponent.

@param

double x
int* e

@return

double

@see libc/tinymath/frexp.c

frexpf

Splits number normalized fraction and exponent.

@param

float x
int* e

@return

float

@see libc/tinymath/frexpf.c

fscanf

Decodes data from stream.

To read a line of data from a well-formed trustworthy file:

int x, y;
char text[256];
fscanf(f, "%d %d %s\n", &x, &y, text);

Please note that this function is brittle by default, which makes it a good fit for yolo coding. With some toil it can be used in a way that makes it reasonably hardened although getline() may be better.

@param

struct FILE* stream
const char* fmt
...

@return

int

@see libc/fmt/vcscanf.c

@see libc/stdio/fscanf.c

fseek

Repositions open file stream.

This function flushes the buffer (unless it's currently in the EOF state) and then calls lseek() on the underlying file. If the stream is in the EOF state, this function can be used to restore it without needing to reopen the file.

@param

struct FILE* f: is a non-null stream handle
long offset: is the byte delta
int whence: can be SEET_SET, SEEK_CUR, or SEEK_END

@return

int

@returns 0 on success or -1 on error

@see libc/stdio/fseek.c

fseek_unlocked

Repositions open file stream.

@param

struct FILE* f: is a non-null stream handle
long offset: is the byte delta
int whence: can be SEET_SET, SEEK_CUR, or SEEK_END

@return

int

@returns 0 on success or -1 on error

@see libc/stdio/fseek_unlocked.c

__fsetlocking

Does nothing and returns FSETLOCKING_INTERNAL.

@param

struct FILE* f
int type

@return

int

@see libc/stdio/fsetlocking.c

fsetpos

@param

struct FILE* stream
const unsigned long* pos

@return

int

@see libc/stdio/fsetpos.c

fstat

Returns information about file, via open()'d descriptor.

On Windows, this implementation always sets st_uid and st_gid to getuid() and getgid(). The st_mode field is generated based on the current umask().

@param

int fd
struct stat* st

@return

int: 0 on success or -1 w/ errno

@raise EBADF if fd isn't a valid file descriptor

@raise EIO if an i/o error happens while reading from file system

@raise EOVERFLOW shouldn't be possible on 64-bit systems

@asyncsignalsafe

@see libc/calls/fstat.c

fstatat

Returns information about thing.

On Windows, this implementation always sets st_uid and st_gid to getuid() and getgid(). Anyone who relies upon the information to secure a multi-tenant personal computer should consider improving it and further note that the st_mode group / other bits will be clear

@param

int dirfd: is normally AT_FDCWD but if it's an open directory and file is a relative path, then path becomes relative to dirfd
const char* path
struct stat* st: is where the result is stored
int flags: can have AT_SYMLINK_NOFOLLOW

@return

int: 0 on success, or -1 w/ errno

@raise EACCES if denied access to component in path prefix

@raise EIO if i/o error occurred while reading from filesystem

@raise ELOOP if a symbolic link loop exists in path

@raise ENAMETOOLONG if a component in path exceeds NAME_MAX

@raise ENOENT on empty string or if component in path doesn't exist

@raise ENOTDIR if a parent component existed that wasn't a directory

@raise EILSEQ if path contains illegal UTF-8 sequences (Windows/MacOS)

@raise ENOTDIR if path is relative and dirfd isn't an open directory

@raise ENOEXEC if path is a zip path and this executable isn't a zip file

@raise EOVERFLOW shouldn't be possible on 64-bit systems

@raise ELOOP may ahappen if SYMLOOP_MAX symlinks were dereferenced

@raise ENAMETOOLONG may happen if path exceeded PATH_MAX

@raise EFAULT if path or st point to invalid memory

@raise EINVAL if flags has unsupported bits

@see S_ISDIR(st.st_mode), S_ISREG()

@asyncsignalsafe

@vforksafe

@see libc/calls/fstatat.c

fstatfs

Returns information about filesystem.

@param

int fd
struct statfs* sf

@return

int: 0 on success, or -1 w/ errno

@raise ENOTSUP if /zip path

@cancelationpoint

@see libc/calls/fstatfs.c

fstatvfs

Returns information about filesystem.

@param

int fd
struct statvfs* sv

@return

int: 0 on success, or -1 w/ errno

@note consider using fstatfs()

@see libc/calls/fstatvfs.c

fsum

Adds doubles in array.

@param

const double* p
unsigned long n

@return

double

@see libc/tinymath/fsum.c

fsumf

Adds floats in array.

@param

const float* p
unsigned long n

@return

double

@see libc/tinymath/fsumf.c

ftell

Returns current position of stream.

@param

struct FILE* f

@return

long

@returns current byte offset from beginning, or -1 w/ errno

@see libc/stdio/ftell.c

ftok

Convert pathname and a project ID to System V IPC key.

@param

const char* path
int id

@return

int

@see libc/calls/ftok.c

__ftrace

Function tracing enabled state.

After ftrace_install() has been called, the logging of C function calls may be controlled by changing this variable. If __ftrace is greater than zero, functions are logged. Otherwise, they aren't.

By convention, functions wishing to disable function tracing for a short time period should say:

void foo() {
  ftrace_enabled(-1);
  bar();
  ftrace_enabled(+1);
}

This way you still have some flexibility to force function tracing, by setting __ftrace to a higher number like 2 or 200. Even though under normal circumstances, __ftrace should only be either zero or one.

@type

int

@see libc/intrin/ftrace.c

ftrace_stackdigs

@type

int

@see libc/runtime/ftrace_stackdigs.c

ftruncate

Changes size of open file.

If the file size is increased, the extended area shall appear as if it were zero-filled. If your file size is decreased, the extra data shall be lost.

This function never changes the file position. This is true even if ftruncate() causes the position to become beyond the end of file in which case, the rules described in the lseek() documentation apply.

Some operating systems implement an optimization, where length is treated as a logical size and the requested physical space won't be allocated until non-zero values get written into it. Our tests show this happens on Linux (usually with 4096 byte granularity), FreeBSD (which favors 512-byte granularity), and MacOS (prefers 4096 bytes) however Windows, OpenBSD, and NetBSD always reserve physical space. This may be inspected using fstat() and consulting stat::st_blocks.

@param

int fd: must be open for writing
long length: may be greater than current current file size

@return

int: 0 on success, or -1 w/ errno

@raise EINVAL if length is negative

@raise EINTR if signal was delivered instead

@raise ECANCELED if thread was cancelled in masked mode

@raise EIO if a low-level i/o error happened

@raise EFBIG or EINVAL if length is too huge

@raise EBADF if fd isn't an open file descriptor

@raise EINVAL if fd is a non-file, e.g. pipe, socket

@raise EINVAL if fd wasn't opened in a writeable mode

@raise EROFS if fd is on a read-only filesystem (e.g. zipos)

@raise ENOSYS on bare metal

@cancelationpoint

@asyncsignalsafe

@see libc/calls/ftruncate.c

ftrylockfile

Tries to acquire reentrant stdio object lock.

@param

struct FILE* f

@return

int: 0 on success, or non-zero if another thread owns the lock

@see libc/stdio/ftrylockfile.c

ftw

Walks file tree.

@param

const char* dirpath
int(*)() fn
int fd_limit

@return

int: 0 on success, -1 on error, or non-zero fn result

@see examples/walk.c for example

@see nftw()

@threadsafe

@see libc/stdio/ftw.c

funlockfile

Releases lock on stdio object.

@param

struct FILE* f

@return

void

@see libc/stdio/funlockfile.c

futimens

Changes access/modified time on open file, the modern way.

XNU only has microsecond (1e-6) accuracy. Windows only has hectonanosecond (1e-7) accuracy. RHEL5 (Linux c. 2007) doesn't support this system call.

@param

int fd: is file descriptor of file whose timestamps will change
struct timespec* ts: is {access, modified} timestamps, or null for current time

@return

int: 0 on success, or -1 w/ errno

@raise EINVAL if flags had an unrecognized value

@raise EPERM if pledge() is in play without fattr promise

@raise EINVAL if ts specifies a nanosecond value that's out of range

@raise EROFS if fd is a zip file or on a read-only filesystem

@raise EBADF if fd isn't an open file descriptor

@raise EFAULT if ts memory was invalid

@raise ENOSYS on RHEL5 or bare metal

@asyncsignalsafe

@see libc/calls/futimens.c

futimes

Sets atime/mtime on file descriptor.

@param

int fd
struct timeval* tv

@return

int: 0 on success, or -1 w/ errno

@raise EBADF if fd isn't an open file descriptor

@raise EROFS if fd is on zip or read-only filesystem

@raise EPERM if pledge() is in play without fattr promise

@raise EINVAL if tv specifies a microsecond value that's out of range

@raise ENOSYS on RHEL5 or bare metal

@see futimens() for modern version

@asyncsignalsafe

@see libc/calls/futimes.c

futimesat

Changes last accessed/modified times on file.

@param

int dirfd
const char* pathname
struct timeval* tv

@return

int: 0 on success or -1 w/ errno

@see utimensat() which uses nanos

@see libc/time/futimesat.c

__fwritable

Returns nonzero if stream allows reading.

@param

struct FILE* f

@return

int

@see libc/stdio/fwritable.c

fwrite

Writes data to stream.

@param

void* data
unsigned long stride: specifies the size of individual items
unsigned long count: is the number of strides to write
struct FILE* f

@return

unsigned long: count on success, [0,count) on EOF, 0 on error or count==0

@see libc/stdio/fwrite.c

fwrite_unlocked

Writes data to stream.

@param

void* data
unsigned long stride: specifies the size of individual items
unsigned long count: is the number of strides to write
struct FILE* f

@return

unsigned long: count on success, [0,count) on EOF, 0 on error or count==0

@see libc/stdio/fwrite_unlocked.c

__fwriting

Returns nonzero if stream is write only.

@param

struct FILE* f

@return

int

@see libc/stdio/fwriting.c

g_gdbsync

@type

int

@see libc/log/gdbsync.c

__g_Qfmt_p

Converts quadruple-precision floating-point number to string.

@param

char* buf
void* V
int ndig
unsigned long bufsize
int nik

@return

char*

@see third_party/gdtoa/g_Qfmt_p.c

g_rando

@type

unsigned long

@see libc/stdio/g_rando.c

g_stderrbuf

@type

char[4096]

@see libc/stdio/stdbuf.c

g_stdoutbuf

@type

char[4096]

@see libc/stdio/stdbuf.c

gai_strerror

@param

int ecode

@return

const char*

@see third_party/musl/gai_strerror.c

__gc

Invokes deferred function calls.

This offers behavior similar to std::unique_ptr. Functions overwrite their return addresses jumping here, and pushing exactly one entry on the shadow stack below. Functions may repeat that process multiple times, in which case the body of this gadget loops and unwinds as a natural consequence.

@param

rax,rdx,xmm0,xmm1,st0,st1: is return value

@return

@see test/libc/runtime/gc_test.c

@see libc/nexgen32e/gc.S

gclongjmp

Jumps up stack to previous setjmp() invocation.

This is the same as longjmp() but also unwinds the stack to free memory, etc. that was registered using gc() or defer(). If GC isn't linked, this behaves the same as longjmp().

@param

rdi: points to the jmp_buf which must be the same stack
esi: is returned by setjmp() invocation (coerced nonzero)

@noreturn

@assume system five nexgen32e abi conformant

@see examples/ctrlc.c

@see libc/nexgen32e/gclongjmp.S

gcvt

@param

double value
int ndigit
char* buf

@return

char*

@see libc/stdio/gcvt.c

gcvt_notice

@type

const char[89]

@see libc/stdio/gcvt.c

gdtoa_notice

@type

const char[168]

@see third_party/gdtoa/notice.c

__get_arg_max

Returns expensive but more correct version of ARG_MAX.

@return

int

@see libc/runtime/getargmax.c

get_current_dir_name

Returns current working directory.

If the PWD environment variable is set, and it's correct, then that'll be returned in its exact canonical or non-canonical form instead of calling getcwd().

@return

char*: pointer that must be free()'d, or NULL w/ errno

@see libc/stdio/get_current_dir_name.c

__get_tmpdir

Returns pretty good temporary directory.

The order of precedence is:

$TMPDIR/ is always favored if defined
GetTempPath(), for the New Technology
/tmp/ to make security scene go crazy

This guarantees an absolute path with a trailing slash. The returned value points to static memory with PATH_MAX bytes. The string will be short enough that at least NAME_MAX bytes remain. This function is thread safe so long as callers don't modified the returned memory

@return

char*

@see libc/calls/tmpdir.c

GetAddr2linePath

@return

const char*

@see libc/log/addr2linepath.c

GetAddr2linePathInit

@return

void

@see libc/log/addr2linepath.c

getauxval

Returns auxiliary value.

@param

unsigned long key

@return

unsigned long: auxiliary value or 0 if key not found

@see libc/sysv/consts.sh

@see System Five Application Binary Interface § 3.4.3

@error ENOENT when value not found

@asyncsignalsafe

@see libc/intrin/getauxval.c

getchar

Reads byte from stdin.

@return

int: byte in range 0..255, or -1 w/ errno

@htreadsafe

@see libc/stdio/getchar.c

getchar_unlocked

Reads byte from stdin.

@return

int: byte in range 0..255, or -1 w/ errno

@see libc/stdio/getchar_unlocked.c

getcontext

Gets machine state.

@return

: 0 on success, or -1 w/ errno

@see makecontext()

@see swapcontext()

@see setcontext()

@see libc/calls/getcontext.S

GetCpuidEmulator

@return

const char*

@see libc/intrin/getcpuidemulator.c

GetCpuidOs

@return

const char*

@see libc/intrin/getcpuidos.c

getcwd

Returns current working directory, e.g.

const char *dirname = gc(getcwd(0,0)); // if malloc is linked
const char *dirname = getcwd(alloca(PATH_MAX),PATH_MAX);

@param

char* buf: is where UTF-8 NUL-terminated path string gets written, which may be NULL to ask this function to malloc a buffer
unsigned long size: is number of bytes available in buf, e.g. PATH_MAX+1, which may be 0 if buf is NULL

@return

char*: buf containing system-normative path or NULL w/ errno

@raise EACCES if the current directory path couldn't be accessed

@raise ERANGE if size wasn't big enough for path and nul byte

@raise ENOMEM on failure to allocate the requested buffer

@raise EINVAL if size is zero and buf is non-null

@raise EFAULT if buf points to invalid memory

@see libc/stdio/getcwd.c

getdelim

Reads string from stream, e.g.

char *line = NULL;
size_t linesize = 0;
while (getdelim(&line, &linesize, '\n', stdin) > 0) {
  chomp(line);
  printf("%s\n", line);
}
free(line);

@param

char** s: is the caller's buffer (in/out) which is extended or allocated automatically, also NUL-terminated is guaranteed
unsigned long* n: is the capacity of s (in/out)
int delim: is the stop char (and NUL is implicitly too)
struct FILE* f

@return

long: number of bytes read >0, including delim, excluding NUL, or -1 w/ errno on EOF or error; see ferror() and feof()

@note this function will ignore EINTR if it occurs mid-line

@raises EBADF if stream isn't open for reading

@see fgetln(), getline(), chomp(), gettok_r()

@see libc/stdio/getdelim.c

getdelim_unlocked

Reads string from unlocked stream.

@param

char** s
unsigned long* n
int delim
struct FILE* f

@return

long

@see getdelim() for documentation

@see libc/stdio/getdelim_unlocked.c

getdomainname

Returns domain of current host.

For example, if the fully-qualified hostname is "host.domain.example" then this SHOULD return "domain.example" however, it might not be the case; it depends on how the host machine is configured.

The nul / mutation semantics are tricky. Here is some safe copypasta:

char domain[254];
if (getdomainname(domain, sizeof(domain))) {
  strcpy(domain, "(none)");
}

On Linux this is the same as /proc/sys/kernel/domainname. However, we turn the weird "(none)" string into empty string.

@param

char* name: receives output name, which is guaranteed to be complete and have a nul-terminator if this function return zero
unsigned long len: is size of name consider using DNS_NAME_MAX + 1 (254)

@return

int: 0 on success, or -1 w/ errno

@raise EINVAL if len is negative

@raise EFAULT if name is an invalid address

@raise ENAMETOOLONG if the underlying system call succeeded, but the returned hostname had a length equal to or greater than len in which case this error is raised and the buffer is modified, with as many bytes of hostname as possible excluding a nul-terminator

@see libc/calls/getdomainname.c

getdomainname_linux

@param

char* name
unsigned long len

@return

int

@see libc/calls/getdomainname-linux.c

getdtablesize

Returns limit on number of open files.

@return

int

@see libc/calls/getdtablesize.c

getegid

Returns effective group ID of calling process.

@return

unsigned int: group id

@see libc/calls/getegid.c

GetElfProgramHeaderAddress

Returns program header at elf.phdr[i].

@param

struct Elf64_Ehdr* elf: points to the start of the executable image
unsigned long mapsize: is the number of bytes past elf we can access
unsigned short i: is the program header index, starting at zero

@return

struct Elf64_Phdr*: program header pointer, or null on error

@see libc/elf/getelfprogramheaderaddress.c

GetElfSectionAddress

Returns pointer to ELF section file content.

This function computes elf + sh_offset with safety checks.

@param

struct Elf64_Ehdr* elf: points to the start of the executable image data
unsigned long mapsize: is the number of bytes of elf we can access
struct Elf64_Shdr* shdr: is from GetElfSectionHeaderAddress(), or null

@return

void*

pointer to section data within image, or null if

shdr was null, or
content wasn't contained within [elf,elf+mapsize), or
an arithmetic overflow occurred

@see libc/elf/getelfsectionaddress.c

GetElfSectionHeaderAddress

Returns section header object at elf.section[i].

@param

struct Elf64_Ehdr* elf: points to the start of the executable image data
unsigned long mapsize: is the number of bytes past elf we can access
unsigned short i: is the index of the section header

@return

struct Elf64_Shdr*

pointer to section header within image, or null if

i was a magic number, i.e. i >= SHN_LORESERVE, or
e_shoff was zero (image has no section headers), or
e_shentsize had fewer than the mandatory 60 bytes, or
section header wasn't contained by [elf,elf+mapsize), or
an arithmetic overflow occurred

@see libc/elf/getelfsectionheaderaddress.c

GetElfSectionName

@param

struct Elf64_Ehdr* elf
unsigned long mapsize
struct Elf64_Shdr* shdr

@return

char*

@see libc/elf/getelfsectionname.c

GetElfSectionNameStringTable

Returns section name string table.

@param

struct Elf64_Ehdr* elf: points to the start of the executable image
unsigned long mapsize: is the number of bytes past elf we can access

@return

char*: double-nul terminated string list, or null on error

@see libc/elf/getelfsectionnamestringtable.c

GetElfSegmentAddress

Returns pointer to ELF segment file content.

This function computes elf + p_offset with safety checks.

@param

struct Elf64_Ehdr* elf: points to the start of the executable image data
unsigned long mapsize: is the number of bytes of elf we can access
struct Elf64_Phdr* phdr: is from GetElfProgramHeaderAddress(), or null

@return

void*

pointer to segment data within image, or null if

phdr was null, or
p_filesz was zero, or
content wasn't contained within [elf,elf+mapsize), or
an arithmetic overflow occurred

@see libc/elf/getelfsegmentaddress.c

GetElfString

Returns strtab + i from elf string table.

@param

struct Elf64_Ehdr* elf: points to the start of the executable image data
unsigned long mapsize: is the number of bytes past elf we can access
const char* strtab: is double-nul string list from GetElfStringTable() which may be null, in which case only the !i name is valid
unsigned int i: is byte index into strtab where needed string starts or zero (no name) in which case empty string is always returned as a pointer to the read-only string literal, rather than in the elf image, since the elf spec permits an empty or absent string table section

@return

char*

a const nul-terminated string pointer, otherwise null if

i was nonzero and strtab was null, or
strtab+i wasn't inside [elf,elf+mapsize), or
a nul byte wasn't present within [strtab+i,elf+mapsize), or
an arithmetic overflow occurred

@see libc/elf/getelfstring.c

GetElfStringTable

Returns pointer to elf string table.

@param

struct Elf64_Ehdr* elf: points to the start of the executable image data
unsigned long mapsize: is the number of bytes past elf we can access
const char* section_name: is usually ".strtab", ".dynstr", or null

@return

char*: pointer to string table within elf image, which should normally be a sequence of NUL-terminated strings whose first string is the empty string; otherwise NULL is returned, when either: (1) section_name is not found, (2) it did not have the SHT_STRTAB section type, (3) the section size was zero noting that the ELF spec does consider that legal, or lastly (4) an overflow or boundary violation occurred

@see libc/elf/getelfstringtable.c

GetElfSymbols

Returns pointer to array of elf symbols.

This is a shortcut composing GetElfSymbolTable() and GetElfSectionAddress(), that can be used as follows:

Elf64_Xword i, n;
Elf64_Sym *st = GetElfSymbols(map, size, SHT_SYMTAB, &n);
for (i = 0; st && i < n; ++i) {
  // st[i] holds a symbol
}

The above code will iterate over the relocatable and/or statically-linked symbols defined by an ELF image.

@param

struct Elf64_Ehdr* elf: points to the start of the executable image data
unsigned long mapsize: is the number of bytes past elf we can access
int section_type: is usually SHT_SYMTAB or SHT_DYNSYM
unsigned long* out_count: optionally receives number of symbols

@return

struct Elf64_Sym*: pointer to array of elf symbol array, otherwise null

@see libc/elf/getelfsymbols.c

GetElfSymbolTable

Returns pointer to the elf section header for a symbol table.

The easiest way to get the symbol table is:

Elf64_Xword i, n;
Elf64_Sym *st = GetElfSymbols(map, size, SHT_SYMTAB, &n);
for (i = 0; st && i < n; ++i) {
  // st[i] holds a symbol
}

This API is more verbose than the GetElfSymbols() shortcut, however calling this the long way makes tricks like the following possible:

Elf64_Xword i, n;
Elf64_Shdr *sh = GetElfSymbolTable(map, size, SHT_SYMTAB, &n);
Elf64_Sym *st = GetElfSectionAddress(map, size, sh);
if (st) {
  for (i = sh->sh_info; i < n; ++i) {
    // st[i] holds a non-local symbol
  }
}

Our code here only cares about STB_GLOBAL and STB_WEAK symbols however SHT_SYMTAB usually has countless STB_LOCAL entries too that must be skipped over. The trick is that the ELF spec requires local symbols be ordered before global symbols, and that the index dividing the two be stored to sh_info. So, if we start iterating there, then we've cleverly avoided possibly dozens of page faults!

@param

struct Elf64_Ehdr* elf: points to the start of the executable image data
unsigned long mapsize: is the number of bytes past elf we can access
int section_type: is usually SHT_SYMTAB or SHT_DYNSYM
unsigned long* out_count: optionally receives number of symbols

@return

struct Elf64_Shdr*: pointer to symbol table section header, otherwise null

@see libc/elf/getelfsymboltable.c

geteuid

Returns effective user ID of calling process.

@return

unsigned int: user id

@see libc/calls/geteuid.c

GetGdbPath

@return

const char*

@see libc/log/gdbpath.c

getgid

Returns real group id of process.

This never fails. On Windows, which doesn't really have this concept, we return a hash of the username.

@return

unsigned int: group id (always successful)

@asyncsignalsafe

@vforksafe

@see libc/calls/getuid.c

getgrent

Returns successive entries in /etc/group database.

@return

struct gr*

@threadunsafe

@see third_party/musl/grp.c

getgrgid

@param

unsigned int gid

@return

struct gr*

@see third_party/musl/grp.c

getgrgid_r

@param

unsigned int gid
struct gr* gr
char* buf
unsigned long size
struct gr** res

@return

int

@see third_party/musl/grp.c

getgrnam

@param

const char* name

@return

struct gr*

@see third_party/musl/grp.c

getgrnam_r

@param

const char* name
struct gr* gr
char* buf
unsigned long size
struct gr** res

@return

int

@see third_party/musl/grp.c

getgrouplist

@param

const char* user
unsigned int gid
unsigned int* groups
int* ngroups

@return

int

@see third_party/musl/grp.c

getgroups

Gets list of supplementary group IDs

@param

int size

maximum number of items that can be stored in list

unsigned int* list

buffer to store output gid_t

@return

int: -1 w/ EFAULT

@see libc/calls/getgroups.c

gethostbyname

@param

const char* name

@return

struct hostent*

@see third_party/musl/gethostbyname.c

gethostbyname_r

@param

const char* name
struct hostent* h
char* buf
unsigned long buflen
struct hostent** res
int* err

@return

int

@see third_party/musl/gethostbyname_r.c

gethostent

@return

struct hostent*

@see third_party/musl/ent.c

gethostname

Returns name of current host.

For example, if the fully-qualified hostname is "host.domain.example" then this SHOULD return "host" however that might not be the case; it depends on how the host machine is configured. It's fair to say if it has a dot, it's a FQDN, otherwise it's a node.

The nul / mutation semantics are tricky. Here is some safe copypasta:

char host[254];
if (gethostname(host, sizeof(host))) {
  strcpy(host, "localhost");
}

On Linux this is the same as /proc/sys/kernel/hostname.

@param

char* name: receives output name, which is guaranteed to be complete and have a nul-terminator if this function return zero
unsigned long len: is size of name consider using DNS_NAME_MAX + 1 (254)

@return

int: 0 on success, or -1 w/ errno

@raise EINVAL if len is negative

@raise EFAULT if name is an invalid address

@see libc/calls/gethostname.c

gethostname_bsd

@param

char* name
unsigned long len
int kind

@return

int

@see libc/calls/gethostname-bsd.c

gethostname_linux

@param

char* name
unsigned long len

@return

int

@see libc/calls/gethostname-linux.c

GetHostsTxtPath

@param

char* path
unsigned long size

@return

const char*

@see libc/calls/gethoststxtpath.c

GetHttpHeader

Returns small number for HTTP header, or -1 if not found.

@param

const char* str
unsigned long len

@return

int

@see net/http/gethttpheader.c

GetHttpHeaderName

@param

int h

@return

const char*

@see net/http/gethttpheadername.c

GetHttpReason

Returns string describing HTTP reason phrase.

@param

int code

@return

const char*

@see https://tools.ietf.org/html/rfc2616

@see https://tools.ietf.org/html/rfc6585

@see net/http/gethttpreason.c

getifaddrs

Gets network interface address list.

@param

struct ifaddrs** out_ifpp

@return

int: 0 on success, or -1 w/ errno

@see tool/viz/getifaddrs.c for example code

@see libc/sock/ifaddrs.c

GetInterpreterExecutableName

Returns path of executable interpreter.

Unlike program_executable_name which is designed to figure out the absolute path of the first argument passed to execve(), what we do here is probe things like /proc and sysctl() to figure out if we were launched by something like ape-loader, and then we return its path. If we can't determine that path, possibly because we're on XNU or OpenBSD, then we return -1 with an error code.

@param

char* p: receives utf8 output
unsigned long n: is byte size of res buffer

@return

char*: p on success or null w/ errno if out of buf or error

@see program_invocation_short_name

@see program_invocation_name

@see program_executable_name

@see libc/runtime/getinterpreterexecutablename.c

GetIpCategoryName

Describes IP address.

@param

int c

@return

const char*

@see CategorizeIp()

@see net/http/getipcategoryname.c

getitimer

Retrieves last setitimer() value, correcting for remaining time.

@param

int which: can be ITIMER_REAL, ITIMER_VIRTUAL, etc.
struct itimerval* curvalue

@return

int: 0 on success or -1 w/ errno

@see libc/thread/getitimer.c

getline

Reads line from stream, e.g.

char *line = NULL;
size_t linesize = 0;
while (getline(&line, &linesize, stdin) > 0) {
  chomp(line);
  printf("%s\n", line);
}
free(line);

This function delegates to getdelim(), which provides further documentation. Concerning lines, please note the \n or \r\n are included in results, and can be removed with chomp().

When reading from the console on Windows in ICANON mode, the returned line will end with \r\n rather than \n.

@param

char** linebuf: is the caller's buffer (in/out) which is extended automatically. *line may be NULL but only if *capacity is 0; NUL-termination is guaranteed FTMP
unsigned long* capacity
struct FILE* f

@return

long: number of bytes read, including delim, excluding NUL, or -1 w/ errno on EOF or error; see ferror() and feof()

@see fgetln(), xgetline(), getdelim(), gettok_r()

@see libc/stdio/getline.c

getloadavg

Returns system load average.

@param

double* a: should be array of 3 doubles
int n: should be 3

@return

int: number of items placed in a or -1 w/ errno

@raise ENOSYS on metal

@see libc/calls/getloadavg.c

GetMagnumStr

@param

struct MagnumStr* ms
int x

@return

const char*

@see libc/fmt/magnumstrs.internal.h

getmntent

@param

struct FILE* f

@return

struct mnt*

@see third_party/musl/mntent.c

getmntent_r

@param

struct FILE* f
struct mnt* mnt
char* linebuf
int buflen

@return

struct mnt*

@see third_party/musl/mntent.c

getnetbyaddr

@param

unsigned int net
int type

@return

struct netent*

@see third_party/musl/netname.c

getnetbyname

@param

const char* name

@return

struct netent*

@see third_party/musl/netname.c

getnetent

@return

struct netent*

@see third_party/musl/ent.c

__getntsyspath

Obtains WIN32 magic path, e.g. GetTempPathA.

@param

rax: is address of ANSI path provider function
rdi: is output buffer
rdx: is output buffer size in bytes that's >0

@return

: eax is string length w/ NUL that's ≤ edx; rdi is rdi+edx

@see libc/calls/getntsyspath.S

getopt

@param

int nargc
char** nargv
const char* options

@return

int

@see third_party/getopt/long.c

getopt_long

@param

int nargc
char** nargv
const char* options
struct option* long_options
int* idx

@return

int

@see third_party/getopt/long.c

getopt_long_only

@param

int nargc
char** nargv
const char* options
struct option* long_options
int* idx

@return

int

@see third_party/getopt/long.c

getpeername

Returns details about remote end of connected socket.

@param

int fd
struct sa* out_addr
unsigned int* inout_addrsize

@return

int: 0 on success or -1 w/ errno

@see getsockname()

@see libc/sock/getsockname.c

getpgid

Returns process group id.

@param

int pid

@return

int

@see libc/calls/getpgid.c

getpgrp

Returns process group id of calling process.

This function is equivalent to getpgid(0).

@return

int

@see libc/calls/getpgrp.c

getpid

Returns process id.

This function does not need to issue a system call. The PID is tracked by a global variable which is updated at fork(). The only exception is when the process is vfork()'d in which case a system call shall be issued. This optimization helps make functions like _rand64() fork-safe, however it could lead to race conditions in programs that mix fork() with threads. In that case, apps should consider using sys_getpid().ax instead to force a system call.

On Linux, and only Linux, getpid() is guaranteed to equal gettid() for the main thread.

@return

int: process id (always successful)

@asyncsignalsafe

@vforksafe

@see libc/intrin/getpid.c

getppid

Returns parent process id.

@return

int: parent process id (always successful)

@note slow on Windows; needs to iterate process tree

@asyncsignalsafe

@vforksafe

@see libc/calls/getppid.c

getpriority

Returns nice value of thing.

Since -1 might be a valid return value for this API, it's necessary to clear errno beforehand and see if it changed, in order to truly determine if an error happened.

On Windows, there's only six priority classes. We define them as -16 (realtime), -10 (high), -5 (above), 0 (normal), 5 (below), 15 (idle) which are the only values that'll roundtrip getpriority/setpriority.

@param

int which

can be one of:

PRIO_PROCESS is supported universally
PRIO_PGRP is supported on unix
PRIO_USER is supported on unix

unsigned int who

is the pid, pgid, or uid (0 means current)

@return

int: value ∈ [-NZERO,NZERO) or -1 w/ errno

@raise EINVAL if which was invalid or unsupported

@raise EPERM if access to process was denied

@raise ESRCH if no such process existed

@see setpriority()

@see libc/proc/getpriority.c

getprotobyname

@param

const char* name

@return

struct p*

@see third_party/musl/proto.c

getprotobynumber

@param

int num

@return

struct p*

@see third_party/musl/proto.c

GetProtocolsTxtPath

@param

char* buf
unsigned long size

@return

const char*

@see libc/calls/getprotocolstxtpath.c

getprotoent

@return

struct p*

@see third_party/musl/proto.c

getpwent

Returns next entry in password database.

@return

struct pw*: pointer to entry static memory, or NULL on EOF

@see setpwent()

@threadunsafe

@see third_party/musl/pwd.c

getpwnam

Returns password database entry for user name.

This is essentially guaranteed to succeed if uid == getenv("USER"), since this implementation will generate an entry based on environ if /etc/passwd doesn't exist, or is fake (e.g. MacOS).

@param

const char* name

@return

struct pw*: pointer to passwd entry static memory, or NULL if not found

@threadunsafe

@see third_party/musl/pwd.c

getpwnam_r

@param

const char* name
struct pw* pw
char* buf
unsigned long size
struct pw** res

@return

int

@see third_party/musl/pwd.c

getpwuid

Returns password database entry for user id.

This is essentially guaranteed to succeed if uid == getuid(), since this implementation will generate an entry based on the environment if /etc/passwd doesn't exist, or is fake (e.g. MacOS).

@param

unsigned int uid

@return

struct pw*: pointer to passwd entry static memory, or NULL if not found

@threadunsafe

@see third_party/musl/pwd.c

getpwuid_r

@param

unsigned int uid
struct pw* pw
char* buf
unsigned long size
struct pw** res

@return

int

@see third_party/musl/pwd.c

getresgid

Gets real, effective, and "saved" group ids.

@param

unsigned int* real: receives real user id, or null to do nothing
unsigned int* effective: receives effective user id, or null to do nothing
unsigned int* saved: receives saved user id, or null to do nothing

@return

int: 0 on success or -1 w/ errno

@see setresuid()

@see libc/calls/getresgid.c

getresuid

Gets real, effective, and "saved" user ids.

@param

unsigned int* real: receives real user id, or null to do nothing
unsigned int* effective: receives effective user id, or null to do nothing
unsigned int* saved: receives saved user id, or null to do nothing

@return

int: 0 on success or -1 w/ errno

@see setresuid()

@see libc/calls/getresuid.c

getrusage

Returns resource usage statistics.

@param

int who: can be RUSAGE_{SELF,CHILDREN,THREAD}
struct rusage* usage

@return

int: 0 on success, or -1 w/ errno

@see libc/proc/getrusage.c

gets

@param

char* s

@return

char*

@see libc/stdio/gets.c

getservbyname

@param

const char* name
const char* prots

@return

struct se*

@see third_party/musl/getservbyname.c

getservbyname_r

@param

const char* name
const char* prots
struct servent* se
char* buf
unsigned long buflen
struct servent** res

@return

int

@see third_party/musl/getservbyname_r.c

getservbyport

@param

int port
const char* prots

@return

struct se*

@see third_party/musl/getservbyport.c

getservbyport_r

@param

int port
const char* prots
struct servent* se
char* buf
unsigned long buflen
struct servent** res

@return

int

@see third_party/musl/getservbyport_r.c

getservent

@return

struct servent*

@see third_party/musl/serv.c

GetServicesTxtPath

@param

char* path
unsigned long size

@return

const char*

@see libc/calls/getservicestxtpath.c

getsid

Creates session and sets the process group id.

@param

int pid

@return

int

@see libc/calls/getsid.c

getsockname

Returns details about network interface kernel granted socket.

@param

int fd
struct sa* out_addr
unsigned int* inout_addrsize

@return

int: 0 on success or -1 w/ errno

@see getpeername()

@see libc/sock/getsockname.c

getsockopt

Retrieves socket setting.

@param

int fd
int level: can be SOL_SOCKET, IPPROTO_TCP, etc.
int optname: can be SO_{REUSE{PORT,ADDR},KEEPALIVE,etc.} etc.
void* out_opt_optval
unsigned int* out_optlen

@return

int: 0 on success, or -1 w/ errno

@error ENOPROTOOPT for unknown (level,optname)

@error EINVAL if out_optlen is invalid somehow

@error ENOTSOCK if fd is valid but not a socket

@error EBADF if fd isn't valid

@error EFAULT if optval memory isn't valid

@see libc/sysv/consts.sh for tuning catalogue

@see setsockopt()

@see libc/sock/getsockopt.c

getsubopt

@param

char** optionp
char** tokens
char** valuep

@return

int

@see third_party/getopt/getsubopt.c

GetSymbolByAddr

Returns name of symbol at address.

@param

long addr

@return

char*

@see libc/runtime/getsymbolbyaddr.c

gettid

Returns current thread id.

On Linux, and Linux only, this is guaranteed to be equal to getpid() if this is the main thread. On NetBSD, gettid() for the main thread is always 1.

@return

int: thread id greater than zero or -1 w/ errno

@asyncsignalsafe

@vforksafe

@see libc/intrin/gettid.c

gettimeofday

Returns system wall time in microseconds, e.g.

int64_t t;
char p[20];
struct tm tm;
struct timeval tv;
gettimeofday(&tv, 0);
t = tv.tv_sec;
gmtime_r(&t, &tm);
iso8601(p, &tm);
printf("%s\n", p);

@param

struct timeval* tv: points to timeval that receives result if non-null
struct timezone* tz: is completely ignored

@return

int: 0 on success, or -1 w/ errno

@raise EFAULT if tv points to invalid memory

@see clock_gettime() for nanosecond precision

@see strftime() for string formatting

@asyncsignalsafe

@vforksafe

@see libc/calls/gettimeofday.c

getuid

Returns real user id of process.

This never fails. On Windows, which doesn't really have this concept, we return a hash of the username.

@return

unsigned int: user id (always successful)

@asyncsignalsafe

@vforksafe

@see libc/calls/getuid.c

getutxent

@return

struct utmpx*

@see libc/runtime/utmp.c

getutxid

@param

struct utmpx* x

@return

struct utmpx*

@see libc/runtime/utmp.c

getutxline

@param

struct utmpx* x

@return

struct utmpx*

@see libc/runtime/utmp.c

getwchar

Reads UTF-8 character from stream.

@return

unsigned int: wide character or -1 on EOF or error

@see libc/stdio/getwchar.c

getwchar_unlocked

Reads UTF-8 character from stream.

@return

unsigned int: wide character or -1 on EOF or error

@see libc/stdio/getwchar_unlocked.c

getx86processormodel

Identifies microarchitecture of host processor.

@param

short key: can be kX86ProcessorModelKey for host info

@return

struct X86ProcessorModel*

@see https://en.wikichip.org/wiki/intel/cpuid

@see https://a4lg.com/tech/x86/database/x86-families-and-models.en.html

@see libc/str/getx86processormodel.c

GetZipCdirComment

Returns comment of zip central directory.

@param

const unsigned char* eocd

@return

void*

@see libc/str/getzipcdircomment.c

GetZipCdirCommentSize

Returns comment of zip central directory.

@param

const unsigned char* eocd

@return

unsigned long

@see libc/str/getzipcdircommentsize.c

GetZipCdirOffset

Returns offset of zip central directory.

@param

const unsigned char* eocd

@return

unsigned long

@see libc/str/getzipcdiroffset.c

GetZipCdirRecords

Returns number of records in zip central directory.

@param

const unsigned char* eocd

@return

unsigned long

@see libc/str/getzipcdirrecords.c

GetZipCdirSize

Returns size of zip central directory.

@param

const unsigned char* eocd

@return

unsigned long

@see libc/str/getzipcdirsize.c

GetZipCfileCompressedSize

Returns compressed size in bytes from zip central directory header.

@param

const unsigned char* z

@return

long

@see libc/str/getzipcfilecompressedsize.c

GetZipCfileMode

Returns st_mode from ZIP central directory record.

@param

const unsigned char* p

@return

int

@see libc/str/getzipcfilemode.c

GetZipCfileOffset

Returns offset of local file header.

@param

const unsigned char* z

@return

long

@see libc/str/getzipcfileoffset.c

GetZipCfileTimestamps

Extracts modified/access/creation timestamps from zip entry.

@param

const unsigned char* cf: is pointer to central directory header for file
ANONYMOUS-STRUCT* mtim: optionally receives last modified timestamp
ANONYMOUS-STRUCT* atim: optionally receives modified timestamp
ANONYMOUS-STRUCT* ctim: optionally receives creation timestamp
int gmtoff: is seconds adjustment for legacy dos timestamps

@return

void

@see libc/str/getzipcfiletimestamps.c

GetZipCfileUncompressedSize

Returns uncompressed size in bytes from zip central directory header.

@param

const unsigned char* z

@return

long

@see libc/str/getzipcfileuncompressedsize.c

GetZipEocd

Locates End Of Central Directory record in ZIP file.

The ZIP spec says this header can be anywhere in the last 64kb. We search it backwards for the ZIP-64 "PK♠•" magic number. If that's not found, then we search again for the original "PK♣♠" magnum. The caller needs to check the first four bytes of the returned value to determine whether to use ZIP_CDIR_xxx() or ZIP_CDIR64_xxx() macros.

@param

void* f: points to file memory
unsigned long n: is byte size of file
int* e: may receive error code when null is returned

@return

void*: pointer to EOCD64 or EOCD, otherwise null

@see libc/str/getzipeocd.c

GetZipLfileCompressedSize

Returns compressed size in bytes from zip local file header.

@param

const unsigned char* z

@return

long

@see libc/str/getziplfilecompressedsize.c

GetZipLfileUncompressedSize

Returns uncompressed size in bytes from zip local file header.

@param

const unsigned char* z

@return

long

@see libc/str/getziplfileuncompressedsize.c

glob

Finds pathnames matching pattern.

For example:

glob_t g = {.gl_offs = 2};
glob("*.*", GLOB_DOOFFS, NULL, &g);
glob("../.*", GLOB_DOOFFS | GLOB_APPEND, NULL, &g);
g.gl_pathv[0] = "ls";
g.gl_pathv[1] = "-l";
execvp("ls", &g.gl_pathv[0]);
globfree(g);

@param

const char* pat: can have star wildcard see fnmatch()
int flags
int(*)() errfunc
struct glob_t* g: will receive matching entries and needs globfree()

@return

int: 0 on success or GLOB_NOMATCH, GLOB_NOSPACE on OOM, or GLOB_ABORTED on read error

@see third_party/musl/glob.c

globfree

Frees entries allocated by glob().

@param

struct glob_t* g

@return

void

@see third_party/musl/glob.c

GoodSocket

Returns new socket with modern goodness enabled.

@param

int family
int type
int protocol
_Bool isserver
struct timeval* timeout

@return

int

@see libc/sock/goodsocket.c

grantpt

Grants access to subordinate pseudoteletypewriter.

@param

int fd

@return

int: 0 on success, or -1 w/ errno

@raise EBADF if fd isn't open

@raise EINVAL if fd is valid but not associated with pty

@raise EACCES if pseudoterminal couldn't be accessed

@see libc/calls/grantpt.c

HasControlCodes

Returns true if C0 or C1 control codes are present

@param

const char* p: is input value
unsigned long n: if -1 implies strlen
int f: can have kControlWs, kControlC0, kControlC1 to forbid

@return

long: index of first forbidden character or -1

@see VisualizeControlCodes()

@see net/http/hascontrolcodes.c

hasmntopt

@param

struct mnt* mnt
const char* opt

@return

char*

@see third_party/musl/mntent.c

heapsort

Sorts array.

Runs in O (N lg N), both average and worst. While heapsort is faster than the worst case of quicksort, the BSD quicksort does median selection so that the chance of finding a data set that will trigger the worst case is nonexistent. Heapsort's only advantage over quicksort is that it requires little additional memory.

@param

void* vbase: is base of array
unsigned long nmemb: is item count
unsigned long size: is item width
int(*)() compar: is a callback returning <0, 0, or >0

@return

int

@see Knuth, Vol. 3, page 145.

@see heapsort_r()

@see mergesort()

@see qsort()

@see libc/mem/heapsort.c

heapsort_r

Sorts array w/ optional callback argument.

@param

void* vbase: is base of array
unsigned long nmemb: is item count
unsigned long size: is item width
int(*)() compar: is a callback returning <0, 0, or >0
void* z: will optionally be passed as the third argument to cmp

@return

int

@see heapsort()

@see libc/mem/heapsort.c

hexpcpy

Turns data into lowercase hex.

This routine always writes a nul terminator, even if n is zero. There's no failure condition for this function.

@param

char* s: must have n*2+1 bytes
void* p: must have n bytes
unsigned long n: is byte length of p

@return

char*: pointer to nul byte in s

@see libc/str/hexpcpy.c

HighwayHash64

Computes Highway Hash.

highwayhash64 n=0                  121 nanoseconds
highwayhash64 n=8                   16 ns/byte         59,865 kb/s
highwayhash64 n=31                   4 ns/byte            222 mb/s
highwayhash64 n=32                   3 ns/byte            248 mb/s
highwayhash64 n=63                   2 ns/byte            387 mb/s
highwayhash64 n=64                   2 ns/byte            422 mb/s
highwayhash64 n=128                  1 ns/byte            644 mb/s
highwayhash64 n=256                  1 ns/byte            875 mb/s
highwayhash64 n=22851              721 ps/byte          1,354 mb/s

@param

void* data
unsigned long size
const unsigned long* key

@return

unsigned long

@see libc/str/highwayhash64.c

highwayhash_notice

@type

const char[53]

@see libc/str/highwayhash64.c

hilbert

Generates Hilbert space-filling curve.

@param

long n
long y
long x

@return

long

@see https://en.wikipedia.org/wiki/Hilbert_curve

@see unhilbert()

@see libc/intrin/hilbert.c

hook_bulk_free

@type

unsigned long(*)()

@see libc/mem/bulk_free.c

hook_calloc

@type

void*(*)()

@see libc/mem/calloc.c

hook_free

@type

void(*)()

@see libc/mem/free.c

hook_malloc

@type

void*(*)()

@see libc/mem/malloc.c

hook_malloc_trim

@type

int(*)()

@see libc/mem/malloc_trim.c

hook_malloc_usable_size

@type

unsigned long(*)()

@see libc/mem/malloc_usable_size.c

hook_memalign

@type

void*(*)()

@see libc/mem/memalign.c

hook_realloc

@type

void*(*)()

@see libc/mem/realloc.c

hook_realloc_in_place

@type

void*(*)()

@see libc/mem/hook_realloc_in_place.c

hstrerror

@param

int ecode

@return

const char*

@see third_party/musl/hstrerror.c

hypot

Returns euclidean distance.

@param

double x
double y

@return

double

@see libc/tinymath/hypot.c

hypotf

Returns euclidean distance.

Max observed error is 1 ulp.

@param

float x
float y

@return

float

@see libc/tinymath/hypotf.c

hypotl

Returns euclidean distance.

@param

long double x
long double y

@return

long double

@see libc/tinymath/hypotl.c

iconv

@param

void* cd
char** in
unsigned long* inb
char** out
unsigned long* outb

@return

unsigned long

@see libc/stdio/iconv.c

iconv_close

@param

void* cd

@return

int

@see libc/stdio/iconv.c

iconv_open

@param

const char* to
const char* from

@return

void*

@see libc/stdio/iconv.c

identity

The identity() function.

@return

: first argument

@see libc/nexgen32e/identity.S

ilogb

Returns log₂𝑥 exponent part of double.

@param

double x

@return

int

@see libc/tinymath/ilogb.c

ilogbf

Returns log₂𝑥 exponent part of double.

@param

float x

@return

int

@see libc/tinymath/ilogbf.c

ilogbl

Returns log₂𝑥 exponent part of double.

@param

long double x

@return

int

@see third_party/compiler_rt/ilogbl.c

in6addr_any

@type

struct in6addr_any

@see libc/sock/in6addr_any.c

in6addr_loopback

@type

struct in6addr_loopback

@see libc/sock/in6addr_loopback.c

IndentLines

Inserts spaces before lines.

@param

const char* p: is input value
unsigned long n: if -1 implies strlen
unsigned long* z: if non-NULL receives output length
unsigned long j: is number of spaces to use

@return

char*: allocated NUL-terminated buffer, or NULL w/ errno

@see net/http/indentlines.c

inet_addr

Converts dotted IPv4 address string to network order binary.

@param

const char* s

@return

unsigned int

@see inet_aton()

@see libc/sock/inet_addr.c

inet_aton

Converts dotted IPv4 address string to network order binary.

@param

const char* s0
ANONYMOUS-STRUCT* dest

@return

int

@see libc/sock/inet_aton.c

inet_ntoa

Converts IPv4 network address to array.

@param

struct in in

@return

char*

@see libc/sock/inet_ntoa.c

inet_ntop

Formats internet address to string.

@param

int af: can be AF_INET or AF_INET6
void* src: is the binary-encoded address, e.g. &addr->sin_addr
char* dst: is the output string buffer
unsigned int size: needs to be 16+ for IPv4 and 46+ for IPv6

@return

const char*: dst on success or NULL w/ errno

@see libc/sock/inet_ntop.c

inet_pton

Converts internet address string to binary.

@param

int af: can be AF_INET or AF_INET6
const char* src: is the ASCII-encoded address
void* dst: is where the binary-encoded net-order address goes

@return

int: 1 on success, 0 on src malformed, or -1 w/ errno

@see libc/sock/inet_pton.c

__inflate

Decompresses raw deflate data.

This uses puff by default since it has a 2kb footprint. If zlib proper is linked, then we favor that instead, since it's faster.

@param

void* out
unsigned long outsize: needs to be known ahead of time by some other means
void* in
unsigned long insize

@return

int: 0 on success or nonzero on failure

@see libc/runtime/inflate.c

inflateBackInit

Initialize internal stream state for decompression using inflateBack() calls. The fields zalloc, zfree and opaque in strm must be initialized before the call. If zalloc and zfree are Z_NULL, then the default library- derived memory allocation routines are used. windowBits is the base two logarithm of the window size, in the range 8..15. window is a caller supplied buffer of that size. Except for special applications where it is assured that deflate was used with small window sizes, windowBits must be 15 and a 32K byte window must be supplied to be able to decompress general deflate streams.

See inflateBack() for the usage of these routines.

@return

int: Z_OK on success, Z_STREAM_ERROR if any of the parameters are invalid, or Z_MEM_ERROR if the internal state could not be allocated.

@see third_party/zlib/zlib.h

_init

Decentralized function for process initialization.

Modules may inject cheap data structure initialization code into this function using the .init.start and .init.end macros. That code can use the LODS and STOS instructions to initialize memory that's restricted to read-only after initialization by PIRO.

This is fast, since the linker is able to roll-up initialization for large codebases comprised of many modules, into a perfectly linear order. It also enables a common pattern we use, which we call “Referencing Is Initialization” (RII).

C/C++ code should favor using ordinary constructors, since under normal circumstances the compiler will clobber RDI and RSI which are granted special meanings within this function.

@param

r12: is argc (still callee saved)
r13: is argv (still callee saved)
r14: is envp (still callee saved)
r15: is envp (still callee saved)

@return

@note rdi is __init_bss_start (callee monotonic lockstep)

@note rsi is __init_rodata_start (callee monotonic lockstep)

@see .init.start & .init.end (libc/macros.internal.h)

@see ape/ape.lds

@see libc/runtime/init.S

__init_bss_start

Decentralized section for unpacked data structures.

Data in this section becomes read-only after initialization.

@return

@see .piro.bss.init (libc/macros.internal.h)

@see libc/runtime/piro.c

@see ape/ape.lds

@see libc/runtime/init.S

__init_rodata_start

Decentralized section for packed data structures & initializers.

@return

@see .initro (libc/macros.internal.h)

@see ape/ape.lds

@see libc/runtime/init.S

initgroups

@param

const char* user
unsigned int gid

@return

int

@see third_party/musl/grp.c

initstate

@param

unsigned int seed
char* state
unsigned long size

@return

char*

@see libc/stdio/random.c

insque

@param

void* element
void* pred

@return

void

@see third_party/musl/insque.c

_intsort

Tiny and reasonably fast sorting for ints.

@param

int* A
unsigned long n

@return

void

@see djbsort

@see libc/str/intsort.c

is_cpp_mangled_gnu3

@param

const char* org

@return

_Bool: Return 0 at false.

@brief Test input string is mangled by IA-64 C++ ABI style.

Test string heads with "_Z" or "_GLOBAL__I_".

@see libc/stdio/demangle.c

__is_stack_overflow

Returns true if signal is most likely a stack overflow.

@param

struct siginfo_t* si
void* arg

@return

char

@see libc/runtime/isstackoverflow.c

IsAcceptableHost

Returns true if host seems legit.

This function may be called after ParseUrl() or ParseHost() has already handled things like percent encoding. There's currently no support for IPv6 and IPv7.

Here's examples of permitted inputs:

""
1.2.3.4
1.2.3.4.arpa
localservice
hello.example
_hello.example
-hello.example
hi-there.example

Here's some examples of forbidden inputs:

::1
1.2.3
1.2.3.4.5
.hi.example
hi..example

@param

const char* s
unsigned long n: if -1 implies strlen

@return

_Bool

@see net/http/isacceptablehost.c

IsAcceptablePath

Returns true if path seems legit.

The substring "//" is disallowed.
We won't serve hidden files (segment starts with '.'). The only exception is /.well-known/.
We won't serve paths with segments equal to "." or "..".

It is assumed that the URI parser already took care of percent escape decoding as well as ISO-8859-1 decoding. The input needs to be a UTF-8 string. This function takes overlong encodings into consideration, so you don't need to call Underlong() beforehand.

@param

const char* data
unsigned long size: if -1 implies strlen

@return

_Bool

@see IsReasonablePath()

@see net/http/isacceptablepath.c

IsAcceptablePort

Returns true if port seems legit.

Here's examples of permitted inputs:

""
0
65535

Here's some examples of forbidden inputs:

-1
65536
https

@param

const char* s
unsigned long n: if -1 implies strlen

@return

_Bool

@see net/http/isacceptableport.c

IsAfrinicIp

Returns true if IPv4 address is managed by AFRINIC.

@param

unsigned int x

@return

_Bool

@see net/http/isafrinicip.c

isalnum

Returns nonzero if c is lower, alpha, or digit.

@param

int c

@return

int

@see libc/str/isalnum.c

isalpha

Returns nonzero if c is upper or lower.

@param

int c

@return

int

@see libc/str/isalpha.c

IsAnonymousIp

Returns true if IPv4 address is anonymous proxy provider.

@param

unsigned int x

@return

_Bool

@see net/http/isanonymousip.c

IsApeLoadable

Returns true if executable image is supported by APE Loader.

@param

char* buf

@return

_Bool

@see libc/calls/isapemagic.c

IsApnicIp

Returns true if IPv4 address is managed by APNIC.

@param

unsigned int x

@return

_Bool

@see net/http/isapnicip.c

IsArinIp

Returns true if IPv4 address is managed by ARIN.

@param

unsigned int x

@return

_Bool

@see net/http/isarinip.c

isascii

Returns nonzero if c is ascii.

@param

int c

@return

int

@see libc/str/isascii.c

IsAtLeastWindows10

@return

int

@see libc/intrin/isatleastwindows10.c

isatty

Tells if file descriptor is a terminal.

@param

int fd: is file descriptor

@return

int: 1 if is terminal, otherwise 0 w/ errno

@raise EBADF if fd isn't a valid file descriptor

@raise ENOTTY if fd is something other than a terminal

@raise EPERM if pledge() was used without tty

@see libc/calls/isatty.c

isblank

Returns nonzero if c is space or tab.

@param

int c

@return

int

@see libc/str/isblank.c

ischardev

Returns true if file descriptor is backed by character i/o.

This function is equivalent to:

struct stat st;
return stat(path, &st) != -1 && S_ISCHR(st.st_mode);

Except faster and with fewer dependencies.

@param

int fd

@return

int

@see isregularfile(), isdirectory(), issymlink(), fileexists()

@see libc/calls/ischardev.c

IsCloudflareIp

Returns true if x is Cloudflare IPv4 address.

@param

unsigned int x

@return

_Bool

@see https://www.cloudflare.com/ips/ (April 8, 2021)

@see net/http/iscloudflare.c

iscntrl

Returns nonzero if c is C0 ASCII control code or DEL.

@param

int c

@return

int

@see libc/str/iscntrl.c

IsCygwin

@return

int

@see libc/intrin/iscygwin.c

isdigit

Returns nonzero if c is decimal digit.

@param

int c

@return

int

@see libc/str/isdigit.c

IsDodIp

Returns true if IP is owned by the U.S. Department of Defense.

@param

unsigned int x

@return

_Bool

@see net/http/isdodip.c

IsElf64Binary

Returns true if elf is a 64-bit elf executable.

@param

struct Elf64_Ehdr* elf: points to the start of the executable image
unsigned long mapsize: is the number of bytes past elf we can access

@return

int: true if elf header looks legit

@see libc/elf/iself64binary.c

IsElfSymbolContent

@param

struct Elf64_Sym* sym

@return

int

@see libc/elf/iselfsymbolcontent.c

isexecutable

Returns true if file exists and is executable.

@param

const char* path

@return

int

@see access(exe, X_OK) which is more accurate on NT

@asyncsignalsafe

@vforksafe

@see libc/calls/isexecutable.c

IsGenuineBlink

@return

int

@see libc/intrin/isgenuineblink.c

isgraph

Returns nonzero if c is printable ascii that isn't space.

@param

int c

@return

int

@see libc/str/isgraph.c

IsLacnicIp

Returns true if IPv4 address is managed by LACNIC.

@param

unsigned int x

@return

_Bool

@see net/http/islacnicip.c

IsLoopbackIp

Returns true if IPv4 address is used for localhost.

@param

unsigned int x

@return

_Bool

@see libc/intrin/isloopbackip.c

islower

Returns nonzero if c is lowercase alpha ascii character.

@param

int c

@return

int

@see libc/str/islower.c

IsMimeType

Returns true if content-type 𝑡 has mime-type 𝑠.

@param

const char* t
unsigned long n
const char* s

@return

_Bool

@see net/http/ismimetype.c

IsMulticastIp

Returns true if IPv4 address is used for multicast.

@param

unsigned int x

@return

_Bool

@see net/http/ismulticastip.c

IsNoCompressExt

@param

const char* p
unsigned long n

@return

_Bool

@see net/http/isnocompressext.c

isprint

Returns nonzero if c is printable ascii including space.

@param

int c

@return

int

@see libc/str/isprint.c

IsPrivateIp

Returns true if IPv4 address is intended for private networks.

@param

unsigned int x

@return

_Bool

@see libc/intrin/isprivateip.c

IsPublicIp

Returns true if IPv4 address is Globally Reachable.

We intentionally omit TEST-NET here which can be used to simulate public Internet traffic using non-Internet IPs.

@param

unsigned int x

@return

_Bool: true 92.4499% of the time

@see IANA IPv4 Special-Purpose Address Registry

@see libc/intrin/ispublicip.c

ispunct

Returns nonzero if c ∈ !"#$%&'()*+,-./:;<=>?@[\]^_`{|}~

@param

int c

@return

int

@see libc/str/ispunct.c

IsQemuUser

Returns true if process is running under qemu-x86_64 or qemu-aarch64.

@return

int

@see libc/calls/isqemu.c

IsReasonablePath

Returns true if path doesn't contain "." or ".." segments.

@param

const char* data
unsigned long size: if -1 implies strlen

@return

_Bool

@see IsAcceptablePath()

@see net/http/isreasonablepath.c

IsRipeIp

Returns true if IPv4 address is managed by RIPE NCC.

@param

unsigned int x

@return

_Bool

@see net/http/isripeip.c

issetugid

Determines if process is tainted.

This function returns 1 if process was launched as a result of an execve() call on a binary that had the setuid or setgid bits set. FreeBSD defines tainted as including processes that changed their effective user / group ids at some point.

@return

int: always successful, 1 if yes, 0 if no

@see libc/calls/issetugid.c

isspace

Returns nonzero if c is space, \t, \r, \n, \f, or \v.

@param

int c

@return

int

@see isblank()

@see libc/str/isspace.c

IsTestnetIp

Returns true if IPv4 address is intended for documentation.

@param

unsigned int x

@return

_Bool

@see RFC5737

@see net/http/istestnetip.c

istext

Returns true if buffer is most likely plaintext.

@param

void* data
unsigned long size

@return

int

@see libc/str/istext.c

isupper

Returns nonzero if c is uppercase alpha ascii character.

@param

int c

@return

int

@see libc/str/isupper.c

isutf8

Returns true if text is utf-8.

isutf8 n=0                  1 nanoseconds
isutf8 n=5                661 ps/byte          1,476 mb/s
isutf8 ascii n=22851       26 ps/byte             35 GB/s
isutf8 unicode n=3193     543 ps/byte          1,795 mb/s

This function considers all ASCII characters including NUL to be valid UTF-8. The conditions for something not being valid are:

Incorrect sequencing of 0300 (FIRST) and 0200 (CONT) chars
Thompson-Pike varint sequence not encodable as UTF-16
Overlong UTF-8 encoding

@param

void* data
unsigned long size: if -1 implies strlen

@return

int

@see libc/str/isutf8.c

IsValidCookieValue

Returns true if string is a valid cookie value (any ASCII excluding control char, whitespace, double quotes, comma, semicolon, and backslash).

@param

const char* s
unsigned long n: if -1 implies strlen

@return

_Bool

@see net/http/isvalidcookievalue.c

IsValidHttpToken

Returns true if string is ASCII without delimiters.

@param

const char* s
unsigned long n: if -1 implies strlen

@return

_Bool

@see net/http/isvalidhttptoken.c

iswalnum

Returns nonzero if c is lower, alpha, or digit.

@param

unsigned int c

@return

int

@see libc/str/iswalnum.c

iswalpha

Returns nonzero if c is alphabetical.

@param

unsigned int c

@return

int

@see libc/str/iswalpha.c

iswblank

Returns nonzero if c is space or tab.

@param

unsigned int c

@return

int

@see libc/str/iswblank.c

iswcntrl

Returns nonzero if c is C0 or C1 control code.

@param

unsigned int c

@return

int

@see libc/str/iswcntrl.c

iswctype

Returns nonzero if c has property.

@param

unsigned int c
unsigned int t: is number returned by wctype

@return

int

@see libc/str/iswctype.c

iswdigit

Returns nonzero if c is decimal digit.

@param

unsigned int c

@return

int

@see libc/str/iswdigit.c

iswgraph

Returns nonzero if c is printable and not a space.

@param

unsigned int c

@return

int

@see libc/str/iswgraph.c

iswlower

Returns nonzero if c is lowercase letter.

@param

unsigned int c

@return

int

@see libc/str/iswlower.c

__isworker

Indicates if current execution context is a worker task.

Setting this to true on things like the forked process of a web server is a good idea since it'll ask the C runtime to not pull magical stunts like attaching GDB to the process on crash.

@type

int

@see libc/intrin/isworker.c

iswprint

Returns nonzero if c is printable.

@param

unsigned int c

@return

int

@see libc/str/iswprint.c

iswpunct

Returns nonzero if c is punctuation mark.

@param

unsigned int c

@return

int

@see libc/str/iswpunct.c

iswseparator

Returns nonzero if 𝑐 isn't alphanumeric.

Line reading interfaces generally define this operation as UNICODE characters that aren't in the letter category (Lu, Ll, Lt, Lm, Lo) and aren't in the number categorie (Nd, Nl, No). We also add a few other things like blocks and emoji (So).

@param

unsigned int c

@return

int

@see libc/str/iswseparator.c

iswspace

Returns nonzero if c is space character.

We define this as invisible characters which move the cursor. That means \t\r\n\f\v and unicodes whose category begins with Z but not ogham since it's not invisible and non-breaking spaces neither since they're not invisible to emacs users.

@param

unsigned int c

@return

int

@see libc/str/iswspace.c

iswupper

Returns nonzero if c is uppercase letter.

@param

unsigned int c

@return

int

@see libc/str/iswupper.c

iswxdigit

Returns nonzero if c is ascii hex digit.

@param

unsigned int c

@return

int

@see libc/str/iswxdigit.c

isxdigit

Returns true if c is hexadecimal digit.

@param

int c

@return

int

@see libc/str/isxdigit.c

IsZipEocd32

Determines if ZIP EOCD record seems legit.

@param

const unsigned char* p
unsigned long n
unsigned long i

@return

int

@see libc/str/iszipeocd32.c

IsZipEocd64

Returns kZipOk if zip64 end of central directory header seems legit.

@param

const unsigned char* p
unsigned long n
unsigned long i

@return

int

@see libc/str/iszipeocd64.c

__join_paths

Joins paths, e.g.

0    + 0    → 0
""   + ""   → ""
"a"  + 0    → "a"
"a"  + ""   → "a/"
0    + "b"  → "b"
""   + "b"  → "b"
"."  + "b"  → "./b"
"b"  + "."  → "b/."
"a"  + "b"  → "a/b"
"a/" + "b"  → "a/b"
"a"  + "b/" → "a/b/"
"a"  + "/b" → "/b"

@param

char* buf
unsigned long size
const char* path
const char* other

@return

char*: joined path, which may be buf, path, or other, or null if (1) buf didn't have enough space, or (2) both path and other were null

@see libc/str/joinpaths.c

JoinStrList

@param

struct StrList* sl
char** buf
unsigned long sep

@return

int

@see libc/stdio/joinstrlist.c

jrand48

@param

unsigned short* s

@return

long

@see third_party/musl/rand48.c

kappendf

Appends formatted string to buffer w/ kprintf, e.g.

char *b = 0;
kappendf(&b, "hello %d\n", 123);
free(b);

@param

char** b
const char* fmt
...

@return

long: bytes appended or -1 if ENOMEM

@see appendz(b).i to get buffer length

@note O(1) amortized buffer growth

@see kprintf()

@see libc/stdio/kappendf.c

kCp437

ibm cp437 unicode table w/ string literal safety

        ░▄██▒▄█ ▐██ ░░░     ▀▀████▒▀█▄
       ▐███▓██░ ██▌            ▀████▄■█▄
      ▐█▓███▀█░██▀   ░          ░▀█████▓▄
     ▐█▓██▀▄█▒██▀  ▄▄░  ▄▄▄ ░░░   ░▀████▒▄
    ▐████▀▄█■█▀      ▀▀             ░█████░
   ▐█▓█▀████▀          ░             ▐▓███▒
   █░███▀▀     ░░░    ▄█       ░░░    █████
  ▐█▓█░▀▀  ░░▄█▄▄▄▄▄  ▀▄ ▌▄▄▄░▄▄▄▄▄   ▐████░
  ▐███▌   ▄▀█████████▄ ▌▐▄████████▄   ▐▓███░
  ▐███░░░▀▄█▀▄▄████▄▀░  ▐████████▒ ▀   ░███░
  ░████░ ▓▀ ▄███████▀▌   ▀▄■████▀▀█▀   ██▀█
   ▓███░ ░▄▀▀░░░ ▀  ░░▌   ▄▀▀▄░░▀░▄▀▄ ▐██▀▄
   ░███░  ▄▓▓▄▄░▀▀█▀█ ▌░░  ▀█▀█▀▀     ▐██▀
 █▀▄▐██   ▀░░   ▄▀ ▐ █    ▀ ▄▄▄░     ░▀▄█▄▀█
 ▌▄  █▓ ▒      ░  █▄█▄▀▄▄▄███▄▀▄ ░░   ░ ▀  █▌
  █▌▄░▌      ░░░▄▀█▀███████▄▀▄▀▄▀▀▄▄▄  █▀█░▐
   ██▄     ░░░▄█▄▀██▄█■██████▄█▄█▄■▀█░  ▐░▐
    ▀██░   ░▄██████████████████▄█▄█ ░█ ░ ▄▀
    ▀▓█▄▓░░  ▒█▀█████████████████████▒ ██▀
     ▀███ ▓▒   ██████████████▀▀▀▀█▄▀ ░▄█▒
      ▀███ ▀█▄▀▄█████▀▀  ▓▓▓▄░   ▐  ░▄██
        ▀██ ▄███████▄████████▀░░   ░▄██
  ▄██▀▀▄ █▄▀▄██▒▒███████████▀▀▀▄░ ░███░
▄██▀▄▄░░▀▐▄████▄ █████▀▄░░█▀▄▀░░  ▄██░
█████▄▄▄███▀░█▌██▄▀▀█████▄▄░░░▄▄███▀██▄ ▄▀▀▀▄▄
 ▀██████▀■▄█▄▄ ░▀███████████████▓▓░░▄██▀▄████▄▄▀▄

█▀█ █  █▀█ █▀█ █▄▀ ▐▀█▀▌█▀█ █▀█ █▄ █ ▀█▀ █▀█ █▀▀
█▀▄ █  █ █ █   █ ▀▄  █  █▀▄ █ █ █ ▀█  █  █   ▀▀█
█▄█ █▄▌█▄█ █▄█ █  █  █  █ █ █▄█ █  █ ▄█▄ █▄█ █▄█

THERE WILL BE BLOCKS               march 01 2017

@return

@see libc/str/str.h

@see kCp437i[]

@see libc/nexgen32e/kcp437.S

kCpuids

Globally precomputed CPUID.

This module lets us check CPUID in 0.06ns rather than 51.00ns. If every piece of native software linked this module, then the world would be a much better place; since all the alternatives are quite toilsome.

@return

@see www.felixcloutier.com/x86/cpuid

@see libc/nexgen32e/kcpuids.S

kDos2Errno

data structure for __dos2errno()

@return

@see libc/sysv/dos2errno.sh for the numbers

@see libc/intrin/kdos2errno.S

kEmptyFd

@type

struct kEmptyFd

@see libc/calls/kemptyfd.c

kEscapeAuthority

@type

const char[256]

@see net/http/kescapeauthority.c

kEscapeFragment

@type

const char[256]

@see net/http/kescapefragment.c

kEscapeIp

@type

const char[256]

@see net/http/kescapeip.c

kEscapeParam

@type

const char[256]

@see net/http/kescapeparam.c

kEscapePath

@type

const char[256]

@see net/http/kescapepath.c

kEscapeSegment

@type

const char[256]

@see net/http/kescapesegment.c

kHostChars

@type

const char[256]

@see net/http/khostchars.c

kHttpRepeatable

Set of standard comma-separate HTTP headers that may span lines.

These headers may specified on multiple lines, e.g.

Allow: GET
Allow: POST

Is the same as:

Allow: GET, POST

Standard headers that aren't part of this set will be overwritten in the event that they're specified multiple times. For example,

Content-Type: application/octet-stream
Content-Type: text/plain; charset=utf-8

Is the same as:

Content-Type: text/plain; charset=utf-8

This set exists to optimize header lookups and parsing. The existence of standard headers that aren't in this set is an O(1) operation. The repeatable headers in this list require an O(1) operation if they are not present, otherwise the extended headers list needs to be crawled.

Please note non-standard headers exist, e.g. Cookie, that may span multiple lines, even though they're not comma-delimited. For those headers we simply don't add them to the perfect hash table.

@type

_Bool[93]

@note we choose to not recognize this grammar for kHttpConnection

@note grep '[A-Z][a-z]*".*":"' rfc2616

@note grep ':.*#' rfc2616

@see RFC7230 § 4.2

@see net/http/khttprepeatable.c

kHttpToken

@type

const char[256]

@see net/http/khttptoken.c

kill

Sends signal to process.

The impact of this action can be terminating the process, or interrupting it to request something happen.

@param

int pid: can be: >0 signals one process by id =0 signals all processes in current process group -1 signals all processes possible (except init) <-1 signals all processes in -pid process group
int sig: can be: >0 can be SIGINT, SIGTERM, SIGKILL, SIGUSR1, etc. =0 checks both if pid exists and we can signal it

@return

int: 0 if something was accomplished, or -1 w/ errno

@raise ESRCH if pid couldn't be found

@raise EPERM if lacked permission to signal process

@raise EPERM if pledge() is in play without proc promised

@raise EINVAL if the provided sig is invalid or unsupported

@asyncsignalsafe

@see libc/proc/kill.c

killpg

Sends signal to process group.

@param

int pgrp
int sig

@return

int

@see libc/proc/killpg.c

kMbBittab

@type

const unsigned int[51]

@see libc/str/mb.c

kMonthYearDay

@type

const unsigned short[12][2]

@see libc/str/kmonthyearday.c

kNtIsInheritable

@type

struct kNtIsInheritable

@see libc/intrin/kntisinheritable.greg.c

kNtStdio

@type

const char[3]

@see libc/intrin/kntstdio.c

kNtSystemDirectory

RII constant holding 'C:/WINDOWS/SYSTEM32' directory.

@return

@note guarantees trailing slash if non-empty

@see libc/calls/kntsystemdirectory.S

kNtWindowsDirectory

RII constant holding 'C:/WINDOWS' directory.

@return

@note guarantees trailing slash if non-empty

@see libc/calls/kntwindowsdirectory.S

kStartTsc

Timestamp of process start.

@type

unsigned long

@see libc/runtime/winmain.greg.h

@see libc/crt/crt.S

@see libc/intrin/kstarttsc.c

kTens

@type

const unsigned long[20]

@see libc/nexgen32e/ktens.c

kWcwidthOsx

@type

const unsigned int[591]

@see libc/str/wcwidth_osx.c

kWcwidthOsxIndex1

@type

const unsigned char[136]

@see libc/str/wcwidth_osx.c

kWcwidthOsxIndex2

@type

const unsigned short[228]

@see libc/str/wcwidth_osx.c

kWcwidthOsxIndex3

@type

const unsigned int[917]

@see libc/str/wcwidth_osx.c

kX86GradeNames

@type

struct IdName[10]

@see libc/intrin/x86names.c

kX86MarchNames

@type

struct IdName[28]

@see libc/intrin/x86names.c

kX86ProcessorModelCount

@type

const unsigned long

@see libc/str/kx86processormodels.c

kX86ProcessorModels

@type

struct X86ProcessorModel[64]

@see libc/str/kx86processormodels.c

kXedChipFeatures

Mapping of enum XedChip -> bitset<enum XedIsaSet>.

See related APIs, e.g. xed_isa_set_is_valid_for_chip().

This information can be reproduced by building Xed and running the C preprocessor on xed-chip-features-table.c (see xed-chips.txt) which turns several thousand lines of non-evolving code into fifty. For example, 0x2800000ul was calculated as: 1UL<<(XED_ISA_SET_I86-64) | 1UL<<(XED_ISA_SET_LAHF-64).

@type

const unsigned long[3][53]

@see third_party/xed/x86features.c

kXedEamode

@type

const unsigned char[3][2]

@see third_party/xed/eamode.c

kXedErrorNames

Xed error code names.

@type

const char[338]

@see XedError

@see third_party/xed/xederror.c

kZlibBaseDist

@type

const int[30]

@see third_party/zlib/treeconst.c

kZlibBaseLength

@type

const int[29]

@see third_party/zlib/treeconst.c

l64a

Converts 32-bit integer to base64, the posix way.

@param

long x

@return

char*

@see a64l() for inverse

@see EncodeBase64()

@see libc/str/l64a.c

labs

Returns absolute value of 𝑥.

@param

long x

@return

long

@see libc/intrin/abs.c

landlock_add_rule

Adds new rule to Landlock ruleset.

@param

int fd
enum rule_type rule_type
void* rule_attr
unsigned int flags

@return

int

@error ENOSYS if Landlock isn't supported

@error EPERM if Landlock supported but SECCOMP BPF shut it down

@error EOPNOTSUPP if Landlock supported but disabled at boot time

@error EINVAL if flags not 0, or inconsistent access in the rule, i.e. landlock_path_beneath_attr::allowed_access is not a subset of the ruleset handled accesses

@error ENOMSG empty allowed_access

@error EBADF fd is not a file descriptor for current thread, or member of rule_attr is not a file descriptor as expected

@error EBADFD fd is not a ruleset file descriptor, or a member of rule_attr is not the expected file descriptor type

@error EPERM fd has no write access to the underlying ruleset

@error EFAULT rule_attr inconsistency

@see libc/calls/landlock_add_rule.c

landlock_create_ruleset

Create new Landlock filesystem sandboxing ruleset.

You may also use this function to query the current ABI version:

landlock_create_ruleset(0, 0, LANDLOCK_CREATE_RULESET_VERSION);

@param

struct landlock_ruleset_attr* attr
unsigned long size
unsigned int flags

@return

int: close exec file descriptor for new ruleset

@error ENOSYS if not running Linux 5.13+

@error EPERM if pledge() or seccomp bpf shut it down

@error EOPNOTSUPP Landlock supported but disabled at boot

@error EINVAL unknown flags, or unknown access, or too small size

@error E2BIG attr or size inconsistencies

@error EFAULT attr or size inconsistencies

@error ENOMSG empty landlock_ruleset_attr::handled_access_fs

@see libc/calls/landlock_create_ruleset.c

landlock_restrict_self

Enforces Landlock ruleset on calling thread.

@param

int fd
unsigned int flags

@return

int

@error EOPNOTSUPP if Landlock supported but disabled at boot time

@error EINVAL if flags isn't zero

@error EBADF if fd isn't file descriptor for the current thread

@error EBADFD if fd is not a ruleset file descriptor

@error EPERM if fd has no read access to underlying ruleset, or current thread is not running with no_new_privs, or it doesn’t have CAP_SYS_ADMIN in its namespace

@error E2BIG if the maximum number of stacked rulesets is reached for current thread

@see libc/calls/landlock_restrict_self.c

lchmod

Changes mode of pathname, w/o dereferencing symlinks.

@param

const char* pathname
unsigned int mode

@return

int: 0 on success, or -1 w/ errno

@see chown() which dereferences symbolic links

@see /etc/passwd for user ids

@see /etc/group for group ids

@see libc/calls/lchmod.c

lchown

Changes owner and/or group of pathname, w/o dereferencing symlinks.

@param

const char* pathname
unsigned int uid: is user id, or -1u to not change
unsigned int gid: is group id, or -1u to not change

@return

int: 0 on success, or -1 w/ errno

@see chown() which dereferences symbolic links

@see /etc/passwd for user ids

@see /etc/group for group ids

@see libc/calls/lchown.c

lcong48

@param

unsigned short* p

@return

void

@see third_party/musl/rand48.c

ldiv

Divides integers yielding numerator and denominator.

@param

long num
long den

@return

struct retval

@see libc/fmt/ldiv.c

LengthInt64

Returns len(str(x)) where x is a signed 64-bit integer.

@param

long x

@return

unsigned int

@see libc/intrin/lengthuint64.c

LengthInt64Thousands

Returns decimal string length of int64 w/ thousands separators.

@param

long x

@return

unsigned int

@see libc/intrin/lengthuint64.c

LengthUint64

Returns len(str(x)) where x is an unsigned 64-bit integer.

@param

unsigned long x

@return

unsigned int

@see libc/intrin/lengthuint64.c

LengthUint64Thousands

Returns decimal string length of uint64 w/ thousands separators.

@param

unsigned long x

@return

unsigned int

@see libc/intrin/lengthuint64.c

lfind

@param

void* key
void* base
unsigned long* nelp
unsigned long width
int(*)() compar

@return

void*

@see third_party/musl/lsearch.c

lgamma

Returns natural logarithm of absolute value of gamma function.

@param

double x

@return

double

@see libc/tinymath/lgamma.c

lgamma_r

Returns natural logarithm of absolute value of Gamma function.

@param

double x
int* signgamp

@return

double

@see libc/tinymath/lgamma_r.c

lgammaf

@param

float x

@return

float

@see libc/tinymath/lgammaf.c

lgammaf_r

Returns natural logarithm of absolute value of Gamma function.

@param

float x
int* signgamp

@return

float

@see libc/tinymath/lgammaf_r.c

link

Creates hard filesystem link.

This allows two names to point to the same file data on disk. They can only be differentiated by examining the inode number.

@param

const char* existingpath
const char* newpath

@return

int: 0 on success, or -1 w/ errno

@asyncsignalsafe

@see libc/calls/link.c

linkat

Creates hard filesystem link.

This allows two names to point to the same file data on disk. They can only be differentiated by examining the inode number.

@param

int olddirfd
const char* oldpath
int newdirfd
const char* newpath
int flags: can have AT_EMPTY_PATH or AT_SYMLINK_NOFOLLOW

@return

int: 0 on success, or -1 w/ errno

@asyncsignalsafe

@see libc/calls/linkat.c

listen

Asks system to accept incoming connections on socket.

The socket() and bind() functions need to be called beforehand. Once this function is called, accept() is used to wait for connections. Using this on connectionless sockets will allow it to receive packets on a designated address.

@param

int fd
int backlog: <= SOMAXCONN

@return

int: 0 on success or -1 w/ errno

@see libc/sock/listen.c

localeconv

@return

struct lconv*

@see libc/str/localeconv.c

lockf

Locks file.

@param

int fd
int op
long size

@return

int

@cancelationpoint when op is F_LOCK

@see third_party/musl/lockf.c

log10f

Calculates log₁₀𝑥.

@param

float x

@return

float

@see libc/tinymath/log10f.c

logb

@param

double x

@return

double

@see libc/tinymath/logb.c

logbf

@param

float x

@return

float

@see libc/tinymath/logbf.c

logbl

@param

long double x

@return

long double

@see third_party/compiler_rt/logbl.c

longjmp

Loads previously saved processor state.

@param

rdi: points to the jmp_buf
esi: is returned by setjmp() invocation (coerced nonzero)

@noreturn

@see gclongjmp()

@see siglongjmp()

@see libc/nexgen32e/longjmp.S

_longsort

Sorting algorithm for longs that doesn't take long.

"What disorder is this? Give me my long sort!"
                          -Lord Capulet

@param

long* A
unsigned long n

@return

void

@see libc/str/longsort.c

lrand48

@return

long

@see third_party/musl/rand48.c

lrint

Rounds to integer in current rounding mode.

The floating-point exception FE_INEXACT is raised if the result is different from the input.

@param

double x

@return

long

@see libc/tinymath/lrint.c

lrintf

Rounds to integer in current rounding mode.

The floating-point exception FE_INEXACT is raised if the result is different from the input.

@param

float x

@return

long

@see libc/tinymath/lrintf.c

lrintl

Rounds to integer in current rounding mode.

The floating-point exception FE_INEXACT is raised if the result is different from the input.

@param

long double x

@return

long

@see libc/tinymath/lrintl.c

lround

Rounds 𝑥 to nearest integer, away from zero.

@param

double x

@return

long

@see libc/tinymath/lround.c

lroundf

Rounds 𝑥 to nearest integer, away from zero.

@param

float x

@return

long

@see libc/tinymath/lroundf.c

lroundl

@param

long double x

@return

long

@see libc/tinymath/lroundl.c

lsearch

@param

void* key
void* base
unsigned long* nelp
unsigned long width
int(*)() compar

@return

void*

@see third_party/musl/lsearch.c

lstat

Returns information about file, w/o traversing symlinks.

@param

const char* pathname
struct stat* st

@return

int

@asyncsignalsafe

@see libc/calls/lstat.c

lutimes

Changes file timestamps, the legacy way.

@param

const char* filename
struct timeval* tv

@return

int

@see libc/calls/lutimes.c

lz4check

@param

void* data

@return

const unsigned char*

@see libc/str/lz4check.c

lz4decode

Decompresses LZ4 file.

We assume (1) the file is mmap()'d or was copied into into memory beforehand; and (2) folks handling untrustworthy data shall place 64kb of guard pages on the ends of each buffer, see mapanon(). We don't intend to support XXHASH; we recommend folks needing checks against data corruption consider crc32c(), or gzip since it's the best at file recovery. Dictionaries are supported; by convention, they are passed in the ≤64kb bytes preceding src.

@param

void* dest
void* src

@return

void*: pointer to end of decoded data, similar to mempcpy()

@see _mapanon(), lz4check()

@see libc/str/lz4decode.c

lz4len

Returns the uncompressed content size for a compressed LZ4 block, without actually decompressing it.

@param

void* blockdata
unsigned long blocksize

@return

unsigned long

@see lz4cpy()

@see libc/str/lz4len.c

madvise

Drops hints to O/S about intended access patterns of mmap()'d memory.

@param

void* addr
unsigned long length
int advice: can be MADV_WILLNEED, MADV_SEQUENTIAL, MADV_FREE, etc.

@return

int: 0 on success, or -1 w/ errno

@raise EINVAL if advice isn't valid or supported by system

@raise EINVAL on Linux if addr/length isn't page size aligned with respect to getauxval(AT_PAGESZ)

@raise ENOMEM on Linux if addr/length overlaps unmapped regions

@see libc/sysv/consts.sh

@see fadvise()

@see libc/calls/madvise.c

__magicu_get

Precomputes magic numbers for unsigned division by constant.

The returned divisor may be passed to __magic_div() to perform unsigned integer division way faster than normal division e.g.

assert(77 / 7 == __magicu_div(77, __magicu_get(7)));

@param

unsigned int d: is intended divisor, which must not be zero

@return

struct magu: magic divisor (never zero)

@see libc/tinymath/magicu.c

major

@param

unsigned long x

@return

unsigned int

@see libc/calls/major.c

makecontext

Creates coroutine gadget, e.g.

ucontext_t uc;
getcontext(&uc);
uc.uc_link = 0;
uc.uc_stack.ss_sp = NewCosmoStack();
uc.uc_stack.ss_size = GetStackSize();
makecontext(&uc, exit, 1, 42);
setcontext(&uc);

Is equivalent to:

exit(42);

The safest way to allocate stack memory is to use NewCosmoStack() and GetStackSize(), which will mmap() a fresh region of memory per a link time configuration, mprotect() some guard pages at the bottom, poison them if ASAN is in play, and then tell the OS that it's stack memory. If that's overkill for your use case, then you could potentially pass stacks as small as 1024 bytes; however they need to come from a stack allocation Cosmo granted to your main process and threads. It needn't be aligned, since this function takes care of that automatically. The address selected shall be uc_stack.ss_ip + uc_stack.ss_size and all the action happens beneath that address.

On AMD64 and ARM64 you may pass up to six long integer args, and up to six vectors (e.g. double, floats, __m128i, uint8x16_t). Thou shall not call code created by Microsoft compilers, even though this should work perfectly fine on Windows, as it is written in the System V ABI, which specifies your parameters are always being passed in registers.

@param

struct ucontext_t* uc

stores processor state; the caller must have:

initialized it using getcontext(uc)
allocated new values for uc->uc_stack
specified a successor context in uc->uc_link

void* func

is the function to call when uc is activated; when func returns, control is passed to uc->uc_link, which if null will result in pthread_exit() being called

int argc

is effectively ignored (see notes above)

...

@return

void

@see setcontext(), getcontext(), swapcontext()

@see libc/thread/makecontext.c

makedev

@param

unsigned int x
unsigned int y

@return

unsigned long

@see libc/calls/makedev.c

makedirs

Creates directory and parent components.

This function is similar to mkdir() except it iteratively creates parent directories and it won't fail if the directory already exists.

@param

const char* path: is a UTF-8 string, preferably relative w/ forward slashes
unsigned int mode: can be, for example, 0755

@return

int: 0 on success or -1 w/ errno

@raise EEXIST if named file already exists as non-directory

@raise ENOTDIR if directory component in path existed as non-directory

@raise ENAMETOOLONG if symlink-resolved path length exceeds PATH_MAX

@raise ENAMETOOLONG if component in path exists longer than NAME_MAX

@raise EROFS if parent directory is on read-only filesystem

@raise ENOSPC if file system or parent directory is full

@raise EACCES if write permission was denied on parent directory

@raise EACCES if search permission was denied on component in path

@raise ENOENT if path is an empty string

@raise ELOOP if loop was detected resolving components of path

@asyncsignalsafe

@see libc/calls/makedirs.c

mallinfo

@param

struct mallinfo*

@return

struct mallinfo

@see libc/mem/mallinfo.c

malloc

Allocates uninitialized memory.

Returns a pointer to a newly allocated chunk of at least n bytes, or null if no space is available, in which case errno is set to ENOMEM on ANSI C systems.

If n is zero, malloc returns a minimum-sized chunk. (The minimum size is 32 bytes on 64bit systems.) It should be assumed that zero bytes are possible access, since that'll be enforced by MODE=asan.

Note that size_t is an unsigned type, so calls with arguments that would be negative if signed are interpreted as requests for huge amounts of space, which will often fail. The maximum supported value of n differs across systems, but is in all cases less than the maximum representable value of a size_t.

@param

unsigned long n

@return

void*: new memory, or NULL w/ errno

@see libc/mem/malloc.c

malloc_inspect_all

@param

void(*)() handler
void* arg

@return

void

@see libc/mem/malloc_inspect_all.c

malloc_trim

Releases freed memory back to system.

@param

unsigned long n: specifies bytes of memory to leave available

@return

int: 1 if it actually released any memory, else 0

@see libc/mem/malloc_trim.c

malloc_usable_size

Returns the number of bytes you can actually use in an allocated chunk, which may be more than you requested (although often not) due to alignment and minimum size constraints.

You can use this many bytes without worrying about overwriting other allocated objects. This is not a particularly great programming practice. malloc_usable_size can be more useful in debugging and assertions, for example:

p = malloc(n)
assert(malloc_usable_size(p) >= 256)

@param

void* p: is address of allocation

@return

unsigned long: total number of bytes

@see dlmalloc_usable_size()

@see libc/mem/malloc_usable_size.c

mallopt

@param

int param_number
int value

@return

int

@see libc/mem/mallopt.c

mblen

@param

const char* s
unsigned long n

@return

int

@see libc/str/mblen.c

mbrlen

@param

const char* s
unsigned long n
unsigned int* t

@return

unsigned long

@see libc/str/mbrlen.c

mbrtoc16

@param

unsigned short* pc16
const char* s
unsigned long n
unsigned int* ps

@return

unsigned long

@see libc/str/mbrtoc16.c

mbrtoc32

@param

unsigned int* pc32
const char* s
unsigned long n
unsigned int* ps

@return

unsigned long

@see libc/str/mbrtoc32.c

mbrtowc

@param

int* wc
const char* src
unsigned long n
unsigned int* st

@return

unsigned long

@see libc/str/mbrtowc.c

mbsinit

@param

const unsigned int* t

@return

int

@see libc/str/mbsinit.c

mbsnrtowcs

@param

int* wcs
const char** src
unsigned long n
unsigned long wn
unsigned int* st

@return

unsigned long

@see libc/str/mbsnrtowcs.c

mbsrtowcs

@param

int* ws
const char** src
unsigned long wn
unsigned int* st

@return

unsigned long

@see libc/str/mbsrtowcs.c

mbstowcs

@param

int* pwc
const char* s
unsigned long wn

@return

unsigned long

@see libc/str/mbstowcs.c

mbtowc

@param

int* wc
const char* src
unsigned long n

@return

int

@see libc/str/mbtowc.c

MeasureEntropy

Returns Shannon entropy of array.

This gives you an idea of the density of information. Cryptographic random should be in the ballpark of 7.9 whereas plaintext will be more like 4.5.

@param

const char* p: is treated as binary octets
unsigned long n: should be at least 1000

@return

double: number between 0 and 8

@see libc/tinymath/measureentropy.c

memalign

Allocates aligned memory.

Returns a pointer to a newly allocated chunk of n bytes, aligned in accord with the alignment argument. The alignment argument shall be rounded up to the nearest two power and higher 2 powers may be used if the allocator imposes a minimum alignment requirement.

@param

unsigned long align: is alignment in bytes, coerced to 1+ w/ 2-power roundup
unsigned long bytes: is number of bytes needed, coerced to 1+

@return

void*: rax is memory address, or NULL w/ errno

@see valloc(), pvalloc()

@see libc/mem/memalign.c

memcasecmp

Compares memory case-insensitively.

memcasecmp n=0                     992 picoseconds
memcasecmp n=1                       1 ns/byte            590 mb/s
memcasecmp n=2                       1 ns/byte            843 mb/s
memcasecmp n=3                       1 ns/byte            885 mb/s
memcasecmp n=4                       1 ns/byte            843 mb/s
memcasecmp n=5                       1 ns/byte            820 mb/s
memcasecmp n=6                       1 ns/byte            770 mb/s
memcasecmp n=7                       1 ns/byte            765 mb/s
memcasecmp n=8                     206 ps/byte          4,724 mb/s
memcasecmp n=9                     220 ps/byte          4,428 mb/s
memcasecmp n=15                    617 ps/byte          1,581 mb/s
memcasecmp n=16                    124 ps/byte          7,873 mb/s
memcasecmp n=17                    155 ps/byte          6,274 mb/s
memcasecmp n=31                    341 ps/byte          2,860 mb/s
memcasecmp n=32                     82 ps/byte         11,810 mb/s
memcasecmp n=33                    100 ps/byte          9,743 mb/s
memcasecmp n=80                     53 ps/byte         18,169 mb/s
memcasecmp n=128                    49 ps/byte         19,890 mb/s
memcasecmp n=256                    45 ps/byte         21,595 mb/s
memcasecmp n=16384                  42 ps/byte         22,721 mb/s
memcasecmp n=32768                  40 ps/byte         24,266 mb/s
memcasecmp n=131072                 40 ps/byte         24,337 mb/s

@param

void* p
void* q
unsigned long n

@return

int: is <0, 0, or >0 based on uint8_t comparison

@see libc/str/memcasecmp.c

memccpy

Copies at most N bytes from SRC to DST until 𝑐 is encountered.

This is little-known C Standard Library approach, dating back to the Fourth Edition of System Five, for copying a C strings to fixed-width buffers, with added generality.

For example, strictly:

char buf[16];
CHECK_NOTNULL(memccpy(buf, s, '\0', sizeof(buf)));

Or unstrictly:

if (!memccpy(buf, s, '\0', sizeof(buf))) strcpy(buf, "?");

Are usually more sensible than the following:

char cstrbuf[16];
snprintf(cstrbuf, sizeof(cstrbuf), "%s", CSTR);

@param

void* dst
void* src
int c: is search character and is masked with 255
unsigned long n

@return

void*: DST + idx(c) + 1, or NULL if 𝑐 ∉ 𝑠₀․․ₙ₋₁

@note DST and SRC can't overlap

@asyncsignalsafe

@see libc/str/memccpy.c

memchr

Returns pointer to first instance of character.

@param

void* s: is memory to search
int c: is search byte which is masked with 255
unsigned long n: is byte length of p

@return

void*: is pointer to first instance of c or NULL if not found

@asyncsignalsafe

@see libc/intrin/memchr.c

memchr16

Returns pointer to first instance of character in range.

@param

void* s
int c
unsigned long n

@return

void*

@see libc/str/memchr16.c

memcmp

Compares memory byte by byte.

memcmp n=0                           2 nanoseconds
memcmp n=1                           2 ns/byte            357 mb/s
memcmp n=2                           1 ns/byte            530 mb/s
memcmp n=3                           1 ns/byte            631 mb/s
𝗺𝗲𝗺𝗰𝗺𝗽 n=4                           1 ns/byte            849 mb/s
memcmp n=5                         816 ps/byte          1,195 mb/s
memcmp n=6                         888 ps/byte          1,098 mb/s
memcmp n=7                         829 ps/byte          1,176 mb/s
𝗺𝗲𝗺𝗰𝗺𝗽 n=8                         773 ps/byte          1,261 mb/s
memcmp n=9                         629 ps/byte          1,551 mb/s
memcmp n=15                        540 ps/byte          1,805 mb/s
𝗺𝗲𝗺𝗰𝗺𝗽 n=16                        211 ps/byte          4,623 mb/s
memcmp n=17                        268 ps/byte          3,633 mb/s
memcmp n=31                        277 ps/byte          3,524 mb/s
memcmp n=32                        153 ps/byte          6,351 mb/s
memcmp n=33                        179 ps/byte          5,431 mb/s
memcmp n=79                        148 ps/byte          6,576 mb/s
𝗺𝗲𝗺𝗰𝗺𝗽 n=80                         81 ps/byte             11 GB/s
memcmp n=128                        76 ps/byte             12 GB/s
memcmp n=256                        60 ps/byte             15 GB/s
memcmp n=16384                      51 ps/byte             18 GB/s
memcmp n=32768                      51 ps/byte             18 GB/s
memcmp n=131072                     52 ps/byte             18 GB/s

@param

void* a
void* b
unsigned long n

@return

int: an integer that's (1) equal to zero if a is equal to b, (2) less than zero if a is less than b, or (3) greater than zero if a is greater than b

@asyncsignalsafe

@see libc/intrin/memcmp.c

memfd_create

Creates anonymous file.

@param

const char* name: is used for the /proc/self/fd/FD symlink
unsigned int flags: can have MFD_CLOEXEC, MFD_ALLOW_SEALING

@return

int

@raise ENOSYS if not RHEL8+

@see libc/calls/memfd_create.c

memfrob

Memfrob implements a crypto algorithm proven to be unbreakable, without meeting its requirements concerning secrecy or length.

@param

void* buf
unsigned long size

@return

void*

@see libc/str/memfrob.c

_meminfo

Prints memory mappings.

@param

int fd

@return

void

@see libc/log/meminfo.c

memmem

Searches for fixed-length substring in memory region.

@param

void* haystack: is the region of memory to be searched
unsigned long haystacklen: is its character count
void* needle: contains the memory for which we're searching
unsigned long needlelen: is its character count

@return

void*: pointer to first result or NULL if not found

@see libc/str/memmem.c

memmove

Copies memory.

memmove n=0                        661 picoseconds
memmove n=1                        661 ps/byte          1,476 mb/s
memmove n=2                        330 ps/byte          2,952 mb/s
memmove n=3                        330 ps/byte          2,952 mb/s
memmove n=4                        165 ps/byte          5,904 mb/s
memmove n=7                        141 ps/byte          6,888 mb/s
memmove n=8                         82 ps/byte             11 GB/s
memmove n=15                        44 ps/byte             21 GB/s
memmove n=16                        41 ps/byte             23 GB/s
memmove n=31                        32 ps/byte             29 GB/s
memmove n=32                        31 ps/byte             30 GB/s
memmove n=63                        21 ps/byte             45 GB/s
memmove n=64                        15 ps/byte             61 GB/s
memmove n=127                       13 ps/byte             73 GB/s
memmove n=128                       31 ps/byte             30 GB/s
memmove n=255                       20 ps/byte             45 GB/s
memmove n=256                       19 ps/byte             49 GB/s
memmove n=511                       16 ps/byte             56 GB/s
memmove n=512                       17 ps/byte             54 GB/s
memmove n=1023                      18 ps/byte             52 GB/s
memmove n=1024                      13 ps/byte             72 GB/s
memmove n=2047                       9 ps/byte             96 GB/s
memmove n=2048                       9 ps/byte             98 GB/s
memmove n=4095                       8 ps/byte            112 GB/s
memmove n=4096                       8 ps/byte            109 GB/s
memmove n=8191                       7 ps/byte            124 GB/s
memmove n=8192                       7 ps/byte            125 GB/s
memmove n=16383                      7 ps/byte            134 GB/s
memmove n=16384                      7 ps/byte            134 GB/s
memmove n=32767                     13 ps/byte             72 GB/s
memmove n=32768                     13 ps/byte             72 GB/s
memmove n=65535                     13 ps/byte             68 GB/s
memmove n=65536                     14 ps/byte             67 GB/s
memmove n=131071                    14 ps/byte             65 GB/s
memmove n=131072                    14 ps/byte             64 GB/s
memmove n=262143                    15 ps/byte             63 GB/s
memmove n=262144                    15 ps/byte             63 GB/s
memmove n=524287                    15 ps/byte             61 GB/s
memmove n=524288                    15 ps/byte             61 GB/s
memmove n=1048575                   15 ps/byte             61 GB/s
memmove n=1048576                   15 ps/byte             61 GB/s
memmove n=2097151                   19 ps/byte             48 GB/s
memmove n=2097152                   27 ps/byte             35 GB/s
memmove n=4194303                   28 ps/byte             33 GB/s
memmove n=4194304                   28 ps/byte             33 GB/s
memmove n=8388607                   28 ps/byte             33 GB/s
memmove n=8388608                   28 ps/byte             33 GB/s

DST and SRC may overlap.

@param

void* dst: is destination
void* src: is memory to copy
unsigned long n: is number of bytes to copy

@return

void*: dst

@asyncsignalsafe

@see libc/intrin/memmove.c

mempcpy

@param

void* dst
void* src
unsigned long n

@return

void*

@see libc/intrin/mempcpy.c

memrchr

Returns pointer to first instance of character.

@param

void* s: is memory to search
int c: is search byte which is masked with 255
unsigned long n: is byte length of p

@return

void*: is pointer to first instance of c or NULL if not found

@asyncsignalsafe

@see libc/intrin/memrchr.c

memrchr16

Returns pointer to first instance of character.

@param

void* s: is memory to search
int c: is search byte which is masked with 65535
unsigned long n: is number of char16_t elements in s

@return

void*: is pointer to first instance of c or NULL if not found

@asyncsignalsafe

@see libc/str/memrchr16.c

memset

Sets memory.

memset n=0                         992 picoseconds
memset n=1                         992 ps/byte            984 mb/s
memset n=2                         330 ps/byte          2,952 mb/s
memset n=3                         330 ps/byte          2,952 mb/s
memset n=4                         165 ps/byte          5,904 mb/s
memset n=7                          94 ps/byte         10,333 mb/s
memset n=8                         124 ps/byte          7,872 mb/s
memset n=15                         66 ps/byte         14,761 mb/s
memset n=16                         62 ps/byte         15,745 mb/s
memset n=31                         32 ps/byte         30,506 mb/s
memset n=32                         20 ps/byte         47,236 mb/s
memset n=63                         26 ps/byte         37,198 mb/s
memset n=64                         20 ps/byte         47,236 mb/s
memset n=127                        23 ps/byte         41,660 mb/s
memset n=128                        12 ps/byte         75,578 mb/s
memset n=255                        18 ps/byte         53,773 mb/s
memset n=256                        12 ps/byte         75,578 mb/s
memset n=511                        17 ps/byte         55,874 mb/s
memset n=512                        12 ps/byte         75,578 mb/s
memset n=1023                       16 ps/byte         58,080 mb/s
memset n=1024                       11 ps/byte         86,375 mb/s
memset n=2047                        9 ps/byte            101 gb/s
memset n=2048                        8 ps/byte            107 gb/s
memset n=4095                        8 ps/byte            113 gb/s
memset n=4096                        8 ps/byte            114 gb/s
memset n=8191                        7 ps/byte            126 gb/s
memset n=8192                        7 ps/byte            126 gb/s
memset n=16383                       7 ps/byte            133 gb/s
memset n=16384                       7 ps/byte            131 gb/s
memset n=32767                      14 ps/byte         69,246 mb/s
memset n=32768                       6 ps/byte            138 gb/s
memset n=65535                      15 ps/byte         62,756 mb/s
memset n=65536                      15 ps/byte         62,982 mb/s
memset n=131071                     18 ps/byte         52,834 mb/s
memset n=131072                     15 ps/byte         62,023 mb/s
memset n=262143                     15 ps/byte         61,169 mb/s
memset n=262144                     16 ps/byte         61,011 mb/s
memset n=524287                     16 ps/byte         60,633 mb/s
memset n=524288                     16 ps/byte         57,902 mb/s
memset n=1048575                    16 ps/byte         60,405 mb/s
memset n=1048576                    16 ps/byte         58,754 mb/s
memset n=2097151                    16 ps/byte         59,329 mb/s
memset n=2097152                    16 ps/byte         58,729 mb/s
memset n=4194303                    16 ps/byte         59,329 mb/s
memset n=4194304                    16 ps/byte         59,262 mb/s
memset n=8388607                    16 ps/byte         59,530 mb/s
memset n=8388608                    16 ps/byte         60,205 mb/s

@param

void* p: is memory address
int c: is masked with 255 and used as repeated byte
unsigned long n: is byte length

@return

void*: p

@asyncsignalsafe

@see libc/intrin/memset.c

memset16

Sets wide memory.

@param

unsigned short* p
unsigned short c
unsigned long n

@return

unsigned short*

@asyncsignalsafe

@see libc/str/memset16.c

mergesort

Sorts array.

@param

void* base
unsigned long nmemb: is item count
unsigned long size: is item width
int(*)() cmp: is a callback returning <0, 0, or >0

@return

int

@see mergesort_r()

@see heapsort()

@see qsort()

@see libc/mem/mergesort.c

mergesort_r

Sorts array w/ optional callback argument.

@param

void* base: is base of array
unsigned long nmemb: is item count
unsigned long size: is item width
int(*)() cmp: is a callback returning <0, 0, or >0
void* z: will optionally be passed as the third argument to cmp

@return

int

@see mergesort()

@see libc/mem/mergesort.c

mincore

Tells you which pages are resident in memory.

@param

void* addr
unsigned long length
unsigned char* vec

@return

int

@see libc/calls/mincore.c

minor

@param

unsigned long x

@return

unsigned int

@see libc/calls/minor.c

mkdir

Creates directory a.k.a. folder.

mkdir o               →  0
mkdir o/yo/yo/yo      → -1 w/ ENOENT
if o/yo is file       → -1 w/ ENOTDIR
if o/yo/yo/yo is dir  → -1 w/ EEXIST
if o/yo/yo/yo is file → -1 w/ EEXIST

@param

const char* path: is a UTF-8 string, preferably relative w/ forward slashes
unsigned int mode: can be, for example, 0755

@return

int: 0 on success or -1 w/ errno

@raise EEXIST if named file already exists

@raise ENOTDIR if directory component in path existed as non-directory

@raise ENAMETOOLONG if symlink-resolved path length exceeds PATH_MAX

@raise ENAMETOOLONG if component in path exists longer than NAME_MAX

@raise EROFS if parent directory is on read-only filesystem

@raise ENOSPC if file system or parent directory is full

@raise EACCES if write permission was denied on parent directory

@raise EACCES if search permission was denied on component in path

@raise ENOENT if a component within path didn't exist

@raise ENOENT if path is an empty string

@raise ELOOP if loop was detected resolving components of path

@see makedirs() which is higher-level

@see mkdirat() for modern call

@asyncsignalsafe

@see libc/calls/mkdir.c

mkdirat

Creates directory a.k.a. folder.

@param

int dirfd: is normally AT_FDCWD but if it's an open directory and path is relative, then path becomes relative to dirfd
const char* path: is a UTF-8 string, preferably relative w/ forward slashes
unsigned int mode: is permissions bits, which is usually 0755

@return

int: 0 on success, or -1 w/ errno

@raise EEXIST if named file already exists

@raise EBADF if path is relative and dirfd isn't AT_FDCWD or valid

@raise ENOTDIR if directory component in path existed as non-directory

@raise ENAMETOOLONG if symlink-resolved path length exceeds PATH_MAX

@raise ENAMETOOLONG if component in path exists longer than NAME_MAX

@raise EROFS if parent directory is on read-only filesystem

@raise ENOSPC if file system or parent directory is full

@raise EACCES if write permission was denied on parent directory

@raise EACCES if search permission was denied on component in path

@raise ENOENT if a component within path didn't exist

@raise ENOENT if path is an empty string

@raise ELOOP if loop was detected resolving components of path

@asyncsignalsafe

@see makedirs()

@see libc/calls/mkdirat.c

mkdtemp

Creates temporary directory, e.g.

char path[] = "/tmp/foo.XXXXXX";
mkdtemp(path);
rmdir(path);

@param

char* template: must end with XXXXXX which will be replaced with random text on success (and not modified on error)

@return

char*: pointer to template on success, or NULL w/ errno

@raise EINVAL if template didn't end with XXXXXX

@cancelationpoint

@see libc/calls/mkdtemp.c

mknod

Creates filesystem inode.

@param

const char* path
unsigned int mode: is octal mode, e.g. 0600; needs to be or'd with one of: S_IFDIR: directory S_IFIFO: named pipe S_IFREG: regular file S_IFSOCK: named socket S_IFBLK: block device (root has authorization) S_IFCHR: character device (root has authorization)
unsigned long dev: it's complicated

@return

int: 0 on success, or -1 w/ errno

@asyncsignalsafe

@see libc/calls/mknod.c

mkostemp

Creates temporary file name and file descriptor, e.g.

char path[] = "/tmp/foo.XXXXXX";
int fd = mkostemp(path, O_CLOEXEC);
printf("%s is opened as %d\n", path, fd);

@param

char* template: is mutated to replace last six X's with rng
unsigned int flags

@return

int: open file descriptor r + w exclusive or -1 w/ errno

@raise EINVAL if template didn't end with XXXXXX

@see openatemp() for one temp roller to rule them all

@see mkostemps() if you need a suffix

@see mkstemp() if you don't need flags

@see mktemp() if you don't need an fd

@see tmpfd() if you don't need a path

@cancelationpoint

@see libc/calls/mkostemp.c

mkostemps

Creates temporary file name and file descriptor, e.g.

char path[] = "/tmp/foo.XXXXXX";
int fd = mkostemp(path, O_CLOEXEC);
printf("%s is opened as %d\n", path, fd);

@param

char* template: is mutated to replace last six X's with rng
int suffixlen
unsigned int flags

@return

int: open file descriptor r + w exclusive or -1 w/ errno

@raise EINVAL if template didn't end with XXXXXX

@see openatemp() for one temp roller to rule them all

@see mkstemp() if you don't need suffix/flags

@see mkstemps() if you don't need flags

@see mkostemp() if you don't need suffix

@see mktemp() if you don't need an fd

@see tmpfd() if you don't need a path

@cancelationpoint

@see libc/calls/mkostemps.c

mkstemp

Creates temporary file name and file descriptor, e.g.

char path[] = "/tmp/foo.XXXXXX";
int fd = mkstemp(path);
printf("%s is opened as %d\n", path, fd);

@param

char* template: is mutated to replace last six X's with rng

@return

int: open file descriptor r + w exclusive or -1 w/ errno

@raise EINVAL if template didn't end with XXXXXX

@see openatemp() for one temp roller to rule them all

@see mkostemp() if you you need a O_CLOEXEC, O_APPEND, etc.

@see mkstemps() if you you need a suffix

@see mktemp() if you don't need an fd

@see tmpfd() if you don't need a path

@cancelationpoint

@see libc/calls/mkstemp.c

mkstemps

Creates temporary file name and file descriptor, e.g.

char path[] = "/tmp/foo.XXXXXX.txt";
int fd = mkstemps(path, 4);
printf("%s is opened as %d\n", path, fd);

@param

char* template: is mutated to replace last six X's with rng
int suffixlen: may be nonzero to permit characters after the "XXXXXX"

@return

int: open file descriptor r + w exclusive or -1 w/ errno

@raise EINVAL if template (less the suffixlen region) didn't end with the string "XXXXXXX"

@see mkostemp() if you you need a O_CLOEXEC, O_APPEND, etc.

@see openatemp() for one temp roller to rule them all

@see mkstemp() if you don't need suffixlen

@see mktemp() if you don't need an fd

@see tmpfd() if you don't need a path

@cancelationpoint

@see libc/calls/mkstemps.c

_mktls

Allocates thread-local storage memory for new thread.

@param

struct CosmoTib** out_tib

@return

char*: buffer that must be released with free()

@see libc/thread/mktls.c

modf

Returns fractional part of 𝑥.

@param

double x
double* iptr

@return

double

@see libc/tinymath/modf.c

modff

@param

float x
float* iptr

@return

float

@see libc/tinymath/modff.c

mount

Mounts file system.

The following flags may be specified:

MS_RDONLY (mount read-only)
MS_NOSUID (don't honor S_ISUID bit)
MS_NODEV (disallow special files)
MS_NOEXEC (disallow program execution)
MS_SYNCHRONOUS (writes are synced at once)
MS_NOATIME (do not update access times)
MS_REMOUNT (tune existing mounting)

The following flags may also be used, but could be set to zero at runtime if the underlying kernel doesn't support them.

MNT_ASYNC (xnu, freebsd, openbsd, netbsd)
MNT_RELOAD (xnu, freebsd, openbsd, netbsd)
MS_STRICTATIME (linux, xnu)
MS_RELATIME (linux, netbsd)
MNT_SNAPSHOT (xnu, freebsd)
MS_MANDLOCK (linux)
MS_DIRSYNC (linux)
MS_NODIRATIME (linux)
MS_BIND (linux)
MS_MOVE (linux)
MS_REC (linux)
MS_SILENT (linux)
MS_POSIXACL (linux)
MS_UNBINDABLE (linux)
MS_PRIVATE (linux)
MS_SLAVE (linux)
MS_SHARED (linux)
MS_KERNMOUNT (linux)
MS_I_VERSION (linux)
MS_LAZYTIME (linux)
MS_ACTIVE (linux)
MS_NOUSER (linux)
MS_RMT_MASK (linux)
MNT_SUIDDIR (freebsd)
MNT_NOCLUSTERR (freebsd)
MNT_NOCLUSTERW (freebsd)

Some example values for the type parameter:

"nfs"
"vfat"
"tmpfs"
"iso8601"

@param

const char* source
const char* target
const char* type
unsigned long flags
void* data

@return

int

@see libc/calls/mount.c

mprotect

Modifies restrictions on virtual memory address range.

@param

void* addr: needs to be 4kb aligned
unsigned long size
int prot: can have PROT_{NONE,READ,WRITE,EXEC,GROWSDOWN,GROWSUP}

@return

int: 0 on success, or -1 w/ errno

@see mmap()

@see libc/runtime/mprotect.c

mrand48

@return

long

@see third_party/musl/rand48.c

msync

Synchronize memory mapping changes to disk.

Without this, there's no guarantee memory is written back to disk. Particularly on RHEL5, OpenBSD, and Windows NT.

@param

void* addr: needs to be 4096-byte page aligned
unsigned long size
int flags: needs MS_ASYNC or MS_SYNC and can have MS_INVALIDATE

@return

int: 0 on success or -1 w/ errno

@raise ECANCELED if thread was cancelled in masked mode

@raise EINTR if we needed to block and a signal was delivered instead

@raise EINVAL if MS_SYNC and MS_ASYNC were both specified

@raise EINVAL if unknown flags were passed

@cancelationpoint

@see libc/runtime/msync.c

_mt19937

Generates random integer on [0, 2^64)-interval.

This uses the Mersenne Twister pseudorandom number generator.

@return

unsigned long

@see smt19937(), Smt19937()

@see libc/stdio/mt19937.c

mt19937_notice

@type

const char[76]

@see libc/stdio/mt19937.c

Mul4x4Adx

Computes 512-bit product of 256-bit and 256-bit numbers.

Instructions: 88 Total Cycles: 36 Total uOps: 120 uOps Per Cycle: 3.33 IPC: 2.44 Block RThroughput: 20.0

@param

rdi: receives 8 quadword result
rsi: is left hand side which must have 4 quadwords
rdx: is right hand side which must have 4 quadwords

@return

@note words are host endian while array is little endian

@mayalias

@see libc/nexgen32e/mul4x4adx.S

Mul6x6Adx

Computes 768-bit product of 384-bit and 384-bit numbers.

Instructions: 152 Total Cycles: 65 Total uOps: 260 uOps Per Cycle: 4.00 IPC: 2.34 Block RThroughput: 43.3

@param

rdi: receives 8 quadword result
rsi: is left hand side which must have 4 quadwords
rdx: is right hand side which must have 4 quadwords

@return

@note words are host endian while array is little endian

@mayalias

@see libc/nexgen32e/mul6x6adx.S

Mul8x8Adx

Computes 1024-bit product of 512-bit and 512-bit numbers.

Instructions: 260 Total Cycles: 98 Total uOps: 452 uOps Per Cycle: 4.61 IPC: 2.65 Block RThroughput: 75.3

@param

rdi: receives 16 quadword result
rsi: is left hand side which must have 8 quadwords
rdx: is right hand side which must have 8 quadwords

@return

@note words are host endian while array is little endian

@mayalias

@see libc/nexgen32e/mul8x8adx.S

musl_libc_notice

@type

const char[67]

@see libc/intrin/musl.c

nan

@param

const char* s

@return

double

@see libc/tinymath/nan.c

nanf

@param

const char* s

@return

float

@see libc/tinymath/nanf.c

nanl

@param

const char* s

@return

long double

@see libc/tinymath/nanl.c

nanosleep

Sleeps for relative amount of time.

@param

struct timespec* req: is the duration of time we should sleep
struct timespec* rem: if non-null will be updated with the remainder of unslept time when -1 w/ EINTR is returned otherwise rem is undefined

@return

int: 0 on success, or -1 w/ errno

@raise EINVAL if req->tv_nsec ∉ [0,1000000000)

@raise ECANCELED if thread was cancelled in masked mode

@raise EINTR if a signal was delivered and rem is updated

@raise EFAULT if req is NULL or req / rem is a bad pointer

@raise ENOSYS on bare metal

@see clock_nanosleep()

@cancelationpoint

@norestart

@see libc/calls/nanosleep.c

nearbyint

Rounds to nearest integer.

@param

double x

@return

double

@see libc/tinymath/nearbyint.c

nearbyintf

Rounds to nearest integer.

@param

float x

@return

float

@see libc/tinymath/nearbyintf.c

nearbyintl

Rounds to nearest integer.

@param

long double x

@return

long double

@see libc/tinymath/nearbyintl.c

newlocale

@param

int catmask
const char* locale
struct __locale_struct* base

@return

struct __locale_struct*

@see libc/str/newlocale.c

nextafter

@param

double x
double y

@return

double

@see libc/tinymath/nextafter.c

nextafterf

@param

float x
float y

@return

float

@see libc/tinymath/nextafterf.c

nextafterl

@param

long double x
long double y

@return

long double

@see libc/tinymath/nextafterl.c

nexttoward

@param

double x
long double y

@return

double

@see libc/tinymath/nexttoward.c

nexttowardf

@param

float x
long double y

@return

float

@see libc/tinymath/nexttowardf.c

nexttowardl

@param

long double x
long double y

@return

long double

@see libc/tinymath/nexttowardl.c

nftw

Walks file tree.

@param

const char* dirpath
int(*)() fn
int fd_limit
int flags

@return

int: 0 on success, -1 on error, or non-zero fn result

@see examples/walk.c for example

@threadsafe

@see libc/stdio/nftw.c

nice

Changes process priority.

@param

int delta: is added to current priority w/ clamping

@return

int: new priority, or -1 w/ errno

@see Linux claims ioprio_set() is tuned automatically by this

@see libc/proc/nice.c

nl_langinfo

@param

int item

@return

char*

@see libc/str/langinfo.c

nl_langinfo_l

@param

int item
struct __locale_struct* loc

@return

char*

@see libc/str/langinfo.c

__nosync

Tunes sync system call availability.

If this value is set to 0x5453455454534146, then the system calls sync(), fsync(), and fdatasync() system calls will do nothing and return success. This is intended to be used for things like making things like Python unit tests go faster because fsync is extremely slow and using tmpfs requires root privileges.

@type

unsigned long

@see libc/calls/nosync.c

nrand48

@param

unsigned short* s

@return

long

@see third_party/musl/rand48.c

ns_get16

@param

const unsigned char* cp

@return

unsigned int

@see third_party/musl/ns_parse.c

ns_get32

@param

const unsigned char* cp

@return

unsigned long

@see third_party/musl/ns_parse.c

ns_initparse

@param

const unsigned char* msg
int msglen
struct ns_msg* handle

@return

int

@see third_party/musl/ns_parse.c

ns_name_uncompress

@param

const unsigned char* msg
const unsigned char* eom
const unsigned char* src
char* dst
unsigned long dstsiz

@return

int

@see third_party/musl/ns_parse.c

ns_parserr

@param

struct ns_msg* handle
enum section section
int rrnum
struct ns_rr* rr

@return

int

@see third_party/musl/ns_parse.c

ns_put16

@param

unsigned int s
unsigned char* cp

@return

void

@see third_party/musl/ns_parse.c

ns_put32

@param

unsigned long l
unsigned char* cp

@return

void

@see third_party/musl/ns_parse.c

ns_skiprr

@param

const unsigned char* ptr
const unsigned char* eom
enum section section
int count

@return

int

@see third_party/musl/ns_parse.c

nsync_notice

@type

const char[82]

@see third_party/nsync/notice.c

nsync_run_once

@param

_Atomic unsigned int* once
void(*)() f

@return

void

@see third_party/nsync/mem/nsync_once.c

nsync_run_once_arg

@param

_Atomic unsigned int* once
void(*)() farg
void* arg

@return

void

@see third_party/nsync/mem/nsync_once.c

nsync_run_once_arg_spin

@param

_Atomic unsigned int* once
void(*)() farg
void* arg

@return

void

@see third_party/nsync/mem/nsync_once.c

nsync_run_once_spin

@param

_Atomic unsigned int* once
void(*)() f

@return

void

@see third_party/nsync/mem/nsync_once.c

__nt2sysv

Translates function call from code built w/ MS-style compiler.

This wraps WinMain() and callback functions passed to Win32 API. Please note an intermediary jump slot is needed to set %rax.

@param

%rax: is function address

@return

: %rax,%xmm0

@note slower than __sysv2nt

@see NT2SYSV() macro

@see libc/nexgen32e/nt2sysv.S

__on_arithmetic_overflow

Arithmetic overflow handler.

This function is provided weakly, so that programs which depend on this library may define it themselves. This default implementation will print a message to standard error and raise SIGTRAP. A custom implementation may return from this function, in which case the op shall have -fwrapv i.e. signed two's complement behavior.

@return

void

@see -ftrapv

@see libc/intrin/onarithmeticoverflow.c

open

Opens file.

This is equivalent to saying:

int fd = openat(AT_FDCWD, file, flags, ...);

@param

const char* file: specifies filesystem path to open
int flags
...

@return

int: file descriptor, or -1 w/ errno

@see openat() for further documentation

@cancelationpoint

@asyncsignalsafe

@restartable

@vforksafe

@see libc/calls/open.c

openatemp

Opens unique temporary file with maximum generality.

This function is similar to mkstemp() in that it does two things:

Generate a unique filename by mutating template
Return a newly opened file descriptor to the name

Exclusive secure access is assured even if /tmp is being used on a UNIX system like Super Dimensional Fortress or CPanel where multiple hostile adverserial users may exist on a single multi-tenant system.

The substring XXXXXX is replaced with 30 bits of base32 entropy and a hundred retries are attempted in the event of collisions. The XXXXXXX pattern must be present at the end of the supplied template string.

If the generated filename needs to have a file extension (rather than ending with random junk) then this API has the helpful suffixlen to specify exactly how long that suffix in the template actually is. For example if the template is "/tmp/notes.XXXXXX.txt" then suffixlen should be 4.

The flags O_RDWR | O_CREAT | O_EXCL are always set and don't need to be specified by the caller. It's a good idea to pass O_CLOEXEC and some applications may want O_APPEND. Cosmopolitan also offers O_UNLINK which will ensure the created file will delete itself on close similar to calling unlink() after this function on template which is mutated on success, except O_UNLINK will work right when running on Windows and it's polyfilled automatically on UNIX.

The mode parameter should usually be 0600 to ensure owner-only read/write access. However it may be useful to set this to 0700 when creating executable files. Please note that sometimes /tmp is mounted by system administrators as noexec. It's also permissible to pass 0 here, since the 0600 bits are always set implicitly.

### Examples

Here's an example of how to replicate the functionality of tmpfile() which creates an unnamed temporary file as an stdio handle, which is guaranteed to either not have a name (unlinked on UNIX), or shall be deleted once closed (will perform kNtFileFlagDeleteOnClose on WIN32)

char path[] = "/tmp/XXXXXX";
int fd = openatemp(AT_FDCWD, path, 0, O_UNLINK, 0);
FILE *tmp = fdopen(fd, "w+");

Here's an example of how to do mktemp() does, where a temporary file name is generated with pretty good POSIX and security best practices

char path[PATH_MAX+1];
const char *tmpdir = getenv("TMPDIR");
strlcpy(path, tmpdir ? tmpdir : "/tmp", sizeof(path));
strlcat(path, "/notes.XXXXXX.txt", sizeof(path));
close(openatemp(AT_FDCWD, path, 4, O_UNLINK, 0));
printf("you can use %s to store your notes\n", path);

@param

int dirfd: is open directory file descriptor, which is ignored if template is an absolute path; or AT_FDCWD to specify getcwd
char* template: is a pathname relative to current directory by default, that needs to have "XXXXXX" at the end of the string; this memory must be mutable and should be owned by the calling thread; it will be modified (only on success) to return the generated filename
int suffixlen: may be nonzero to permit characters after the "XXXXXX"
int flags: could have O_APPEND, O_CLOEXEC, O_UNLINK, O_SYNC, etc.
int mode: is conventionally 0600, for owner-only non-exec access

@return

int: exclusive open file descriptor for file at the generated path stored to template, or -1 w/ errno

@raise EINVAL if template (less the suffixlen region) didn't end with the string "XXXXXXX"

@raise EINVAL if suffixlen was negative or too large

@cancelationpoint

@see libc/calls/openatemp.c

openbsd_libm_notice

@type

const char[87]

@see libc/intrin/folibm.c

openbsd_sorting_notice

@type

const char[85]

@see libc/mem/opensort.c

openbsd_strings_notice

@type

const char[86]

@see libc/str/todd.c

openpty

Opens new pseudo teletypewriter.

@param

int* mfd: receives controlling tty rw fd on success
int* sfd: receives subordinate tty rw fd on success
char* name
struct linux* tio: may be passed to tune a century of legacy behaviors
struct winsize* wsz: may be passed to set terminal display dimensions

@return

int: 0 on success, or -1 w/ errno

@params flags is usually O_RDWR|O_NOCTTY

@see libc/calls/openpty.c

optarg

@type

char*

@see third_party/getopt/long.c

opterr

@type

int

@see third_party/getopt/long.c

optind

@type

int

@see third_party/getopt/long.c

optopt

@type

int

@see third_party/getopt/long.c

optreset

@type

int

@see third_party/getopt/long.c

packsswb

Casts shorts to signed chars w/ saturation.

𝑎 ← {CLAMP[𝑏ᵢ]|𝑖∈[0,4)} ║ {CLAMP[𝑐ᵢ]|𝑖∈[4,8)}

@param

char* a
const short* b
const short* c

@return

void

@see packuswb()

@mayalias

@see libc/intrin/packsswb.c

packuswb

Casts shorts to unsigned chars w/ saturation.

𝑎 ← {CLAMP[𝑏ᵢ]|𝑖∈[0,4)} ║ {CLAMP[𝑐ᵢ]|𝑖∈[4,8)}

@param

unsigned char* a
const short* b
const short* c

@return

void

@see packsswb()

@mayalias

@see libc/intrin/packuswb.c

paddw

Adds 16-bit integers.

@param

short* a
const short* b
const short* c

@return

void

@note shorts can't overflow so ubsan won't report it when it happens

@see paddsw()

@mayalias

@see libc/intrin/paddw.c

__paginate

Displays wall of text in terminal with pagination.

@param

int fd
const char* s

@return

void

@see libc/proc/paginate.c

palignr

Overlaps vectors.

𝑖= 0 means 𝑐←𝑎

0<𝑖<16 means 𝑐←𝑎║𝑏

𝑖=16 means 𝑐←𝑏

16<𝑖<32 means 𝑐←𝑏║0

𝑖≥32 means 𝑐←0

@param

void* c
void* b
void* a
unsigned long i

@return

void

@note not compatible with mmx

@see pvalignr()

@mayalias

@see libc/intrin/palignr.c

__palignrs

Jump table for palignr() with non-constexpr immediate parameter.

@return

@note needs ssse3 cf. prescott c. 2004 cf. bulldozer c. 2011

@see palignr()

@see libc/intrin/palignrs.S

pandn

Nands 128-bit integers.

@param

unsigned long* a
const unsigned long* b
const unsigned long* c

@return

void

@mayalias

@see libc/intrin/pandn.c

ParseCidr

Parse IPv4 network address.

For example, a router address might be 10.10.10.1/24 in which case the IP address word 0x0a0a0a01 would be returned, whose CIDR would be 24. That means your IP address is on a network with 24 bits which converts to a netmask 0xffffff00 by using 1u << (32 - res.cidr). You may specify the IP address portion as an integer. As an example, the value 168430081/1 would be the same as 10.10.10.1/1

@param

const char* s
unsigned long n: if -1 implies strlen

@return

struct c: ip is uint32 IPv4 address, or -1 on failure; cidr is number of bits in network, on interval [1,32]; it defaults to 32; if the return ip is -1 then cidr is undefined

@see net/http/parsecidr.c

ParseContentLength

Parses Content-Length header.

@param

const char* s
unsigned long n

@return

long: -1 on invalid or overflow, otherwise >=0 value

@see net/http/parsecontentlength.c

ParseForwarded

Parses X-Forwarded-For.

This header is used by reverse proxies. For example:

X-Forwarded-For: 203.0.110.2, 203.0.113.42:31337

The port is optional and will be set to zero if absent.

@param

const char* s: is input data
unsigned long n: if -1 implies strlen
unsigned int* ip: receives last/right ip on success if not NULL
unsigned short* port: receives port on success if not NULL

@return

int: 0 on success or -1 on failure

@see RFC7239's poorly designed Forwarded header

@see net/http/parseforwarded.c

ParseHost

Parses HTTP Host header.

The input is ISO-8859-1 which is transcoded to UTF-8. Therefore we assume percent-encoded bytes are expressed as UTF-8. Returned values might contain things like NUL characters, C0, and C1 control codes. UTF-8 isn't checked for validity and may contain overlong values. Absent can be discerned from empty by checking if the pointer is set.

This function turns an HTTP header HOST[:PORT] into two strings, one for host and the other for port. You may then call IsAcceptableHost() and IsAcceptablePort() to see if they are valid values. After that a function like sscanf() can be used to do the thing you likely thought this function would do.

This function doesn't initialize h since it's assumed this will be called conditionally after ParseRequestUri() if the host is absent. Fields unrelated to authority won't be impacted by this function.

@param

const char* s: is value like 127.0.0.1 or foo.example:80
unsigned long n: is byte length and -1 implies strlen
struct Url* h: is needs to be initialized by caller

@return

char*: memory backing UrlView needing free

@see net/http/parseurl.c

ParseHttpMethod

Converts HTTP method to word encoding.

For example, ParseHttpMethod("GET", -1) will return kHttpGet.

@param

const char* str
unsigned long len: if -1 implies strlen

@return

unsigned long: word encoded method, or 0 if invalid

@see net/http/parsehttpmethod.c

ParseHttpRange

Parses HTTP Range request header.

Here are some example values:

Range: bytes=0-                 (everything)
Range: bytes=0-499              (first 500 bytes)
Range: bytes=500-999            (second 500 bytes)
Range: bytes=-500               (final 500 bytes)
Range: bytes=0-0,-1             (first and last and always)
Range: bytes=500-600,601-999    (overlong but legal)

@param

const char* p
unsigned long n
long resourcelength
long* out_start
long* out_length

@return

_Bool

@see net/http/parsehttprange.c

ParseIp

Parse IPv4 host address.

@param

const char* s
unsigned long n: if -1 implies strlen

@return

long: -1 on failure, otherwise 32-bit host-order unsigned integer

@see ParseCidr()

@see net/http/parseip.c

ParseParams

Parses HTTP POST key-value params.

These are similar to the parameters found in a Request-URI, except usually submitted via an HTTP POST request. We translate + into space. The mime type is application/x-www-form-urlencoded.

This parser is charset agnostic. Returned values might contain things like NUL characters, NUL, control codes, and non-canonical encodings. Absent can be discerned from empty by checking if the pointer is set.

There's no failure condition for this routine. This is a permissive parser that doesn't impose character restrictions beyond what is necessary for parsing.

@param

const char* s: is value like foo=bar&x=y&z
unsigned long n: is byte length and -1 implies strlen
struct params* h: must be zeroed by caller and this appends if reused

@return

char*: UrlView memory with same n needing free (h.p needs free too)

@see net/http/parseurl.c

ParsePromises

Parses the arguments to pledge() into a bitmask.

@param

const char* promises
unsigned long* out: receives the integral promises mask, which zero is defined as the set of all promises, and -1 is defined as the empty set of promises, which is equivalent to promises being an empty string
unsigned long current

@return

int: 0 on success, or -1 if invalid

@see libc/calls/parsepromises.c

ParseUrl

Parses URL.

This parser is charset agnostic. Percent encoded bytes are decoded for all fields (with the exception of scheme). Returned values might contain things like NUL characters, spaces, control codes, and non-canonical encodings. Absent can be discerned from empty by checking if the pointer is set.

There's no failure condition for this routine. This is a permissive parser. This doesn't normalize path segments like . or .. so use IsAcceptablePath() to check for those. No restrictions are imposed beyond that which is strictly necessary for parsing. All the s that is provided will be consumed to the one of the fields. Strict conformance is enforced on some fields more than others, like scheme, since it's the most non-deterministically defined field of them all.

Please note this is a URL parser, not a URI parser. Which means we support everything the URI spec says we should do except for the things we won't do, like tokenizing path segments into an array and then nesting another array beneath each of those for storing semicolon parameters. So this parser won't make SIP easy. What it can do is parse HTTP URLs and most URIs like s:opaque, better in fact than most things which claim to be URI parsers.

@param

const char* s

is value like /hi?x=y&z or http://a.example/hi#x

unsigned long n

is byte length and -1 implies strlen

struct Url* h

is assumed to be uninitialized

int f

is flags which may have:

FLAGS_PLUS to turn + into space in query params
FLAGS_LATIN1 to transcode ISO-8859-1 input into UTF-8

@return

char*: memory backing UrlView needing free (and h.params.p too)

@see URI Generic Syntax RFC3986 RFC2396

@see EncodeUrl()

@see net/http/parseurl.c

pathconf

@param

const char* path
int name

@return

long

@see libc/runtime/fpathconf.c

pclose

Closes stream created by popen().

This function may be interrupted or cancelled, however it won't actually return until the child process has terminated. Thus we always release the resource, and errors are purely advisory.

@param

struct FILE* f

@return

int: termination status of subprocess, or -1 w/ ECHILD

@raise ECANCELED if thread was cancelled in masked mode

@raise ECHILD if child pid didn't exist

@raise EINTR if signal was delivered

@cancelationpoint

@see libc/stdio/pclose.c

pcmpgtb

Compares signed 8-bit integers w/ greater than predicate.

Note that operands can be xor'd with 0x80 for unsigned compares.

@param

char* a
const char* b
const char* c

@return

void

@mayalias

@see libc/intrin/pcmpgtb.c

pcmpgtw

Compares signed 16-bit integers w/ greater than predicate.

@param

short* a
const short* b
const short* c

@return

void

@mayalias

@see libc/intrin/pcmpgtw.c

perror

Writes error messages to standard error.

@param

const char* thing

@return

void

@see libc/calls/perror.c

pipe

Creates file-less file descriptors for interprocess communication.

@param

int* pipefd

@return

int: 0 on success or -1 w/ errno

@raise EFAULT if pipefd is NULL or an invalid address

@raise EMFILE if RLIMIT_NOFILE is exceedde

@asyncsignalsafe

@see pipe2()

@see libc/calls/pipe.c

pipe2

Creates file-less file descriptors for interprocess communication.

This function offers atomic operation on all supported platforms except for XNU and RHEL5 where it's polyfilled.

@param

int* pipefd: is used to return (reader, writer) file descriptors
int flags: can have O_CLOEXEC or O_DIRECT or O_NONBLOCK

@return

int: 0 on success, or -1 w/ errno and pipefd isn't modified

@params flags may contain O_CLOEXEC, O_NONBLOCK, or the non-POSIX packet mode flag O_DIRECT, which is EINVAL on MacOS / OpenBSD

@raise EINVAL if flags has invalid or unsupported bits

@raise EFAULT if pipefd doesn't point to valid memory

@raise EMFILE if process RLIMIT_NOFILE has been reached

@raise ENFILE if system-wide file limit has been reached

@see libc/calls/pipe2.c

pivot_root

Changes root mount.

@param

const char* new_root
const char* put_old

@return

int

@raise ENOSYS on non-Linux

@see libc/calls/pivot_root.c

pmaddubsw

Multiplies bytes and adds adjacent results w/ short saturation.

𝑤ᵢ ← CLAMP[ 𝑏₂ᵢ𝑐₂ᵢ + 𝑏₍₂ᵢ₊₁₎𝑐₍₂ᵢ₊₁₎ ]

@param

short* w
const unsigned char* b
const char* c

@return

void

@note SSSE3 w/ Prescott c. 2004, Bulldozer c. 2011

@note greatest simd op, like, ever

@mayalias

@see libc/intrin/pmaddubsw.c

pmovmskb

Turns result of byte comparison into bitmask.

@param

const unsigned char* p

@return

unsigned int

@see pcmpeqb(), bsf(), etc.

@see libc/intrin/pmovmskb.c

pmulhrsw

Multiplies Q15 numbers.

@param

short* a
const short* b
const short* c

@return

void

@note goes fast w/ ssse3 (intel c. 2004, amd c. 2011)

@note a.k.a. packed multiply high w/ round & scale

@see Q2F(15,𝑥), F2Q(15,𝑥)

@mayalias

@see libc/intrin/pmulhrsw.c

pochisq

@param

const double ax
const int df

@return

double

@see libc/tinymath/poz.c

poll

Waits for something to happen on multiple file descriptors at once.

Warning: XNU has an inconsistency with other platforms. If you have pollfds with fd≥0 and none of the meaningful events flags are added e.g. POLLIN then XNU won't check for POLLNVAL. This matters because one of the use-cases for poll() is quickly checking for open files.

Note: Polling works best on Windows for sockets. We're able to poll input on named pipes. But for anything that isn't a socket, or pipe with POLLIN, (e.g. regular file) then POLLIN/POLLOUT are always set into revents if they're requested, provided they were opened with a mode that permits reading and/or writing.

Note: Windows has a limit of 64 file descriptors and ENOMEM with -1 is returned if that limit is exceeded. In practice the limit is not this low. For example, pollfds with fd<0 don't count. So the caller could flip the sign bit with a short timeout, to poll a larger set.

@param

struct pollfd* fds
unsigned long nfds
int timeout_ms: if 0 means don't wait and -1 means wait forever

@return

int: number of items fds whose revents field has been set to nonzero to describe its events, or 0 if the timeout elapsed, or -1 w/ errno; fds[𝑖].revents is always zero initializaed and then will be populated with POLL{IN,OUT,PRI,HUP,ERR,NVAL} if something was determined about the file descriptor

@raise ECANCELED if thread was cancelled in masked mode

@raise EINTR if signal was delivered

@cancelationpoint

@asyncsignalsafe

@norestart

@see libc/calls/poll.c

popcnt

Returns number of bits set in integer.

@param

unsigned long x

@return

unsigned long

@see libc/intrin/popcnt.c

posix_madvise

Advises kernel about memory intentions, the POSIX way.

@param

void* addr
unsigned long len
int advice

@return

int: 0 on success, or errno on error

@raise EINVAL if advice isn't valid or supported by system

@raise EINVAL on Linux if addr/length isn't page size aligned with respect to getauxval(AT_PAGESZ)

@raise ENOMEM on Linux if addr/length overlaps unmapped regions

@returnserrno

@see libc/calls/posix_madvise.c

posix_memalign

Allocates aligned memory, the POSIX way.

Allocates a chunk of n bytes, aligned in accord with the alignment argument. Differs from memalign() only in that it:

Assigns the allocated memory to *pp rather than returning it
Fails and returns EINVAL if the alignment is not a power of two
Fails and returns ENOMEM if memory cannot be allocated

@param

void** pp: receives pointer, only on success
unsigned long alignment: must be 2-power multiple of sizeof(void *)
unsigned long bytes: is number of bytes to allocate

@return

int: return 0 or EINVAL or ENOMEM w/o setting errno

@see memalign()

@returnserrno

@see libc/mem/posix_memalign.c

posix_openpt

Opens new pseudo teletypewriter.

@param

int flags

@return

int: fd of master pty, or -1 w/ errno; file descriptor, or -1 w/ errno

@params flags is usually O_RDWR|O_NOCTTY

@see libc/calls/posix_openpt.c

posix_spawn_file_actions_addchdir_np

Add chdir() action to spawn.

@param

ANONYMOUS-STRUCT** file_actions: was initialized by posix_spawn_file_actions_init()
const char* path: will be safely copied

@return

int: 0 on success, or errno on error

@raise ENOMEM if insufficient memory was available

@see libc/proc/posix_spawn_file_actions_addchdir_np.c

posix_spawn_file_actions_addclose

Add a close action to object.

@param

ANONYMOUS-STRUCT** file_actions: was initialized by posix_spawn_file_actions_init()
int fildes

@return

int: 0 on success, or errno on error

@raise ENOMEM if we require more vespene gas

@raise EBADF if fildes is negative

@see libc/proc/posix_spawn_file_actions_addclose.c

posix_spawn_file_actions_adddup2

Add a dup2 action to object.

@param

ANONYMOUS-STRUCT** file_actions: was initialized by posix_spawn_file_actions_init()
int fildes
int newfildes

@return

int: 0 on success, or errno on error

@raise EBADF if 'fildes' or newfildes is negative

@raise ENOMEM if insufficient memory was available

@see libc/proc/posix_spawn_file_actions_adddup2.c

posix_spawn_file_actions_addfchdir_np

Add fchdir() action to spawn.

@param

ANONYMOUS-STRUCT** file_actions
int fildes

@return

int: 0 on success, or errno on error

@raise ENOMEM if insufficient memory was available

@raise EBADF if fildes is negative

@see libc/proc/posix_spawn_file_actions_addfchdir_np.c

posix_spawn_file_actions_addopen

Add an open action to object.

@param

ANONYMOUS-STRUCT** file_actions: was initialized by posix_spawn_file_actions_init()
int fildes: is what open() result gets duplicated to
const char* path: will be safely copied
int oflag
unsigned int mode

@return

int: 0 on success, or errno on error

@raise ENOMEM if insufficient memory was available

@raise EBADF if fildes is negative

@see libc/proc/posix_spawn_file_actions_addopen.c

posix_spawn_file_actions_destroy

Destroys posix_spawn() file actions list.

This function is safe to call multiple times.

@param

ANONYMOUS-STRUCT** file_actions: was initialized by posix_spawn_file_actions_init()

@return

int: 0 on success, or errno on error

@see libc/proc/posix_spawn_file_actions_destroy.c

posix_spawn_file_actions_init

Initializes posix_spawn() file actions list.

File actions get applied in the same order as they're registered.

@param

ANONYMOUS-STRUCT** file_actions: will need posix_spawn_file_actions_destroy()

@return

int: 0 on success, or errno on error

@see libc/proc/posix_spawn_file_actions_init.c

posix_spawnattr_destroy

Destroys posix_spawn() attributes object.

This function is safe to call multiple times.

@param

ANONYMOUS-STRUCT** attr: was initialized by posix_spawnattr_init()

@return

int: 0 on success, or errno on error

@see libc/proc/posix_spawnattr_destroy.c

posix_spawnattr_getflags

Gets posix_spawn() flags.

@param

struct _posix_spawna** attr: was initialized by posix_spawnattr_init()
short* flags

@return

int: 0 on success, or errno on error

@see libc/proc/posix_spawnattr_getflags.c

posix_spawnattr_getpgroup

Gets process group id associated with attributes.

@param

struct _posix_spawna** attr: was initialized by posix_spawnattr_init()
int* pgroup: receives the result on success

@return

int: 0 on success, or errno on error

@see libc/proc/posix_spawnattr_getpgroup.c

posix_spawnattr_getrlimit

Gets resource limit for spawned process.

@param

struct _posix_spawna** attr
int resource
struct rlimit* rlim

@return

int: 0 on success, or errno on error

@raise EINVAL if resource is invalid or unsupported by host

@raise ENOENT if resource is absent

@see libc/proc/posix_spawnattr_getrlimit.c

posix_spawnattr_getschedparam

Gets scheduler parameter.

@param

struct _posix_spawna** attr: was initialized by posix_spawnattr_init()
struct schedparam* schedparam: receives the result

@return

int: 0 on success, or errno on error

@see libc/proc/posix_spawnattr_getschedparam.c

posix_spawnattr_getschedpolicy

Gets scheduler policy that'll be used for spawned process.

@param

struct _posix_spawna** attr: was initialized by posix_spawnattr_init()
int* schedpolicy: receives the result

@return

int: 0 on success, or errno on error

@see libc/proc/posix_spawnattr_getschedpolicy.c

posix_spawnattr_getsigdefault

Retrieves which signals will be restored to SIG_DFL.

@param

struct _posix_spawna** attr
unsigned long* sigdefault

@return

int: 0 on success, or errno on error

@see libc/proc/posix_spawnattr_getsigdefault.c

posix_spawnattr_getsigmask

Gets signal mask for sigprocmask() in child process.

The signal mask is applied to the child process in such a way that signal handlers from the parent process can't get triggered in the child process.

@param

struct _posix_spawna** attr
unsigned long* sigmask

@return

int: 0 on success, or errno on error

@see libc/proc/posix_spawnattr_getsigmask.c

posix_spawnattr_init

Initialize posix_spawn() attributes object with default values.

@param

struct _posix_spawna** attr: needs to be passed to posix_spawnattr_destroy() later

@return

int: 0 on success, or errno on error

@raise ENOMEM if we require more vespene gas

@see libc/proc/posix_spawnattr_init.c

posix_spawnattr_setflags

Sets posix_spawn() flags.

@param

struct _posix_spawna** attr

was initialized by posix_spawnattr_init()

short flags

may have any of the following

POSIX_SPAWN_RESETIDS
POSIX_SPAWN_SETPGROUP
POSIX_SPAWN_SETSIGDEF
POSIX_SPAWN_SETSIGMASK
POSIX_SPAWN_SETSCHEDPARAM
POSIX_SPAWN_SETSCHEDULER
POSIX_SPAWN_SETSID
POSIX_SPAWN_SETRLIMIT

@return

int: 0 on success, or errno on error

@raise EINVAL if flags has invalid bits

@see libc/proc/posix_spawnattr_setflags.c

posix_spawnattr_setpgroup

Specifies process group into which child process is placed.

Setting pgroup to zero will ensure newly created processes are placed within their own brand new process group.

You also need to pass POSIX_SPAWN_SETPGROUP to posix_spawnattr_setflags() for it to take effect.

@param

struct _posix_spawna** attr: was initialized by posix_spawnattr_init()
int pgroup: is the process group id, or 0 for self

@return

int: 0 on success, or errno on error

@see libc/proc/posix_spawnattr_setpgroup.c

posix_spawnattr_setrlimit

Sets resource limit on spawned process.

You also need to pass POSIX_SPAWN_SETRLIMIT to posix_spawnattr_setflags() for it to take effect.

@param

struct _posix_spawna** attr
int resource
struct rlimit* rlim

@return

int: 0 on success, or errno on error

@raise EINVAL if resource is invalid

@see libc/proc/posix_spawnattr_setrlimit.c

posix_spawnattr_setschedparam

Specifies scheduler parameter override for spawned process.

You also need to pass POSIX_SPAWN_SETSCHEDPARAM to posix_spawnattr_setflags() for it to take effect.

@param

struct _posix_spawna** attr: was initialized by posix_spawnattr_init()
struct schedparam* schedparam: receives the result

@return

int: 0 on success, or errno on error

@see libc/proc/posix_spawnattr_setschedparam.c

posix_spawnattr_setschedpolicy

Specifies scheduler policy override for spawned process.

You also need to pass POSIX_SPAWN_SETSCHEDULER to posix_spawnattr_setflags() for it to take effect.

@param

struct _posix_spawna** attr: was initialized by posix_spawnattr_init()
int schedpolicy

@return

int: 0 on success, or errno on error

@see libc/proc/posix_spawnattr_setschedpolicy.c

posix_spawnattr_setsigdefault

Specifies which signals should be restored to SIG_DFL.

This routine isn't necessary in most cases, since posix_spawn() by default will try to avoid vfork() race conditions by tracking what signals have a handler function and then resets them automatically within the child process, before applying the child's signal mask. This function may be used to ensure the SIG_IGN disposition will not propagate across execve in cases where this process explicitly set the signals to SIG_IGN earlier (since posix_spawn() will not issue O(128) system calls just to be totally pedantic about that).

You also need to pass POSIX_SPAWN_SETSIGDEF to posix_spawnattr_setflags() for it to take effect.

@param

struct _posix_spawna** attr
const unsigned long* sigdefault

@return

int: 0 on success, or errno on error

@see libc/proc/posix_spawnattr_setsigdefault.c

posix_spawnattr_setsigmask

Specifies signal mask for sigprocmask() in child process.

You also need to pass POSIX_SPAWN_SETSIGMASK to posix_spawnattr_setflags() for it to take effect.

@param

struct _posix_spawna** attr
const unsigned long* sigmask

@return

int: 0 on success, or errno on error

@see libc/proc/posix_spawnattr_setsigmask.c

posix_spawnp

Spawns process the POSIX way w/ PATH search.

@param

int* pid: is non-NULL and will be set to child pid in parent
const char* path: of executable is PATH searched unless it contains a slash
ANONYMOUS-STRUCT** file_actions
ANONYMOUS-STRUCT** attrp
char** argv
char** envp

@return

int: 0 on success or error number on failure

@see libc/proc/posix_spawnp.c

ppoll

Waits for something to happen on multiple file descriptors at once.

This function is the same as saying:

sigset_t old;
sigprocmask(SIG_SETMASK, sigmask, &old);
poll(fds, nfds, timeout);
sigprocmask(SIG_SETMASK, old, 0);

Except it happens atomically when the kernel supports doing that. On kernel such as XNU and NetBSD which don't, this wrapper will fall back to using the example above. Consider using pselect() which is atomic on all supported platforms.

The Linux Kernel modifies the timeout parameter. This wrapper gives it a local variable due to POSIX requiring that timeout be const. If you need that information from the Linux Kernel use sys_ppoll().

@param

struct pollfd* fds
unsigned long nfds
struct timespec* timeout: if null will block indefinitely
const unsigned long* sigmask: may be null in which case no mask change happens

@return

int

@raise ECANCELED if thread was cancelled in masked mode

@raise EINTR if signal was delivered

@cancelationpoint

@asyncsignalsafe

@norestart

@see libc/calls/ppoll.c

pread

Reads from file at offset.

This function never changes the current position of fd.

@param

int fd: is something open()'d earlier, noting pipes might not work
void* buf: is copied into, cf. copy_file_range(), sendfile(), etc.
unsigned long size: in range [1..0x7ffff000] is reasonable
long offset: is bytes from start of file at which read begins

@return

long: [1..size] bytes on success, 0 on EOF, or -1 w/ errno; with exception of size==0, in which case return zero means no error

@raise ESPIPE if fd isn't seekable

@raise EINVAL if offset is negative

@raise EBADF if fd isn't an open file descriptor

@raise EIO if a complicated i/o error happened

@raise EINTR if signal was delivered instead

@raise ECANCELED if thread was cancelled in masked mode

@see pwrite(), write()

@cancelationpoint

@asyncsignalsafe

@vforksafe

@see libc/calls/pread.c

printf

Formats and writes text to stdout.

Cosmopolitan supports most of the standard formatting behaviors described by man 3 printf, in addition to the following

%jjd, %jjx, etc. are {,u}int128_t (cosmopolitan only)
%'d or %,d may be used to insert thousands separators. The prior is consistent with C; the latter is consistent with Python.
%m inserts strerror(errno) into the formatted output. This is consistent with glibc, musl, and uclibc.
%hs converts UTF-16/UCS-2 → UTF-8, which can be helpful on Windows. Formatting (e.g. %-10hs) will use monospace display width rather than string length or codepoint count.
%ls (or %Ls) converts UTF-32 → UTF-8. Formatting (e.g. %-10ls) will use monospace display width rather than string length.
The %#s and %#c alternate forms display values using the standard IBM standard 256-letter alphabet. Using %#.*s to specify length will allow true binary (i.e. with NULs) to be formatted.
The %'s and %'c alternate forms are Cosmopolitan extensions for escaping string literals for C/C++ and Python. The outer quotation marks can be added automatically using %`s. If constexpr format strings are used, we can avoid linking cescapec() too.
The backtick modifier (%`s and %`c) and repr() directive (%r) both ask the formatting machine to represent values as real code rather than using arbitrary traditions for displaying values. This means it implies the quoting modifier, wraps the value with {,u,L}['"] quotes, displays NULL as "NULL" rather than "(null)".

@param

const char* fmt
...

@return

int

@see __fmt() for intuitive reference documentation

@see {,v}{,s{,n},{,{,x}as},f,d}printf

@see libc/stdio/printf.c

PrintGarbage

Prints list of deferred operations on shadow stack.

@return

void

@see libc/runtime/printgarbage.c

PrintWindowsMemory

Prints to stderr all memory mappings that exist according to WIN32.

The high and size parameters may optionally be specified so that memory mappings which overlap [high,high+size) will get printed in ANSI bold red text.

@param

const char* high
unsigned long size

@return

void

@see libc/log/printwindowsmemory.c

program_invocation_name

Supplies argv[0] the GNU way.

If argv[0] isn't supplied, this value will be null.

@return

@see program_invocation_short_name

@see GetProgramExecutableName()

@see libc/nexgen32e/program_invocation_name.S

pselect

Does what poll() does except with bitset API.

This function is the same as saying:

sigset_t old;
sigprocmask(SIG_SETMASK, sigmask, &old);
select(nfds, readfds, writefds, exceptfds, timeout);
sigprocmask(SIG_SETMASK, old, 0);

Except it happens atomically.

This system call is supported on all platforms. It's like select() except that it atomically changes the sigprocmask() during the op.

@param

int nfds
struct old_exceptfds* readfds
struct old_exceptfds* writefds
struct old_exceptfds* exceptfds
struct timespec* timeout
const unsigned long* sigmask

@return

int

@raise ECANCELED if thread was cancelled in masked mode

@raise EINTR if signal was delivered

@cancelationpoint

@asyncsignalsafe

@norestart

@see libc/calls/pselect.c

psraw

Divides shorts by two power.

@param

short* a
const short* b
unsigned char k

@return

void

@note c needs to be a literal, asmconstexpr, or linkconstsym

@note arithmetic shift right will sign extend negatives

@mayalias

@see libc/intrin/psraw.c

psrawv

Divides shorts by two power.

@param

short* a
const short* b
const unsigned long* c

@return

void

@note arithmetic shift right will sign extend negatives

@mayalias

@see libc/intrin/psrawv.c

pthread_atfork

Registers fork() handlers.

Parent and child functions are called in the same order they're registered. Prepare functions are called in reverse order.

Here's an example of how pthread_atfork() can be used:

static struct {
  pthread_once_t once;
  pthread_mutex_t lock;
  // data structures...
} g_lib;

static void lib_wipe(void) {
  pthread_mutex_init(&g_lib.lock, 0);
}

static void lib_lock(void) {
  pthread_mutex_lock(&g_lib.lock);
}

static void lib_unlock(void) {
  pthread_mutex_unlock(&g_lib.lock);
}

static void lib_setup(void) {
  lib_wipe();
  pthread_atfork(lib_lock, lib_unlock, lib_wipe);
}

static void lib_init(void) {
  pthread_once(&g_lib.once, lib_setup);
}

void lib(void) {
  lib_init();
  lib_lock();
  // do stuff...
  lib_unlock();
}

@param

void(*)() prepare: is run by fork() before forking happens
void(*)() parent: is run by fork() after forking happens in parent process
void(*)() child: is run by fork() after forking happens in childe process

@return

int: 0 on success, or errno on error

@raise ENOMEM if we require more vespene gas

@see libc/intrin/pthread_atfork.c

pthread_attr_destroy

Destroys pthread attributes.

@param

struct pthread_attr_t* attr

@return

int: 0 on success, or errno on error

@see libc/thread/pthread_attr_destroy.c

pthread_attr_getdetachstate

Gets thread detachable attribute.

@param

struct pthread_attr_t* attr

int* detachstate

is set to one of the following

PTHREAD_CREATE_JOINABLE (default)
PTHREAD_CREATE_DETACHED

@return

int: 0 on success, or error on failure

@see libc/thread/pthread_attr_getdetachstate.c

pthread_attr_getguardsize

Returns size of unmapped pages at bottom of stack.

@param

struct pthread_attr_t* attr
unsigned long* guardsize: will be set to guard size in bytes

@return

int: 0 on success, or errno on error

@see libc/thread/pthread_attr_getguardsize.c

pthread_attr_getinheritsched

Returns thread inherit schedule attribute.

@param

struct pthread_attr_t* attr
int* inheritsched

@return

int

@see libc/thread/pthread_attr_getinheritsched.c

pthread_attr_getschedparam

Gets thread scheduler parameter attribute.

@param

struct pthread_attr_t* attr
struct sched_param* param

@return

int

@see libc/thread/pthread_attr_getschedparam.c

pthread_attr_getschedpolicy

Gets thread scheduler policy attribute

@param

struct pthread_attr_t* attr
int* policy

@return

int

@see libc/thread/pthread_attr_getschedpolicy.c

pthread_attr_getscope

Gets contention scope attribute.

@param

struct pthread_attr_t* attr
int* contentionscope

@return

int: 0 on success, or errno on error

@see libc/thread/pthread_attr_getscope.c

pthread_attr_getsigmask_np

Gets signal mask on thread attributes object.

@param

struct pthread_attr_t* attr: is the thread attributes object
unsigned long* sigmask: will receive the output signal mask on success, or null if a simple presence check is desired

@return

int: 0 on success, errno on error, or PTHREAD_ATTR_NO_SIGMASK_NP if there wasn't any signal mask present in attr

@see libc/thread/pthread_attr_getsigmask_np.c

pthread_attr_getstack

Returns configuration for thread stack.

This is a getter for a configuration attribute. By default, zeros are returned. If pthread_attr_setstack() was called earlier, then this'll return those earlier supplied values.

@param

struct pthread_attr_t* attr
void** stackaddr: will be set to stack address in bytes
unsigned long* stacksize

@return

int: 0 on success, or errno on error

@see pthread_attr_setstacksize()

@see libc/thread/pthread_attr_getstack.c

pthread_attr_getstacksize

Returns size of thread stack.

This defaults to GetStackSize().

@param

struct pthread_attr_t* a
unsigned long* x: will be set to stack size in bytes

@return

int: 0 on success, or errno on error

@see pthread_attr_setstacksize()

@see libc/thread/pthread_attr_getstacksize.c

pthread_attr_init

Initializes pthread attributes.

@param

struct pthread_attr_t* attr

@return

int: 0 on success, or errno on error

@see pthread_attr_setdetachstate()

@see pthread_attr_setsigmask_np()

@see pthread_attr_setstack()

@see pthread_attr_setstacksize()

@see pthread_attr_setguardsize()

@see pthread_attr_setschedparam()

@see pthread_attr_setschedpolicy()

@see pthread_attr_setinheritsched()

@see pthread_attr_setscope()

@see libc/thread/pthread_attr_init.c

pthread_attr_setdetachstate

Sets thread detachable attribute, e.g.

pthread_attr_t attr;
pthread_attr_init(&attr);
pthread_attr_setdetachstate(&attr, PTHREAD_CREATE_DETACHED);
pthread_create(0, &attr, func, 0);
pthread_attr_destroy(&attr);

@param

struct pthread_attr_t* attr

int detachstate

can be one of

PTHREAD_CREATE_JOINABLE (default)
PTHREAD_CREATE_DETACHED

@return

int: 0 on success, or error on failure

@raises EINVAL if detachstate is invalid

@see libc/thread/pthread_attr_setdetachstate.c

pthread_attr_setguardsize

Sets size of unmapped pages at bottom of stack.

This value will be rounded up to the host microprocessor page size, which is usually 4096 or 16384. It's important to write code in such a way that that code can't skip over the guard area. GCC has warnings like -Wframe-larger-than=4096 -Walloca-larger-than=4096 which help guarantee your code is safe in this regard. It should be assumed the guard pages exist beneath the stack pointer, rather than the bottom of the stack, since guard pages are also used to grow down commit, which can be poked using CheckLargeStackAllocation().

@param

struct pthread_attr_t* attr
unsigned long guardsize: contains guard size in bytes

@return

int: 0 on success, or errno on error

@raise EINVAL if guardsize is zero

@see libc/thread/pthread_attr_setguardsize.c

pthread_attr_setinheritsched

Sets thread scheduler inheritance attribute, e.g.

pthread_t id;
pthread_attr_t attr;
pthread_attr_init(&attr);
struct sched_param pri = {sched_get_priority_min(SCHED_OTHER)};
pthread_attr_setinheritsched(&attr, PTHREAD_EXPLICIT_SCHED);
pthread_attr_setschedpolicy(&attr, SCHED_OTHER);
pthread_attr_setschedparam(&attr, &pri);
pthread_create(&id, &attr, func, 0);
pthread_attr_destroy(&attr);
pthread_join(id, 0);

@param

struct pthread_attr_t* attr

int inheritsched

may be one of:

PTHREAD_INHERIT_SCHED the default
PTHREAD_EXPLICIT_SCHED to enable rescheduling

@return

int: 0 on success, or errno on error

@raise EINVAL on bad value

@see libc/thread/pthread_attr_setinheritsched.c

pthread_attr_setschedparam

Sets thread scheduler parameter attribute, e.g.

pthread_t id;
pthread_attr_t attr;
pthread_attr_init(&attr);
struct sched_param pri = {sched_get_priority_min(SCHED_OTHER)};
pthread_attr_setinheritsched(&attr, PTHREAD_EXPLICIT_SCHED);
pthread_attr_setschedpolicy(&attr, SCHED_OTHER);
pthread_attr_setschedparam(&attr, &pri);
pthread_create(&id, &attr, func, 0);
pthread_attr_destroy(&attr);
pthread_join(id, 0);

@param

struct pthread_attr_t* attr
struct sched_param* param: specifies priority on scheduling policies that need it

@return

int

@see pthread_attr_setschedpolicy()

@see sched_get_priority_min()

@see sched_get_priority_max()

@see sched_setparam()

@see libc/thread/pthread_attr_setschedparam.c

pthread_attr_setschedpolicy

Sets thread scheduler policy attribute, e.g.

pthread_t id;
pthread_attr_t attr;
pthread_attr_init(&attr);
struct sched_param pri = {sched_get_priority_min(SCHED_OTHER)};
pthread_attr_setinheritsched(&attr, PTHREAD_EXPLICIT_SCHED);
pthread_attr_setschedpolicy(&attr, SCHED_OTHER);
pthread_attr_setschedparam(&attr, &pri);
pthread_create(&id, &attr, func, 0);
pthread_attr_destroy(&attr);
pthread_join(id, 0);

@param

struct pthread_attr_t* attr

int policy

may be one of:

SCHED_OTHER the default policy
SCHED_FIFO for real-time scheduling (usually needs root)
SCHED_RR for round-robin scheduling (usually needs root)
SCHED_IDLE for lowest effort (Linux and FreeBSD only)
SCHED_BATCH for "batch" style execution of processes if supported (Linux), otherwise it's treated as SCHED_OTHER

@return

int

@see sched_setscheduler()

@see libc/thread/pthread_attr_setschedpolicy.c

pthread_attr_setscope

Sets contention scope attribute.

@param

struct pthread_attr_t* attr

int contentionscope

may be one of:

PTHREAD_SCOPE_SYSTEM to fight the system for resources
PTHREAD_SCOPE_PROCESS to fight familiar threads for resources

@return

int: 0 on success, or errno on error

@raise ENOTSUP if contentionscope isn't supported on host OS

@raise EINVAL if contentionscope was invalid

@see libc/thread/pthread_attr_setscope.c

pthread_attr_setsigmask_np

Sets signal mask on thread attributes object.

For example, to spawn a thread that won't interfere with signals:

pthread_t id;
sigset_t mask;
pthread_attr_t attr;
sigfillset(&mask);
pthread_attr_init(&attr);
pthread_attr_setsigmask_np(&attr, &mask);
pthread_attr_setdetachstate(&attr, PTHREAD_CREATE_DETACHED);
pthread_create(&id, &attr, Worker, 0);
pthread_attr_destroy(&attr);

@param

struct pthread_attr_t* attr: is the thread attributes object
const unsigned long* sigmask: will be copied into attributes, or if it's null, then the existing signal mask presence on the object will be cleared

@return

int: 0 on success, or errno on error

@see libc/thread/pthread_attr_setsigmask_np.c

pthread_attr_setstack

Configures custom allocated stack for thread, e.g.

pthread_t id;
pthread_attr_t attr;
char *stk = NewCosmoStack();
pthread_attr_init(&attr);
pthread_attr_setstack(&attr, stk, GetStackSize());
pthread_create(&id, &attr, func, 0);
pthread_attr_destroy(&attr);
pthread_join(id, 0);
FreeCosmoStack(stk);

Your stack must have at least PTHREAD_STACK_MIN bytes, which Cosmpolitan Libc defines as GetStackSize(). It's a link-time constant used by Actually Portable Executable that's 128 kb by default. See libc/runtime/stack.h for docs on your stack limit since the APE ELF phdrs are the one true source of truth here.

Cosmpolitan Libc runtime magic (e.g. ftrace) and memory safety (e.g. kprintf) assumes that stack sizes are two-powers and are aligned to that two-power. Conformance isn't required since we say caveat emptor to those who don't maintain these invariants please consider using NewCosmoStack(), which is always perfect or use mmap(0, GetStackSize() << 1, ...) for a bigger stack.

Unlike pthread_attr_setstacksize(), this function permits just about any parameters and will change the values and allocation as needed to conform to the mandatory requirements of the host operating system even if it doesn't meet the stricter needs of Cosmopolitan Libc userspace libraries. For example with malloc allocations, things like page size alignment, shall be handled automatically for compatibility with existing codebases.

The same stack shouldn't be used for two separate threads. Use fresh stacks for each thread so that ASAN can be much happier.

@param

struct pthread_attr_t* attr
void* stackaddr: is address of stack allocated by caller, and may be NULL in which case default behavior is restored
unsigned long stacksize: is size of caller allocated stack

@return

int: 0 on success, or errno on error

@raise EINVAL if parameters were unacceptable

@see pthread_attr_setstacksize()

@see libc/thread/pthread_attr_setstack.c

pthread_attr_setstacksize

Defines minimum stack size for thread.

@param

struct pthread_attr_t* a
unsigned long stacksize: contains stack size in bytes

@return

int: 0 on success, or errno on error

@raise EINVAL if stacksize is less than PTHREAD_STACK_MIN

@see libc/thread/pthread_attr_setstacksize.c

pthread_barrier_destroy

Destroys barrier.

@param

struct pthread_barrier_t* barrier

@return

int: 0 on success, or error on failure

@raise EINVAL if threads are still inside the barrier

@see libc/thread/pthread_barrier_destroy.c

pthread_barrier_init

Initializes barrier.

@param

struct pthread_barrier_t* barrier
const char* attr: may be null
unsigned int count: is how many threads need to call pthread_barrier_wait() before the barrier is released, which must be greater than zero

@return

int: 0 on success, or error number on failure

@raise EINVAL if count isn't greater than zero

@raise ENOMEM if insufficient memory exists

@see libc/thread/pthread_barrier_init.c

pthread_barrierattr_destroy

Destroys barrier attributes.

@param

char* attr

@return

int: 0 on success, or error on failure

@see libc/thread/pthread_barrierattr_destroy.c

pthread_barrierattr_getpshared

Gets barrier process sharing.

@param

const char* attr

int* pshared

is set to one of the following

PTHREAD_PROCESS_PRIVATE (default)
PTHREAD_PROCESS_SHARED (unsupported)

@return

int: 0 on success, or error on failure

@see libc/thread/pthread_barrierattr_getpshared.c

pthread_barrierattr_init

Initializes barrier attributes.

@param

char* attr

@return

int: 0 on success, or error on failure

@see libc/thread/pthread_barrierattr_init.c

pthread_barrierattr_setpshared

Sets barrier process sharing.

@param

char* attr

int pshared

can be one of

PTHREAD_PROCESS_PRIVATE (default)
PTHREAD_PROCESS_SHARED (unsupported)

@return

int: 0 on success, or error on failure

@raises EINVAL if pshared is invalid

@see libc/thread/pthread_barrierattr_setpshared.c

pthread_cleanup_push

@param

struct _pthread_cleanup_buffer* cb
void(*)() routine
void* arg

@return

void

@see libc/intrin/pthread_cleanup_push.c

pthread_cond_broadcast

Wakes all threads waiting on condition, e.g.

pthread_cond_t cond = PTHREAD_COND_INITIALIZER;
pthread_mutex_t lock = PTHREAD_MUTEX_INITIALIZER;
// ...
pthread_mutex_lock(&lock);
pthread_cond_broadcast(&cond);
pthread_mutex_unlock(&lock);

This function has no effect if there aren't any threads currently waiting on the condition.

@param

struct pthread_cond_t* cond

@return

int: 0 on success, or errno on error

@see pthread_cond_signal

@see pthread_cond_wait

@see libc/thread/pthread_cond_broadcast.c

pthread_cond_destroy

Destroys condition.

@param

struct pthread_cond_t* cond

@return

int: 0 on success, or error number on failure

@raise EINVAL if threads are still waiting on condition

@see libc/thread/pthread_cond_destroy.c

pthread_cond_init

Initializes condition.

@param

struct pthread_cond_t* cond
const char* attr: may be null

@return

int: 0 on success, or error number on failure

@see libc/thread/pthread_cond_init.c

pthread_cond_signal

Wakes at least one thread waiting on condition, e.g.

pthread_cond_t cond = PTHREAD_COND_INITIALIZER;
pthread_mutex_t lock = PTHREAD_MUTEX_INITIALIZER;
// ...
pthread_mutex_lock(&lock);
pthread_cond_signal(&cond, &lock);
pthread_mutex_unlock(&lock);

This function has no effect if there aren't any threads currently waiting on the condition.

@param

struct pthread_cond_t* cond

@return

int: 0 on success, or errno on error

@see pthread_cond_broadcast

@see pthread_cond_wait

@see libc/thread/pthread_cond_signal.c

pthread_cond_wait

Waits for condition, e.g.

pthread_cond_t cond = PTHREAD_COND_INITIALIZER;
pthread_mutex_t lock = PTHREAD_MUTEX_INITIALIZER;
// ...
pthread_mutex_lock(&lock);
pthread_cond_wait(&cond, &lock);
pthread_mutex_unlock(&lock);

@param

struct pthread_cond_t* cond
struct pthread_mutex_t* mutex: needs to be held by thread when calling this function

@return

int: 0 on success, or errno on error

@raise ECANCELED if calling thread was cancelled in masked mode

@raise EPERM if mutex is PTHREAD_MUTEX_ERRORCHECK and the lock isn't owned by the current thread

@see pthread_cond_timedwait

@see pthread_cond_broadcast

@see pthread_cond_signal

@cancelationpoint

@see libc/thread/pthread_cond_wait.c

pthread_condattr_destroy

Destroys condition attributes.

@param

char* attr

@return

int: 0 on success, or error on failure

@see libc/thread/pthread_condattr_destroy.c

pthread_condattr_getpshared

Gets condition process sharing.

@param

const char* attr

int* pshared

is set to one of the following

PTHREAD_PROCESS_PRIVATE (default)
PTHREAD_PROCESS_SHARED

@return

int: 0 on success, or error on failure

@see libc/thread/pthread_condattr_getpshared.c

pthread_condattr_init

Initializes condition attributes.

@param

char* attr

@return

int: 0 on success, or error on failure

@see libc/thread/pthread_condattr_init.c

pthread_condattr_setpshared

Sets condition process sharing.

@param

char* attr

int pshared

can be one of

PTHREAD_PROCESS_PRIVATE (default)
PTHREAD_PROCESS_SHARED (unsupported)

@return

int: 0 on success, or error on failure

@raises EINVAL if pshared is invalid

@see libc/thread/pthread_condattr_setpshared.c

pthread_detach

Asks POSIX thread to free itself automatically upon termination.

If this function is used, then it's important to use pthread_exit() rather than exit() since otherwise your program isn't guaranteed to gracefully terminate.

Detaching a non-joinable thread is undefined behavior. For example, pthread_detach() can't be called twice on the same thread.

@param

unsigned long thread

@return

int: 0 on success, or errno with error

@raise EINVAL if thread isn't joinable

@returnserrno

@see libc/thread/pthread_detach.c

pthread_equal

Compares thread ids;

@param

unsigned long t1
unsigned long t2

@return

int: nonzero if equal, otherwise zero

@see libc/thread/pthread_equal.c

pthread_exit

Terminates current POSIX thread.

For example, a thread could terminate early as follows:

pthread_exit((void *)123);

The result value could then be obtained when joining the thread:

void *rc;
pthread_join(id, &rc);
assert((intptr_t)rc == 123);

Under normal circumstances a thread can exit by simply returning from the callback function that was supplied to pthread_create(). This may be used if the thread wishes to exit at any other point in the thread lifecycle, in which case this function is responsible for ensuring we invoke gc(), _defer(), and pthread_cleanup_push() callbacks, and also pthread_key_create() destructors.

If the current thread is an orphaned thread, or is the main thread when no other threads were created, then this will terminated your process with an exit code of zero. It's not possible to supply a non-zero exit status to wait4() via this function.

Once a thread has exited, access to its stack memory is undefined. The behavior of calling pthread_exit() from cleanup handlers and key destructors is also undefined.

@param

void* rc: is reported later to pthread_join()

@noreturn

@see libc/thread/pthread_exit.c

pthread_getaffinity_np

Gets CPU affinity for thread.

@param

unsigned long thread
unsigned long size: is bytes in bitset, which should be sizeof(cpu_set_t)
struct cpuset_t* bitset

@return

int: 0 on success, or errno on error

@raise EINVAL if size or bitset is invalid

@raise ENOSYS if not Linux, FreeBSD, or NetBSD

@raise ESRCH if thread isn't alive

@see libc/thread/pthread_getaffinity_np.c

pthread_getattr_np

Gets thread attributes.

These attributes are copied from the ones supplied when pthread_create() was called. However this function supplies additional runtime information too:

The detached state. You can use pthread_attr_getdetachstate() on the attr result to see, for example, if a thread detached itself or some other thread detached it, after it was spawned.
The thread's stack. You can use pthread_attr_getstack() to see the address and size of the stack that was allocated by cosmo for your thread. This is useful for knowing where the stack is. It can also be useful If you explicitly configured a stack too, since we might have needed to slightly tune the address and size to meet platform requirements.
You can view changes pthread_create() may have made to the stack guard size by calling pthread_attr_getguardsize() on attr

@param

unsigned long thread
struct pt_attr* attr: is output argument that receives attributes, which should find its way to pthread_attr_destroy() when it's done being used

@return

int: 0 on success, or errno on error

@raise ENOMEM is listed as a possible result by LSB 5.0

@see libc/thread/pthread_getattr_np.c

pthread_getname_np

Gets name of thread registered with system, e.g.

char name[64];
pthread_getname_np(thread, name, sizeof(name));

If the thread doesn't have a name, then empty string is returned. This implementation guarantees buf is always modified, even on error, and will always be nul-terminated. If size is 0 then this function returns 0. Your buf is also chomped to remove newlines.

@param

unsigned long thread
char* name
unsigned long size

@return

int: 0 on success, or errno on error

@raise ERANGE if size wasn't large enough, in which case your result will still be returned truncated if possible

@raise ENOSYS on MacOS, Windows, and FreeBSD

@see libc/thread/pthread_getname_np.c

pthread_getschedparam

Gets most recently set scheduling of thread.

@param

unsigned long thread
int* policy
struct sched_param* param

@return

int

@see libc/thread/pthread_getschedparam.c

pthread_getthreadid_np

Returns thread id of current POSIX thread.

@return

int

@see libc/thread/pthread_getthreadid_np.c

pthread_getunique_np

Returns system thread id of POSIX thread.

@param

unsigned long thread
int* out_tid

@return

int: 0 on success, or errno on error

@see libc/thread/pthread_getunique_np.c

pthread_join

Waits for thread to terminate.

Multiple threads joining the same thread is undefined behavior. If a deferred or masked cancelation happens to the calling thread either before or during the waiting process then the target thread will not be joined. Calling pthread_join() on a non-joinable thread, e.g. one that's been detached, is undefined behavior. If a thread attempts to join itself, then the behavior is undefined.

@param

unsigned long thread
void** value_ptr: if non-null will receive pthread_exit() argument if the thread called pthread_exit(), or PTHREAD_CANCELED if pthread_cancel() destroyed the thread instead

@return

int: 0 on success, or errno on error

@raise ECANCELED if calling thread was cancelled in masked mode

@cancelationpoint

@returnserrno

@see libc/thread/pthread_join.c

pthread_key_create

Allocates TLS slot.

This function creates a thread-local storage registration, that will apply to all threads. The new identifier is written to key, and it can be passed to the pthread_setspecific() and pthread_getspecific() functions to set and get its associated value. Each thread will have its key value initialized to zero upon creation. It is also possible to use pthread_key_delete() to unregister a key.

If dtor is non-null, then it'll be called upon pthread_exit() when the key's value is nonzero. The key's value is set to zero before it is called. The ordering of multiple destructor calls is unspecified. The same key can be destroyed PTHREAD_DESTRUCTOR_ITERATIONS times, in cases where it gets set again by a destructor.

@param

unsigned int* key: is set to the allocated key on success
void(*)() dtor: specifies an optional destructor callback

@return

int: 0 on success, or errno on error

@raise EAGAIN if PTHREAD_KEYS_MAX keys exist

@see libc/thread/pthread_key_create.c

pthread_kill

Sends signal to thread.

@param

unsigned long thread
int sig

@return

int: 0 on success, or errno on error

@raise ESRCH if tid was valid but no such thread existed

@raise EAGAIN if RLIMIT_SIGPENDING was exceeded

@raise EINVAL if sig wasn't a legal signal

@raise EPERM if permission was denied

@asyncsignalsafe

@see libc/thread/pthread_kill.c

pthread_mutex_destroy

Destroys mutex.

@param

struct pthread_mutex_t* mutex

@return

int: 0 on success, or error number on failure

@raise EINVAL if mutex is locked in our implementation

@see libc/intrin/pthread_mutex_destroy.c

pthread_mutex_init

Initializes mutex, e.g.

pthread_mutex_t lock;
pthread_mutexattr_t attr;
pthread_mutexattr_init(&attr);
pthread_mutexattr_settype(&attr, PTHREAD_MUTEX_NORMAL);
pthread_mutex_init(&lock, &attr);
pthread_mutexattr_destroy(&attr);
// ...
pthread_mutex_destroy(&lock);

@param

struct pthread_mutex_t* mutex
struct pthread_mutexattr_t* attr: may be null

@return

int: 0 on success, or error number on failure

@see libc/intrin/pthread_mutex_init.c

pthread_mutex_lock

Locks mutex.

Here's an example of using a normal mutex:

pthread_mutex_t lock = PTHREAD_MUTEX_INITIALIZER;
pthread_mutex_lock(&lock);
// do work...
pthread_mutex_unlock(&lock);
pthread_mutex_destroy(&lock);

Cosmopolitan permits succinct notation for normal mutexes:

pthread_mutex_t lock = {0};
pthread_mutex_lock(&lock);
// do work...
pthread_mutex_unlock(&lock);

Here's an example of the proper way to do recursive mutexes:

pthread_mutex_t lock;
pthread_mutexattr_t attr;
pthread_mutexattr_init(&attr);
pthread_mutexattr_settype(&attr, PTHREAD_MUTEX_RECURSIVE);
pthread_mutex_init(&lock, &attr);
pthread_mutexattr_destroy(&attr);
pthread_mutex_lock(&lock);
// do work...
pthread_mutex_unlock(&lock);
pthread_mutex_destroy(&lock);

This function does nothing in vfork() children.

@param

struct __fds_lock_obj* mutex

@return

int: 0 on success, or error number on failure

@see pthread_spin_lock()

@vforksafe

@see libc/intrin/pthread_mutex_lock.c

pthread_mutex_trylock

Attempts acquiring lock.

Unlike pthread_mutex_lock() this function won't block and instead returns an error immediately if the lock couldn't be acquired.

@param

struct pthread_mutex_t* mutex

@return

int: 0 if lock was acquired, otherwise an errno

@raise EAGAIN if maximum number of recursive locks is held

@raise EBUSY if lock is currently held in read or write mode

@raise EINVAL if mutex doesn't refer to an initialized lock

@raise EDEADLK if mutex is PTHREAD_MUTEX_ERRORCHECK and the current thread already holds this mutex

@see libc/intrin/pthread_mutex_trylock.c

pthread_mutex_unlock

Releases mutex.

This function does nothing in vfork() children.

@param

struct pthread_mutex_t* mutex

@return

int: 0 on success or error number on failure

@raises EPERM if in error check mode and not owned by caller

@vforksafe

@see libc/intrin/pthread_mutex_unlock.c

pthread_mutexattr_destroy

Destroys mutex attr.

@param

struct pthread_mutexattr_t* attr

@return

int: 0 on success, or error number on failure

@see libc/intrin/pthread_mutexattr_destroy.c

pthread_mutexattr_getpshared

Gets mutex process sharing.

@param

struct pthread_mutexattr_t* attr

int* pshared

is set to one of the following

PTHREAD_PROCESS_PRIVATE (default)
PTHREAD_PROCESS_SHARED

@return

int: 0 on success, or error on failure

@see libc/intrin/pthread_mutexattr_getpshared.c

pthread_mutexattr_gettype

Gets mutex type.

@param

struct pthread_mutexattr_t* attr

int* type

will be set to one of these on success

PTHREAD_MUTEX_NORMAL
PTHREAD_MUTEX_RECURSIVE
PTHREAD_MUTEX_ERRORCHECK

@return

int: 0 on success, or error on failure

@see libc/intrin/pthread_mutexattr_gettype.c

pthread_mutexattr_init

Initializes mutex attr.

@param

struct pthread_mutexattr_t* attr

@return

int: 0 on success, or error number on failure

@see libc/intrin/pthread_mutexattr_init.c

pthread_mutexattr_setpshared

Sets mutex process sharing.

@param

struct pthread_mutexattr_t* attr

int pshared

can be one of

PTHREAD_PROCESS_PRIVATE (default)
PTHREAD_PROCESS_SHARED

@return

int: 0 on success, or error on failure

@raises EINVAL if pshared is invalid

@see libc/intrin/pthread_mutexattr_setpshared.c

pthread_mutexattr_settype

Sets mutex type.

@param

struct pthread_mutexattr_t* attr

int type

can be one of

PTHREAD_MUTEX_NORMAL
PTHREAD_MUTEX_DEFAULT
PTHREAD_MUTEX_RECURSIVE
PTHREAD_MUTEX_ERRORCHECK

@return

int: 0 on success, or error on failure

@raises EINVAL if type is invalid

@see libc/intrin/pthread_mutexattr_settype.c

pthread_once

Ensures initialization function is called exactly once, e.g.

static void *g_factory;

static void InitFactory(void) {
  g_factory = expensive();
}

void *GetFactory(void) {
  static pthread_once_t once = PTHREAD_ONCE_INIT;
  pthread_once(&once, InitFactory);
  return g_factory;
}

If multiple threads try to initialize at the same time, then only a single one will call init and the other threads will block until the winner has returned from the init function.

@param

struct pthread_once_t* once
void(*)() init

@return

int: 0 on success, or errno on error

@see libc/thread/pthread_once.c

pthread_pause_np

Yields hyperthread.

@return

void

@see libc/intrin/pthread_pause_np.c

pthread_rwlock_destroy

Destroys read-write lock.

@param

struct pthread_rwlock_t* rwlock

@return

int: 0 on success, or error number on failure

@raise EINVAL if any threads still hold the lock

@see libc/thread/pthread_rwlock_destroy.c

pthread_rwlock_init

Initializes read-write lock.

@param

struct pthread_rwlock_t* rwlock
const char* attr: may be null

@return

int: 0 on success, or error number on failure

@see libc/thread/pthread_rwlock_init.c

pthread_rwlock_rdlock

Acquires read lock on read-write lock.

@param

struct pthread_rwlock_t* rwlock

@return

int: 0 on success, or errno on error

@see libc/thread/pthread_rwlock_rdlock.c

pthread_rwlock_tryrdlock

Attempts acquiring read lock on read-write lock.

@param

struct pthread_rwlock_t* rwlock

@return

int: 0 if lock was acquired, otherwise an errno

@raise EBUSY if lock is currently held in write mode

@raise EAGAIN if maximum number of read locks are held

@raise EINVAL if rwlock doesn't refer to an initialized r/w lock

@see libc/thread/pthread_rwlock_tryrdlock.c

pthread_rwlock_trywrlock

Attempts acquiring write lock on read-write lock.

@param

struct pthread_rwlock_t* rwlock

@return

int: 0 if lock was acquired, otherwise an errno

@raise EBUSY if lock is currently held in read or write mode

@raise EINVAL if rwlock doesn't refer to an initialized r/w lock

@see libc/thread/pthread_rwlock_trywrlock.c

pthread_rwlock_unlock

Unlocks read-write lock.

@param

struct pthread_rwlock_t* rwlock

@return

int: 0 on success, or errno on error

@raise EINVAL if lock is in a bad state

@see libc/thread/pthread_rwlock_unlock.c

pthread_rwlock_wrlock

Acquires write lock on read-write lock.

@param

struct pthread_rwlock_t* rwlock

@return

int: 0 on success, or errno on error

@see libc/thread/pthread_rwlock_wrlock.c

pthread_rwlockattr_destroy

Destroys read-write lock attributes.

@param

char* attr

@return

int: 0 on success, or error on failure

@see libc/thread/pthread_rwlockattr_destroy.c

pthread_rwlockattr_getpshared

Gets read-write lock process sharing.

@param

const char* attr

int* pshared

is set to one of the following

PTHREAD_PROCESS_PRIVATE (default)
PTHREAD_PROCESS_SHARED (unsupported)

@return

int: 0 on success, or error on failure

@see libc/thread/pthread_rwlockattr_getpshared.c

pthread_rwlockattr_init

Initializes read-write lock attributes.

@param

char* attr

@return

int: 0 on success, or error on failure

@see libc/thread/pthread_rwlockattr_init.c

pthread_rwlockattr_setpshared

Sets read-write lock process sharing.

@param

char* attr

int pshared

can be one of

PTHREAD_PROCESS_PRIVATE (default)
PTHREAD_PROCESS_SHARED (unsupported)

@return

int: 0 on success, or error on failure

@raises EINVAL if pshared is invalid

@see libc/thread/pthread_rwlockattr_setpshared.c

pthread_self

Returns current POSIX thread.

@return

unsigned long

@asyncsignalsafe

@see libc/thread/pthread_self.c

pthread_setcanceltype

Sets cancelation strategy.

@param

int type

may be one of:

PTHREAD_CANCEL_DEFERRED (default)
PTHREAD_CANCEL_ASYNCHRONOUS

int* oldtype

optionally receives old value

@return

int: 0 on success, or errno on error

@raise ENOTSUP on Windows if asynchronous

@raise EINVAL if type has bad value

@see pthread_cancel() for docs

@see libc/thread/pthread_setcanceltype.c

pthread_setname_np

Registers custom name of thread with system, e.g.

void *worker(void *arg) {
  pthread_setname_np(pthread_self(), "justine");
  pause();
  return 0;
}

int main(int argc, char *argv[]) {
  pthread_t id;
  pthread_create(&id, 0, worker, 0);
  pthread_join(id, 0);
}

ProTip: The htop software is good at displaying thread names.

@param

unsigned long thread
const char* name

@return

int: 0 on success, or errno on error

@raise ERANGE if length of name exceeded system limit, in which case the name may have still been set with os using truncation

@raise ENOSYS on Windows and AMD64-XNU

@see pthread_getname_np()

@see libc/thread/pthread_setname_np.c

pthread_setschedparam

Changes scheduling of thread, e.g.

struct sched_param p = {sched_get_priority_min(SCHED_OTHER)};
pthread_setschedparam(thread, SCHED_OTHER, &p);

@param

unsigned long thread

int policy

may be one of:

SCHED_OTHER the default policy
SCHED_FIFO for real-time scheduling (usually needs root)
SCHED_RR for round-robin scheduling (usually needs root)
SCHED_IDLE for lowest effort (Linux and FreeBSD only)
SCHED_BATCH for "batch" style execution of processes if supported (Linux), otherwise it's treated as SCHED_OTHER

struct sched_param* param

@return

int

@raise ENOSYS on XNU, Windows, OpenBSD

@raise EPERM if not authorized to use scheduler in question (e.g. trying to use a real-time scheduler as non-root on Linux) or possibly because pledge() was used and isn't allowing this

@see sched_get_priority_min()

@see sched_get_priority_max()

@see sched_setscheduler()

@see libc/thread/pthread_setschedparam.c

pthread_setschedprio

Sets scheduler parameter on thread.

@param

unsigned long thread
int prio

@return

int

@see libc/thread/pthread_setschedprio.c

pthread_sigmask

Examines and/or changes blocked signals on current thread.

@param

int how
const unsigned long* set
unsigned long* old

@return

int: 0 on success, or errno on error

@asyncsignalsafe

@see libc/thread/pthread_sigmask.c

pthread_spin_destroy

Destroys spin lock.

@param

struct pthread_spinlock_t* spin

@return

int: 0 on success, or errno on error

@see libc/intrin/pthread_spin_destroy.c

pthread_spin_init

Initializes spin lock.

@param

struct pthread_spinlock_t* spin
int pshared: is ignored, since this implementation always permits multiple processes to operate on the same spin locks

@return

int: 0 on success, or errno on error

@see pthread_spin_destroy

@see pthread_spin_lock

@see libc/intrin/pthread_spin_init.c

pthread_spin_lock

Acquires spin lock, e.g.

pthread_spinlock_t lock;
pthread_spin_init(&lock, PTHREAD_PROCESS_PRIVATE);
pthread_spin_lock(&lock);
// do work...
pthread_spin_unlock(&lock);
pthread_spin_destroy(&lock);

This function has undefined behavior when spin wasn't intialized, was destroyed, or if the lock's already held by the calling thread.

@param

struct pthread_spinlock_t* spin

@return

int: 0 on success, or errno on error

@see pthread_spin_trylock

@see pthread_spin_unlock

@see pthread_spin_init

@see libc/intrin/pthread_spin_lock.c

pthread_spin_trylock

Acquires spin lock if available.

This function has undefined behavior when spin wasn't intialized, was destroyed, or if the lock's already held by the calling thread.

@param

struct pthread_spinlock_t* spin

@return

int: 0 on success, or errno on error

@raise EBUSY if lock is already held

@see libc/intrin/pthread_spin_trylock.c

pthread_spin_unlock

Releases spin lock.

Calling this function when the lock isn't held by the calling thread has undefined behavior.

@param

struct pthread_spinlock_t* spin

@return

int: 0 on success, or errno on error

@see pthread_spin_lock

@see libc/intrin/pthread_spin_unlock.c

pthread_yield_np

Yields current thread's remaining timeslice to operating system.

@return

int: 0 on success, or error number on failure

@see libc/calls/pthread_yield_np.c

ptrace

Traces process.

This API is terrible. Consider using sys_ptrace().

@param

int request: can be PTRACE_xxx
...

@return

long

@note de facto linux only atm

@vforksafe

@see libc/calls/ptrace.c

ptsname

Gets name subordinate pseudoteletypewriter.

@param

int fd

@return

char*: static string path on success, or NULL w/ errno

@see libc/calls/ptsname.c

ptsname_r

Gets name subordinate pseudoteletypewriter.

@param

int fd
char* buf
unsigned long size

@return

int: 0 on success, or errno on error

@see libc/calls/ptsname_r.c

punpckhbw

Interleaves high bytes.

@param

unsigned char* a
const unsigned char* b
const unsigned char* c

@return

void

@mayalias

@see libc/intrin/punpckhbw.c

punpckhwd

Interleaves high words.

     0  1  2  3  4  5  6  7
  B  aa bb cc dd EE FF GG HH
  C  ii jj kk ll MM NN OO PP
                 └┤ └┤ └┤ └┤
         ┌────────┘  │  │  │
         │     ┌─────┘  │  │
         │     │     ┌──┘  │
     ┌───┤ ┌───┤ ┌───┤ ┌───┤
→ A  EE MM FF NN GG OO HH PP

@param

unsigned short* a
const unsigned short* b
const unsigned short* c

@return

void

@mayalias

@see libc/intrin/punpckhwd.c

punpcklbw

Interleaves low bytes.

     0 1 2 3 4 5 6 7 8 9 A B C D E F
  B  A B C D E F G H i j k l m n o p
  C  Q R S T U V W X y z α σ π μ τ ε
     │ │ │ │ │ │ │ │
     │ │ │ └─────┐
     │ │ └───┐   │  etc...
     │ └─┐   │   │
     ├─┐ ├─┐ ├─┐ ├─┐
→ A  A Q B R C S D T E U F V G W H X

@param

unsigned char* a
const unsigned char* b
const unsigned char* c

@return

void

@mayalias

@see libc/intrin/punpcklbw.c

punpcklwd

Interleaves low words.

     0  1  2  3  4  5  6  7
  B  AA BB CC DD ee ff gg hh
  C  II JJ KK LL mm nn oo pp
     ├┘ ├┘ ├┘ ├┘
     │  │  │  └────────┐
     │  │  └─────┐     │
     │  └──┐     │     │
     ├───┐ ├───┐ ├───┐ ├───┐
→ A  AA II BB JJ CC KK DD LL

@param

unsigned short* a
const unsigned short* b
const unsigned short* c

@return

void

@mayalias

@see libc/intrin/punpcklwd.c

putchar

Writes byte to stdout.

@param

int c

@return

int: c (as unsigned char) if written or -1 w/ errno

@see libc/stdio/putchar.c

putchar_unlocked

Writes byte to stdout.

@param

int c

@return

int: c (as unsigned char) if written or -1 w/ errno

@see libc/stdio/putchar_unlocked.c

puts

Writes string w/ trailing newline to stdout.

@param

const char* s

@return

int: non-negative number on success, or EOF on error with errno set and the ferror(stdout) state is updated

@see libc/stdio/puts.c

puts_unlocked

Writes string w/ trailing newline to stdout.

@param

const char* s

@return

int: non-negative number on success, or EOF on error with errno set and the ferror(stdout) state is updated

@see libc/stdio/puts_unlocked.c

pututxline

@param

struct utmpx* p

@return

struct utmpx*

@see libc/runtime/utmp.c

putwc_unlocked

Writes wide character to stream.

@param

int wc
struct FILE* f

@return

unsigned int: wc if written or -1 w/ errno

@see libc/stdio/putwc_unlocked.c

putwchar

Writes wide character to stdout.

@param

int wc

@return

unsigned int: wc if written or -1 w/ errno

@see libc/stdio/putwchar.c

putwchar_unlocked

Writes wide character to stdout.

@param

int wc

@return

unsigned int: wc if written or -1 w/ errno

@see libc/stdio/putwchar_unlocked.c

pwrite

Writes to file at offset.

This function never changes the current position of fd.

@param

int fd: is something open()'d earlier, noting pipes might not work
void* buf: is copied from, cf. copy_file_range(), sendfile(), etc.
unsigned long size: in range [1..0x7ffff000] is reasonable
long offset: is bytes from start of file at which write begins, which can exceed or overlap the end of file, in which case your file will be extended

@return

long: [1..size] bytes on success, or -1 w/ errno; noting zero is impossible unless size was passed as zero to do an error check

@see pread(), write()

@cancelationpoint

@asyncsignalsafe

@vforksafe

@see libc/calls/pwrite.c

qsort

Sorts array.

This implementation uses the Quicksort routine from Bentley & McIlroy's "Engineering a Sort Function", 1992, Bell Labs.

This version differs from Bentley & McIlroy in the following ways:

The partition value is swapped into a[0] instead of being stored out of line.
The swap function can swap 32-bit aligned elements on 64-bit platforms instead of swapping them as byte-aligned.
It uses David Musser's introsort algorithm to fall back to heapsort(3) when the recursion depth reaches 2*lg(n + 1). This avoids quicksort's quadratic behavior for pathological input without appreciably changing the average run time.
Tail recursion is eliminated when sorting the larger of two subpartitions to save stack space.

@param

void* a: is base of array
unsigned long n: is item count
unsigned long es: is item width
int(*)() cmp: is a callback returning <0, 0, or >0

@return

void

@see mergesort()

@see heapsort()

@see qsort_r()

@see djbsort()

@see libc/mem/qsort.c

qsort_r

Sorts array w/ optional callback parameter.

@param

void* a: is base of array
unsigned long n: is item count
unsigned long es: is item width
int(*)() cmp: is a callback returning <0, 0, or >0
void* arg: is passed to callback

@return

void

@see qsort()

@see libc/mem/qsort.c

quick_exit

Exits process faster.

@param

int exitcode: is masked with 255

@noreturn

@see libc/intrin/quick_exit.c

radix_sort_int32

@param

int* A
unsigned long n

@return

int

@see libc/mem/radix_sort_int32.c

radix_sort_int64

@param

long* A
unsigned long n

@return

int

@see libc/mem/radix_sort_int64.c

raise

Sends signal to self.

This is basically the same as:

pthread_kill(pthread_self(), sig);

Note SIG_DFL still results in process death for most signals.

POSIX defines raise() errors as returning non-zero and makes setting errno optional. Every platform we've tested in our support vector returns -1 with errno on error (like a normal system call).

@param

int sig: can be SIGALRM, SIGINT, SIGTERM, SIGKILL, etc.

@return

int: 0 on success, or -1 w/ errno

@raise EINVAL if sig is invalid

@asyncsignalsafe

@see libc/calls/raise.c

rand

Returns 31-bit linear congruential pseudorandom number, e.g.

int x = rand();
assert(x >= 0);

This function always returns a positive number. If srand() isn't called, then it'll return the same sequence each time your program runs. Faster and more modern alternatives exist to this function.

This function is not thread safe in the sense that multiple threads might simultaneously generate the same random values.

@return

int

@note this function does well on bigcrush and practrand

@note this function is not intended for cryptography

@see lemur64(), _rand64(), rdrand()

@threadunsafe

@see libc/stdio/rand.c

random

@return

long

@see libc/stdio/random.c

rawmemchr

Returns pointer to first instance of character.

@param

void* s
int c: is search byte which is masked with 255

@return

void*: is pointer to first instance of c

@see libc/str/rawmemchr.c

rawmemchr16

Returns pointer to first instance of character in range.

@param

void* s
int c

@return

void*

@see libc/str/rawmemchr16.c

rdrand

Retrieves 64-bits of hardware random data from RDRAND instruction.

If RDRAND isn't available (we check CPUID and we also disable it automatically for microarchitectures where it's slow or buggy) then we try getrandom(), ProcessPrng(), or sysctl(KERN_ARND). If those aren't available then we try /dev/urandom and if that fails, we try getauxval(AT_RANDOM), and if not we finally use RDTSC and getpid().

@return

unsigned long

@note this function could block a nontrivial time on old computers

@note this function is indeed intended for cryptography

@note this function takes around 300 cycles

@see rngset(), rdseed(), _rand64()

@asyncsignalsafe

@vforksafe

@see libc/calls/rdrand.c

rdseed

Retrieves 64-bits of true random data from RDSEED instruction.

If RDSEED isn't available, we'll try RDRAND (which we automatically disable for microarchitectures where it's known to be slow or buggy). If RDRAND isn't available then we try getrandom(), ProcessPrng(), or sysctl(KERN_ARND). If those aren't available then we try /dev/urandom and if that fails, we use RDTSC and getpid().

@return

unsigned long

@note this function could block a nontrivial time on old computers

@note this function is indeed intended for cryptography

@note this function takes around 800 cycles

@see rngset(), rdrand(), _rand64()

@asyncsignalsafe

@vforksafe

@see libc/stdio/rdseed.c

read

Reads data from file descriptor.

This function changes the current file position. For documentation on file position behaviors and gotchas, see the lseek() function. This function may be used on socket file descriptors, including on Windows.

@param

int fd: is something open()'d earlier
void* buf: is copied into, cf. copy_file_range(), sendfile(), etc.
unsigned long size: in range [1..0x7ffff000] is reasonable

@return

long: [1..size] bytes on success, 0 on EOF, or -1 w/ errno; with exception of size==0, in which case return zero means no error

@raise EBADF if fd is negative or not an open file descriptor

@raise EBADF if fd is open in O_WRONLY mode

@raise EFAULT if size is nonzero and buf points to bad memory

@raise EPERM if pledge() is in play without the stdio promise

@raise EIO if low-level i/o error happened

@raise EINTR if signal was delivered instead

@raise ECANCELED if thread was cancelled in masked mode

@raise ENOTCONN if fd is a socket and it isn't connected

@raise ECONNRESET if socket peer forcibly closed connection

@raise ETIMEDOUT if socket transmission timeout occurred

@raise EAGAIN if O_NONBLOCK is in play and read needs to block, or SO_RCVTIMEO is in play and the time interval elapsed

@raise ENOBUFS is specified by POSIX

@raise ENXIO is specified by POSIX

@cancelationpoint

@asyncsignalsafe

@restartable

@vforksafe

@see libc/calls/read.c

readansi

Reads single keystroke or control sequence from character device.

When reading ANSI UTF-8 text streams, characters and control codes are oftentimes encoded as multi-byte sequences. This function knows how long each sequence is, so that each read consumes a single thing from the underlying file descriptor, e.g.

"a"               ALFA
"\316\261"        ALPHA
"\e[38;5;202m"    ORANGERED
"\e[A"            UP
"\e\e[A"          ALT-UP
"\001"            CTRL-ALFA
"\e\001"          ALT-CTRL-ALFA
"\eOP"            PF1
"\000"            NUL
"\e]rm -rf /\e\\" OSC
"\302\233A"       UP
"\300\200"        NUL

This routine generalizes to ascii, utf-8, chorded modifier keys, function keys, color codes, c0/c1 control codes, cursor movement, mouse movement, etc.

Userspace buffering isn't required, since ANSI escape sequences and UTF-8 are decoded without peeking. Noncanonical overlong encodings can cause the stream to go out of sync. This function recovers such events by ignoring continuation bytes at the beginning of each read.

@param

int fd
char* p: is guaranteed to receive a NUL terminator if n>0
unsigned long n

@return

long: number of bytes read (helps differentiate "\0" vs. "")

@see examples/ttyinfo.c

@see ANSI X3.64-1979

@see ISO/IEC 6429

@see FIPS-86

@see ECMA-48

@see libc/calls/readansi.c

readlink

Reads symbolic link.

@param

const char* path: must be a symbolic link pathname
char* buf: will receive symbolic link contents, and won't be modified unless the function succeeds (with the exception of no-malloc nt) and this buffer will *not* be nul-terminated
unsigned long bufsiz

@return

long: number of bytes written to buf, or -1 w/ errno; if the return is equal to bufsiz then truncation may have occurred

@see readlinkat(AT_FDCWD, ...) for modern version of this

@error EINVAL if path isn't a symbolic link

@asyncsignalsafe

@see libc/calls/readlink.c

readlinkat

Reads symbolic link.

This does *not* nul-terminate the buffer.

@param

int dirfd: is normally AT_FDCWD but if it's an open directory and file is a relative path, then file is opened relative to dirfd
const char* path: must be a symbolic link pathname
char* buf: will receive symbolic link contents, and won't be modified unless the function succeeds (with the exception of no-malloc nt) and this buffer will *not* be nul-terminated
unsigned long bufsiz

@return

long: number of bytes written to buf, or -1 w/ errno; if the return is equal to bufsiz then truncation may have occurred

@raise EINVAL if path isn't a symbolic link

@raise ENOENT if path didn't exist

@raise ENOTDIR if parent component existed that's not a directory

@raise ENOTDIR if base component ends with slash and is not a dir

@raise ENAMETOOLONG if symlink-resolved path length exceeds PATH_MAX

@raise ENAMETOOLONG if component in path exists longer than NAME_MAX

@raise EBADF on relative path when dirfd isn't open or AT_FDCWD

@raise ELOOP if a loop was detected resolving parent components

@asyncsignalsafe

@see libc/calls/readlinkat.c

readv

Reads data to multiple buffers.

This is the same thing as read() except it has multiple buffers. This yields a performance boost in situations where it'd be expensive to stitch data together using memcpy() or issuing multiple syscalls. This wrapper is implemented so that readv() calls where iovlen<2 may be passed to the kernel as read() instead. This yields a 100 cycle performance boost in the case of a single small iovec.

@param

int fd
struct iovec* iov
int iovlen

@return

long: number of bytes actually read, or -1 w/ errno

@cancelationpoint

@restartable

@see libc/calls/readv.c

_real1

Generates number on [0,1]-real-interval, e.g.

double x = _real1(lemur64())

@param

unsigned long x

@return

double

@see lemur64(), mt19937()

@see libc/stdio/real1.c

_real2

Generates number on [0,1)-real-interval, e.g.

double x = _real2(lemur64())

@param

unsigned long x

@return

double

@see lemur64(), mt19937()

@see libc/stdio/real2.c

_real3

Generates number on (0,1)-real-interval, e.g.

double x = _real3(lemur64())

@param

unsigned long x

@return

double

@see lemur64(), mt19937()

@see libc/stdio/real3.c

realloc

Allocates / resizes / frees memory, e.g.

Returns a pointer to a chunk of size n that contains the same data as does chunk p up to the minimum of (n, p's size) bytes, or null if no space is available.

If p is NULL, then realloc() is equivalent to malloc().

If p is not NULL and n is 0, then realloc() shrinks the allocation to zero bytes. The allocation isn't freed and still continues to be a uniquely allocated piece of memory. However it should be assumed that zero bytes can be accessed, since that's enforced by MODE=asan.

The returned pointer may or may not be the same as p. The algorithm prefers extending p in most cases when possible, otherwise it employs the equivalent of a malloc-copy-free sequence.

Please note that p is NOT free()'d should realloc() fail, thus:

if ((p2 = realloc(p, n2))) {
  p = p2;
  ...
} else {
  ...
}

if n is for fewer bytes than already held by p, the newly unused space is lopped off and freed if possible.

The old unix realloc convention of allowing the last-free'd chunk to be used as an argument to realloc is not supported.

@param

void* p: is address of current allocation or NULL
unsigned long n: is number of bytes needed

@return

void*: rax is result, or NULL w/ errno w/o free(p)

@see dlrealloc()

@see libc/mem/realloc.c

realloc_in_place

Resizes the space allocated for p to size n, only if this can be done without moving p (i.e., only if there is adjacent space available if n is greater than p's current allocated size, or n is less than or equal to p's size). This may be used instead of plain realloc if an alternative allocation strategy is needed upon failure to expand space, for example, reallocation of a buffer that must be memory-aligned or cleared. You can use realloc_in_place to trigger these alternatives only when needed.

@param

void* p: is address of current allocation
unsigned long n: is number of bytes needed

@return

void*: rax is result, or NULL w/ errno

@see dlrealloc_in_place()

@see libc/mem/hook_realloc_in_place.c

reallocarray

Manages array memory, the BSD way.

@param

void* ptr: may be NULL for malloc() behavior
unsigned long nmemb: may be 0 for free() behavior; shrinking is promised too
unsigned long itemsize

@return

void*: new address or NULL w/ errno and ptr is NOT free()'d

@see libc/mem/reallocarray.c

reboot

Reboots system.

The howto argument may be one of the following:

RB_AUTOBOOT
RB_POWER_OFF
RB_HALT_SYSTEM
RB_SW_SUSPEND (linux and windows only)
RB_KEXEC (linux only)
RB_ENABLE_CAD (linux only)
RB_DISABLE_CAD (linux only)

There's an implicit sync() operation before the reboot happens. This can be prevented by or'ing howto with RB_NOSYNC. Setting this option will also prevent apps on Windows from having time to close themselves.

@param

int howto

@return

int

@see libc/calls/reboot.c

recv

Receives data from network socket.

@param

int fd: is the file descriptor returned by socket()
void* buf: is where received network data gets copied
unsigned long size: is the byte capacity of buf
int flags: can have MSG_OOB, MSG_PEEK, MSG_DONTWAIT, MSG_WAITALL

@return

long: number of bytes received, 0 on remote close, or -1 w/ errno

@error EINTR, EHOSTUNREACH, ECONNRESET (UDP ICMP Port Unreachable), EPIPE (if MSG_NOSIGNAL), EMSGSIZE, ENOTSOCK, EFAULT, etc.

@cancelationpoint

@asyncsignalsafe

@restartable (unless SO_RCVTIMEO)

@see libc/sock/recv.c

recvfrom

Receives data from network.

This function blocks unless MSG_DONTWAIT is passed. In that case, the non-error EWOULDBLOCK might be returned. It basically means we didn't wait around to learn an amount of bytes were written that we know in advance are guaranteed to be atomic.

@param

int fd: is the file descriptor returned by socket()
void* buf: is where received network data gets copied
unsigned long size: is the byte capacity of buf
int flags: can have MSG_OOB, MSG_PEEK, and MSG_DONTWAIT
struct sa* opt_out_srcaddr: receives the binary ip:port of the data's origin
unsigned int* opt_inout_srcaddrsize: is srcaddr capacity which gets updated

@return

long: number of bytes received, 0 on remote close, or -1 w/ errno

@error EINTR, EHOSTUNREACH, ECONNRESET (UDP ICMP Port Unreachable), EPIPE (if MSG_NOSIGNAL), EMSGSIZE, ENOTSOCK, EFAULT, etc.

@cancelationpoint

@asyncsignalsafe

@restartable (unless SO_RCVTIMEO)

@see libc/sock/recvfrom.c

recvmsg

Sends a message from a socket.

Note: Ancillary data currently isn't polyfilled across platforms.

@param

int fd

is the file descriptor returned by socket()

struct msg2* msg

is a pointer to a struct msghdr containing all the allocated

   buffers where to store incoming data.

int flags

MSG_OOB, MSG_DONTROUTE, MSG_PARTIAL, MSG_NOSIGNAL, etc.

@return

long: number of bytes received, or -1 w/ errno

@error EINTR, EHOSTUNREACH, ECONNRESET (UDP ICMP Port Unreachable), EPIPE (if MSG_NOSIGNAL), EMSGSIZE, ENOTSOCK, EFAULT, etc.

@cancelationpoint

@asyncsignalsafe

@restartable (unless SO_RCVTIMEO)

@see libc/sock/recvmsg.c

regerror

Converts regular expression error code to string.

@param

int e: is error code
struct regex_t* preg
char* buf
unsigned long size

@return

unsigned long: number of bytes needed to hold entire string

@see third_party/regex/regerror.c

remainder

Returns remainder of dividing 𝑥 by 𝑦.

@param

double x
double y

@return

double

@see libc/tinymath/remainder.c

remainderl

Returns remainder of dividing 𝑥 by 𝑦.

@param

long double x
long double y

@return

long double

@see libc/tinymath/remainderl.c

remove

Deletes "file" or empty directory associtaed with name.

@param

const char* name

@return

int: 0 on success or -1 w/ errno

@see unlink() and rmdir() which this abstracts

@see libc/calls/remove.c

remque

@param

void* element

@return

void

@see third_party/musl/insque.c

remquo

Computes remainder and part of quotient.

@param

double x
double y
int* quo

@return

double

@see libc/tinymath/remquo.c

remquof

Computes remainder and part of quotient.

@param

float x
float y
int* quo

@return

float

@see libc/tinymath/remquof.c

remquol

Computes remainder and part of quotient.

@param

long double x
long double y
int* quo

@return

long double

@see libc/tinymath/remquol.c

rename

Moves file the Unix way.

This is generally an atomic operation with the file system, since all it's doing is changing a name associated with an inode. However, that means rename() doesn't permit your oldpathname and newpathname to be on separate file systems, in which case this returns EXDEV. That's also the case on Windows.

@param

const char* oldpathname
const char* newpathname

@return

int: 0 on success or -1 w/ errno

@asyncsignalsafe

@see libc/calls/rename.c

renameat

Renames files relative to directories.

@param

int olddirfd: is normally AT_FDCWD but if it's an open directory and oldpath is relative, then oldpath become relative to dirfd
const char* oldpath
int newdirfd: is normally AT_FDCWD but if it's an open directory and newpath is relative, then newpath become relative to dirfd
const char* newpath

@return

int: 0 on success, or -1 w/ errno

@see libc/calls/renameat.c

ReplenishTokens

Atomically increments all signed bytes in array, without overflowing.

Under the token bucket model, operations are denied by default unless tokens exist to allow them. This function must be called periodically from a single background thread to replenish the buckets with tokens. For example, this function may be called once per second which allows one operation per second on average with bursts up to 127 per second. This policy needn't be applied uniformly. For example, you might find out that a large corporation funnels all their traffic through one ip address, so you could replenish their tokens multiple times a second.

@param

_Atomic unsigned long* w: is word array that aliases byte token array
unsigned long n: is number of 64-bit words in w array

@return

void

@see net/http/tokenbucket.c

res_init

@return

int

@see third_party/musl/res_init.c

res_querydomain

@param

const char* name
const char* domain
int class
int type
unsigned char* dest
int len

@return

int

@see third_party/musl/res_querydomain.c

rewind

Moves standard i/o stream to beginning of file.

Like fseek(), this function can be used to restore a stream from the EOF state, without reopening it.

@param

struct FILE* f

@return

void

@see libc/stdio/rewind.c

rint

Rounds to integer in current rounding mode.

The floating-point exception FE_INEXACT is raised if the result is different from the input.

@param

double x

@return

double

@see libc/tinymath/rint.c

rintf

Rounds to integer in current rounding mode.

The floating-point exception FE_INEXACT is raised if the result is different from the input.

@param

float x

@return

float

@see libc/tinymath/rintf.c

rldecode

Thirteen byte decompressor.

@param

di: points to output buffer
si: points to uint8_t {len₁,byte₁}, ..., {0,0}

@return

@mode long,legacy,real

@see libc/nexgen32e/rldecode.S

_rlinit_vesa

Routine to activate additional VESA functionality if the user holds down a magic key, when booting from bare metal.

@return

: CF = 0 if we decided to set a new video mode, CF = 1 otherwise

@see libc/vga/rlinit-vesa.S

rmdir

Deletes empty directory.

@param

const char* path

@return

int: 0 on success, or -1 w/ errno

@see libc/calls/rmdir.c

rmrf

Recursively removes file or directory.

@param

const char* path

@return

int: 0 on success, or -1 w/ errno

@see libc/x/rmrf.c

round

Rounds 𝑥 to nearest integer, away from zero.

@param

double x

@return

double

@see libc/tinymath/round.c

roundf

Rounds 𝑥 to nearest integer, away from zero.

@param

float x

@return

float

@see libc/tinymath/roundf.c

rt_add

@param

void* buf
int bufl

@return

void

@see libc/tinymath/randtest.c

rt_end

@param

double* r_ent
double* r_chisq
double* r_mean
double* r_montepicalc
double* r_scc

@return

void

@see libc/tinymath/randtest.c

rt_init

@param

int binmode

@return

void

@see libc/tinymath/randtest.c

rusage_add

Accumulates resource statistics in y to x.

@param

struct rusage* x
struct rusage* y

@return

void

@see libc/calls/rusage_add.c

scalb

Returns 𝑥 × 2ʸ.

@param

double x
double y

@return

double

@see libc/tinymath/scalb.c

scalbf

@param

float x
float fn

@return

float

@see libc/tinymath/scalbf.c

scalbln

Returns 𝑥 × 2ʸ.

@param

double x
long n

@return

double

@see libc/tinymath/scalbln.c

scalblnf

Returns 𝑥 × 2ʸ.

@param

float x
long n

@return

float

@see libc/tinymath/scalblnf.c

scalblnl

@param

long double x
long n

@return

long double

@see libc/intrin/scalblnl.c

scalbn

Returns 𝑥 × 2ʸ.

@param

double x
int n

@return

double

@see libc/intrin/scalbn.c

scalbnf

Returns 𝑥 × 2ʸ.

@param

float x
int n

@return

float

@see libc/intrin/scalbnf.c

scalbnl

Returns 𝑥 × 2ʸ.

@param

long double x
int n

@return

long double

@see libc/intrin/scalbnl.c

scandir

@param

const char* path
struct dirent*** res
int(*)() sel
int(*)() cmp

@return

int

@see libc/stdio/scandir.c

scanf

Standard input decoder.

@param

const char* fmt
...

@return

int

@see libc/fmt/vcscanf.h

@see libc/stdio/scanf.c

sched_get_priority_max

Returns maximum sched_param::sched_priority for policy.

@param

int policy

@return

int: priority, or -1 w/ errno

@raise ENOSYS on XNU, Windows, OpenBSD

@raise EINVAL if policy is invalid

@see libc/calls/sched_get_priority_max.c

sched_get_priority_min

Returns minimum sched_param::sched_priority for policy.

@param

int policy

@return

int: priority, or -1 w/ errno

@raise ENOSYS on XNU, Windows, OpenBSD

@raise EINVAL if policy is invalid

@see libc/calls/sched_get_priority_min.c

sched_getcpu

Returns ID of CPU on which thread is currently scheduled.

@return

int: cpu number on success, or -1 w/ errno

@see libc/calls/sched_getcpu.c

sched_getparam

Gets scheduler policy parameter.

@param

int pid
struct p* param

@return

int: 0 on success, or -1 w/ errno

@raise ENOSYS on XNU, Windows, OpenBSD

@see libc/calls/sched_getparam.c

sched_getscheduler

Gets scheduler policy for pid.

@param

int pid: is the id of the process whose scheduling policy should be queried. Setting pid to zero means the same thing as getpid(). This applies to all threads associated with the process. Linux is special; the kernel treats this as a thread id (noting that getpid() == gettid() is always the case on Linux for the main thread) and will only take effect for the specified tid. Therefore this function is POSIX-compliant iif !__threaded.

@return

int: scheduler policy, or -1 w/ errno

@error ESRCH if pid not found

@error EPERM if not permitted

@error EINVAL if pid is negative on Linux

@see libc/calls/sched_getscheduler.c

sched_rr_get_interval

Returns round-robin SCHED_RR quantum for pid.

@param

int pid: is id of process (where 0 is same as getpid())
struct timespec* tp: receives output interval

@return

int: 0 on success, or -1 w/ errno

@error ENOSYS if not Linux or FreeBSD

@error EFAULT if tp memory is invalid

@error EINVAL if invalid pid

@error ESRCH if could not find pid

@see libc/calls/sched_rr_get_interval.c

sched_setparam

Sets scheduler policy parameter.

@param

int pid
struct sched_param* param

@return

int: 0 on success, or -1 w/ errno

@raise ENOSYS on XNU, Windows, OpenBSD

@vforksafe

@see libc/calls/sched_setparam.c

sched_setscheduler

Sets scheduling policy of process, e.g.

struct sched_param p = {sched_get_priority_max(SCHED_OTHER)};
LOGIFNEG1(sched_setscheduler(0, SCHED_OTHER, &p));

Processes with numerically higher priority values are scheduled before processes with numerically lower priority values.

@param

int pid

is the id of the process whose scheduling policy should be changed. Setting pid to zero means the same thing as getpid(). This applies to all threads associated with the process. Linux is special; the kernel treats this as a thread id (noting that getpid() == gettid() is always the case on Linux for the main thread) and will only take effect for the specified tid. Therefore this function is POSIX-compliant iif !__threaded.

int policy

specifies the kernel's timesharing strategy.

The policy must have one of:

SCHED_OTHER (or SCHED_NORMAL) for the default policy
SCHED_RR for real-time round-robin scheduling
SCHED_FIFO for real-time first-in first-out scheduling
SCHED_BATCH for "batch" style execution of processes if supported (Linux), otherwise it's treated as SCHED_OTHER
SCHED_IDLE for running very low priority background jobs if it's supported (Linux), otherwise this is SCHED_OTHER. Pledging away scheduling privilege is permanent for your process; if a subsequent attempt is made to restore the SCHED_OTHER policy then this system call will EPERM (but on older kernels like RHEL7 this isn't the case). This policy isn't available on old Linux kernels like RHEL5, where it'll raise EINVAL.

The policy may optionally bitwise-or any one of:

SCHED_RESET_ON_FORK will cause the scheduling policy to be automatically reset to SCHED_NORMAL upon fork() if supported; otherwise this flag is polyfilled as zero, so that it may be safely used (without having to check if the o/s is Linux).

struct sched_param* param

must be set to the scheduler parameter, which should be greater than or equal to sched_get_priority_min(policy) and less than or equal to sched_get_priority_max(policy). Linux allows the static priority range 1 to 99 for the SCHED_FIFO and SCHED_RR policies, and the priority 0 is used for the remaining policies. You should still consider calling the function, because on NetBSD the correct priority might be -1.

@return

int: the former scheduling policy of the specified process. If this function fails, then the scheduling policy is not changed, and -1 w/ errno is returned.

@raise ENOSYS on XNU, Windows, OpenBSD

@raise EPERM if not authorized to use scheduler in question (e.g. trying to use a real-time scheduler as non-root on Linux) or possibly because pledge() was used and isn't allowing this

@raise EINVAL if param is NULL

@raise EINVAL if policy is invalid

@raise EINVAL if param has value out of ranges defined by policy

@vforksafe

@see libc/calls/sched_setscheduler.c

sched_yield

Relinquishes scheduled quantum.

@return

: 0 on success, or -1 w/ errno

@see libc/calls/sched_yield.S

seccomp

Tunes Linux security policy.

This system call was first introduced in Linux 3.17. We polyfill automatically features like SECCOMP_SET_MODE_STRICT, for kernels dating back to 2.6.23, whenever possible.

@param

unsigned int operation
unsigned int flags
void* args

@return

int

@raise ENOSYS on non-Linux.

@see libc/calls/seccomp.c

secure_getenv

Returns environment variable, securely.

This is the same as getenv() except it'll return null if current process is a setuid / setgid program.

@param

const char* name: is environment variable key name, which may not be null

@return

char*

@see libc/calls/secure_getenv.c

seed48

@param

unsigned short* s

@return

unsigned short*

@see third_party/musl/rand48.c

select

Does what poll() does except with bitset API.

This system call is supported on all platforms. However, on Windows, this is polyfilled to translate into poll(). So it's recommended that poll() be used instead.

@param

int nfds
struct old_exceptfds* readfds
struct old_exceptfds* writefds
struct old_exceptfds* exceptfds
struct old_timeout* timeout

@return

int

@raise ECANCELED if thread was cancelled in masked mode

@raise EINTR if signal was delivered

@cancelationpoint

@asyncsignalsafe

@norestart

@see libc/calls/select.c

sem_close

Closes named semaphore.

Calling sem_close() on a semaphore not created by sem_open() has undefined behavior. Using sem after calling sem_close() from either the current process or forked processes sharing the same address is also undefined behavior. If any threads in this process or forked children are currently blocked on sem then calling sem_close() has undefined behavior.

@param

struct sem_t* sem: was created with sem_open()

@return

int: 0 on success, or -1 w/ errno

@see libc/thread/sem_open.c

sem_getvalue

Returns semaphore value.

@param

struct sem_t* sem: was created by sem_init()
int* sval: receives output value

@return

int: 0 on success, or -1 w/ errno

@see libc/thread/sem_getvalue.c

sem_init

Initializes unnamed semaphore.

Calling sem_init() on an already initialized semaphore is undefined.

@param

struct sem_t* sem: should make its way to sem_destroy() if this succeeds
int pshared: if semaphore may be shared between processes, provided sem is backed by mmap(MAP_ANONYMOUS | MAP_SHARED) memory
unsigned int value: is initial count of semaphore

@return

int: 0 on success, or -1 w/ errno

@raise EINVAL if value exceeds SEM_VALUE_MAX

@see libc/thread/sem_init.c

sem_open

Initializes and opens named semaphore.

This function tracks open semaphore objects within a process. When a process calls sem_open() multiple times with the same name, then the same shared memory address will be returned, unless it was unlinked.

@param

const char* name

is arbitrary string that begins with a slash character

int oflag

can have any of:

O_CREAT to create the named semaphore if it doesn't exist, in which case two additional arguments must be supplied
O_EXCL to raise EEXIST if semaphore already exists

...

@return

struct sem_t*: semaphore object which needs sem_close(), or SEM_FAILED w/ errno

@raise ENOSPC if file system is full when name would be O_CREATed

@raise EINVAL if oflag has bits other than O_CREAT | O_EXCL

@raise EINVAL if value is negative or exceeds SEM_VALUE_MAX

@raise EEXIST if O_CREAT|O_EXCL is used and semaphore exists

@raise EACCES if we didn't have permission to create semaphore

@raise EACCES if recreating open semaphore pending an unlink

@raise EMFILE if process RLIMIT_NOFILE has been reached

@raise ENFILE if system-wide file limit has been reached

@raise ENOMEM if we require more vespene gas

@raise EINTR if signal handler was called

@see libc/thread/sem_open.c

sem_unlink

Removes named semaphore.

This causes the file resource to be deleted. If processes have this semaphore currently opened, then on platforms like Windows deletion may be postponed until the last process calls sem_close().

@param

const char* name: can be absolute path or should be component w/o slashes

@return

int: 0 on success, or -1 w/ errno

@raise ACCESS if Windows is being fussy about deleting open files

@raise EPERM if pledge() is in play w/o cpath promise

@raise ENOENT if named semaphore doesn't exist

@raise EACCES if permission is denied

@raise ENAMETOOLONG if too long

@see libc/thread/sem_open.c

sem_wait

Locks semaphore.

@param

struct sem_t* sem

@return

int: 0 on success, or -1 w/ errno

@raise ECANCELED if calling thread was cancelled in masked mode

@raise EINTR if signal was delivered instead

@raise EDEADLK if deadlock was detected

@raise EINVAL if sem is invalid

@cancelationpoint

@see libc/thread/sem_wait.c

send

Sends data to network socket.

@param

int fd: is the file descriptor returned by socket()
void* buf: is the data to send, which we'll copy if necessary
unsigned long size: is the byte-length of buf
int flags: can have MSG_OOB, MSG_DONTROUTE, and MSG_DONTWAIT

@return

long: number of bytes transmitted, or -1 w/ errno

@error EINTR, EHOSTUNREACH, ECONNRESET (UDP ICMP Port Unreachable), EPIPE (if MSG_NOSIGNAL), EMSGSIZE, ENOTSOCK, EFAULT, etc.

@cancelationpoint

@asyncsignalsafe

@restartable (unless SO_RCVTIMEO)

@see libc/sock/send.c

sendmsg

Sends a message on a socket.

@param

int fd

is the file descriptor returned by socket()

struct msghdr* msg

is a pointer to a struct msghdr containing all the required

   parameters (the destination address, buffers, ...)

int flags

MSG_OOB, MSG_DONTROUTE, MSG_PARTIAL, MSG_NOSIGNAL, etc.

@return

long: number of bytes transmitted, or -1 w/ errno

@error EINTR, EHOSTUNREACH, ECONNRESET (UDP ICMP Port Unreachable), EPIPE (if MSG_NOSIGNAL), EMSGSIZE, ENOTSOCK, EFAULT, etc.

@cancelationpoint

@asyncsignalsafe

@restartable (unless SO_RCVTIMEO)

@see libc/sock/sendmsg.c

sendto

Sends data over network.

@param

int fd: is the file descriptor returned by socket()
void* buf: is the data to send, which we'll copy if necessary
unsigned long size: is the byte-length of buf
int flags: can have MSG_OOB, MSG_DONTROUTE, and MSG_DONTWAIT
struct sa* opt_addr: is a binary ip:port destination override, which is mandatory for UDP if connect() wasn't called
unsigned int addrsize: is the byte-length of addr's true polymorphic form

@return

long: number of bytes transmitted, or -1 w/ errno

@error EINTR, EHOSTUNREACH, ECONNRESET (UDP ICMP Port Unreachable), EPIPE (if MSG_NOSIGNAL), EMSGSIZE, ENOTSOCK, EFAULT, etc.

@cancelationpoint

@asyncsignalsafe

@restartable (unless SO_RCVTIMEO)

@see libc/sock/sendto.c

setbuf

Sets buffer on stdio stream.

@param

struct FILE* f
char* buf

@return

void

@see libc/stdio/setbuf.c

setbuffer

Sets buffer on stdio stream.

@param

struct FILE* f
char* buf: may optionally be non-NULL to set the stream's underlying buffer, which the stream will own, but won't free
unsigned long size: is ignored if buf is NULL

@return

void

@see libc/stdio/setbuffer.c

setcontext

Sets machine context.

@param

struct ucontext_t* uc

@return

int: -1 on error w/ errno, otherwise won't return unless sent back

@see swapcontext()

@see makecontext()

@see getcontext()

@see libc/calls/ucontext.c

setegid

Sets effective group ID.

@param

unsigned int egid

@return

int: 0 on success, or -1 w/ errno

@raise EINVAL if euid not in legal range

@raise EPERM if lack privileges

@see libc/calls/setegid.c

seteuid

Sets effective user ID.

@param

unsigned int euid

@return

int: 0 on success, or -1 w/ errno

@raise EINVAL if euid not in legal range

@raise EPERM if lack privileges

@see libc/calls/seteuid.c

setfsgid

Sets user id of current process for file system ops.

@param

unsigned int gid

@return

int: previous filesystem gid

@see libc/calls/setfsgid.c

setfsuid

Sets user id of current process for file system ops.

@param

unsigned int uid

@return

int: previous filesystem uid

@see libc/calls/setfsuid.c

setgid

Sets group id of current process.

@param

unsigned int gid

@return

int: 0 on success, or -1 w/ errno

@raise EINVAL if gid not in legal range

@raise EPERM if lack privileges

@see libc/calls/setgid.c

setgrent

Rewinds to beginning of group database.

@return

void

@threadunsafe

@see third_party/musl/grp.c

setgroups

Sets list of supplementary group IDs.

On recent versions of Linux only, it's possible to say:

setgroups(0, NULL);

Which will cause subsequent calls to EPERM.

@param

unsigned long size: number of items in list
const unsigned int* list: input set of gid_t to set

@return

int: -1 w/ EFAULT

@see libc/calls/setgroups.c

sethostent

@param

int x

@return

void

@see third_party/musl/ent.c

setitimer

Schedules delivery of one-shot or intermittent interrupt signal, e.g.

Raise SIGALRM every 1.5s:

sigaction(SIGALRM,
          &(struct sigaction){.sa_handler = OnSigalrm},
          NULL);
setitimer(ITIMER_REAL,
          &(const struct itimerval){{1, 500000},
                                    {1, 500000}},
          NULL);

Single-shot alarm to interrupt connect() after 50ms:

sigaction(SIGALRM,
          &(struct sigaction){.sa_handler = OnSigalrm,
                              .sa_flags = SA_RESETHAND},
          NULL);
setitimer(ITIMER_REAL,
          &(const struct itimerval){{0, 0}, {0, 50000}},
          NULL);
if (connect(...) == -1 && errno == EINTR) { ... }

Disarm existing timer:

setitimer(ITIMER_REAL, &(const struct itimerval){0}, NULL);

If the goal is to use alarms to interrupt blocking i/o routines, e.g. read(), connect(), etc. then it's important to install the signal handler using sigaction() rather than signal(), because the latter sets the SA_RESTART flag.

Timers are not inherited across fork.

@param

int which: can be ITIMER_REAL, ITIMER_VIRTUAL, etc.
struct itimerval* newvalue: specifies the interval ({0,0} means one-shot) and duration ({0,0} means disarm) in microseconds ∈ [0,999999] and if this parameter is NULL, we'll polyfill getitimer() behavior
struct itimerval* oldvalue

@return

int: 0 on success or -1 w/ errno

@asyncsignalsafe

@see libc/thread/setitimer.c

setjmp

Saves cpu state.

@param

rdi: points to jmp_buf

@return

: rax 0 when set and !0 when longjmp'd

@returnstwice

@assume system five nexgen32e abi conformant

@note code built w/ microsoft abi compiler can't call this

@see longjmp(), gclongjmp()

@see libc/nexgen32e/setjmp.S

setkey

@param

const char* key

@return

void

@see third_party/musl/encrypt.c

setlinebuf

Puts stream in line-buffering mode.

@param

struct FILE* f

@return

void

@see libc/stdio/setlinebuf.c

setlocale

Sets program locale.

Cosmopolitan only supports the C or POSIX locale with UTF-8.

@param

int category
const char* locale

@return

char*

@see libc/str/setlocale.c

setmntent

@param

const char* name
const char* mode

@return

struct FILE*

@see third_party/musl/mntent.c

setpgid

Changes process group for process.

@param

int pid: is process id (may be zero for current process)
int pgid: is process group id (may be zero for current process)

@return

int: 0 on success, or -1 w/ errno

@vforksafe

@see libc/calls/setpgid.c

setpgrp

Sets the process group ID.

@return

int

@see libc/calls/setpgrp.c

setpriority

Sets nice value of thing.

@param

int which

can be one of:

PRIO_PROCESS is supported universally
PRIO_PGRP is supported on unix
PRIO_USER is supported on unix

unsigned int who

is the pid, pgid, or uid, 0 meaning current

int value

∈ [-NZERO,NZERO) which is clamped automatically

@return

int: 0 on success, or -1 w/ errno

@raise EINVAL if which was invalid or unsupported

@error EACCES if value lower that RLIMIT_NICE

@error EACCES on Linux without CAP_SYS_NICE

@raise EPERM if access to process was denied

@raise ESRCH if the process didn't exist

@see getpriority()

@see libc/proc/setpriority.c

setprotoent

@param

int stayopen

@return

void

@see third_party/musl/proto.c

setpwent

Rewinds global handle to password database.

@return

void

@see getpwent()

@threadunsafe

@see third_party/musl/pwd.c

setregid

Sets real and/or effective group ids.

@param

unsigned int rgid: is real group id or -1 to leave it unchanged
unsigned int egid: is effective group id or -1 to leave it unchanged

@return

int: 0 on success or -1 w/ errno

@see libc/calls/setregid.c

setresgid

Sets real, effective, and "saved" group ids.

@param

unsigned int real: sets real group id or -1 to do nothing
unsigned int effective: sets effective group id or -1 to do nothing
unsigned int saved: sets saved group id or -1 to do nothing

@return

int

@see setresuid(), getauxval(AT_SECURE)

@raise ENOSYS on Windows NT

@see libc/calls/setresgid.c

setresuid

Sets real, effective, and "saved" user ids.

@param

unsigned int real: sets real user id or -1 to do nothing
unsigned int effective: sets effective user id or -1 to do nothing
unsigned int saved: sets saved user id or -1 to do nothing

@return

int

@see setresgid(), getauxval(AT_SECURE)

@raise ENOSYS on Windows NT

@see libc/calls/setresuid.c

setreuid

Sets real and/or effective user ids.

@param

unsigned int ruid: is real user id or -1 to leave it unchanged
unsigned int euid: is effective user id or -1 to leave it unchanged

@return

int: 0 on success or -1 w/ errno

@see libc/calls/setreuid.c

setservent

@param

int stayopen

@return

void

@see third_party/musl/serv.c

setsid

Creates session and sets the process group id.

@return

int: new session id, or -1 w/ errno

@raise EPERM if already the leader

@see libc/calls/setsid.c

setsockopt

Modifies socket settings.

Basic usage:

int yes = 1;
setsockopt(fd, SOL_SOCKET, SO_REUSEADDR, &yes, sizeof(yes));

@param

int fd
int level: can be SOL_SOCKET, SOL_IP, SOL_TCP, etc.
int optname: can be SO_{REUSE{PORT,ADDR},KEEPALIVE,etc.} etc.
void* optval
unsigned int optlen

@return

int: 0 on success, or -1 w/ errno

@error ENOPROTOOPT for unknown (level,optname)

@error EINVAL if optlen is invalid somehow

@error ENOTSOCK if fd is valid but not a socket

@error EBADF if fd isn't valid

@error EFAULT if optval memory isn't valid

@see libc/sysv/consts.sh for tuning catalogue

@see getsockopt()

@see libc/sock/setsockopt.c

setstate

@param

char* state

@return

char*

@see libc/stdio/random.c

settimeofday

Changes time.

@param

struct timeval* tv
struct timezone* tz

@return

int

@see libc/calls/settimeofday.c

setuid

Sets user id of current process.

@param

unsigned int uid

@return

int: 0 on success, or -1 w/ errno

@raise EINVAL if uid not in legal range

@raise EAGAIN on temporary failure

@raise EAGAIN change would cause RLIMIT_NPROC to be exceeded

@raise EPERM if lack privileges

@see libc/calls/setuid.c

setutxent

@return

void

@see libc/runtime/utmp.c

setvbuf

Tunes buffering settings for an stdio stream.

@param

struct FILE* f
char* buf: may optionally be non-NULL to set the stream's underlying buffer which the caller still owns and won't free, otherwise the existing buffer is used
int mode: may be _IOFBF, _IOLBF, or _IONBF
unsigned long size: is ignored if buf is NULL

@return

int: 0 on success or -1 on error

@see libc/stdio/setvbuf.c

sha1_transform_avx2

Performs Intel® AVX2™ optimized SHA-1 update.

This implementation is based on the previous SSSE3 release: Visit http://software.intel.com/en-us/articles/ and refer to improving-the-performance-of-the-secure-hash-algorithm-1/

Updates 20-byte SHA-1 record at start of 'state', from 'input', for even number of 'blocks' consecutive 64-byte blocks.

void sha1_transform_avx2(struct sha1_state *state,
                         const uint8_t *input,
                         int blocks);

@param

%rdi: points to output digest
%rsi: points to input data
%rdx: is number of 64-byte blocks to process

@return

@see X86_HAVE(SHA)

@see libc/nexgen32e/sha1.S

sha1_transform_ni

Performs Intel® SHA-NI™ optimized SHA-1 update.

The function takes a pointer to the current hash values, a pointer to the input data, and a number of 64 byte blocks to process. Once all blocks have been processed, the digest pointer is updated with the resulting hash value. The function only processes complete blocks, there is no functionality to store partial blocks. All message padding and hash value initialization must be done outside the update function.

The indented lines in the loop are instructions related to rounds processing. The non-indented lines are instructions related to the message schedule.

void sha1_transform_ni(uint32_t digest[static 5],
                       const void *data,
                       uint32_t numBlocks);

@param

%rdi: points to output digest
%rsi: points to input data
%rdx: is number of 64-byte blocks to process

@return

@see X86_HAVE(SHA)

@see libc/nexgen32e/sha1ni.S

sha256_transform_ni

Performs Intel® SHA-NI™ optimized SHA-256 update.

The indented lines in the loop are instructions related to rounds processing. The non-indented lines are instructions related to the message schedule.

void sha256_transform_ni(uint32_t digest[static 8],
                         const void *data,
                         int32_t numBlocks);

@param

%rdi: points to output digest
%rsi: points to input data
%rdx: is number of blocks to process

@return

@see X86_HAVE(SHA)

@see libc/nexgen32e/sha256ni.S

shm_open

Opens POSIX named memory object.

@param

const char* name: should begin with a / and shouldn't contain subsequent slash characters, and furthermore shouldn't exceed NAME_MAX, for maximum portability; POSIX defines it as opening a multi-process object and leaves all other names implementation defined; and we choose (in this implementation) to define those names as meaning the same thing while not imposing any length limit; cosmo always feeds your name through BLAKE2B to create a .sem file existing under /dev/shm if available, otherwise it will go under /tmp
int oflag
unsigned int mode

@return

int: open file descriptor, or -1 w/ errno

@see libc/calls/shm_open.c

shm_path_np

Returns filesystem pathname of named semaphore.

@param

const char* name: is name of semaphore which should begin with slash
char* buf: is temporary storage with at least 78 bytes

@return

void: pointer to file system path

@raise ENAMETOOLONG if constructed path would exceed size

@see libc/calls/shm_path_np.c

shm_unlink

Deletes POSIX named memory object.

@param

const char* name

@return

int

@see libc/calls/shm_unlink.c

shutdown

Disables sends or receives on a socket, without closing.

@param

int fd: is the open file descriptor for the socket
int how: can be SHUT_RD, SHUT_WR, or SHUT_RDWR

@return

int: 0 on success or -1 on error

@asyncsignalsafe

@see libc/sock/shutdown.c

__sig_restore

Restores thread to state before signal.

@param

rdi points: to ucontext_t with machine state

@noreturn

@see libc/calls/restore.S

sigaddset

Adds signal to set.

@param

unsigned long* set
int sig

@return

int: 0 on success, or -1 w/ errno

@raise EINVAL if 1 ≤ sig ≤ NSIG isn't the case

@asyncsignalsafe

@see libc/intrin/sigaddset.c

sigandset

Bitwise ANDs two signal sets.

@param

unsigned long* set
const unsigned long* x
const unsigned long* y

@return

int: 0 on success, or -1 w/ errno

@asyncsignalsafe

@vforksafe

@see libc/intrin/sigandset.c

sigcountset

Returns population count of signal set.

@param

const unsigned long* set

@return

int: value greater than or equal to zero

@asyncsignalsafe

@see libc/intrin/sigcountset.c

sigdelset

Removes signal from set.

@param

unsigned long* set
int sig

@return

int: 0 on success, or -1 w/ errno

@raises EINVAL if 1 ≤ sig ≤ NSIG isn't the case

@asyncsignalsafe

@see libc/intrin/sigdelset.c

sigemptyset

Removes all signals from set.

@param

unsigned long* set

@return

int: 0 on success, or -1 w/ errno

@asyncsignalsafe

@see libc/intrin/sigemptyset.c

sigfillset

Fills up signal set.

@param

unsigned long* set

@return

int: 0 on success, or -1 w/ errno

@asyncsignalsafe

@vforksafe

@see libc/intrin/sigfillset.c

sigignore

Configures process to ignore signal.

@param

int sig

@return

int

@see libc/calls/sigignore.c

siginterrupt

Tunes whether signal can interrupt restartable system calls.

@param

int sig
int flag

@return

int

@see libc/calls/siginterrupt.c

sigisemptyset

Determines if signal set is empty.

@param

const unsigned long* set

@return

int: 1 if empty, 0 if non-empty, or -1 w/ errno

@asyncsignalsafe

@vforksafe

@see libc/intrin/sigisemptyset.c

sigismember

Returns true if signal is member of set.

@param

const unsigned long* set
int sig

@return

int: 1 if set, 0 if not set, or -1 w/ errno

@raises EINVAL if 1 ≤ sig ≤ NSIG isn't the case

@asyncsignalsafe

@vforksafe

@see libc/intrin/sigismember.c

siglongjmp

Loads previously saved processor state.

@param

rdi: points to the jmp_buf
esi: is returned by setjmp() invocation (coerced nonzero)

@noreturn

@see gclongjmp()

@see siglongjmp()

@see libc/nexgen32e/longjmp.S

signal

Installs kernel interrupt handler, e.g.

void GotCtrlC(int sig) { ... }
CHECK_NE(SIG_ERR, signal(SIGINT, GotCtrlC));

@param

int sig
void(*)() func

@return

void(*)(): old signal handler on success or SIG_ERR w/ errno

@note this function has BSD semantics, i.e. SA_RESTART

@see sigaction() which has more features and docs

@see libc/calls/signal.c

signgam

@type

int

@see libc/tinymath/signgam.c

significand

Return mantissa of 𝑥 scaled to range [1,2).

@param

double x

@return

double

@see libc/tinymath/significand.c

significandf

Return mantissa of 𝑥 scaled to range [1,2).

@param

float x

@return

float

@see libc/tinymath/significandf.c

significandl

Return mantissa of 𝑥 scaled to range [1,2).

@param

long double x

@return

long double

@see libc/tinymath/significandl.c

sigorset

Bitwise ORs two signal sets.

@param

unsigned long* set
const unsigned long* x
const unsigned long* y

@return

int: 0 on success, or -1 w/ errno

@asyncsignalsafe

@vforksafe

@see libc/intrin/sigorset.c

sigpending

Determines the blocked pending signals

@param

unsigned long* pending: is where the bitset of pending signals is returned, which may not be null

@return

int: 0 on success, or -1 w/ errno

@raise EFAULT if pending points to invalid memory

@asyncsignalsafe

@see libc/calls/sigpending.c

sigprocmask

Changes signal blocking state of calling thread, e.g.:

sigset_t neu,old;
sigfillset(&neu);
sigprocmask(SIG_BLOCK, &neu, &old);
sigprocmask(SIG_SETMASK, &old, NULL);

@param

int how: can be SIG_BLOCK (U), SIG_UNBLOCK (/), SIG_SETMASK (=)
const unsigned long* opt_set
unsigned long* opt_out_oldset

@return

int: 0 on success, or -1 w/ errno

@raise EFAULT if set or oldset is bad memory

@raise EINVAL if how is invalid

@asyncsignalsafe

@restartable

@vforksafe

@see libc/intrin/sigprocmask.c

sigqueue

Sends signal to process, with data.

The impact of this action can be terminating the process, or interrupting it to request something happen.

@param

int pid: can be: >0 signals one process by id =0 signals all processes in current process group -1 signals all processes possible (except init) <-1 signals all processes in -pid process group
int sig: can be: >0 can be SIGINT, SIGTERM, SIGKILL, SIGUSR1, etc. =0 checks both if pid exists and we can signal it
union value value

@return

int: 0 if something was accomplished, or -1 w/ errno

@note this isn't supported on OpenBSD

@asyncsignalsafe

@see libc/calls/sigqueue.c

sigsetjmp

Saves caller CPU state and signal mask.

@param

rdi: points to jmp_buf
esi: if non-zero will cause mask to be saved

@return

: eax 0 when set and !0 when longjmp'd

@returnstwice

@see libc/runtime/sigsetjmp.S

sigtimedwait

Waits for signal synchronously, w/ timeout.

@param

const unsigned long* set: is signals for which we'll be waiting
struct linux* info: if not null shall receive info about signal
struct timespec* timeout: is relative deadline and null means wait forever

@return

int: signal number on success, or -1 w/ errno

@raise EINTR if an asynchronous signal was delivered instead

@raise ECANCELED if thread was cancelled in masked mode

@raise EINVAL if nanoseconds parameter was out of range

@raise EAGAIN if deadline expired

@raise ENOSYS on Windows, XNU, OpenBSD, Metal

@raise EFAULT if invalid memory was supplied

@cancelationpoint

@see libc/calls/sigtimedwait.c

sigwait

@param

const unsigned long* mask
int* sig

@return

int

@see libc/calls/sigwait.c

sigwaitinfo

Waits for signal synchronously.

@param

const unsigned long* mask
struct siginfo_t* si

@return

int: signal number on success, or -1 w/ errno

@raise EINTR if an asynchronous signal was delivered instead

@raise ECANCELED if thread was cancelled in masked mode

@raise ENOSYS on OpenBSD, XNU, and Windows

@see sigtimedwait()

@cancelationpoint

@see libc/calls/sigwaitinfo.c

sin

Returns sine of 𝑥.

@param

double x

@return

double

@note should take ~5ns

@see libc/tinymath/sin.c

sincos

Returns sine and cosine of 𝑥.

@param

double x
double* sin
double* cos

@return

void

@note should take ~10ns

@see libc/tinymath/sincos.c

sincosf

Returns sine and cosine of y.

This is a fast sincosf implementation. Worst-case ULP is 0.5607, maximum relative error is 0.5303 * 2^-23. A single-step range reduction is used for small values. Large inputs have their range reduced using fast integer arithmetic.

@param

float y
float* sinp
float* cosp

@return

void

@raise EDOM if y is an infinity

@see libc/tinymath/sincosf.c

sincosl

Returns sine and cosine of 𝑥.

@param

long double x
long double* sin
long double* cos

@return

void

@see libc/tinymath/sincosl.c

sinf

Returns sine of y.

This is a fast sinf implementation. The worst-case ULP is 0.5607 and the maximum relative error is 0.5303 * 2^-23. A single-step range reduction is used for small values. Large inputs have their range reduced using fast integer arithmetic.

@param

float y

@return

float

@raise EDOM and FE_INVALID if y is an infinity

@see libc/tinymath/sinf.c

sinhf

Returns hyperbolic sine of 𝑥.

sinh(x) = (exp(x) - 1/exp(x))/2
        = (exp(x)-1 + (exp(x)-1)/exp(x))/2
        = x + x^3/6 + o(x^5)

@param

float x

@return

float

@see libc/tinymath/sinhf.c

sinl

Returns sine of 𝑥.

@param

long double x

@return

long double

@see libc/tinymath/sinl.c

sizefmt

Represents size as readable string.

@param

char* p: is output buffer
unsigned long x
unsigned long b: should be 1024 or 1000

@return

char*: pointer to nul byte

@see libc/intrin/sizefmt.c

sizetol

Converts size string to long.

The following unit suffixes may be used

k or K for kilo (multiply by 𝑏¹)
m or M for mega (multiply by 𝑏²)
g or G for giga (multiply by 𝑏³)
t or T for tera (multiply by 𝑏⁴)
p or P for peta (multiply by 𝑏⁵)
e or E for exa (multiply by 𝑏⁶)

If a permitted alpha character is supplied, then any additional characters after it (e.g. kbit, Mibit, TiB) are ignored. Spaces before the integer are ignored, and overflows will be detected.

Negative numbers are permissible, as well as a leading + sign. To tell the difference between an error return and -1 you must clear errno before calling and test whether it changed.

@param

const char* s: is non-null nul-terminated input string
long b: is multiplier which should be 1000 or 1024

@return

long: size greater than or equal 0 or -1 on error

@error EINVAL if error is due to bad syntax

@error EOVERFLOW if error is due to overflow

@see libc/fmt/sizetol.c

sleb64

Encodes signed integer to array.

uleb64 INT64_MAX    l:        10𝑐         3𝑛𝑠
zleb64 INT64_MAX    l:        13𝑐         4𝑛𝑠
sleb64 INT64_MAX    l:        16𝑐         5𝑛𝑠
uleb128 INT64_MAX   l:        18𝑐         6𝑛𝑠
zleb128 INT64_MAX   l:        18𝑐         6𝑛𝑠
sleb128 INT64_MAX   l:        24𝑐         8𝑛𝑠
zleb64 INT64_MIN    l:        13𝑐         4𝑛𝑠
sleb64 INT64_MIN    l:        16𝑐         5𝑛𝑠
zleb128 INT64_MIN   l:        19𝑐         6𝑛𝑠
sleb128 INT64_MIN   l:        24𝑐         8𝑛𝑠

@param

char* p: is output array
long x: is number

@return

char*: p + i

@see libc/fmt/sleb64.c

smoothsort

Sorts array.

@param

void* base: points to an array to sort in-place
unsigned long count: is the item count
unsigned long width: is the size of each item
int(*)() cmp: is a callback returning <0, 0, or >0

@return

void

@see smoothsort_r()

@see qsort()

@see libc/str/smoothsort.c

smoothsort_notice

@type

const char[86]

@see libc/str/smoothsort.c

smoothsort_r

Sorts array.

@param

void* base: points to an array to sort in-place
unsigned long count: is the item count
unsigned long width: is the size of each item
int(*)() cmp: is a callback returning <0, 0, or >0
void* arg: will optionally be passed as the third argument to cmp

@return

void

@see smoothsort()

@see qsort()

@see libc/str/smoothsort.c

_smt19937

Initializes mt[NN] with small seed value.

@param

unsigned long seed

@return

void

@see mt19937(), Smt19937()

@see libc/stdio/mt19937.c

_Smt19937

Initializes mt[NN] with array.

@param

unsigned long* K: is the array for initializing keys
unsigned long n: is its length

@return

void

@see mt19937(), smt19937()

@see libc/stdio/mt19937.c

snprintf

Formats string to buffer.

@param

char* buf
unsigned long count
const char* fmt
...

@return

int: number of bytes written, excluding the NUL terminator; or, if the output buffer wasn't passed, or was too short, then the number of characters that *would* have been written is returned

@see __fmt() and printf() for detailed documentation

@asyncsignalsafe

@vforksafe

@see libc/stdio/snprintf.c

sockaddr2bsd

Converts sockaddr (Linux/Windows) → sockaddr_bsd (XNU/BSD).

@param

void* addr
unsigned int addrsize
union sockaddr_storage_bsd* out_addr
unsigned int* out_addrsize

@return

int

@see libc/sock/sockaddr2bsd.c

sockaddr2linux

Converts sockaddr_bsd (XNU/BSD) → sockaddr (Linux/Windows).

@param

union sockaddr_storage_bsd* addr
unsigned int addrsize
union sockaddr_storage_linux* out_addr
unsigned int* inout_addrsize

@return

void

@see libc/sock/sockaddr2linux.c

socket

Creates new system resource for network communication, e.g.

int fd = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP);

@param

int family: can be AF_UNIX, AF_INET, AF_INET6, etc.
int type: can be SOCK_STREAM (for TCP), SOCK_DGRAM (e.g. UDP), or SOCK_RAW (IP) so long as IP_HDRINCL was passed to setsockopt(); and additionally, may be or'd with SOCK_NONBLOCK, SOCK_CLOEXEC
int protocol: can be IPPROTO_TCP, IPPROTO_UDP, or IPPROTO_ICMP

@return

int: socket file descriptor or -1 w/ errno

@raise EAFNOSUPPORT if family isn't supported by system or platform

@see libc/sysv/consts.sh

@asyncsignalsafe

@see libc/sock/socket.c

socketpair

Creates bidirectional pipe, e.g.

int sv[2];
socketpair(AF_UNIX, SOCK_STREAM, 0, sv);

@param

int family: should be AF_UNIX or synonymously AF_LOCAL
int type: can be SOCK_STREAM or SOCK_DGRAM and additionally, may be or'd with SOCK_NONBLOCK, SOCK_CLOEXEC
int protocol
int* sv: a vector of 2 integers to store the created sockets

@return

int: 0 if success, -1 in case of error

@error EFAULT, EPFNOSUPPORT, etc.

@see libc/sysv/consts.sh

@asyncsignalsafe

@see libc/sock/socketpair.c

SortStrList

@param

struct StrList* sl

@return

void

@see libc/stdio/sortstrlist.c

splice

Transfers data to/from pipe.

@param

int infd
long* opt_in_out_inoffset: may be specified if infd isn't a pipe and is used as both an input and output parameter for pread() behavior
int outfd
long* opt_in_out_outoffset: may be specified if outfd isn't a pipe and is used as both an input and output parameter for pwrite() behavior
unsigned long uptobytes
unsigned int flags: can have SPLICE_F_{MOVE,NONBLOCK,MORE,GIFT}

@return

long: number of bytes transferred, 0 on input end, or -1 w/ errno

@raise EBADF if infd or outfd aren't open files or append-only

@raise ENOTSUP if infd or outfd is a zip file descriptor

@raise ESPIPE if an offset arg was specified for a pipe fd

@raise EINVAL if offset was given for non-seekable device

@raise EINVAL if file system doesn't support splice()

@raise EFAULT if one of the pointers memory is bad

@raise EINVAL if flags is invalid

@raise ENOSYS if not Linux 5.9+

@see copy_file_range() for file ↔ file

@see sendfile() for seekable → socket

@see libc/calls/splice.c

sprintf

Formats string to buffer that's hopefully large enough.

@param

char* buf
const char* fmt
...

@return

int

@see __fmt() and printf() for detailed documentation

@see snprintf() for same w/ buf size param

@asyncsignalsafe

@vforksafe

@see libc/stdio/sprintf.c

sqrt

Returns square root of 𝑥.

@param

double x

@return

double

@see libc/tinymath/sqrt.c

sqrtf

Returns square root of 𝑥.

@param

float x

@return

float

@see libc/tinymath/sqrtf.c

sqrtl

Returns square root of 𝑥.

@param

long double x

@return

long double

@see libc/tinymath/sqrtl.c

srand

Seeds random number generator that's used by rand().

@param

unsigned int seed

@return

void

@see libc/stdio/srand.c

srand48

@param

long seed

@return

void

@see third_party/musl/rand48.c

srandom

@param

unsigned int seed

@return

void

@see libc/stdio/random.c

sscanf

String decoder.

@param

const char* str
const char* fmt
...

@return

int

@see libc/fmt/vcscanf.h (for docs and implementation)

@see libc/stdio/sscanf.c

__stack_call

Calls function on different stack.

@param

%rdi: is arg1
%rsi: is arg2
%rdx: is arg3
%rcx: is arg4
%r8: is func
%r9: is stack

@return

: %rax is res

@see libc/intrin/stackcall.S

__stack_chk_guard

Canary for -fstack-protector.

This global is referenced by synthetic code generated by GCC. The -mstack-protector-guard=global flag might need to be passed.

@return

@note this value is protected by piro

@see libc/intrin/stackchkguard.S

__start_fatal

Prints initial part of fatal message.

@param

const char* file
int line

@return

void

@note this is support code for __check_fail(), __assert_fail(), etc.

@see libc/log/startfatal.c

startswith

Returns true if s has prefix.

@param

const char* s: is a NUL-terminated string
const char* prefix: is also NUL-terminated

@return

int

@see libc/str/startswith.c

startswith16

Returns true if s has prefix.

@param

const unsigned short* s: is a NUL-terminated string
const unsigned short* prefix: is also NUL-terminated

@return

int

@see libc/str/startswith16.c

startswithi

Checks if string starts with prefix, case insensitively.

@param

const char* s
const char* prefix

@return

int

@see libc/str/startswithi.c

stat

Returns information about file.

This function is equivalent to:

struct stat st;
fstatat(AT_FDCWD, path, &st, 0);

@param

const char* path
struct stat* st

@return

int

@see fstatat() for further documentation

@asyncsignalsafe

@see libc/calls/stat.c

statfs2statvfs

@param

struct statvfs* sv
struct statfs* sf

@return

void

@see libc/calls/statfs2statvfs.c

statvfs

Returns information about filesystem.

@param

const char* path
struct statvfs* sv

@return

int: 0 on success, or -1 w/ errno

@note consider using statfs()

@see libc/calls/statvfs.c

stime

Changes time, the old fashioned way.

@param

const long* t

@return

int

@see libc/calls/stime.c

stpcpy

Copies bytes from 𝑠 to 𝑑 until a NUL is encountered.

@param

char* d
const char* s

@return

char*: pointer to nul byte

@note 𝑑 and 𝑠 can't overlap

@asyncsignalsafe

@see libc/intrin/stpcpy.c

stpncpy

Prepares static search buffer.

If SRC is too long, it's truncated and *not* NUL-terminated.
If SRC is too short, the remainder is zero-filled.

@param

char* dst: is output buffer
const char* src: is a nul-terminated string
unsigned long dstlen: is size of dst buffer

@return

char*: pointer to first nul-terminator, otherwise dest + stride

@asyncsignalsafe

@see strncpy()

@see memccpy()

@see strlcpy()

@see libc/str/stpncpy.c

__strace

System call logging enabled state.

If Cosmopolitan was compiled with the SYSDEBUG macro (this is the default behavior, except in tiny and release modes) then __strace shall control whether or not system calls are logged to fd 2. If it's greater than zero, syscalls are logged. Otherwise, they're aren't.

By convention, functions wishing to disable syscall tracing for a short time period should say:

void foo() {
  strace_enabled(-1);
  bar();
  strace_enabled(+1);
}

This way you still have some flexibility to force syscall tracing, by setting __strace to a higher number like 2 or 200. Even though under normal circumstances, __strace should only be either zero or one.

@type

int

@see libc/sysv/strace.greg.c

strcasecmp

Compares NUL-terminated strings ascii case-insensitively.

@param

const char* a: is first non-null nul-terminated string pointer
const char* b: is second non-null nul-terminated string pointer

@return

int: is <0, 0, or >0 based on tolower(uint8_t) comparison

@asyncsignalsafe

@see libc/str/strcasecmp.c

strcasecmp16

Compares NUL-terminated UCS-2 strings case-insensitively.

@param

const unsigned short* l
const unsigned short* r

@return

int: is <0, 0, or >0 based on uint16_t comparison

@asyncsignalsafe

@see libc/str/strcasecmp16.c

strcasestr

Searches for substring case-insensitively.

@param

const char* haystack: is the search area, as a NUL-terminated string
const char* needle: is the desired substring, also NUL-terminated

@return

char*: pointer to first substring within haystack, or NULL

@note this implementation goes fast in practice but isn't hardened against pathological cases, and therefore shouldn't be used on untrustworthy data

@asyncsignalsafe

@see strstr()

@see libc/str/strcasestr.c

strcat

Appends 𝑠 to 𝑑.

@param

char* d
const char* s

@return

char*: 𝑑

@asyncsignalsafe

@see libc/str/strcat.c

strcat16

Appends 𝑠 to 𝑑.

@param

unsigned short* d
const unsigned short* s

@return

unsigned short*: 𝑑

@asyncsignalsafe

@see libc/str/strcat16.c

strchr

Returns pointer to first instance of character.

@param

const char* s: is a NUL-terminated string
int c: is masked with 255 as byte to search for

@return

char*: pointer to first instance of c or NULL if not found noting that if c is NUL we return pointer to terminator

@asyncsignalsafe

@vforksafe

@see libc/intrin/strchr.c

strchr16

Returns pointer to first instance of character.

@param

const unsigned short* s
int c

@return

unsigned short*

@see libc/str/strchr16.c

strchrnul

Returns pointer to first instance of character.

If c is not found then a pointer to the nul byte is returned.

@param

const char* s: is a NUL-terminated string
int c: is masked with 255 as byte to search for

@return

char*: pointer to first instance of c, or pointer to NUL terminator if c is not found

@see libc/intrin/strchrnul.c

strchrnul16

Returns pointer to first instance of character.

@param

const unsigned short* s
int c

@return

unsigned short*

@see libc/str/strchrnul16.c

strcmp

Compares NUL-terminated strings.

@param

const char* a: is first non-null NUL-terminated string pointer
const char* b: is second non-null NUL-terminated string pointer

@return

int: is <0, 0, or >0 based on uint8_t comparison

@asyncsignalsafe

@see libc/intrin/strcmp.c

strcmp16

Compares NUL-terminated UCS-2 strings.

@param

const unsigned short* l
const unsigned short* r

@return

int: is <0, 0, or >0 based on uint16_t comparison

@asyncsignalsafe

@see libc/str/strcmp16.c

strcoll

Compares strings in the C locale.

@param

const char* p
const char* q

@return

int

@see libc/str/strcoll.c

strcpy

Copies bytes from 𝑠 to 𝑑 until a NUL is encountered.

@param

char* d
const char* s

@return

char*: original dest

@note 𝑑 and 𝑠 can't overlap

@asyncsignalsafe

@see libc/intrin/strcpy.c

strcpy16

Copies NUL-terminated UCS-2 or UTF-16 string.

𝑑 and 𝑠 must not overlap unless 𝑑 ≤ 𝑠.

@param

unsigned short* d: is dination memory
const unsigned short* s: is a NUL-terminated 16-bit string

@return

unsigned short*: original d

@asyncsignalsafe

@see libc/str/strcpy16.c

strcspn

Returns prefix length, consisting of chars not in reject. a.k.a. Return index of first byte that's in charset.

@param

const char* s
const char* reject: is nul-terminated character set

@return

unsigned long

@see strspn(), strtok_r()

@asyncsignalsafe

@see libc/str/strcspn.c

strcspn16

Returns prefix length, consisting of chars not in reject. a.k.a. Return index of first byte that's in charset.

@param

const unsigned short* s
const unsigned short* reject: is nul-terminated character set

@return

unsigned long

@see strspn(), strtok_r()

@asyncsignalsafe

@see libc/str/strcspn16.c

strdup

Allocates new copy of string.

@param

const char* s: is a NUL-terminated byte string

@return

char*: new string or NULL w/ errno

@error ENOMEM

@see libc/mem/strdup.c

_strerdoc

Converts errno value to descriptive sentence.

@param

int x

@return

const char*: non-null rodata string or null if not found

@see libc/fmt/magnumstrs.internal.h

_strerrno

Converts errno value to symbolic name.

@param

int x

@return

const char*: non-null rodata string or null if not found

@see libc/fmt/magnumstrs.internal.h

strerror

Returns string describing err.

The application shall not modify the string returned.

@param

int err

@return

char*

@see strerror_r()

@threadunsafe

@see libc/intrin/strerror.c

strerror_r

Converts errno value to string.

@param

int err: is error number or zero if unknown
char* buf
unsigned long size

@return

int: 0 on success, or errno on error

@raise ERANGE if insufficient buffer was available, in which case a nul-terminated string is still copied to buf

@see libc/intrin/strerror_r.c

strfmon

@param

char* s
unsigned long n
const char* fmt
...

@return

long

@see third_party/musl/strfmon.c

strfmon_l

@param

char* s
unsigned long n
struct __locale_struct* loc
const char* fmt
...

@return

long

@see third_party/musl/strfmon.c

strfry

Jumbles up string.

@param

char* s

@return

char*

@see libc/stdio/strfry.c

strftime

Converts time to string, e.g.

char b[64];
int64_t sec;
struct tm tm;
time(&sec);
localtime_r(&sec, &tm);
strftime(b, sizeof(b), "%Y-%m-%dT%H:%M:%S%z", &tm);       // ISO8601
strftime(b, sizeof(b), "%a, %d %b %Y %H:%M:%S %Z", &tm);  // RFC1123

@param

char* s
unsigned long maxsize
const char* format
struct tm_1* t

@return

unsigned long: bytes copied excluding nul, or 0 on error

@see FormatHttpDateTime()

@see libc/time/strftime.c

strftime_l

@param

char* s
unsigned long maxsize
const char* format
struct tm_1* t
struct __locale_struct* locale

@return

unsigned long

@see libc/time/strftime.c

strftime_notice

@type

const char[78]

@see libc/time/strftime.c

stripext

Removes file extension.

@param

char* s: is mutated

@return

char*: s

@see libc/fmt/stripext.c

stripexts

Removes file extensions.

@param

char* s: is mutated

@return

char*: s

@see libc/fmt/stripexts.c

strlcat

Appends string, the BSD way.

Appends src to string dst of size dsize (unlike strncat, dsize is the full size of dst, not space left). At most dsize-1 characters will be copied. Always NUL terminates (unless dsize <= strlen(dst)). Returns strlen(src) + MIN(dsize, strlen(initial dst)). If retval >= dsize, truncation occurred.

@param

char* dst
const char* src
unsigned long dsize

@return

unsigned long

@asyncsignalsafe

@vforksafe

@see libc/str/strlcat.c

strlcpy

Copies string, the BSD way.

Copy string src to buffer dst of size dsize. At most dsize-1 chars will be copied. Always NUL terminates (unless dsize == 0). Returns strlen(src); if retval >= dsize, truncation occurred.

@param

char* dst
const char* src
unsigned long dsize

@return

unsigned long

@see libc/str/strlcpy.c

strlen16

Returns length of NUL-terminated utf-16 string.

@param

const unsigned short* s: is non-null NUL-terminated string pointer

@return

unsigned long: number of shorts (excluding NUL)

@asyncsignalsafe

@see libc/str/strlen16.c

strncasecmp

Compares NUL-terminated strings case-insensitively w/ limit.

@param

const char* a: is first non-null NUL-terminated string pointer
const char* b: is second non-null NUL-terminated string pointer
unsigned long n

@return

int: is <0, 0, or >0 based on uint8_t comparison

@asyncsignalsafe

@see libc/str/strncasecmp.c

strncasecmp16

Compares NUL-terminated UCS-2 strings case-insensitively w/ limit.

@param

const unsigned short* a: is first non-null NUL-terminated char16 string pointer
const unsigned short* b: is second non-null NUL-terminated char16 string pointer
unsigned long n

@return

int: is <0, 0, or >0 based on uint8_t comparison

@asyncsignalsafe

@see libc/str/strncasecmp16.c

strncat

Appends at most 𝑛 bytes from 𝑠 to 𝑑.

@param

char* d
const char* s
unsigned long n

@return

char*: 𝑑

@note 𝑑 and 𝑠 can't overlap

@asyncsignalsafe

@see libc/str/strncat.c

strncat16

Appends at most 𝑛 shorts from 𝑠 to 𝑑.

@param

unsigned short* d
const unsigned short* s
unsigned long n

@return

unsigned short*: 𝑑

@note 𝑑 and 𝑠 can't overlap

@asyncsignaslenafe

@see libc/str/strncat16.c

strncmp

Compares NUL-terminated strings w/ limit.

@param

const char* a: is first non-null NUL-terminated string pointer
const char* b: is second non-null NUL-terminated string pointer
unsigned long n

@return

int: is <0, 0, or >0 based on uint8_t comparison

@asyncsignalsafe

@see libc/intrin/strncmp.c

strncmp16

Compares NUL-terminated UCS-2 strings w/ limit.

@param

const unsigned short* a: is first non-null NUL-terminated char16 string pointer
const unsigned short* b: is second non-null NUL-terminated char16 string pointer
unsigned long n

@return

int: is <0, 0, or >0 based on uint8_t comparison

@asyncsignalsafe

@see libc/str/strncmp16.c

strncpy

Prepares static search buffer.

If SRC is too long, it's truncated and *not* NUL-terminated.
If SRC is too short, the remainder is zero-filled.

@param

char* dst: is output buffer
const char* src: is a nul-terminated string
unsigned long dstlen: is size of dst buffer

@return

char*: dst

@asyncsignalsafe

@see stpncpy()

@see strlcpy()

@see memccpy()

@see libc/str/strncpy.c

strndup

Allocates new copy of string, with byte limit.

@param

const char* s: is a NUL-terminated byte string
unsigned long n: if less than strlen(s) will truncate the string

@return

char*: new string or NULL w/ errno

@error ENOMEM

@see libc/mem/strndup.c

strnwidth

Returns monospace display width of UTF-8 string.

Control codes are discounted
ANSI escape sequences are discounted
East asian glyphs, emoji, etc. count as two

@param

const char* s: is NUL-terminated string
unsigned long n: is max bytes to consider
unsigned long o: is offset for doing tabs

@return

int: monospace display width

@see libc/str/strnwidth.c

strnwidth16

Returns monospace display width of UTF-16 or UCS-2 string.

@param

const unsigned short* p
unsigned long n
unsigned long o

@return

int

@see libc/str/strnwidth16.c

strpbrk

Returns pointer to first byte matching any in accept, or NULL.

@param

const char* s
const char* accept

@return

char*

@asyncsignalsafe

@see libc/str/strpbrk.c

strpbrk16

Returns pointer to first byte matching any in accept, or NULL.

@param

const unsigned short* s
const unsigned short* accept

@return

unsigned short*

@asyncsignalsafe

@see libc/str/strpbrk16.c

strrchr

Searches for last instance of character in string.

@param

const char* s: is NUL-terminated string to search
int c: is treated as unsigned char

@return

char*: address of last c in s, or NULL if not found

@asyncsignalsafe

@see libc/intrin/strrchr.c

strrchr16

Searches for last instance of char16_t in string.

@param

const unsigned short* s: is NUL-terminated char16_t string to search
int c: is treated as char16_t

@return

unsigned short*: address of last c in s, or NULL if not found

@asyncsignalsafe

@see libc/str/strrchr16.c

strsep

Tokenizes string.

This works by mutating the caller's pointer and the string itself. The returned value is the next available token, or NULL if we've reached the end. Upon each call, *str is updated to point past the terminator we inserted. Multiple delimiter bytes may be passed, which are treated as a set of characters, not a substring.

@param

char** str: on first call points to var holding string to be tokenized and is used by this function to track state on subsequent calls
const char* delim: is a set of characters that constitute separators

@return

char*: next token or NULL when we've reached the end or *str==NULL

@note unlike strtok() this does empty tokens and is re-entrant

@see libc/str/strsep.c

strsignal

Returns string describing signal code.

This returns "0" for 0 which is the empty value. Symbolic names should be available for signals 1 through 32. If the system supports real-time signals, they're returned as SIGRTMIN+%d. For all other 32-bit signed integer, a plain integer representation is returned.

This function is thread safe when sig is a known signal magnum. Otherwise a pointer to static memory is returned which is unsafe.

@param

int sig: is signal number which should be in range 1 through 128

@return

char*: string which is valid code describing signal

@see strsignal_r()

@see sigaction()

@threadunsafe

@see libc/intrin/strsignal.c

strspn

Returns prefix length, consisting of chars in accept.

@param

const char* s
const char* accept: is nul-terminated character set

@return

unsigned long

@see strcspn(), strtok_r()

@asyncsignalsafe

@see libc/str/strspn.c

strspn16

Returns prefix length, consisting of chars in accept.

@param

const unsigned short* s
const unsigned short* accept: is nul-terminated character set

@return

unsigned long

@see strcspn(), strtok_r()

@asyncsignalsafe

@see libc/str/strspn16.c

strstr

Searches for substring.

@param

const char* haystack: is the search area, as a NUL-terminated string
const char* needle: is the desired substring, also NUL-terminated

@return

char*: pointer to first substring within haystack, or NULL

@note this implementation goes fast in practice but isn't hardened against pathological cases, and therefore shouldn't be used on untrustworthy data

@asyncsignalsafe

@see strcasestr()

@see memmem()

@see libc/str/strstr.c

strstr16

Searches for substring.

@param

const unsigned short* haystack: is the search area, as a NUL-terminated string
const unsigned short* needle: is the desired substring, also NUL-terminated

@return

unsigned short*: pointer to first substring within haystack, or NULL

@asyncsignalsafe

@see memmem()

@see libc/str/strstr16.c

strtod

@param

const char* s00
char** se

@return

double

@see third_party/gdtoa/strtod.c

strtof

@param

const char* s
char** sp

@return

float

@see third_party/gdtoa/strtof.c

strtok

Extracts non-empty tokens from string.

@param

char* s: is mutated and should be NULL on subsequent calls
const char* sep: is a NUL-terminated set of bytes to consider separators

@return

char*: pointer to next token or NULL for end

@see strtok_r() and strsep() for superior functions

@threadunsafe

@see libc/str/strtok.c

strtok_r

Extracts non-empty tokens from string.

@param

char* s: is mutated and should be NULL on subsequent calls
const char* sep: is a NUL-terminated set of bytes to consider separators
char** state: tracks progress between calls

@return

char*: pointer to next token or NULL for end

@see strsep() which is similar

@asyncsignalsafe

@see libc/str/strtok_r.c

strtol

Decodes signed integer from ASCII string.

atoi 10⁸              22𝑐         7𝑛𝑠
strtol 10⁸            37𝑐        12𝑛𝑠
strtoul 10⁸           35𝑐        11𝑛𝑠
wcstol 10⁸            30𝑐        10𝑛𝑠
wcstoul 10⁸           30𝑐        10𝑛𝑠
strtoimax 10⁸         80𝑐        26𝑛𝑠
strtoumax 10⁸         78𝑐        25𝑛𝑠
wcstoimax 10⁸         77𝑐        25𝑛𝑠
wcstoumax 10⁸         76𝑐        25𝑛𝑠

@param

const char* s: is a non-null nul-terminated string
char** endptr: if non-null will always receive a pointer to the char following the last one this function processed, which is usually the NUL byte, or in the case of invalid strings, would point to the first invalid character
int base: can be anywhere between [2,36] or 0 to auto-detect based on the the prefixes 0 (octal), 0x (hexadecimal), 0b (binary), or decimal (base 10) by default

@return

long: the decoded signed saturated number

@raise EINVAL if base isn't 0 or 2..36

@raise ERANGE on overflow

@see libc/fmt/strtol.c

strtold

Converts string to long double.

@param

const char* s
char** endptr

@return

long double

@see libc/stdio/strtold.c

strtoul

Decodes unsigned integer from ASCII string.

@param

const char* s: is a non-null nul-terminated string
char** endptr: if non-null will always receive a pointer to the char following the last one this function processed, which is usually the NUL byte, or in the case of invalid strings, would point to the first invalid character
int base: can be anywhere between [2,36] or 0 to auto-detect based on the the prefixes 0 (octal), 0x (hexadecimal), 0b (binary), or decimal (base 10) by default

@return

unsigned long: decoded integer mod 2⁶⁴ negated if leading -

@raise ERANGE on overflow

@see libc/fmt/strtoul.c

strverscmp

Compares two version strings.

@param

const char* l0
const char* r0

@return

int

@see libc/str/strverscmp.c

strwidth

Returns monospace display width of UTF-8 string.

Control codes are discounted
ANSI escape sequences are discounted
East asian glyphs, emoji, etc. count as two

@param

const char* s: is NUL-terminated string
unsigned long o: is string offset for computing tab widths

@return

int: monospace display width

@see libc/str/strwidth.c

strwidth16

Returns monospace display width of UTF-16 or UCS-2 string.

@param

const unsigned short* s
unsigned long o

@return

int

@see libc/str/strwidth16.c

suboptarg

@type

char*

@see third_party/getopt/getsubopt.c

svigna

Seeds vigna() pseudorandom number generator.

@param

unsigned long seed

@return

void

@see vigna(), vigna_r()

@see libc/stdio/vigna.c

swapcontext

Saves machine to 𝑥 and activates 𝑦, i.e.

getcontext(x);
setcontext(y);

Except using this API is safer and goes 2x faster:

swapcontext(x, y);

@return

: 0 on success, or -1 w/ errno

@returnstwice

@see libc/calls/swapcontext.S

swprintf

@param

int* ws
unsigned long n
const int* format
...

@return

int

@see libc/stdio/swprintf.c

symlink

Creates symbolic link.

This is like link() but adds a tiny indirection to make the fact that the file is a link obvious. It also enables certain other features, like the ability to be broken.

@param

const char* target: can be relative and needn't exist
const char* linkpath: is what gets created

@return

int: 0 on success, or -1 w/ errno

@note Windows NT only lets admins do this

@asyncsignalsafe

@see libc/calls/symlink.c

symlinkat

Creates symbolic link.

This is like link() but adds a tiny indirection to make the fact that the file is a link obvious. It also enables certain other features, like the ability to be broken.

@param

const char* target: can be relative and needn't exist
int newdirfd
const char* linkpath: is what gets created

@return

int: 0 on success, or -1 w/ errno

@raise EPERM if a non-admin on Windows NT tries to use this

@asyncsignalsafe

@see libc/calls/symlinkat.c

syncfs

Syncs filesystem associated with file descriptor.

Since Linux 5.8, syncfs() will report an error if an inode failed to be written during the time since syncfs() was last called.

@param

int fd

@return

int: 0 on success, or -1 w/ errno

@raise EIO if some kind of data/metadata write error happened

@raise ENOSPC if disk space was exhausted during sync

@raise EDQUOT (or ENOSPC) on some kinds of NFS errors

@raise EBADF if fd isn't a valid file descriptor

@raise EROFS if fd is a zip file

@raise ENOSYS on non-Linux

@see libc/calls/syncfs.c

sys_clone_linux

Invokes clone() system call on GNU/Systemd.

@param

rdi x0 is: flags
rsi x1 is: top of stack
rdx x2 is: ptid
rcx x3 is: ctid
r8 x4 is: tls
r9 x5 is: func(void*,int)→int
8(rsp) x6 is: arg

@return

: tid of child on success, or -errno on error

@see libc/runtime/clone-linux.S

syscall

Translation layer for some Linux system calls:

SYS_gettid
SYS_getrandom

@param

long number
...

@return

long: system call result, or -1 w/ errno

@see libc/stdio/syscall.c

syscon_start

Sections for varint encoded magic numbers.

These sections are all ordered by (group_name, constant_name). They're populated by modules simply referencing the symbols.

@return

@see libc/sysv/consts.sh

@see libc/sysv/consts/syscon_h

@see libc/sysv/syscon.S

_sysret

Handles return path of system call on Linux.

@param

unsigned long res

@return

unsigned long

@see libc/sysv/sysret.c

__systemfive

Performs System Five System Call.

Cosmopolitan is designed to delegate all function calls into the Linux, FreeBSD, OpenBSD, and XNU kernels via this function, with few exceptions. This function should generally only be called by generated thunks in the libc/sysv/syscalls/ directory.

It's safe to call this function on Windows, where it will always return -1 with errno == ENOSYS. Further note that -1 is the only return value that means error, a common anti-pattern is to check for values less than 0 (which is more problematic on 32-bit).

It is important to consider that system calls are one order of a magnitude more expensive than normal function calls. For example getpid() on Linux usually takes 500ns, and cached i/o calls will take 1µs or more. So we don't need to inline them like Chromium.

Another thing to consider is that BSDs only loosely follow the System Five ABI for the SYSCALL instruction. For example Linux always follows the six argument limit but the FreeBSD sendfile system call accepts a seventh argument that is passed on stack and OpenBSD modifies functions like mmap so that the sixth arg is passed on the stack. There's also the carry flag convention that XNU, FreeBSD, and OpenBSD inherited from 386BSD aka Jolix

@param

%rax: function ordinal supplied by jump slot
%rdi,%rsi,%rdx,%rcx,%r8,%r9: and rest on stack

@return

: %rax:%rdx is result, or -1 w/ errno on error

@clob %rcx,%r10,%r11

@see syscalls.sh

@see libc/sysv/systemfive.S

systemvpe

Executes program and waits for it to complete, e.g.

systemvpe("ls", (char *[]){"ls", dir, 0}, environ);

This function is designed to do the same thing as system() except rather than taking a shell script argument it accepts an array of strings which are safely passed directly to execve().

This function is 5x faster than system() and generally safer, for most command running use cases that don't need to control the i/o file descriptors.

@param

const char* prog: is path searched (if it doesn't contain a slash) from the $PATH environment variable in environ (not your envp)
char** argv
char** envp

@return

int: -1 if child process couldn't be created, otherwise a wait status that can be accessed using macros like WEXITSTATUS(s), WIFSIGNALED(s), WTERMSIG(s), etc.

@see system()

@see libc/proc/systemvpe.c

tan

Returns tangent of x.

@param

double x

@return

double

@see libc/tinymath/tan.c

tanh

Returns hyperbolic tangent of 𝑥.

@param

double x

@return

double

@see libc/tinymath/tanh.c

tanhf

Returns hyperbolic tangent of 𝑥.

@param

float x

@return

float

@define tanhf(x)=(expf(x)-expf(-x))/(expf(x)+expf(-x))

@define tanhf(x)=(expf(2.f*x)-1.f)/(expf(2.f*x)-1.f+2.f)

@see libc/tinymath/tanhf.c

tanl

Returns tangent of x.

@param

long double x

@return

long double

@see libc/tinymath/tanl.c

tcgetattr

Obtains the termios struct.

Here are the approximate defaults you can expect across platforms:

c_iflag        = ICRNL IXON
c_oflag        = OPOST ONLCR NL0 CR0 TAB0 BS0 VT0 FF0
c_cflag        = ISIG CREAD CS8
c_lflag        = ISIG ICANON ECHO ECHOE ECHOK IEXTEN ECHOCTL ECHOKE
cfgetispeed()  = B38400
cfgetospeed()  = B38400
c_cc[VINTR]    = CTRL-C
c_cc[VQUIT]    = CTRL-\   # ignore this comment
c_cc[VERASE]   = CTRL-?
c_cc[VKILL]    = CTRL-U
c_cc[VEOF]     = CTRL-D
c_cc[VTIME]    = CTRL-@
c_cc[VMIN]     = CTRL-A
c_cc[VSTART]   = CTRL-Q
c_cc[VSTOP]    = CTRL-S
c_cc[VSUSP]    = CTRL-Z
c_cc[VEOL]     = CTRL-@
c_cc[VSWTC]    = CTRL-@
c_cc[VREPRINT] = CTRL-R
c_cc[VDISCARD] = CTRL-O
c_cc[VWERASE]  = CTRL-W
c_cc[VLNEXT]   = CTRL-V
c_cc[VEOL2]    = CTRL-@

@param

int fd: open file descriptor that isatty()
struct linux* tio: is where result is stored

@return

int: 0 on success, or -1 w/ errno

@asyncsignalsafe

@see libc/calls/tcgetattr.c

tcgetpgrp

Returns which process group controls terminal.

@param

int fd

@return

int: process group id on success, or -1 w/ errno

@raise ENOTTY if fd is isn't controlling teletypewriter

@raise EBADF if fd isn't an open file descriptor

@raise ENOSYS on Windows and Bare Metal

@asyncsignalsafe

@see libc/calls/tcgetpgrp.c

tcgetsid

Returns session id controlling terminal.

@param

int fd

@return

int

@see libc/calls/tcgetsid.c

tcgetwinsize

Gets terminal window size.

@param

int fd
struct winsize* ws

@return

int

@see libc/calls/tcgetwinsize.c

tcsetattr

Sets struct on teletypewriter w/ drains and flushes.

@param

int fd

open file descriptor that isatty()

int opt

can be:

TCSANOW: sets console settings
TCSADRAIN: drains output, and sets console settings
TCSAFLUSH: drops input, drains output, and sets console settings

struct linux* tio

@return

int: 0 on success, -1 w/ errno

@asyncsignalsafe

@see libc/calls/tcsetattr.c

tcsetpgrp

Sets foreground process group id.

@param

int fd
int pgrp

@return

int: 0 on success, or -1 w/ errno

@raise EINVAL if pgrp is invalid

@raise EBADF if fd isn't an open file descriptor

@raise EPERM if pgrp didn't match process in our group

@raise ENOTTY if fd is isn't controlling teletypewriter

@raise EIO if process group of writer is orphoned, calling thread is not blocking SIGTTOU, and process isn't ignoring SIGTTOU

@asyncsignalsafe

@see libc/calls/tcsetpgrp.c

tcsetsid

Associates session with controlling tty.

@param

int fd
int pid

@return

int: 0 on success, or -1 w/ errno

@raise EBADF if fd isn't an open file descriptor

@raise ENOTTY if fd is isn't controlling teletypewriter

@raise EINVAL if pid isn't session id associated with this process

@raise EPERM if calling process isn't the session leader

@raise ENOSYS on Windows and Bare Metal

@see libc/calls/tcsetsid.c

tcsetwinsize

Sets terminal window size attributes.

@param

int fd
struct winsize* ws

@return

int

@see libc/calls/tcsetwinsize.c

tdelete

@param

void* key
void** rootp
int(*)() cmp

@return

void*

@see third_party/musl/tdelete.c

tdestroy

@param

void* root
void(*)() freekey

@return

void

@see third_party/musl/tdestroy.c

tempnam

Creates name for temporary file.

@param

const char* dir
const char* pfx

@return

char*

@see third_party/musl/tempnam.c

__text_windows_start

Special area for Windows NT support code.

Isolating this code adds value for Windows users by minimizing page faults through improved locality. On System Five the PIRO runtime can unmap these pages.

@return

@see libc/runtime/piro.c

@see ape/ape.lds

@see libc/runtime/init.S

tfind

@param

void* key
void** rootp
int(*)() cmp

@return

void*

@see third_party/musl/tfind.c

__tfork_thread

Creates thread on OpenBSD.

@param

rdi: is params
rsi: is size of params
rdx: is start function
rcx: is start parameter

@return

: thread id or negative errno

@see libc/runtime/clone-openbsd.S

tgamma

Calculates gamma function of 𝑥.

@param

double x

@return

double

@see libc/tinymath/tgamma.c

tgammaf

@param

float x

@return

float

@see libc/tinymath/tgammaf.c

__threaded

Contains TID of main thread or 0 if threading isn't enabled.

@type

int

@see libc/nexgen32e/threaded.c

time

Returns time as seconds from UNIX epoch.

@param

long* opt_out_ret: can receive return value on success

@return

long: seconds since epoch, or -1 w/ errno

@asyncsignalsafe

@see libc/calls/time.c

timespec_add

Adds two nanosecond timestamps.

@param

struct x x
struct y y

@return

struct y

@see libc/calls/timespec_add.c

timespec_cmp

Compares nanosecond timestamps.

@param

struct a a
struct b b

@return

int: 0 if equal, -1 if a < b, or +1 if a > b

@see libc/calls/timespec_cmp.c

timespec_frommicros

Converts timespec interval from microseconds.

@param

long x

@return

struct ts

@see libc/calls/timespec_frommicros.c

timespec_fromnanos

Converts timespec interval from nanoseconds.

@param

long x

@return

struct ts

@see libc/calls/timespec_fromnanos.c

timespec_get

Returns high-precision timestamp, the C11 way.

@param

struct timespec* ts: receives CLOCK_REALTIME timestamp
int base: must be TIME_UTC

@return

int: base on success, or 0 on failure

@see timespec_real()

@see libc/calls/timespec_get.c

timespec_getres

Returns high-precision timestamp granularity, the C23 way.

@param

struct timespec* ts: receives granularity as a relative timestamp
int base: must be TIME_UTC

@return

int: base on success, or 0 on failure

@see libc/calls/timespec_getres.c

timespec_mono

Returns current monotonic time.

This function uses a CLOCK_MONOTONIC clock and never fails.

@return

struct ts

@see timespec_real()

@see libc/calls/timespec_mono.c

timespec_sub

Subtracts two nanosecond timestamps.

@param

struct a a
struct b b

@return

struct b

@see libc/calls/timespec_sub.c

timespec_tomicros

Reduces ts from 1e-9 to 1e-6 granularity w/ ceil rounding.

This function uses ceiling rounding. For example, if ts is one nanosecond, then one microsecond will be returned. Ceil rounding is needed by many interfaces, e.g. setitimer(), because the zero timestamp has a special meaning.

This function also detects overflow in which case INT64_MAX or INT64_MIN may be returned. The errno variable isn't changed.

@param

struct ts ts

@return

long: 64-bit scalar holding microseconds since epoch

@see timespec_totimeval()

@see libc/calls/timespec_tomicros.c

timespec_tomillis

Reduces ts from 1e-9 to 1e-3 granularity w/ ceil rounding.

This function uses ceiling rounding. For example, if ts is one nanosecond, then one millisecond will be returned. Ceil rounding is needed by many interfaces, e.g. setitimer(), because the zero timestamp has a special meaning.

This function also detects overflow in which case INT64_MAX or INT64_MIN may be returned. The errno variable isn't changed.

@param

struct ts ts

@return

long: 64-bit scalar milliseconds since epoch

@see libc/calls/timespec_tomillis.c

timespec_tonanos

Converts timespec to scalar.

This returns the absolute number of nanoseconds in a timespec. If overflow happens, then INT64_MAX or INT64_MIN is returned. The errno variable isn't changed.

@param

struct x x

@return

long: 64-bit integer holding nanoseconds since epoch

@see libc/calls/timespec_tonanos.c

timespec_totimeval

Reduces ts from 1e-9 to 1e-6 granularity w/ ceil rounding.

@param

struct ts ts

@return

struct timeval: microseconds since epoch

@see timespec_tomicros()

@see libc/calls/timespec_totimeval.c

TimeSpecToWindowsTime

@param

struct t t

@return

long

@see libc/str/timespectowindowstime.c

timeval_add

Adds two microsecond timestamps.

@param

struct x x
struct y y

@return

struct y

@see libc/calls/timeval_add.c

timeval_cmp

Compares microsecond timestamps.

@param

struct a a
struct b b

@return

int: 0 if equal, -1 if a < b, or +1 if a > b

@see libc/calls/timeval_cmp.c

timeval_frommicros

Converts timeval interval from microseconds.

@param

long x

@return

struct tv

@see libc/calls/timeval_frommicros.c

timeval_frommillis

Converts timeval interval from milliseconds.

@param

long x

@return

struct tv

@see libc/calls/timeval_frommillis.c

timeval_real

Returns current time w/ microsecond precision.

@return

struct tv

@see timespec_real()

@see libc/calls/timeval_real.c

timeval_sub

Subtracts two nanosecond timestamps.

@param

struct a a
struct b b

@return

struct b

@see libc/calls/timeval_sub.c

timeval_tomicros

Converts timeval to scalar.

This returns the absolute number of microseconds in a timeval. If overflow happens, then INT64_MAX or INT64_MIN is returned. The errno variable isn't changed.

@param

struct x x

@return

long: 64-bit integer holding microseconds since epoch

@see libc/calls/timeval_tomicros.c

timeval_tomillis

Reduces ts from 1e-6 to 1e-3 granularity w/ ceil rounding.

This function returns the absolute number of milliseconds in a timeval. Ceiling rounding is used. For example, if ts is one nanosecond, then one millisecond will be returned. Ceil rounding is needed by many interfaces, e.g. setitimer(), because the zero timestamp has a valial meaning.

This function also detects overflow in which case INT64_MAX or INT64_MIN may be returned. The errno variable isn't changed.

@param

struct ts ts

@return

long: 64-bit scalar milliseconds since epoch

@see libc/calls/timeval_tomillis.c

timeval_toseconds

Converts timeval to seconds.

This function uses ceil rounding, so 1µs becomes 1s. The addition operation is saturating so timeval_toseconds(timeval_max) returns INT64_MAX.

@param

struct tv tv

@return

long

@see libc/calls/timeval_toseconds.c

TimeValToWindowsTime

@param

struct t t

@return

long

@see libc/str/timevaltowindowstime.c

timezone

@type

long

@see libc/time/timezone.c

timingsafe_bcmp

Tests inequality of first 𝑛 bytes of 𝑝 and 𝑞.

@param

void* a
void* b
unsigned long n

@return

int: nonzero if unequal, otherwise zero

@see timingsafe_memcmp()

@asyncsignalsafe

@see libc/str/timingsafe_bcmp.c

timingsafe_memcmp

Lexicographically compares the first 𝑛 bytes in 𝑝 and 𝑞.

The following expression:

timingsafe_memcmp(p, q, n)

Is functionally equivalent to:

MAX(-1, MIN(1, memcmp(p, q, n)))

Running time is independent of the byte sequences compared, making this safe to use for comparing secret values such as cryptographic MACs. In contrast, memcmp() may short-circuit after finding the first differing byte.

timingsafe_memcmp n=0              661 picoseconds
timingsafe_memcmp n=1                1 ns/byte            590 mb/s
timingsafe_memcmp n=2                1 ns/byte            738 mb/s
timingsafe_memcmp n=3                1 ns/byte            805 mb/s
timingsafe_memcmp n=4                1 ns/byte            843 mb/s
timingsafe_memcmp n=5                1 ns/byte            922 mb/s
timingsafe_memcmp n=6                1 ns/byte            932 mb/s
timingsafe_memcmp n=7                1 ns/byte            939 mb/s
timingsafe_memcmp n=8              992 ps/byte            984 mb/s
timingsafe_memcmp n=9              992 ps/byte            984 mb/s
timingsafe_memcmp n=15             926 ps/byte          1,054 mb/s
timingsafe_memcmp n=16             950 ps/byte          1,026 mb/s
timingsafe_memcmp n=17             933 ps/byte          1,045 mb/s
timingsafe_memcmp n=31             896 ps/byte          1,089 mb/s
timingsafe_memcmp n=32             888 ps/byte          1,098 mb/s
timingsafe_memcmp n=33             972 ps/byte          1,004 mb/s
timingsafe_memcmp n=80             913 ps/byte          1,068 mb/s
timingsafe_memcmp n=128            891 ps/byte          1,095 mb/s
timingsafe_memcmp n=256            873 ps/byte          1,118 mb/s
timingsafe_memcmp n=16384          858 ps/byte          1,138 mb/s
timingsafe_memcmp n=32768          856 ps/byte          1,140 mb/s
timingsafe_memcmp n=131072         857 ps/byte          1,138 mb/s
bcmp ne n=256                        3 ps/byte            246 gb/s
bcmp eq n=256                       32 ps/byte         30,233 mb/s
memcmp ne n=256                      3 ps/byte            246 gb/s
memcmp eq n=256                     31 ps/byte         31,493 mb/s
timingsafe_bcmp ne n=256            27 ps/byte         35,992 mb/s
timingsafe_bcmp eq n=256            27 ps/byte         35,992 mb/s
timingsafe_memcmp ne n=256         877 ps/byte          1,113 mb/s
timingsafe_memcmp eq n=256         883 ps/byte          1,105 mb/s

@param

void* p
void* q
unsigned long n

@return

int: -1, 0, or 1 based on comparison

@note each byte is interpreted as unsigned char

@see timingsafe_bcmp() it's 100x faster

@asyncsignalsafe

@see libc/str/timingsafe_memcmp.c

timingsafe_memcmp_notice

@type

const char[61]

@see libc/str/timingsafe_memcmp.c

tinyprint

Writes strings to file descriptor, e.g.

tinyprint(1, "hello", " ", "world", "\n", NULL);

This function is intended so that small command line programs (e.g. build utilities) can print succinct error messages automatically to standard io without linking too much binary footprint.

@param

int fd: is file descriptor
const char* s: is NUL-terminated string, or NULL
...

@return

long: bytes written on success, or -1 w/ errno

@see libc/calls/tinyprint.c

tmpfile

Opens stream backed by anonymous file, e.g.

FILE *f;
if (!(f = tmpfile())) {
  perror("tmpfile");
  exit(1);
}
// do stuff
fclose(f);

This creates a secure temporary file inside $TMPDIR. If it isn't defined, then /tmp is used on UNIX and GetTempPath() is used on the New Technology. This resolution of $TMPDIR happens once in a ctor.

Once fclose() is called, the returned file is guaranteed to be deleted automatically. On UNIX the file is unlink()'d before this function returns. On the New Technology it happens upon fclose().

On newer Linux only (c. 2013) it's possible to turn the anonymous returned file back into a real file, by doing this:

linkat(AT_FDCWD, gc(xasprintf("/proc/self/fd/%d", fileno(f))),
       AT_FDCWD, "real.txt", AT_SYMLINK_FOLLOW)

On the New Technology, temporary files created by this function should have better performance, because kNtFileAttributeTemporary asks the kernel to more aggressively cache and reduce i/o ops.

Favor tmpfd() or tmpfile() over open(O_TMPFILE) because the latter is Linux-only and will cause open() failures on all other platforms.

@return

struct FILE*

@see tmpfd() if you don't want to link stdio/malloc

@raise ECANCELED if thread was cancelled in masked mode

@raise EINTR if signal was delivered

@cancelationpoint

@asyncsignalsafe

@vforksafe

@see libc/stdio/tmpfile.c

tmpnam

Generates temporary file name.

@param

char* buf: may be null to generate /tmp/tmpnam_XXXXXX to a static buffer (it works on Windows) that is not thread safe; otherwise the caller must supply a buffer with L_tmpnam bytes available

@return

char*: unique generated filename, or null on failure; buf memory is only mutated on success

@see libc/stdio/tmpnam.c

tmpnam_r

Generates temporary file name, reentrantly.

This function is the same as tmpnam() except buf can't be NULL.

@param

char* buf: must have L_tmpnam bytes available

@return

char*: pointer to buf which is populated with a unique generated filename, or null w/ errno on failure; buffer content will only be mutated on success

@see libc/stdio/tmpnam_r.c

toascii

Narrows number to ASCII.

@param

int c

@return

int

@see libc/str/toascii.c

tolower

Converts character to ascii lower case.

@param

int c

@return

int

@see libc/str/tolower.c

touch

Creates new file or changes modified time on existing one.

@param

const char* file: is a UTF-8 string, which may or may not exist
unsigned int mode: is an octal user/group/other permission, e.g. 0755

@return

int: 0 on success, or -1 w/ errno

@see creat()

@see libc/calls/touch.c

toupper

Converts character to upper case.

@param

int c

@return

int

@see libc/str/toupper.c

towctrans

@param

unsigned int c
const int* t

@return

unsigned int

@see libc/str/towctrans.c

towlower

Converts wide character to lower case.

@param

unsigned int c

@return

unsigned int

@see libc/str/towlower.c

towupper

Converts wide character to upper case.

@param

unsigned int c

@return

unsigned int

@see libc/str/towupper.c

tpenc

Encodes Thompson-Pike variable-length integer.

@param

unsigned int c

@return

unsigned long

@see libc/intrin/tpenc.c

traceme

@type

int

@see libc/log/traceme.c

truncate

Changes size of file.

If the file size is increased, the extended area shall appear as if it were zero-filled. If your file size is decreased, the extra data shall be lost.

@param

const char* path: is name of file that shall be resized
long length

@return

int: 0 on success, or -1 w/ errno

@raise EINVAL if length is negative

@raise EINTR if signal was delivered instead

@raise ECANCELED if thread was cancelled in masked mode

@raise EFBIG or EINVAL if length is too huge

@raise EFAULT if path points to invalid memory

@raise EACCES if we don't have permission to search a component of path

@raise ENOTDIR if a directory component in path exists as non-directory

@raise ENAMETOOLONG if symlink-resolved path length exceeds PATH_MAX

@raise ENAMETOOLONG if component in path exists longer than NAME_MAX

@raise ELOOP if a loop was detected resolving components of path

@raise EROFS if path is on a read-only filesystem (e.g. zip)

@raise ENOENT if path doesn't exist or is an empty string

@raise ETXTBSY if path is an executable being executed

@raise ENOSYS on bare metal

@cancelationpoint

@see ftruncate()

@see libc/calls/truncate.c

tsearch

@param

void* key
void** rootp
int(*)() cmp

@return

void*

@see third_party/musl/tsearch.c

ttyname

Returns name of terminal.

This function isn't required to be thread safe, consider ttyname_r().

@param

int fd

@return

char*: terminal path on success, or null w/ errno

@see ttyname_r()

@see libc/calls/ttyname.c

twalk

@param

void* root
void(*)() action

@return

void

@see third_party/musl/twalk.c

tzname

@type

char*[2]

@see libc/time/timezone.c

ualarm

Sets microsecond-precision alarm.

This generates a SIGALRM signal after usecs microseconds. If reload is non-zero, then it'll keep generating SIGALRM every reload microseconds after the first signal.

@param

unsigned int usecs
unsigned int reload

@return

unsigned int

@asyncsignalsafe

@see libc/thread/ualarm.c

__udivmodti4

Performs 128-bit unsigned division and remainder.

@param

unsigned __int128 a: is dividend
unsigned __int128 b: is divisor
unsigned __int128* rem: receives remainder if not NULL

@return

unsigned __int128

@see libc/intrin/udivmodti4.c

uint64toarray_radix16

@param

unsigned long x
char* b

@return

unsigned long

@see libc/fmt/itoa64radix16.greg.c

uleb64

Encodes unsigned integer to array.

uleb64 INT64_MAX    l:        10𝑐         3𝑛𝑠
zleb64 INT64_MAX    l:        13𝑐         4𝑛𝑠
sleb64 INT64_MAX    l:        16𝑐         5𝑛𝑠
uleb128 INT64_MAX   l:        18𝑐         6𝑛𝑠
zleb128 INT64_MAX   l:        18𝑐         6𝑛𝑠
sleb128 INT64_MAX   l:        24𝑐         8𝑛𝑠
zleb64 INT64_MIN    l:        13𝑐         4𝑛𝑠
sleb64 INT64_MIN    l:        16𝑐         5𝑛𝑠
zleb128 INT64_MIN   l:        19𝑐         6𝑛𝑠
sleb128 INT64_MIN   l:        24𝑐         8𝑛𝑠

@param

char* p: is output array
unsigned long x: is number

@return

char*: p + i

@see libc/fmt/uleb64.c

ulock_wait

@param

unsigned int operation
void* addr
unsigned long value
unsigned int timeout_micros

@return

int

@see libc/intrin/ulock.c

ulock_wake

@param

unsigned int operation
void* addr
unsigned long wake_value

@return

int

@see libc/intrin/ulock.c

umask

Sets file mode creation mask.

On Windows, the value of umask() determines how Cosmopolitan goes about creating synthetic st_mode bits. The default umask is 077 which is based on the assumption that Windows is being used for a single user. Don't assume that Cosmopolitan Libc will help you to secure a multitenant Windows computer.

@param

unsigned int newmask

@return

unsigned int: previous mask

@note always succeeds

@see libc/calls/umask.c

unbing

Turns CP437 unicode glyph into its binary representation.

@param

int c: is a unicode character

@return

int: byte representation, or -1 if ch wasn't ibm cp437

@see bing()

@see libc/fmt/unbing.c

unbingbuf

Decodes human-readable CP437 glyphs into binary, e.g.

char binged[5];
char golden[5] = "\0\1\2\3\4";
unbingbuf(binged, sizeof(binged), u" ☺☻♥♦", -1);
CHECK_EQ(0, memcmp(binged, golden, 5));

@param

void* buf: is caller owned
unsigned long size: is byte length of buf
const unsigned short* glyphs: is UCS-2 encoded CP437 representation of binary data
int fill: if -1 will memset any remaining buffer space

@return

void*

@note no NUL terminator is added to end of buf

@see tunbing(), unbingstr(), unbing()

@see libc/x/unbingbuf.c

unbingstr

Decodes human-readable CP437 glyphs into binary, e.g.

CHECK_EQ(0, memcmp(gc(unbingstr(u" ☺☻♥♦")), "\0\1\2\3\4", 5));

@param

const unsigned short* s

@return

void*

@note no NUL terminator is added to end of buf

@see tunbing(), unbingbuf(), unbing()

@see libc/x/unbingstr.c

Unchunk

Removes chunk transfer encoding from message body in place.

@param

struct HttpUnchunker* u
char* p: is modified in place
unsigned long n
unsigned long* l: receives content length if not null

@return

long: bytes processed, 0 if need more data, or -1 on failure

@see net/http/unchunk.c

Underlong

Canonicalizes overlong Thompson-Pike encodings.

Please note that the IETF banned these numbers, so if you want to enforce their ban you can simply strcmp() the result to check for the existence of banned numbers.

@param

const char* p: is input value
unsigned long n: if -1 implies strlen
unsigned long* z: if non-NULL receives output length

@return

char*: allocated NUL-terminated buffer, or NULL w/ errno

@see net/http/underlong.c

ungetc

Pushes byte back to stream.

@param

int c
struct FILE* f

@return

int

@see libc/stdio/ungetc.c

ungetc_unlocked

Pushes byte back to stream.

@param

int c
struct FILE* f

@return

int

@see libc/stdio/ungetc_unlocked.c

ungetwc

Pushes wide character back to stream.

@param

unsigned int c
struct FILE* f

@return

unsigned int

@see libc/stdio/ungetwc.c

ungetwc_unlocked

Pushes wide character back to stream.

@param

unsigned int c
struct FILE* f

@return

unsigned int

@see libc/stdio/ungetwc_unlocked.c

unhilbert

Decodes Hilbert space-filling curve.

@param

long n
long i

@return

struct m

@see https://en.wikipedia.org/wiki/Hilbert_curve

@see hilbert()

@see libc/intrin/hilbert.c

unlink

Removes file.

This may be used to delete files but it can't be used to delete directories. The exception are symlinks, which this will delete however not the linked directory.

@param

const char* name

@return

int: 0 on success, or -1 w/ errno

@asyncsignalsafe

@see libc/calls/unlink.c

unlinkat

Deletes inode and maybe the file too.

This may be used to delete files and directories and symlinks.

@param

int dirfd: is normally AT_FDCWD but if it's an open directory and path is relative, then path becomes relative to dirfd
const char* path: is the thing to delete
int flags: can have AT_REMOVEDIR

@return

int: 0 on success, or -1 w/ errno

@see libc/calls/unlinkat.c

unlockpt

Unlocks pseudoteletypewriter pair.

@param

int fd

@return

int: 0 on success, or -1 w/ errno

@raise EBADF if fd isn't open

@raise EINVAL if fd is valid but not associated with pty

@see libc/calls/unlockpt.c

unmount

Unmounts file system.

The following flags may be specified:

MNT_FORCE

The following flags may also be used, but could be set to zero at runtime if the underlying kernel doesn't support them.

MNT_DETACH: lazily unmount; Linux-only
MNT_EXPIRE
UMOUNT_NOFOLLOW
MNT_BYFSID

@param

const char* target
int flags

@return

int

@see libc/calls/unmount.c

unuleb64

Decodes unsigned integer from array.

@param

const char* p: is input array
unsigned long n: is capacity of p
unsigned long* x: receives number number

@return

int: bytes decoded or -1 on error

@see libc/fmt/unuleb64.c

unzleb64

Decodes array to signed integer w/ zig-zag encoding.

@param

const char* p: is array
unsigned long n: is byte length of array
long* o: optionally receives decoded integer

@return

int: bytes decoded or -1 on error

@see zleb64()

@see libc/fmt/unzleb64.c

updwtmpx

@param

const char* x
struct utmpx* y

@return

void

@see libc/runtime/utmp.c

uselocale

@param

struct __locale_struct* l

@return

struct __locale_struct*

@see libc/str/uselocale.c

utf16to32

Transcodes UTF-16 to UTF-32.

@param

const unsigned short* p: is input value
unsigned long n: if -1 implies strlen
unsigned long* z: if non-NULL receives output length

@return

int*

@see libc/x/utf16to32.c

utf16to8

Transcodes UTF-16 to UTF-8.

@param

const unsigned short* p: is input value
unsigned long n: if -1 implies strlen
unsigned long* z: if non-NULL receives output length

@return

char*

@see libc/x/utf16to8.c

utf32to8

Transcodes UTF-32 to UTF-8.

@param

const int* p: is input value
unsigned long n: if -1 implies wcslen
unsigned long* z: if non-NULL receives output length

@return

char*

@see libc/x/utf32to8.c

utf8to16

Transcodes UTF-8 to UTF-16.

@param

const char* p: is input value
unsigned long n: if -1 implies strlen
unsigned long* z: if non-NULL receives output length

@return

unsigned short*

@see libc/x/utf8to16.c

utf8to32

Transcodes UTF-8 to UTF-32.

@param

const char* p: is input value
unsigned long n: if -1 implies strlen
unsigned long* z: if non-NULL receives output length

@return

int*

@see libc/x/utf8to32.c

utime

Changes last accessed/modified times on file.

@param

const char* path
struct utimbuf* times: if NULL means now

@return

int: 0 on success, or -1 w/ errno

@see utimensat() for modern version

@asyncsignalsafe

@see libc/calls/utime.c

utimensat

Sets access/modified time on file, the modern way.

XNU only has microsecond (1e-6) accuracy and there's no dirfd-relative support. Windows only has hectonanosecond (1e-7) accuracy. RHEL5 doesn't support dirfd or flags and will truncate timestamps to seconds.

If you'd rather specify an open file descriptor rather than its filesystem path, then consider using futimens().

@param

int dirfd: can be AT_FDCWD or an open directory
const char* path: is filename whose timestamps should be modified
struct timespec* ts: is {access, modified} timestamps, or null for current time
int flags: can have AT_SYMLINK_NOFOLLOW

@return

int: 0 on success, or -1 w/ errno

@raise EINVAL if flags had an unrecognized value

@raise EINVAL on XNU or RHEL5 when any flags are used

@raise EPERM if pledge() is in play without fattr promise

@raise EACCES if unveil() is in play and path isn't unveiled

@raise EINVAL if ts specifies a nanosecond value that's out of range

@raise ENAMETOOLONG if symlink-resolved path length exceeds PATH_MAX

@raise ENAMETOOLONG if component in path exists longer than NAME_MAX

@raise EBADF if dirfd isn't a valid fd or AT_FDCWD

@raise EFAULT if path or ts memory was invalid

@raise EROFS if path is on read-only filesystem (e.g. zipos)

@raise ENOTSUP on XNU or RHEL5 when dirfd isn't AT_FDCWD

@raise ENOSYS on bare metal

@asyncsignalsafe

@see libc/calls/utimensat.c

utimes

Changes last accessed/modified timestamps on file.

@param

const char* path
struct timeval* tv: is access/modified timestamps, or NULL which means now

@return

int: 0 on success, or -1 w/ errno

@note truncates to second precision on rhel5

@see utimensat() for modern version

@asyncsignalsafe

@see libc/calls/utimes.c

vdprintf

Formats string directly to system i/o device.

@param

int fd
const char* fmt
struct __va_list* va

@return

int

@asyncsignalsafe

@vforksafe

@see libc/stdio/vdprintf.c

__vdsosym

Returns address of "Virtual Dynamic Shared Object" function on Linux.

@param

const char* version
const char* name

@return

void*

@see libc/calls/vdsofunc.greg.c

versionsort

@param

struct dirent** a
struct dirent** b

@return

int

@see libc/stdio/versionsort.c

vfork

Forks process without copying page tables.

This function lets a process spawn another process without copying the page tables. The parent process gets suspended until the child calls either execve() or _Exit(), and they share memory during that time. That's at least how we want vfork() to work. Support for these behaviors is patchy. It is also error-prone to use this function in an environment with signal handlers and threads. The best way to use this is by calling posix_spawn() which works around the dangers and determines at runtime the best way to pass error codes

@return

: pid of child process or 0 if forked process

@returnstwice

@vforksafe

@see libc/proc/vfork.S

vfprintf

Formats and writes text to stream.

@param

struct FILE* f
const char* fmt
struct __va_list* va

@return

int

@see printf() for further documentation

@see libc/stdio/vfprintf.c

vfprintf_unlocked

Formats and writes text to stream.

@param

struct FILE* f
const char* fmt
struct __va_list* va

@return

int

@see printf() for further documentation

@see libc/stdio/vfprintf_unlocked.c

vfscanf

Stream decoder.

@param

struct FILE* stream
const char* fmt
struct __va_list* ap

@return

int

@see libc/fmt/vcscanf.h

@see libc/stdio/vfscanf.c

vga_console

Code snippet for initializing the VGA video mode for bare metal.

If a program requests VGA support (by yoinking vga_console), and it is started in bare metal mode, then try to ensure that the VGA monitor is in a known mode. This is easier to do while the program is still running in real mode.

This module also ropes in the sys_writev_vga routine, which implements the actual VGA console output under x86-64 long mode.

@return

@see rlinit & .sort.text.real.init.* (ape/ape.S)

@see ape/ape.lds

@see sys_writev_vga (libc/vga/writev-vga.c)

@see libc/vga/rlinit-init-vga.S

vigna

Returns deterministic pseudorandom data, e.g.

uint64_t x = vigna();

You can generate different types of numbers as follows:

int64_t x = vigna() >> 1;    // make positive signed integer
double x = _real1(vigna());  // make float on [0,1]-interval

You can seed this random number generator using:

svigna(rdseed());

You may use the reentrant version of this function:

static uint64_t s = 0;
uint64_t x = svigna_r(&s);

If you want to fill a buffer with data then rngset() implements vigna's algorithm to do that extremely well:

char buf[4096];
rngset(buf, sizeof(buf), vigna, 0);

If you want a fast pseudorandom number generator that seeds itself automatically on startup and fork(), then consider _rand64. If you want true random data then consider rdseed, rdrand, and getrandom.

@return

unsigned long: 64 bits of pseudorandom data

@note this function is not intended for cryptography

@note this function passes bigcrush and practrand

@note this function takes at minimum 4 cycles

@see libc/stdio/vigna.c

vigna_r

Returns pseudorandom data.

@param

unsigned long* state

@return

unsigned long

@see vigna() for easy api

@see libc/stdio/vigna.c

VisualizeControlCodes

Makes control codes and trojan source plainly viewable.

This is useful for logging data like HTTP messages, where we don't want full blown C string literal escaping, but we don't want things like raw ANSI control codes from untrusted devices in our terminals.

This function also canonicalizes overlong encodings. Therefore it isn't necessary to say VisualizeControlCodes(Underlong(𝑥))) since VisualizeControlCodes(𝑥) will do the same thing.

@param

const char* data: is input value
unsigned long size: if -1 implies strlen
unsigned long* out_size: if non-NULL receives output length

@return

char*: allocated NUL-terminated buffer, or NULL w/ errno

@see net/http/visualizecontrolcodes.c

vprintf

Formats and writes text to stdout.

@param

const char* fmt
struct __va_list* va

@return

int

@see printf() for further documentation

@see libc/stdio/vprintf.c

vscanf

String decoder.

@param

const char* fmt
struct __va_list* ap

@return

int

@see libc/fmt/vcscanf.h

@see libc/stdio/vscanf.c

vsnprintf

Formats string to buffer w/ preexisting vararg state.

@param

char* buf: stores output
unsigned long size: is byte capacity buf
const char* fmt
struct __va_list* va

@return

int: number of bytes written, excluding the NUL terminator; or, if the output buffer wasn't passed, or was too short, then the number of characters that *would* have been written is returned

@see __fmt() and printf() for detailed documentation

@asyncsignalsafe

@vforksafe

@see libc/stdio/vsnprintf.c

vsprintf

Formats string to buffer hopefully large enough w/ vararg state.

@param

char* buf
const char* fmt
struct __va_list* va

@return

int

@see __fmt() and printf() for detailed documentation

@see vsnprintf() for modern alternative w/ buf size param

@see libc/stdio/vsprintf.c

vsscanf

Decodes string.

@param

const char* str
const char* fmt
struct __va_list* va

@return

int

@see libc/fmt/vcscanf.h (for docs and implementation)

@note to offer the best performance, we assume small codebases needing vsscanf() won't need sscanf() too; and as such, there's a small code size penalty to using both

@see libc/stdio/vsscanf.c

wait

Waits for status to change on any child process.

@param

int* opt_out_wstatus: optionally returns status code, and *wstatus may be inspected using WEEXITSTATUS(), etc.

@return

int: process id of terminated child or -1 w/ errno

@cancelationpoint

@asyncsignalsafe

@restartable

@vforksafe

@see libc/proc/wait.c

wait3

Waits for status to change on any child process.

@param

int* opt_out_wstatus: optionally returns status code, and *wstatus may be inspected using WEEXITSTATUS(), etc.
int options: can have WNOHANG, WUNTRACED, WCONTINUED, etc.
struct rusage* opt_out_rusage: optionally returns accounting data

@return

int: process id of terminated child or -1 w/ errno

@cancelationpoint

@asyncsignalsafe

@restartable

@see libc/proc/wait3.c

wait4

Waits for status to change on process.

@param

int pid: >0 targets specific process, =0 means any proc in a group, -1 means any child process, <-1 means any proc in specific group
int* opt_out_wstatus: optionally returns status code, and *wstatus may be inspected using WEEXITSTATUS(), etc.
int options: can have WNOHANG, WUNTRACED, WCONTINUED, etc.
struct ruchlds* opt_out_rusage: optionally returns accounting data

@return

int: process id of terminated child or -1 w/ errno

@cancelationpoint

@asyncsignalsafe

@restartable

@see libc/proc/wait4.c

waitpid

Waits for status to change on process.

@param

int pid: >0 targets specific process, =0 means any proc in a group, -1 means any child process, <-1 means any proc in specific group
int* opt_out_wstatus: optionally returns status code, and *wstatus may be inspected using WEXITSTATUS(), etc.
int options: can have WNOHANG, WUNTRACED, WCONTINUED, etc.

@return

int: process id of terminated child or -1 w/ errno

@cancelationpoint

@asyncsignalsafe

@restartable

@see libc/proc/waitpid.c

wchomp

Mutates line to remove line-ending characters.

@param

int* line: is NULL-propagating

@return

int*

@see getline

@see libc/str/wchomp.c

wcrtomb

@param

char* s
int wc
unsigned int* st

@return

unsigned long

@see libc/str/wcrtomb.c

wcscasecmp

Compares NUL-terminated wide strings case-insensitively.

@param

const int* a: is first non-null NUL-terminated string pointer
const int* b: is second non-null NUL-terminated string pointer

@return

int: is <0, 0, or >0 based on uint8_t comparison

@asyncsignalsafe

@see libc/str/wcscasecmp.c

wcscat

Appends 𝑠 to 𝑑.

@param

int* d
const int* s

@return

int*: 𝑑

@asyncsignalsafe

@see libc/str/wcscat.c

wcschr

Returns pointer to first instance of character.

@param

const int* s
int c

@return

int*

@see libc/str/wcschr.c

wcschrnul

@param

const int* s
int c

@return

int*

@see libc/str/wcschrnul.c

wcscmp

Compares NUL-terminated wide strings.

@param

const int* a: is first non-null NUL-terminated string pointer
const int* b: is second non-null NUL-terminated string pointer

@return

int: is <0, 0, or >0 based on uint8_t comparison

@asyncsignalsafe

@see libc/str/wcscmp.c

wcscpy

Copies NUL-terminated wide character string.

𝑑 and 𝑠 must not overlap unless 𝑑 ≤ 𝑠.

@param

int* d: is destination memory
const int* s: is a NUL-terminated string

@return

int*: original d

@asyncsignalsafe

@see libc/str/wcscpy.c

wcscspn

Returns prefix length, consisting of chars not in reject. a.k.a. Return index of first byte that's in charset.

@param

const int* s
const int* reject: is nul-terminated character set

@return

unsigned long

@see strspn(), strtok_r()

@asyncsignalsafe

@see libc/str/wcscspn.c

wcsdup

Allocates copy of wide string.

@param

const int* s

@return

int*

@see libc/mem/wcsdup.c

wcsendswith

Returns true if s has suffix.

@param

const int* s: is a NUL-terminated string
const int* suffix: is also NUL-terminated

@return

int

@see libc/str/wcsendswith.c

wcslen

Returns length of NUL-terminated wide string.

@param

const int* s: is non-null NUL-terminated wide string pointer

@return

unsigned long: number of wide characters (excluding NUL)

@asyncsignalsafe

@see libc/str/wcslen.c

wcsncasecmp

Compares NUL-terminated wide strings case-insensitively w/ limit.

@param

const int* a: is first non-null NUL-terminated string pointer
const int* b: is second non-null NUL-terminated string pointer
unsigned long n

@return

int: is <0, 0, or >0 based on uint8_t comparison

@asyncsignalsafe

@see libc/str/wcsncasecmp.c

wcsncat

Appends at most 𝑛 wides from 𝑠 to 𝑑.

@param

int* d
const int* s
unsigned long n

@return

int*: 𝑑

@note 𝑑 and 𝑠 can't overlap

@asyncsignaslenafe

@see libc/str/wcsncat.c

wcsncmp

Compares NUL-terminated wide strings w/ limit.

@param

const int* a: is first non-null NUL-terminated string pointer
const int* b: is second non-null NUL-terminated string pointer
unsigned long n

@return

int: is <0, 0, or >0 based on uint8_t comparison

@asyncsignalsafe

@see libc/str/wcsncmp.c

wcsncpy

@param

int* d
const int* s
unsigned long n

@return

int*

@see libc/str/wcsncpy.c

wcsnlen

Returns length of NUL-terminated wide string w/ limit.

@param

const int* s: is wide string
unsigned long n: is max length (a count of wide characters, not bytes)

@return

unsigned long: length in characters

@asyncsignalsafe

@see libc/str/wcsnlen.c

wcsnlen_s

Returns length of NUL-terminated wide string w/ limit & blankets.

@param

const int* s: is wide string
unsigned long n: is max length (a count of wide characters, not bytes)

@return

unsigned long: length in characters

@asyncsignalsafe

@see libc/str/wcsnlen_s.c

wcsnrtombs

@param

char* dst
const int** wcs
unsigned long wn
unsigned long n
unsigned int* st

@return

unsigned long

@see libc/str/wcsnrtombs.c

wcsnwidth

Returns monospace display width of wide character string.

@param

const int* pwcs
unsigned long n
unsigned long o

@return

int

@see libc/str/wcsnwidth.c

wcspbrk

Returns pointer to first byte matching any in accept, or NULL.

@param

const int* s
const int* accept

@return

int*

@asyncsignalsafe

@see libc/str/wcspbrk.c

wcsrchr

Searches for last instance of wchar_t in string.

@param

const int* s: is NUL-terminated wchar_t string to search
int c: is the needle

@return

int*: address of last c in s, or NULL if not found

@asyncsignalsafe

@see libc/str/wcsrchr.c

wcsrtombs

@param

char* s
const int** ws
unsigned long n
unsigned int* st

@return

unsigned long

@see libc/str/wcsrtombs.c

wcsspn

Returns prefix length, consisting of chars in accept.

@param

const int* s
const int* accept: is nul-terminated character set

@return

unsigned long

@see strcspn(), strtok_r()

@asyncsignalsafe

@see libc/str/wcsspn.c

wcsstartswith

Returns true if s has prefix.

@param

const int* s: is a NUL-terminated string
const int* prefix: is also NUL-terminated

@return

int

@see libc/str/wcsstartswith.c

wcsstr

Searches for substring.

@param

const int* haystack: is the search area, as a NUL-terminated string
const int* needle: is the desired substring, also NUL-terminated

@return

int*: pointer to first substring within haystack, or NULL

@asyncsignalsafe

@see memmem()

@see libc/str/wcsstr.c

wcstod

@param

const int* nptr
int** endptr

@return

double

@see libc/stdio/wcstod.c

wcstof

@param

const int* nptr
int** endptr

@return

float

@see libc/stdio/wcstof.c

wcstok

Extracts non-empty tokens from string.

@param

int* s: is mutated and should be NULL on subsequent calls
const int* sep: is a NUL-terminated set of wchars to consider separators
int** state: tracks progress between calls

@return

int*: pointer to next token or NULL for end

@see libc/str/wcstok.c

wcstol

Decodes signed long integer from wide string.

@param

const int* s: is a non-null nul-terminated string
int** endptr: if non-null will always receive a pointer to the char following the last one this function processed, which is usually the NUL byte, or in the case of invalid strings, would point to the first invalid character
int base: can be anywhere between [2,36] or 0 to auto-detect based on the the prefixes 0 (octal), 0x (hexadecimal), 0b (binary), or decimal (base 10) by default

@return

long: the decoded signed saturated number

@see libc/fmt/wcstol.c

wcstold

@param

const int* nptr
int** endptr

@return

long double

@see libc/stdio/wcstold.c

wcstombs

@param

char* s
const int* ws
unsigned long n

@return

unsigned long

@see libc/str/wcstombs.c

wcstoul

Decodes unsigned integer from wide string.

@param

const int* s: is a non-null nul-terminated string
int** endptr: if non-null will always receive a pointer to the char following the last one this function processed, which is usually the NUL byte, or in the case of invalid strings, would point to the first invalid character
int base: can be anywhere between [2,36] or 0 to auto-detect based on the the prefixes 0 (octal), 0x (hexadecimal), 0b (binary), or decimal (base 10) by default

@return

unsigned long: decoded integer mod 2⁶⁴ negated if leading -

@see libc/fmt/wcstoul.c

wcswidth

Returns monospace display width of wide character string.

@param

const int* pwcs
unsigned long o

@return

int

@see libc/str/wcswidth.c

wcsxfrm

@param

int* d
const int* s
unsigned long n

@return

unsigned long

@see libc/str/wcsxfrm.c

wctob

@param

unsigned int c

@return

int

@see libc/str/wctob.c

wctomb

@param

char* s
int wc

@return

int

@see libc/str/wctomb.c

wctrans

@param

const char* s

@return

const int*

@see libc/str/wctrans.c

wctype

Returns number representing character class name.

@param

const char* s: can be "alnum", "alpha", "blank", "cntrl", "digit", "graph", "lower", "print", "punct", "space", "upper", "xdigit"

@return

unsigned int: nonzero id or 0 if not found

@see libc/str/wctype.c

wcwidth

Returns cell width of monospace character.

@param

int c

@return

int

@see libc/str/wcwidth.c

_weakfree

Thunks free() if it's linked, otherwise do nothing.

@param

void* p

@return

void

@see libc/runtime/weakfree.c

WindowsDurationToTimeSpec

@param

long x

@return

ANONYMOUS-STRUCT

@see libc/str/windowsdurationtotimespec.c

WindowsDurationToTimeVal

@param

long x

@return

ANONYMOUS-STRUCT

@see libc/str/windowsdurationtotimeval.c

WindowsTimeToTimeSpec

Converts Windows COBOL timestamp to UNIX epoch in nanoseconds.

@param

long x

@return

ANONYMOUS-STRUCT

@see libc/str/windowstimetotimespec.c

WindowsTimeToTimeVal

Converts Windows COBOL timestamp to UNIX epoch in microseconds.

@param

long x

@return

ANONYMOUS-STRUCT

@see libc/str/windowstimetotimeval.c

wmemchr

Returns pointer to first instance of character in range.

@param

const int* s
int c
unsigned long n

@return

int*

@asyncsignalsafe

@see libc/str/wmemchr.c

wmemcmp

Compares arrays of 32-bit signed integers.

@param

const int* a: is first memory array
const int* b: is second memory array
unsigned long n: is number of elements in a and b to consider

@return

int: is <0, 0, or >0 based on int32_t comparison

@asyncsignalsafe

@see libc/str/wmemcmp.c

wmemcpy

@param

int* dest
const int* src
unsigned long count

@return

int*

@see libc/str/wmemcpy.c

wmemmove

@param

int* dest
const int* src
unsigned long count

@return

int*

@see libc/str/wmemmove.c

wmempcpy

@param

int* dest
const int* src
unsigned long count

@return

int*

@see libc/str/wmempcpy.c

wmemrchr

Returns pointer to first instance of character.

@param

const int* s: is memory to search
int c: is search word
unsigned long n: is number of wchar_t elements in s

@return

void*: is pointer to first instance of c or NULL if not found

@asyncsignalsafe

@see libc/str/wmemrchr.c

wmemset

Sets wide memory.

@param

int* p
int c
unsigned long n

@return

int*

@asyncsignalsafe

@see libc/str/wmemset.c

write

Writes data to file descriptor.

@param

int fd: is open file descriptor
void* buf: is copied from, cf. copy_file_range(), sendfile(), etc.
unsigned long size

@return

long: [1..size] bytes on success, or -1 w/ errno; noting zero is impossible unless size was passed as zero to do an error check

@raise EBADF if fd is negative or not an open file descriptor

@raise EBADF if fd wasn't opened with O_WRONLY or O_RDWR

@raise EPIPE if fd is a pipe whose other reader end was closed, after the SIGPIPE signal was delivered, blocked, or ignored

@raise EFBIG if RLIMIT_FSIZE soft limit was exceeded, after the SIGXFSZ signal was either delivered, blocked, or ignored

@raise EFAULT if size is nonzero and buf points to bad memory

@raise EPERM if pledge() is in play without the stdio promise

@raise ENOSPC if device containing fd is full

@raise EIO if low-level i/o error happened

@raise EINTR if signal was delivered instead

@raise ECANCELED if thread was cancelled in masked mode

@raise EAGAIN if O_NONBLOCK is in play and write needs to block

@raise ENOBUFS if kernel lacked internal resources; which FreeBSD and XNU say could happen with sockets, and OpenBSD documents it as a general possibility; whereas other system don't specify it

@raise ENXIO is specified only by POSIX and XNU when a request is made of a nonexistent device or outside device capabilities

@cancelationpoint

@asyncsignalsafe

@restartable

@vforksafe

@see libc/calls/write.c

writev

Writes data from multiple buffers.

This is the same thing as write() except it has multiple buffers. This yields a performance boost in situations where it'd be expensive to stitch data together using memcpy() or issuing multiple syscalls. This wrapper is implemented so that writev() calls where iovlen<2 may be passed to the kernel as write() instead. This yields a 100 cycle performance boost in the case of a single small iovec.

Please note that it's not an error for a short write to happen. This can happen in the kernel if EINTR happens after some of the write has been committed. It can also happen if we need to polyfill this system call using write().

@param

int fd
struct iovec* iov
int iovlen

@return

long: number of bytes actually handed off, or -1 w/ errno

@cancelationpoint

@restartable

@see libc/calls/writev.c

WSAGetOverlappedResult

Gets overlap i/o result.

@param

unsigned long s
struct NtOverlapped* lpOverlapped
unsigned int* out_lpcbTransfer
int fWait
unsigned int* out_lpdwFlags

@return

int: true on success, or false on failure

@note this wrapper takes care of ABI, STRACE(), and __winsockerr()

@see libc/intrin/wsagetoverlappedresult.c

WSAStartup

Winsock2 prototypes.

@return

int

@note Some of the functions exported by WS2_32.DLL, e.g. bind(), overlap with the names used by System V. Prototypes for these functions are declared within their respective wrappers.

@see libc/nt/winsock.h

xasprintf

Returns dynamically formatted string.

@param

const char* fmt
...

@return

char*: must be free()'d or gc()'d

@note greatest of all C functions

@see libc/x/xasprintf.c

xbarf

Writes data to file.

@param

const char* path
void* data
unsigned long size: can be -1 to strlen(data)

@return

int: 0 on success or -1 w/ errno

@note this is uninterruptible

@see libc/x/xbarf.c

xbasename

Returns base portion of path.

@param

const char* path

@return

char*

@see libc/x/xbasename.c

xcalloc

Allocates initialized memory, or dies.

@param

unsigned long count
unsigned long size

@return

void*

@see libc/x/xcalloc.c

xdirname

Returns directory portion of path.

@param

const char* path

@return

char*

@see libc/x/xdirname.c

xdtoa

Converts double to string the easy way.

@param

double d

@return

char*: string that needs to be free'd

@see libc/x/xdtoa.c

xdtoaf

Converts double to string w/ high-accuracy the easy way.

@param

float d

@return

char*: string that needs to be free'd

@see libc/x/xdtoaf.c

xdtoal

Converts long double to string the easy way.

@param

long double d

@return

char*: string that needs to be free'd

@see libc/x/xdtoal.c

xed_get_chip_features

@param

struct XedChipFeatures* p
int chip

@return

void

@see third_party/xed/x86isa.c

xed_isa_set_is_valid_for_chip

@param

int isa_set
int chip

@return

_Bool

@see third_party/xed/x86isa.c

xed_test_chip_features

@param

struct XedChipFeatures* p
int isa_set

@return

_Bool

@see third_party/xed/x86isa.c

xfixpath

Fixes $PATH environment variable on Windows.

@return

void

@see libc/x/xfixpath.c

xgetline

Reads line from stream.

@param

struct FILE* f

@return

char*: allocated line that needs free() and usually chomp() too, or NULL on ferror() or feof()

@see getdelim() for a more difficult api

@see chomp()

@see libc/x/xgetline.c

xhomedir

Returns home directory.

@return

char*

@see libc/x/xhomedir.c

xiso8601ts

Returns allocated string representation of nanosecond timestamp.

@param

struct ts* opt_ts

@return

char*

@see libc/time/xiso8601.c

xiso8601tv

Returns allocated string representation of microsecond timestamp.

@param

struct timeval* opt_tv

@return

char*

@see libc/time/xiso8601.c

xjoinpaths

Joins paths, e.g.

"a"  + "b"  → "a/b"
"a/" + "b"  → "a/b"
"a"  + "b/" → "a/b/"
"a"  + "/b" → "/b"
"."  + "b"  → "b"
""   + "b"  → "b"

@param

const char* path
const char* other

@return

char*: newly allocated string of resulting path

@see libc/x/xjoinpaths.c

xload

Inflates data once atomically, e.g.

void *GetData(void) {
  static _Atomic(void *) ptr;
  static const unsigned char rodata[] = {...};
  return xload(&ptr, rodata, 112, 1024);
}

The above is an example of how this helper may be used to have lazy loading of big infrequently accessed image data.

@param

void** a: points to your static pointer holder
void* p: is read-only data compressed using raw deflate
unsigned long n: is byte length of deflated data
unsigned long m: is byte length of inflated data

@return

void*: pointer to inflated data

@see libc/x/xload.c

xmalloc

Allocates uninitialized memory, or dies.

@param

unsigned long bytes

@return

void*

@see libc/x/xmalloc.c

xmemalign

Allocates aligned memory, or dies.

@param

unsigned long alignment
unsigned long bytes

@return

void*

@see libc/x/xmemalign.c

xmemalignzero

Allocates aligned cleared memory, or dies.

@param

unsigned long alignment
unsigned long bytes

@return

void*

@see libc/x/xmemalignzero.c

xrealloc

Allocates/expands/shrinks/frees memory, or die.

This API enables you to do the following:

p = xrealloc(p, n)

The standard behaviors for realloc() still apply:

!p means xmalloc (returns non-NULL)
p && n means resize (returns non-NULL)
p && !n means free (returns NULL)

The complexity of resizing is guaranteed to be amortized.

@param

void* p
unsigned long n

@return

void*

@see libc/x/xrealloc.c

xsigaction

Installs handler for kernel interrupt, e.g.:

onctrlc(sig) { exit(128+sig); }
CHECK_NE(-1, xsigaction(SIGINT, onctrlc, SA_RESETHAND, 0, 0));

@param

int sig: can be SIGINT, SIGTERM, etc.
void* handler: is SIG_DFL, SIG_IGN, or a pointer to a 0≤arity≤3 callback function passed (sig, siginfo_t *, ucontext_t *).
unsigned long flags: can have SA_RESETHAND, SA_RESTART, SA_SIGINFO, etc.
unsigned long mask: is 1ul«SIG₁[…|1ul«SIGₙ] bitset to block in handler
struct sa* old: optionally receives previous handler

@return

int: 0 on success, or -1 w/ errno

@see libc/sysv/consts.sh

@asyncsignalsafe

@vforksafe

@see libc/x/xsigaction.c

xslurp

Reads entire file into memory.

@param

const char* path
unsigned long* opt_out_size

@return

void*: NUL-terminated malloc'd contents, or NULL w/ errno

@note this is uninterruptible

@see libc/x/xslurp.c

xspawn

Spawns process using fork().

@param

struct rusage* r: if provided gets accounting data

@return

int: wstatus, or -2 on child, or -1 w/ errno

@see libc/x/xspawn.c

xstrcat

Concatenates strings / chars to newly allocated memory, e.g.

xstrcat("hi", ' ', "there")

Or without the C99 helper macro:

(xstrcat)("hi", ' ', "there", NULL)

This goes twice as fast as the more powerful xasprintf(). It's not quadratic like strcat(). It's much slower than high-effort stpcpy(), particularly with string literals.

@param

const char* s
...

@return

char*

@see gc()

@see libc/x/xstrcat.c

xstrdup

Allocates new copy of string, or dies.

@param

const char* s

@return

char*

@see libc/x/xstrdup.c

xstripext

Removes file extension.

@param

const char* s: is mutated

@return

char*: s

@see libc/x/xstripext.c

xstripexts

Removes file extensions.

@param

const char* s: is mutated

@return

char*: s

@see libc/x/xstripexts.c

xstrmul

Multiplies string.

@param

const char* s
unsigned long n

@return

char*

@see libc/x/xstrmul.c

xstrndup

Allocates new copy of string, with byte limit.

@param

const char* s: is a NUL-terminated byte string
unsigned long n: if less than strlen(s) will truncate the string

@return

char*: new string or NULL w/ errno

@error ENOMEM

@see libc/x/xstrndup.c

xunbing

Decodes CP437 glyphs to bounds-checked binary buffer, e.g.

char *mem = xunbing(u" ☺☻♥♦"); EXPECT_EQ(0, memcmp("\0\1\2\3\4", mem, 5)); tfree(mem);

@param

const unsigned short* binglyphs

@return

void*

@see xunbing(), unbingstr(), unbing()

@see libc/x/tunbing.c

xunbinga

Same as xunbing() w/ alignment guarantee.

@param

unsigned long a
const unsigned short* binglyphs

@return

void*

@see libc/x/tunbing.c

xvalloc

Allocates frame-aligned memory, or dies.

@param

unsigned long size

@return

void*

@see libc/x/xvalloc.c

xvasprintf

Returns dynamically formatted string.

@param

const char* fmt
struct __va_list* va

@return

char*: fully formatted string, which must be free()'d

@see xasprintf()

@see libc/x/xvasprintf.c

xvspawn

Spawns process using vfork().

@param

void(*)() f: is child callback
void* ctx
struct rusage* r: if provided gets accounting data

@return

int: wstatus, or -1 w/ errno

@see libc/x/xvspawn.c

xwrite

Writes data uninterruptibly.

@param

int fd
void* p
unsigned long n

@return

int: 0 on success, or -1 w/ errno

@see libc/x/xwrite.c

zleb64

Encodes signed integer to array w/ zig-zag encoding.

uleb64 INT64_MAX    l:        10𝑐         3𝑛𝑠
zleb64 INT64_MAX    l:        13𝑐         4𝑛𝑠
sleb64 INT64_MAX    l:        16𝑐         5𝑛𝑠
uleb128 INT64_MAX   l:        18𝑐         6𝑛𝑠
zleb128 INT64_MAX   l:        18𝑐         6𝑛𝑠
sleb128 INT64_MAX   l:        24𝑐         8𝑛𝑠

@param

char* p: is output array which should have 10 items
long x: is number

@return

char*: p + i

@see unzleb64()

@see libc/fmt/zleb64.c

zlib_notice

@type

const char[115]

@see third_party/zlib/notice.c