Section 3p: POSIX Functions

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Man pages in this section:

a64l
These functions maintain numbers stored in radix-64 ASCII characters. This is a notation by which 32-bit integers can be represented by up to six characters...
abort
The abort() function shall cause abnormal process termination to occur, unless the signal SIGABRT is being caught and the signal handler does not return. The...
abs
The abs() function shall compute the absolute value of its integer operand, i. If the result cannot be represented, the behavior is undefined.
accept
The accept() function shall extract the first connection on the queue of pending connections, create a new socket with the same socket type protocol and address...
access
The access() function shall check the file named by the pathname pointed to by the path argument for accessibility according to the bit pattern contained in...
acos
These functions shall compute the principal value of the arc cosine of their argument x. The value of x should be in the range [-1,1]. An application wishing to...
acosh
These functions shall compute the inverse hyperbolic cosine of their argument x. An application wishing to check for error situations should set errno to zero...
acosl
arc cosine functions
aio_cancel
The aio_cancel() function shall attempt to cancel one or more asynchronous I/O requests currently outstanding against file descriptor fildes. The aiocbp...
aio_error
The aio_error() function shall return the error status associated with the aiocb structure referenced by the aiocbp argument. The error status for an...
aio_fsync
The aio_fsync() function shall asynchronously perform a file synchronization operation, as specified by the op argument, for I/O operations associated with the...
aio_read
The aio_read() function shall read aiocbp->aio_nbytes from the file associated with aiocbp->aio_fildes into the buffer pointed to by aiocbp->aio_buf. The...
aio_return
The aio_return() function shall return the return status associated with the aiocb structure referenced by the aiocbp argument. The return status for an...
aio_suspend
The aio_suspend() function shall suspend the calling thread until at least one of the asynchronous I/O operations referenced by the list argument has completed...
aio_write
The aio_write() function shall write aiocbp->aio_nbytes to the file associated with aiocbp->aio_fildes from the buffer pointed to by aiocbp->aio_buf. The...
alarm
The alarm() function shall cause the system to generate a SIGALRM signal for the process after the number of realtime seconds specified by seconds have elapsed...
alphasort
The alphasort() function can be used as the comparison function for the scandir() function to sort the directory entries, d1 and d2, into alphabetical order...
asctime
convert date and time to a string
asin
These functions shall compute the principal value of the arc sine of their argument x. The value of x should be in the range [-1,1]. An application wishing to...
asinh
These functions shall compute the inverse hyperbolic sine of their argument x. An application wishing to check for error situations should set errno to zero and...
asinl
arc sine function
assert
The assert() macro shall insert diagnostics into programs; it shall expand to a void expression. When it is executed, if expression (which shall have a scalar...
atan
These functions shall compute the principal value of the arc tangent of their argument x. An application wishing to check for error situations should set errno...
atan2
These functions shall compute the principal value of the arc tangent of y/x, using the signs of both arguments to determine the quadrant of the return value. An...
atanf
arc tangent function
atanh
These functions shall compute the inverse hyperbolic tangent of their argument x. An application wishing to check for error situations should set errno to zero...
atanl
arc tangent function
atexit
The atexit() function shall register the function pointed to by func, to be called without arguments at normal program termination. At normal program...
atof
convert a string to a double-precision number
atoi
convert a string to an integer
atol
convert a string to a long integer
basename
The basename() function shall take the pathname pointed to by path and return a pointer to the final component of the pathname, deleting any trailing '/'...
bind
The bind() function shall assign a local socket address address to a socket identified by descriptor socket that has no local socket address assigned. Sockets...
bsearch
The bsearch() function shall search an array of nel objects, the initial element of which is pointed to by base, for an element that matches the object pointed...
btowc
The btowc() function shall determine whether c constitutes a valid (one-byte) character in the initial shift state. The behavior of this function shall be...
cabs
These functions shall compute the complex absolute value (also called norm, modulus, or magnitude) of z.
cacos
These functions shall compute the complex arc cosine of z, with branch cuts outside the interval [-1, +1] along the real axis.
cacosh
These functions shall compute the complex arc hyperbolic cosine of z, with a branch cut at values less than 1 along the real axis.
cacosl
complex arc cosine functions
calloc
The calloc() function shall allocate unused space for an array of nelem elements each of whose size in bytes is elsize. The space shall be initialized to all...
carg
These functions shall compute the argument (also called phase angle) of z, with a branch cut along the negative real axis.
casin
These functions shall compute the complex arc sine of z, with branch cuts outside the interval [-1, +1] along the real axis.
casinh
These functions shall compute the complex arc hyperbolic sine of z, with branch cuts outside the interval [-i, +i] along the imaginary axis.
casinl
complex arc sine functions
catan
These functions shall compute the complex arc tangent of z, with branch cuts outside the interval [-i, +i] along the imaginary axis.
catanh
These functions shall compute the complex arc hyperbolic tangent of z, with branch cuts outside the interval [-1, +1] along the real axis.
catanl
complex arc tangent functions
catclose
The catclose() function shall close the message catalog identified by catd. If a file descriptor is used to implement the type nl_catd, that file descriptor...
catgets
The catgets() function shall attempt to read message msg_id, in set set_id, from the message catalog identified by catd. The catd argument is a message catalog...
catopen
The catopen() function shall open a message catalog and return a message catalog descriptor. The name argument specifies the name of the message catalog to be...
cbrt
These functions shall compute the real cube root of their argument x.
ccos
These functions shall compute the complex cosine of z.
ccosh
These functions shall compute the complex hyperbolic cosine of z.
ccosl
complex cosine functions
ceil
These functions shall compute the smallest integral value not less than x.
cexp
These functions shall compute the complex exponent of z, defined as ez.
cfgetispeed
The cfgetispeed() function shall extract the input baud rate from the termios structure to which the termios_p argument points. This function shall return...
cfgetospeed
The cfgetospeed() function shall extract the output baud rate from the termios structure to which the termios_p argument points. This function shall return...
cfsetispeed
The cfsetispeed() function shall set the input baud rate stored in the structure pointed to by termios_p to speed. There shall be no effect on the baud rates...
cfsetospeed
The cfsetospeed() function shall set the output baud rate stored in the structure pointed to by termios_p to speed. There shall be no effect on the baud rates...
chdir
The chdir() function shall cause the directory named by the pathname pointed to by the path argument to become the current working directory; that is, the...
chmod
The chmod() function shall change S_ISUID, S_ISGID, S_ISVTX, and the file permission bits of the file named by the pathname pointed to by the path argument to...
chown
The chown() function shall change the user and group ownership of a file. The path argument points to a pathname naming a file. The user ID and group ID of the...
cimag
These functions shall compute the imaginary part of z.
clearerr
The clearerr() function shall clear the end-of-file and error indicators for the stream to which stream points. The clearerr() function shall not change the...
clock
The clock() function shall return the implementation's best approximation to the processor time used by the process since the beginning of an...
clock_getcpuclockid
The clock_getcpuclockid() function shall return the clock ID of the CPU-time clock of the process specified by pid. If the process described by pid exists and...
clock_getres
The clock_getres() function shall return the resolution of any clock. Clock resolutions are implementation-defined and cannot be set by a process. If the...
clock_nanosleep
If the flag TIMER_ABSTIME is not set in the flags argument, the clock_nanosleep() function shall cause the current thread to be suspended from execution until...
clock_settime
clock and timer functions
clog
These functions shall compute the complex natural (base e) logarithm of z, with a branch cut along the negative real axis.
close
The close() function shall deallocate the file descriptor indicated by fildes. To deallocate means to make the file descriptor available for return by...
closedir
The closedir() function shall close the directory stream referred to by the argument dirp. Upon return, the value of dirp may no longer point to an accessible...
closelog
The syslog() function shall send a message to an implementation-defined logging facility, which may log it in an implementation-defined system log, write it to...
confstr
The confstr() function shall return configuration-defined string values. Its use and purpose are similar to sysconf(), but it is used where string values rather...
conj
These functions shall compute the complex conjugate of z, by reversing the sign of its imaginary part.
connect
The connect() function shall attempt to make a connection on a connection-mode socket or to set or reset the peer address of a connectionless-mode socket.
copysign
These functions shall produce a value with the magnitude of x and the sign of y. On implementations that represent a signed zero but do not treat negative zero...
cos
These functions shall compute the cosine of their argument x, measured in radians. An application wishing to check for error situations should set errno to zero...
cosh
These functions shall compute the hyperbolic cosine of their argument x. An application wishing to check for error situations should set errno to zero and call...
cosl
cosine function
cpow
These functions shall compute the complex power function xy, with a branch cut for the first parameter along the negative real axis.
cproj
These functions shall compute a projection of z onto the Riemann sphere: z projects to z, except that all complex infinities (even those with one infinite part...
creal
These functions shall compute the real part of z.
creat
create a new file or rewrite an existing one
crypt
The crypt() function is a string encoding function. The algorithm is implementation-defined. The key argument points to a string to be encoded.
csin
These functions shall compute the complex sine of z.
csinh
These functions shall compute the complex hyperbolic sine of z.
csinl
complex sine functions
csqrt
These functions shall compute the complex square root of z, with a branch cut along the negative real axis.
ctan
These functions shall compute the complex tangent of z.
ctanh
These functions shall compute the complex hyperbolic tangent of z.
ctanl
complex tangent functions
ctermid
The ctermid() function shall generate a string that, when used as a pathname, refers to the current controlling terminal for the current process. If ctermid()...
ctime
For ctime(): The ctime() function shall convert the time pointed to by clock, representing time in seconds since the Epoch, to local time in the form of a...
daylight
daylight savings time flag
dbm_clearerr
These functions create, access, and modify a database. A datum consists of at least two members, dptr and dsize. The dptr member points to an object that is...
difftime
The difftime() function shall compute the difference between two calendar times (as returned by time()): time1- time0.
dirfd
The dirfd() function shall return a file descriptor referring to the same directory as the dirp argument. This file descriptor shall be closed by a call to...
dirname
The dirname() function shall take a pointer to a character string that contains a pathname, and return a pointer to a string that is a pathname of the parent...
div
The div() function shall compute the quotient and remainder of the division of the numerator numer by the denominator denom. If the division is inexact, the...
dlclose
The dlclose() function shall inform the system that the symbol table handle specified by handle is no longer needed by the application. An application writer...
dlerror
The dlerror() function shall return a null-terminated character string (with no trailing <newline>) that describes the last error that occurred during dynamic...
dlopen
The dlopen() function shall make the symbols (function identifiers and data object identifiers) in the executable object file specified by file available to the...
dlsym
The dlsym() function shall obtain the address of a symbol (a function identifier or a data object identifier) defined in the symbol table identified by the...
dprintf
print formatted output
drand48
This family of functions shall generate pseudo-random numbers using a linear congruential algorithm and 48-bit integer arithmetic. The drand48() and erand48()...
dup
The dup() function provides an alternative interface to the service provided by fcntl() using the F_DUPFD command.
duplocale
The duplocale() function shall create a duplicate copy of the locale object referenced by the locobj argument. If the locobj argument is LC_GLOBAL_LOCALE...
encrypt
The encrypt() function shall provide access to an implementation-defined encoding algorithm. The key generated by setkey() is used to encrypt the string block...
endgrent
The getgrent() function shall return a pointer to a structure containing the broken-out fields of an entry in the group database. When first called, getgrent()...
endhostent
These functions shall retrieve information about hosts. This information is considered to be stored in a database that can be accessed sequentially or randomly...
endnetent
These functions shall retrieve information about networks. This information is considered to be stored in a database that can be accessed sequentially or...
endprotoent
These functions shall retrieve information about protocols. This information is considered to be stored in a database that can be accessed sequentially or...
endpwent
These functions shall retrieve information about users. The getpwent() function shall return a pointer to a structure containing the broken-out fields of an...
endservent
These functions shall retrieve information about network services. This information is considered to be stored in a database that can be accessed sequentially...
endutxent
These functions shall provide access to the user accounting database. The getutxent() function shall read the next entry from the user accounting database. If...
environ
Refer to exec and the Base Definitions volume of POSIX.1‐2008, Chapter 8, Environment Variables.
erand48
generate uniformly distributed pseudo-random numbers
erf
error functions
erfc
These functions shall compute the complementary error function 1.0 - erf(x). An application wishing to check for error situations should set errno to zero and...
erff
error functions
errno
The lvalue errno is used by many functions to return error values. Many functions provide an error number in errno, which has type int and is defined in...
exec
The exec family of functions shall replace the current process image with a new process image. The new image shall be constructed from a regular, executable...
exit
The value of status may be 0, EXIT_SUCCESS, EXIT_FAILURE, or any other value, though only the least significant 8 bits (that is, status & 0377) shall be...
_Exit
For _Exit(): The value of status may be 0, EXIT_SUCCESS, EXIT_FAILURE, or any other value, though only the least significant 8 bits (that is, status & 0377)...
exp
These functions shall compute the base-e exponential of x. An application wishing to check for error situations should set errno to zero and call...
exp2
These functions shall compute the base-2 exponential of x. An application wishing to check for error situations should set errno to zero and call...
expm1
These functions shall compute ex-1.0. An application wishing to check for error situations should set errno to zero and call feclearexcept(FE_ALL_EXCEPT) before...
fabs
These functions shall compute the absolute value of their argument x,|x|.
faccessat
determine accessibility of a file relative to directory file descriptor
fattach
The fattach() function shall attach a STREAMS-based file descriptor to a file, effectively associating a pathname with fildes. The application shall ensure that...
fchdir
The fchdir() function shall be equivalent to chdir() except that the directory that is to be the new current working directory is specified by the file...
fchmod
The fchmod() function shall be equivalent to chmod() except that the file whose permissions are changed is specified by the file descriptor fildes. If fildes...
fchmodat
change mode of a file relative to directory file descriptor
fchown
The fchown() function shall be equivalent to chown() except that the file whose owner and group are changed is specified by the file descriptor fildes.
fchownat
change owner and group of a file relative to directory file descriptor
fclose
The fclose() function shall cause the stream pointed to by stream to be flushed and the associated file to be closed. Any unwritten buffered data for the stream...
fcntl
The fcntl() function shall perform the operations described below on open files. The fildes argument is a file descriptor.
fdatasync
The fdatasync() function shall force all currently queued I/O operations associated with the file indicated by file descriptor fildes to the synchronized I/O...
FD_CLR
macros for synchronous I/O multiplexing
fdetach
The fdetach() function shall detach a STREAMS-based file from the file to which it was attached by a previous call to fattach(). The path argument points to the...
fdim
These functions shall determine the positive difference between their arguments. If x is greater than y, x-y is returned. If x is less than or equal to y, +0 is...
fdopen
The fdopen() function shall associate a stream with a file descriptor.
fdopendir
The fdopendir() function shall be equivalent to the opendir() function except that the directory is specified by a file descriptor rather than by a name. The...
feclearexcept
The feclearexcept() function shall attempt to clear the supported floating-point exceptions represented by excepts.
fegetenv
The fegetenv() function shall attempt to store the current floating-point environment in the object pointed to by envp. The fesetenv() function shall attempt to...
fegetexceptflag
The fegetexceptflag() function shall attempt to store an implementation-defined representation of the states of the floating-point status flags indicated by the...
fegetround
The fegetround() function shall get the current rounding direction. The fesetround() function shall establish the rounding direction represented by its argument...
feholdexcept
The feholdexcept() function shall save the current floating-point environment in the object pointed to by envp, clear the floating-point status flags, and then...
feof
The feof() function shall test the end-of-file indicator for the stream pointed to by stream. The feof() function shall not change the setting of errno if...
feraiseexcept
The feraiseexcept() function shall attempt to raise the supported floating-point exceptions represented by the argument excepts. The order in which these...
ferror
The ferror() function shall test the error indicator for the stream pointed to by stream. The ferror() function shall not change the setting of errno if stream...
fesetenv
set current floating-point environment
fesetexceptflag
Refer to fegetexceptflag().
fesetround
set current rounding direction
fetestexcept
The fetestexcept() function shall determine which of a specified subset of the floating-point exception flags are currently set. The excepts argument specifies...
feupdateenv
The feupdateenv() function shall attempt to save the currently raised floating-point exceptions in its automatic storage, attempt to install the floating-point...
fexecve
execute a file
fflush
If stream points to an output stream or an update stream in which the most recent operation was not input, fflush() shall cause any unwritten data for that...
ffs
The ffs() function shall find the first bit set (beginning with the least significant bit) in i, and return the index of that bit. Bits are numbered starting at...
fgetc
If the end-of-file indicator for the input stream pointed to by stream is not set and a next byte is present, the fgetc() function shall obtain the next byte as...
fgetpos
The fgetpos() function shall store the current values of the parse state (if any) and file position indicator for the stream pointed to by stream in the object...
fgets
The fgets() function shall read bytes from stream into the array pointed to by s, until n-1 bytes are read, or a <newline> is read and transferred to s, or an...
fgetwc
The fgetwc() function shall obtain the next character (if present) from the input stream pointed to by stream, convert that to the corresponding wide-character...
fgetws
The fgetws() function shall read characters from the stream, convert these to the corresponding wide-character codes, place them in the wchar_t array pointed to...
fileno
The fileno() function shall return the integer file descriptor associated with the stream pointed to by stream.
flockfile
These functions shall provide for explicit application-level locking of stdio (FILE *) objects. These functions can be used by a thread to delineate a sequence...
floor
These functions shall compute the largest integral value not greater than x.
fma
These functions shall compute (x * y) + z, rounded as one ternary operation: they shall compute the value (as if) to infinite precision and round once to the...
fmax
These functions shall determine the maximum numeric value of their arguments. NaN arguments shall be treated as missing data: if one argument is a NaN and the...
fmemopen
The fmemopen() function shall associate the buffer given by the buf and size arguments with a stream. The buf argument shall be either a null pointer or point...
fmin
These functions shall determine the minimum numeric value of their arguments. NaN arguments shall be treated as missing data: if one argument is a NaN and the...
fmod
These functions shall return the floating-point remainder of the division of x by y. An application wishing to check for error situations should set errno to...
fmtmsg
The fmtmsg() function shall display messages in a specified format instead of the traditional printf() function. Based on a message's classification component...
fnmatch
The fnmatch() function shall match patterns as described in the Shell and Utilities volume of POSIX.1‐2008, Section 2.13.1, Patterns Matching a Single Character...
fopen
The fopen() function shall open the file whose pathname is the string pointed to by pathname, and associates a stream with it. The mode argument points to a...
fork
The fork() function shall create a new process.
fpathconf
The fpathconf() and pathconf() functions shall determine the current value of a configurable limit or option (variable) that is associated with a file or...
fpclassify
The fpclassify() macro shall classify its argument value as NaN, infinite, normal, subnormal, zero, or into another implementation-defined category. First, an...
fprintf
Excluding dprintf(): The fprintf() function shall place output on the named output stream. The printf() function shall place output on the standard output...
fputc
The fputc() function shall write the byte specified by c (converted to an unsigned char) to the output stream pointed to by stream, at the position indicated by...
fputs
The fputs() function shall write the null-terminated string pointed to by s to the stream pointed to by stream. The terminating null byte shall not be written...
fputwc
The fputwc() function shall write the character corresponding to the wide-character code wc to the output stream pointed to by stream, at the position indicated...
fputws
The fputws() function shall write a character string corresponding to the (null-terminated) wide-character string pointed to by ws to the stream pointed to by...
fread
The fread() function shall read into the array pointed to by ptr up to nitems elements whose size is specified by size in bytes, from the stream pointed to by...
free
The free() function shall cause the space pointed to by ptr to be deallocated; that is, made available for further allocation. If ptr is a null pointer, no...
freeaddrinfo
The freeaddrinfo() function shall free one or more addrinfo structures returned by getaddrinfo(), along with any additional storage associated with those...
freelocale
The freelocale() function shall cause the resources allocated for a locale object returned by a call to the newlocale() or duplocale() functions to be released...
freopen
The freopen() function shall first attempt to flush the stream associated with stream as if by a call to fflush(stream). Failure to flush the stream...
frexp
These functions shall break a floating-point number num into a normalized fraction and an integral power of 2. The integer exponent shall be stored in the int...
fscanf
The fscanf() function shall read from the named input stream. The scanf() function shall read from the standard input stream stdin. The sscanf() function shall...
fseek
The fseek() function shall set the file-position indicator for the stream pointed to by stream. If a read or write error occurs, the error indicator for the...
fsetpos
The fsetpos() function shall set the file position and state indicators for the stream pointed to by stream according to the value of the object pointed to by...
fstat
The fstat() function shall obtain information about an open file associated with the file descriptor fildes, and shall write it to the area pointed to by buf...
fstatat
The stat() function shall obtain information about the named file and write it to the area pointed to by the buf argument. The path argument points to a...
fstatvfs
The fstatvfs() function shall obtain information about the file system containing the file referenced by fildes. The statvfs() function shall obtain information...
fsync
The fsync() function shall request that all data for the open file descriptor named by fildes is to be transferred to the storage device associated with the...
ftell
The ftell() function shall obtain the current value of the file-position indicator for the stream pointed to by stream. The ftell() function shall not change...
ftok
The ftok() function shall return a key based on path and id that is usable in subsequent calls to msgget(), semget(), and shmget(). The application shall ensure...
ftruncate
If fildes is not a valid file descriptor open for writing, the ftruncate() function shall fail. If fildes refers to a regular file, the ftruncate() function...
ftrylockfile
stdio locking functions
ftw
The ftw() function shall recursively descend the directory hierarchy rooted in path. For each object in the hierarchy, ftw() shall call the function pointed to...
funlockfile
stdio locking functions
futimens
The futimens() and utimensat() functions shall set the access and modification times of a file to the values of the times argument. The futimens() function...
fwide
The fwide() function shall determine the orientation of the stream pointed to by stream. If mode is greater than zero, the function first attempts to make the...
fwprintf
The fwprintf() function shall place output on the named output stream. The wprintf() function shall place output on the standard output stream stdout. The...
fwrite
The fwrite() function shall write, from the array pointed to by ptr, up to nitems elements whose size is specified by size, to the stream pointed to by stream...
fwscanf
The fwscanf() function shall read from the named input stream. The wscanf() function shall read from the standard input stream stdin. The swscanf() function...
gai_strerror
The gai_strerror() function shall return a text string describing an error value for the getaddrinfo() and getnameinfo() functions listed in the <netdb.h>...
getaddrinfo
get address information
getc
The getc() function shall be equivalent to fgetc(), except that if it is implemented as a macro it may evaluate stream more than once, so the argument should...
getchar
The getchar() function shall be equivalent to getc(stdin).
getchar_unlocked
Refer to getc_unlocked().
getc_unlocked
Versions of the functions getc(), getchar(), putc(), and putchar() respectively named getc_unlocked(), getchar_unlocked(), putc_unlocked(), and...
getcwd
The getcwd() function shall place an absolute pathname of the current working directory in the array pointed to by buf, and return buf. The pathname shall...
getdate
The getdate() function shall convert a string representation of a date or time into a broken-down time. The external variable or macro getdate_err, which has...
getdelim
The getdelim() function shall read from stream until it encounters a character matching the delimiter character. The delimiter argument is an int, the value of...
getegid
The getegid() function shall return the effective group ID of the calling process.
getenv
The getenv() function shall search the environment of the calling process (see the Base Definitions volume of POSIX.1‐2008, Chapter 8, Environment Variables)...
geteuid
The geteuid() function shall return the effective user ID of the calling process.
getgid
The getgid() function shall return the real group ID of the calling process.
getgrent
get the group database entry
getgrgid
The getgrgid() function shall search the group database for an entry with a matching gid. The getgrgid() function need not be thread-safe. The getgrgid_r()...
getgrnam
The getgrnam() function shall search the group database for an entry with a matching name. The getgrnam() function need not be thread-safe. The getgrnam_r()...
getgroups
The getgroups() function shall fill in the array grouplist with the current supplementary group IDs of the calling process. It is implementation-defined whether...
gethostent
network host database functions
gethostid
The gethostid() function shall retrieve a 32-bit identifier for the current host.
gethostname
The gethostname() function shall return the standard host name for the current machine. The namelen argument shall specify the size of the array pointed to by...
getitimer
The getitimer() function shall store the current value of the timer specified by which into the structure pointed to by value. The setitimer() function shall...
getline
read a delimited record from stream
getlogin
The getlogin() function shall return a pointer to a string containing the user name associated by the login activity with the controlling terminal of the...
getmsg
The getmsg() function shall retrieve the contents of a message located at the head of the STREAM head read queue associated with a STREAMS file and place the...
getnameinfo
The getnameinfo() function shall translate a socket address to a node name and service location, all of which are defined as in freeaddrinfo(). The sa argument...
getnetbyaddr
network database functions
getopt
The getopt() function is a command-line parser that shall follow Utility Syntax Guidelines 3, 4, 5, 6, 7, 9, and 10 in the Base Definitions volume of...
getpeername
The getpeername() function shall retrieve the peer address of the specified socket, store this address in the sockaddr structure pointed to by the address...
getpgid
The getpgid() function shall return the process group ID of the process whose process ID is equal to pid. If pid is equal to 0, getpgid() shall return the...
getpgrp
The getpgrp() function shall return the process group ID of the calling process.
getpid
The getpid() function shall return the process ID of the calling process.
getpmsg
receive next message from a STREAMS file
getppid
The getppid() function shall return the parent process ID of the calling process.
getpriority
The getpriority() function shall obtain the nice value of a process, process group, or user. The setpriority() function shall set the nice value of a process...
getprotobyname
network protocol database functions
getpwent
get user database entry
getpwnam
The getpwnam() function shall search the user database for an entry with a matching name. The getpwnam() function need not be thread-safe. Applications wishing...
getpwuid
The getpwuid() function shall search the user database for an entry with a matching uid. The getpwuid() function need not be thread-safe. Applications wishing...
getrlimit
The getrlimit() function shall get, and the setrlimit() function shall set, limits on the consumption of a variety of resources. Each call to either getrlimit()...
getrusage
The getrusage() function shall provide measures of the resources used by the current process or its terminated and waited-for child processes. If the value of...
gets
The gets() function shall read bytes from the standard input stream, stdin, into the array pointed to by s, until a <newline> is read or an end-of-file...
getservbyname
network services database functions
getsid
The getsid() function shall obtain the process group ID of the process that is the session leader of the process specified by pid. If pid is (pid_t)0, it...
getsockname
The getsockname() function shall retrieve the locally-bound name of the specified socket, store this address in the sockaddr structure pointed to by the address...
getsockopt
The getsockopt() function manipulates options associated with a socket. The getsockopt() function shall retrieve the value for the option specified by the...
getsubopt
The getsubopt() function shall parse suboption arguments in a flag argument. Such options often result from the use of getopt(). The getsubopt() argument...
gettimeofday
The gettimeofday() function shall obtain the current time, expressed as seconds and microseconds since the Epoch, and store it in the timeval structure pointed...
getuid
The getuid() function shall return the real user ID of the calling process.
getutxent
get user accounting database entries
getwc
The getwc() function shall be equivalent to fgetwc(), except that if it is implemented as a macro it may evaluate stream more than once, so the argument should...
getwchar
The getwchar() function shall be equivalent to getwc(stdin).
glob
The glob() function is a pathname generator that shall implement the rules defined in the Shell and Utilities volume of POSIX.1‐2008, Section 2.13, Pattern...
gmtime
For gmtime(): The gmtime() function shall convert the time in seconds since the Epoch pointed to by timer into a broken-down time, expressed as Coordinated...
grantpt
The grantpt() function shall change the mode and ownership of the slave pseudo-terminal device associated with its master pseudo-terminal counterpart. The...
hcreate
The hcreate(), hdestroy(), and hsearch() functions shall manage hash search tables. The hcreate() function shall allocate sufficient space for the table, and...
htonl
These functions shall convert 16-bit and 32-bit quantities between network byte order and host byte order. On some implementations, these functions are defined...
hypot
These functions shall compute the value of the square root of x2+y2 without undue overflow or underflow. An application wishing to check for error situations...
iconv
The iconv() function shall convert the sequence of characters from one codeset, in the array specified by inbuf, into a sequence of corresponding characters in...
iconv_close
The iconv_close() function shall deallocate the conversion descriptor cd and all other associated resources allocated by iconv_open(). If a file descriptor is...
iconv_open
The iconv_open() function shall return a conversion descriptor that describes a conversion from the codeset specified by the string pointed to by the fromcode...
if_freenameindex
The if_freenameindex() function shall free the memory allocated by if_nameindex(). The ptr argument shall be a pointer that was returned by if_nameindex()...
if_indextoname
The if_indextoname() function shall map an interface index to its corresponding name. When this function is called, ifname shall point to a buffer of at least...
if_nameindex
The if_nameindex() function shall return an array of if_nameindex structures, one structure per interface. The end of the array is indicated by a structure with...
if_nametoindex
The if_nametoindex() function shall return the interface index corresponding to name ifname.
ilogb
These functions shall return the exponent part of their argument x. Formally, the return value is the integral part of logr|x| as a signed integral value, for...
imaxabs
The imaxabs() function shall compute the absolute value of an integer j. If the result cannot be represented, the behavior is undefined.
imaxdiv
The imaxdiv() function shall compute numer / denom and numer % denom in a single operation.
inet_addr
The inet_addr() function shall convert the string pointed to by cp, in the standard IPv4 dotted decimal notation, to an integer value suitable for use as an...
inet_ntop
The inet_ntop() function shall convert a numeric address into a text string suitable for presentation. The af argument shall specify the family of the address...
initstate
The random() function shall use a non-linear additive feedback random-number generator employing a default state array size of 31 long integers to return...
insque
The insque() and remque() functions shall manipulate queues built from doubly-linked lists. The queue can be either circular or linear. An application using...
ioctl
The ioctl() function shall perform a variety of control functions on STREAMS devices. For non-STREAMS devices, the functions performed by this call are...
isalnum
For isalnum(): The isalnum() and isalnum_l() functions shall test whether c is a character of class alpha or digit in the current locale, or in the locale...
isalpha
For isalpha(): The isalpha() and isalpha_l() functions shall test whether c is a character of class alpha in the current locale, or in the locale represented by...
isascii
The isascii() function shall test whether c is a 7-bit US-ASCII character code. The isascii() function is defined on all integer values.
isastream
The isastream() function shall test whether fildes, an open file descriptor, is associated with a STREAMS-based file.
isatty
The isatty() function shall test whether fildes, an open file descriptor, is associated with a terminal device.
isblank
For isblank(): The isblank() and isblank_l() functions shall test whether c is a character of class blank in the current locale, or in the locale represented by...
iscntrl
For iscntrl(): The iscntrl() and iscntrl_l() functions shall test whether c is a character of class cntrl in the current locale, or in the locale represented by...
isdigit
For isdigit(): The isdigit() and isdigit_l() functions shall test whether c is a character of class digit in the current locale, or in the locale represented by...
isfinite
The isfinite() macro shall determine whether its argument has a finite value (zero, subnormal, or normal, and not infinite or NaN). First, an argument...
isgraph
For isgraph(): The isgraph() and isgraph_l() functions shall test whether c is a character of class graph in the current locale, or in the locale represented by...
isgreater
The isgreater() macro shall determine whether its first argument is greater than its second argument. The value of isgreater(x, y) shall be equal to (x) > (y)...
isgreaterequal
The isgreaterequal() macro shall determine whether its first argument is greater than or equal to its second argument. The value of isgreaterequal(x, y) shall...
isinf
The isinf() macro shall determine whether its argument value is an infinity (positive or negative). First, an argument represented in a format wider than its...
isless
The isless() macro shall determine whether its first argument is less than its second argument. The value of isless(x, y) shall be equal to (x) < (y); however...
islessequal
The islessequal() macro shall determine whether its first argument is less than or equal to its second argument. The value of islessequal(x, y) shall be equal...
islessgreater
The islessgreater() macro shall determine whether its first argument is less than or greater than its second argument. The islessgreater(x, y) macro is similar...
islower
For islower(): The islower() and islower_l() functions shall test whether c is a character of class lower in the current locale, or in the locale represented by...
isnan
The isnan() macro shall determine whether its argument value is a NaN. First, an argument represented in a format wider than its semantic type is converted to...
isnormal
The isnormal() macro shall determine whether its argument value is normal (neither zero, subnormal, infinite, nor NaN). First, an argument represented in a...
isprint
For isprint(): The isprint() and isprint_l() functions shall test whether c is a character of class print in the current locale, or in the locale represented by...
ispunct
For ispunct(): The ispunct() and ispunct_l() functions shall test whether c is a character of class punct in the current locale, or in the locale represented by...
isspace
For isspace(): The isspace() and isspace_l() functions shall test whether c is a character of class space in the current locale, or in the locale represented by...
isunordered
The isunordered() macro shall determine whether its arguments are unordered.
isupper
For isupper(): The isupper() and isupper_l() functions shall test whether c is a character of class upper in the current locale, or in the locale represented by...
iswalnum
For iswalnum(): The iswalnum() and iswalnum_l() functions shall test whether wc is a wide-character code representing a character of class alpha or digit in the...
iswalpha
For iswalpha(): The iswalpha() and iswalpha_l() functions shall test whether wc is a wide-character code representing a character of class alpha in the current...
iswblank
For iswblank(): The iswblank() and iswblank() functions shall test whether wc is a wide-character code representing a character of class blank in the current...
iswcntrl
For iswcntrl(): The iswcntrl() and iswcntrl_l() functions shall test whether wc is a wide-character code representing a character of class cntrl in the current...
iswctype
For iswctype(): The iswctype() and iswctype_l() functions shall determine whether the wide-character code wc has the character class charclass, returning true...
iswdigit
For iswdigit(): The iswdigit() and iswdigit_l() functions shall test whether wc is a wide-character code representing a character of class digit in the current...
iswgraph
For iswgraph(): The iswgraph() and iswgraph_l() functions shall test whether wc is a wide-character code representing a character of class graph in the current...
iswlower
For iswlower(): The iswlower() and iswlower_l() functions shall test whether wc is a wide-character code representing a character of class lower in the current...
iswprint
For iswprint(): The iswprint() and iswprint_l() functions shall test whether wc is a wide-character code representing a character of class print in the current...
iswpunct
For iswpunct(): The iswpunct() and iswpunct_l() functions shall test whether wc is a wide-character code representing a character of class punct in the current...
iswspace
For iswspace(): The iswspace() and iswspace_l() functions shall test whether wc is a wide-character code representing a character of class space in the current...
iswupper
For iswupper(): The iswupper() and iswupper_l() functions shall test whether wc is a wide-character code representing a character of class upper in the current...
iswxdigit
For iswxdigit(): The iswxdigit() and iswxdigit_l() functions shall test whether wc is a wide-character code representing a character of class xdigit in the...
isxdigit
For isxdigit(): The isxdigit() and isxdigit_l() functions shall test whether c is a character of class xdigit in the current locale, or in the locale...
j0
The j0(), j1(), and jn() functions shall compute Bessel functions of x of the first kind of orders 0, 1, and n, respectively. An application wishing to check...
jrand48
generate a uniformly distributed pseudo-random long signed integer
kill
The kill() function shall send a signal to a process or a group of processes specified by pid. The signal to be sent is specified by sig and is either one from...
killpg
The killpg() function shall send the signal specified by sig to the process group specified by pgrp. If pgrp is greater than 1, killpg(pgrp, sig) shall be...
l64a
convert a 32-bit integer to a radix-64 ASCII string
labs
The labs() function shall compute the absolute value of the long integer operand i. The llabs() function shall compute the absolute value of the long long...
lchown
The lchown() function shall be equivalent to chown(), except in the case where the named file is a symbolic link. In this case, lchown() shall change the...
lcong48
seed a uniformly distributed pseudo-random signed long integer generator
ldexp
These functions shall compute the quantity x * 2exp. An application wishing to check for error situations should set errno to zero and call...
ldiv
These functions shall compute the quotient and remainder of the division of the numerator numer by the denominator denom. If the division is inexact, the...
lfind
find entry in a linear search table
lgamma
These functions shall compute log_e&boxv;Γ(x)&boxv; where Γ(x) is defined as ∫0∞e^-tt^x-1dt. The argument x need not be a non-positive integer (Γ(x) is defined...
link
The link() function shall create a new link (directory entry) for the existing file, path1. The path1 argument points to a pathname naming an existing file. The...
lio_listio
The lio_listio() function shall initiate a list of I/O requests with a single function call. The mode argument takes one of the values LIO_WAIT or LIO_NOWAIT...
listen
The listen() function shall mark a connection-mode socket, specified by the socket argument, as accepting connections. The backlog argument provides a hint to...
llabs
return a long integer absolute value
lldiv
compute quotient and remainder of a long division
llrint
These functions shall round their argument to the nearest integer value, rounding according to the current rounding direction. An application wishing to check...
llround
These functions shall round their argument to the nearest integer value, rounding halfway cases away from zero, regardless of the current rounding direction. An...
localeconv
The localeconv() function shall set the components of an object with the type struct lconv with the values appropriate for the formatting of numeric quantities...
localtime
For localtime(): The localtime() function shall convert the time in seconds since the Epoch pointed to by timer into a broken-down time, expressed as a local...
lockf
The lockf() function shall lock sections of a file with advisory-mode locks. Calls to lockf() from threads in other processes which attempt to lock the locked...
log
These functions shall compute the natural logarithm of their argument x, loge(x). An application wishing to check for error situations should set errno to zero...
log10
These functions shall compute the base 10 logarithm of their argument x, log10(x). An application wishing to check for error situations should set errno to zero...
log1p
These functions shall compute loge(1.0 + x). An application wishing to check for error situations should set errno to zero and call feclearexcept(FE_ALL_EXCEPT)...
log2
These functions shall compute the base 2 logarithm of their argument x, log2(x). An application wishing to check for error situations should set errno to zero...
logb
These functions shall compute the exponent of x, which is the integral part of logr |x|, as a signed floating-point value, for non-zero x, where r is the radix...
logf
natural logarithm function
longjmp
The longjmp() function shall restore the environment saved by the most recent invocation of setjmp() in the same process, with the corresponding jmp_buf...
_longjmp
The _longjmp() and _setjmp() functions shall be equivalent to longjmp() and setjmp(), respectively, with the additional restriction that _longjmp() and...
lrand48
generate uniformly distributed pseudo-random non-negative long integers
lrint
These functions shall round their argument to the nearest integer value, rounding according to the current rounding direction. An application wishing to check...
lround
These functions shall round their argument to the nearest integer value, rounding halfway cases away from zero, regardless of the current rounding direction. An...
lsearch
The lsearch() function shall linearly search the table and return a pointer into the table for the matching entry. If the entry does not occur, it shall be...
lseek
move the read/write file offset
lstat
get file status
malloc
The malloc() function shall allocate unused space for an object whose size in bytes is specified by size and whose value is unspecified. The order and...
mblen
If s is not a null pointer, mblen() shall determine the number of bytes constituting the character pointed to by s.
mbrlen
If s is not a null pointer, mbrlen() shall determine the number of bytes constituting the character pointed to by s.
mbrtowc
convert a character to a wide-character code (restartable)
mbsinit
If ps is not a null pointer, the mbsinit() function shall determine whether the object pointed to by ps describes an initial conversion state.
mbsrtowcs
For mbsrtowcs(): The mbsrtowcs() function shall convert a sequence of characters, beginning in the conversion state described by the object pointed to by ps...
mbstowcs
The mbstowcs() function shall convert a sequence of characters that begins in the initial shift state from the array pointed to by s into a sequence of...
mbtowc
If s is not a null pointer, mbtowc() shall determine the number of bytes that constitute the character pointed to by s. It shall then determine the...
memccpy
The memccpy() function shall copy bytes from memory area s2 into s1, stopping after the first occurrence of byte c (converted to an unsigned char) is copied, or...
memchr
The memchr() function shall locate the first occurrence of c (converted to an unsigned char) in the initial n bytes (each interpreted as unsigned char) pointed...
memcmp
The memcmp() function shall compare the first n bytes (each interpreted as unsigned char) of the object pointed to by s1 to the first n bytes of the object...
memcpy
The memcpy() function shall copy n bytes from the object pointed to by s2 into the object pointed to by s1. If copying takes place between objects that overlap...
memmove
The memmove() function shall copy n bytes from the object pointed to by s2 into the object pointed to by s1. Copying takes place as if the n bytes from the...
memset
The memset() function shall copy c (converted to an unsigned char) into each of the first n bytes of the object pointed to by s.
mkdir
The mkdir() function shall create a new directory with name path. The file permission bits of the new directory shall be initialized from mode. These file...
mkdtemp
The mkdtemp() function uses the contents of template to construct a unique directory name. The string provided in template shall be a pathname ending with six...
mkfifo
The mkfifo() function shall create a new FIFO special file named by the pathname pointed to by path. The file permission bits of the new FIFO shall be...
mknod
The mknod() function shall create a new file named by the pathname to which the argument path points.
mkstemp
create a unique directory
mktime
The mktime() function shall convert the broken-down time, expressed as local time, in the structure pointed to by timeptr, into a time since the Epoch value...
mlock
The mlock() function shall cause those whole pages containing any part of the address space of the process starting at address addr and continuing for len bytes...
mlockall
The mlockall() function shall cause all of the pages mapped by the address space of a process to be memory-resident until unlocked or until the process exits or...
mmap
The mmap() function shall establish a mapping between an address space of a process and a memory object.
modf
These functions shall break the argument x into integral and fractional parts, each of which has the same sign as the argument. It stores the integral part as a...
mprotect
The mprotect() function shall change the access protections to be that specified by prot for those whole pages containing any part of the address space of the...
mq_close
The mq_close() function shall remove the association between the message queue descriptor, mqdes, and its message queue. The results of using this message queue...
mq_getattr
The mq_getattr() function shall obtain status information and attributes of the message queue and the open message queue description associated with the message...
mq_notify
If the argument notification is not NULL, this function shall register the calling process to be notified of message arrival at an empty message queue...
mq_open
The mq_open() function shall establish the connection between a process and a message queue with a message queue descriptor. It shall create an open message...
mq_receive
The mq_receive() function shall receive the oldest of the highest priority message(s) from the message queue specified by mqdes. If the size of the buffer in...
mq_send
The mq_send() function shall add the message pointed to by the argument msg_ptr to the message queue specified by mqdes. The msg_len argument specifies the...
mq_setattr
The mq_setattr() function shall set attributes associated with the open message queue description referenced by the message queue descriptor specified by mqdes.
mq_timedreceive
receive a message from a message queue (ADVANCED REALTIME)
mq_timedsend
send a message to a message queue (ADVANCED REALTIME)
mq_unlink
The mq_unlink() function shall remove the message queue named by the string name. If one or more processes have the message queue open when mq_unlink() is...
mrand48
generate uniformly distributed pseudo-random signed long integers
msgctl
The msgctl() function operates on XSI message queues (see the Base Definitions volume of POSIX.1‐2008, Section 3.225, Message Queue). It is unspecified whether...
msgget
The msgget() function operates on XSI message queues (see the Base Definitions volume of POSIX.1‐2008, Section 3.225, Message Queue). It is unspecified whether...
msgrcv
The msgrcv() function operates on XSI message queues (see the Base Definitions volume of POSIX.1‐2008, Section 3.225, Message Queue). It is unspecified whether...
msgsnd
The msgsnd() function operates on XSI message queues (see the Base Definitions volume of POSIX.1‐2008, Section 3.225, Message Queue). It is unspecified whether...
msync
The msync() function shall write all modified data to permanent storage locations, if any, in those whole pages containing any part of the address space of the...
munlock
unlock a range of process address space
munlockall
unlock the address space of a process
munmap
The munmap() function shall remove any mappings for those entire pages containing any part of the address space of the process starting at addr and continuing...
nan
return quiet NaN
nanosleep
The nanosleep() function shall cause the current thread to be suspended from execution until either the time interval specified by the rqtp argument has elapsed...
nearbyint
These functions shall round their argument to an integer value in floating-point format, using the current rounding direction and without raising the inexact...
newlocale
The newlocale() function shall create a new locale object or modify an existing one. If the base argument is (locale_t)0, a new locale object shall be created...
nextafter
The nextafter(), nextafterf(), and nextafterl() functions shall compute the next representable floating-point value following x in the direction of y. Thus, if...
nftw
The nftw() function shall recursively descend the directory hierarchy rooted in path.
nice
The nice() function shall add the value of incr to the nice value of the calling process. A nice value of a process is a non-negative number for which a more...
nl_langinfo
The nl_langinfo() and nl_langinfo_l() functions shall return a pointer to a string containing information relevant to the particular language or cultural area...
nrand48
generate uniformly distributed pseudo-random non-negative long integers
ntohl
convert values between host and network byte order
open
The open() function shall establish the connection between a file and a file descriptor. It shall create an open file description that refers to a file and a...
openat
open file relative to directory file descriptor
opendir
open directory associated with file descriptor
openlog
open a connection to the logging facility
open_memstream
The open_memstream() and open_wmemstream() functions shall create an I/O stream associated with a dynamically allocated memory buffer. The stream shall be...
optarg
options parsing variables
pathconf
get configurable pathname variables
pause
The pause() function shall suspend the calling thread until delivery of a signal whose action is either to execute a signal-catching function or to terminate...
pclose
The pclose() function shall close a stream that was opened by popen(), wait for the command to terminate, and return the termination status of the process that...
perror
write error messages to standard error
pipe
The pipe() function shall create a pipe and place two file descriptors, one each into the arguments fildes[0] and fildes[1], that refer to the open file...
poll
The poll() function provides applications with a mechanism for multiplexing input/output over a set of file descriptors. For each member of the array pointed to...
popen
The popen() function shall execute the command specified by the string command. It shall create a pipe between the calling program and the executed command, and...
posix_fadvise
The posix_fadvise() function shall advise the implementation on the expected behavior of the application with respect to the data in the file associated with...
posix_fallocate
The posix_fallocate() function shall ensure that any required storage for regular file data starting at offset and continuing for len bytes is allocated on the...
posix_madvise
The posix_madvise() function shall advise the implementation on the expected behavior of the application with respect to the data in the memory starting at...
posix_memalign
The posix_memalign() function shall allocate size bytes aligned on a boundary specified by alignment, and shall return a pointer to the allocated memory in...
posix_mem_offset
The posix_mem_offset() function shall return in the variable pointed to by off a value that identifies the offset (or location), within a memory object, of the...
posix_openpt
The posix_openpt() function shall establish a connection between a master device for a pseudo-terminal and a file descriptor. The file descriptor is used by...
posix_spawn
The posix_spawn() and posix_spawnp() functions shall create a new process (child process) from the specified process image. The new process image shall be...
posix_spawnattr_destroy
The posix_spawnattr_destroy() function shall destroy a spawn attributes object. A destroyed attr attributes object can be reinitialized using...
posix_spawnattr_getflags
The posix_spawnattr_getflags() function shall obtain the value of the spawn-flags attribute from the attributes object referenced by attr. The...
posix_spawnattr_getpgroup
The posix_spawnattr_getpgroup() function shall obtain the value of the spawn-pgroup attribute from the attributes object referenced by attr. The...
posix_spawnattr_getschedparam
The posix_spawnattr_getschedparam() function shall obtain the value of the spawn-schedparam attribute from the attributes object referenced by attr. The...
posix_spawnattr_getschedpolicy
The posix_spawnattr_getschedpolicy() function shall obtain the value of the spawn-schedpolicy attribute from the attributes object referenced by attr. The...
posix_spawnattr_getsigdefault
The posix_spawnattr_getsigdefault() function shall obtain the value of the spawn-sigdefault attribute from the attributes object referenced by attr. The...
posix_spawnattr_getsigmask
The posix_spawnattr_getsigmask() function shall obtain the value of the spawn-sigmask attribute from the attributes object referenced by attr. The...
posix_spawnattr_init
Refer to posix_spawnattr_destroy().
posix_spawnattr_setflags
Refer to posix_spawnattr_getflags().
posix_spawnattr_setpgroup
Refer to posix_spawnattr_getpgroup().
posix_spawnattr_setschedparam
Refer to posix_spawnattr_getschedparam().
posix_spawnattr_setschedpolicy
Refer to posix_spawnattr_getschedpolicy().
posix_spawnattr_setsigdefault
Refer to posix_spawnattr_getsigdefault().
posix_spawnattr_setsigmask
Refer to posix_spawnattr_getsigmask().
posix_spawn_file_actions_addclose
These functions shall add or delete a close or open action to a spawn file actions object. A spawn file actions object is of type posix_spawn_file_actions_t...
posix_spawn_file_actions_adddup2
The posix_spawn_file_actions_adddup2() function shall add a dup2() action to the object referenced by file_actions that shall cause the file descriptor fildes...
posix_spawn_file_actions_addopen
Refer to posix_spawn_file_actions_addclose().
posix_spawn_file_actions_destroy
The posix_spawn_file_actions_destroy() function shall destroy the object referenced by file_actions; the object becomes, in effect, uninitialized. An...
posix_spawnp
spawn a process (ADVANCED REALTIME)
posix_trace_attr_destroy
The posix_trace_attr_destroy() function shall destroy an initialized trace attributes object. A destroyed attr attributes object can be reinitialized using...
posix_trace_attr_getclockres
The posix_trace_attr_getclockres() function shall copy the clock resolution of the clock used to generate timestamps from the clock-resolution attribute of the...
posix_trace_attr_getinherited
The posix_trace_attr_getinherited() and posix_trace_attr_setinherited() functions, respectively, shall get and set the inheritance policy stored in the...
posix_trace_attr_getlogsize
The posix_trace_attr_getlogsize() function shall copy the log size, in bytes, from the log-max-size attribute of the attributes object pointed to by the attr...
posix_trace_attr_getname
Refer to posix_trace_attr_getclockres().
posix_trace_attr_getstreamfullpolicy
Refer to posix_trace_attr_getinherited().
posix_trace_attr_getstreamsize
Refer to posix_trace_attr_getlogsize().
posix_trace_attr_init
Refer to posix_trace_attr_destroy().
posix_trace_attr_setinherited
Refer to posix_trace_attr_getinherited().
posix_trace_attr_setlogsize
Refer to posix_trace_attr_getlogsize().
posix_trace_attr_setname
Refer to posix_trace_attr_getclockres().
posix_trace_attr_setstreamfullpolicy
Refer to posix_trace_attr_getinherited().
posix_trace_attr_setstreamsize
Refer to posix_trace_attr_getlogsize().
posix_trace_clear
The posix_trace_clear() function shall reinitialize the trace stream identified by the argument trid as if it were returning from the posix_trace_create()...
posix_trace_close
The posix_trace_close() function shall deallocate the trace log identifier indicated by trid, and all of its associated resources. If there is no valid trace...
posix_trace_create
The posix_trace_create() function shall create an active trace stream. It allocates all the resources needed by the trace stream being created for tracing the...
posix_trace_event
The posix_trace_event() function shall record the event_id and the user data pointed to by data_ptr in the trace stream into which the calling process is being...
posix_trace_eventid_equal
The posix_trace_eventid_equal() function shall compare the trace event type identifiers event1 and event2 from the same trace stream or the same trace log...
posix_trace_eventid_open
Refer to posix_trace_event().
posix_trace_eventset_add
These primitives manipulate sets of trace event types. They operate on data objects addressable by the application, not on the current trace event filter of any...
posix_trace_eventtypelist_getnext_id
The first time posix_trace_eventtypelist_getnext_id() is called, the function shall return in the variable pointed to by event the first trace event type...
posix_trace_flush
Refer to posix_trace_create().
posix_trace_get_attr
The posix_trace_get_attr() function shall copy the attributes of the active trace stream identified by trid into the object pointed to by the attr argument. If...
posix_trace_get_filter
The posix_trace_get_filter() function shall retrieve, into the argument pointed to by set, the actual trace event filter from the trace stream specified by...
posix_trace_getnext_event
The posix_trace_getnext_event() function shall report a recorded trace event either from an active trace stream without log or a pre-recorded trace stream...
posix_trace_get_status
Refer to posix_trace_get_attr().
posix_trace_open
Refer to posix_trace_close().
posix_trace_set_filter
Refer to posix_trace_get_filter().
posix_trace_shutdown
Refer to posix_trace_create().
posix_trace_start
The posix_trace_start() and posix_trace_stop() functions, respectively, shall start and stop the trace stream identified by the argument trid. The effect of...
posix_trace_timedgetnext_event
Refer to posix_trace_getnext_event().
posix_trace_trid_eventid_open
Refer to posix_trace_eventid_equal().
posix_trace_trygetnext_event
Refer to posix_trace_getnext_event().
posix_typed_mem_get_info
The posix_typed_mem_get_info() function shall return, in the posix_tmi_length field of the posix_typed_mem_info structure pointed to by info, the maximum length...
posix_typed_mem_open
The posix_typed_mem_open() function shall establish a connection between the typed memory object specified by the string pointed to by name and a file...
pow
These functions shall compute the value of x raised to the power y, xy. If x is negative, the application shall ensure that y is an integer value. An...
pread
read from a file
printf
print formatted output
pselect
The pselect() function shall examine the file descriptor sets whose addresses are passed in the readfds, writefds, and errorfds parameters to see whether some...
psiginfo
The psiginfo() and psignal() functions shall print a message out on stderr associated with a signal number. If message is not null and is not the empty string...
pthread_atfork
The pthread_atfork() function shall declare fork handlers to be called before and after fork(), in the context of the thread that called fork(). The prepare...
pthread_attr_destroy
The pthread_attr_destroy() function shall destroy a thread attributes object. An implementation may cause pthread_attr_destroy() to set attr to an...
pthread_attr_getdetachstate
The detachstate attribute controls whether the thread is created in a detached state. If the thread is created detached, then use of the ID of the newly created...
pthread_attr_getguardsize
The pthread_attr_getguardsize() function shall get the guardsize attribute in the attr object. This attribute shall be returned in the guardsize parameter. The...
pthread_attr_getinheritsched
The pthread_attr_getinheritsched() and pthread_attr_setinheritsched() functions, respectively, shall get and set the inheritsched attribute in the attr...
pthread_attr_getschedparam
The pthread_attr_getschedparam() and pthread_attr_setschedparam() functions, respectively, shall get and set the scheduling parameter attributes in the attr...
pthread_attr_getschedpolicy
The pthread_attr_getschedpolicy() and pthread_attr_setschedpolicy() functions, respectively, shall get and set the schedpolicy attribute in the attr argument...
pthread_attr_getscope
The pthread_attr_getscope() and pthread_attr_setscope() functions, respectively, shall get and set the contentionscope attribute in the attr object. The...
pthread_attr_getstack
The pthread_attr_getstack() and pthread_attr_setstack() functions, respectively, shall get and set the thread creation stack attributes stackaddr and stacksize...
pthread_attr_getstacksize
The pthread_attr_getstacksize() and pthread_attr_setstacksize() functions, respectively, shall get and set the thread creation stacksize attribute in the attr...
pthread_attr_init
Refer to pthread_attr_destroy().
pthread_attr_setdetachstate
Refer to pthread_attr_getdetachstate().
pthread_attr_setguardsize
Refer to pthread_attr_getguardsize().
pthread_attr_setinheritsched
Refer to pthread_attr_getinheritsched().
pthread_attr_setschedparam
Refer to pthread_attr_getschedparam().
pthread_attr_setschedpolicy
Refer to pthread_attr_getschedpolicy().
pthread_attr_setscope
Refer to pthread_attr_getscope().
pthread_attr_setstack
Refer to pthread_attr_getstack().
pthread_attr_setstacksize
Refer to pthread_attr_getstacksize().
pthread_barrierattr_destroy
The pthread_barrierattr_destroy() function shall destroy a barrier attributes object. A destroyed attr attributes object can be reinitialized using...
pthread_barrierattr_getpshared
The pthread_barrierattr_getpshared() function shall obtain the value of the process-shared attribute from the attributes object referenced by attr. The...
pthread_barrierattr_init
Refer to pthread_barrierattr_destroy().
pthread_barrierattr_setpshared
Refer to pthread_barrierattr_getpshared().
pthread_barrier_destroy
The pthread_barrier_destroy() function shall destroy the barrier referenced by barrier and release any resources used by the barrier. The effect of subsequent...
pthread_barrier_wait
The pthread_barrier_wait() function shall synchronize participating threads at the barrier referenced by barrier. The calling thread shall block until the...
pthread_cancel
The pthread_cancel() function shall request that thread be canceled. The target thread's cancelability state and type determines when the cancellation takes...
pthread_cleanup_pop
The pthread_cleanup_pop() function shall remove the routine at the top of the calling thread's cancellation cleanup stack and optionally invoke it (if execute...
pthread_condattr_destroy
The pthread_condattr_destroy() function shall destroy a condition variable attributes object; the object becomes, in effect, uninitialized. An implementation...
pthread_condattr_getclock
The pthread_condattr_getclock() function shall obtain the value of the clock attribute from the attributes object referenced by attr. The...
pthread_condattr_getpshared
The pthread_condattr_getpshared() function shall obtain the value of the process-shared attribute from the attributes object referenced by attr. The...
pthread_condattr_init
Refer to pthread_condattr_destroy().
pthread_condattr_setclock
Refer to pthread_condattr_getclock().
pthread_condattr_setpshared
Refer to pthread_condattr_getpshared().
pthread_cond_broadcast
These functions shall unblock threads blocked on a condition variable. The pthread_cond_broadcast() function shall unblock all threads currently blocked on the...
pthread_cond_destroy
The pthread_cond_destroy() function shall destroy the given condition variable specified by cond; the object becomes, in effect, uninitialized. An...
pthread_cond_signal
Refer to pthread_cond_broadcast().
pthread_cond_timedwait
The pthread_cond_timedwait() and pthread_cond_wait() functions shall block on a condition variable. The application shall ensure that these functions are called...
pthread_create
The pthread_create() function shall create a new thread, with attributes specified by attr, within a process. If attr is NULL, the default attributes shall be...
pthread_detach
The pthread_detach() function shall indicate to the implementation that storage for the thread thread can be reclaimed when that thread terminates. If thread...
pthread_equal
This function shall compare the thread IDs t1 and t2.
pthread_exit
The pthread_exit() function shall terminate the calling thread and make the value value_ptr available to any successful join with the terminating thread. Any...
pthread_getconcurrency
Unbound threads in a process may or may not be required to be simultaneously active. By default, the threads implementation ensures that a sufficient number of...
pthread_getcpuclockid
The pthread_getcpuclockid() function shall return in clock_id the clock ID of the CPU-time clock of the thread specified by thread_id, if the thread specified...
pthread_getschedparam
The pthread_getschedparam() and pthread_setschedparam() functions shall, respectively, get and set the scheduling policy and parameters of individual threads...
pthread_getspecific
The pthread_getspecific() function shall return the value currently bound to the specified key on behalf of the calling thread. The pthread_setspecific()...
pthread_join
The pthread_join() function shall suspend execution of the calling thread until the target thread terminates, unless the target thread has already terminated...
pthread_key_create
The pthread_key_create() function shall create a thread-specific data key visible to all threads in the process. Key values provided by pthread_key_create() are...
pthread_key_delete
The pthread_key_delete() function shall delete a thread-specific data key previously returned by pthread_key_create(). The thread-specific data values...
pthread_kill
The pthread_kill() function shall request that a signal be delivered to the specified thread. As in kill(), if sig is zero, error checking shall be performed...
pthread_mutexattr_destroy
The pthread_mutexattr_destroy() function shall destroy a mutex attributes object; the object becomes, in effect, uninitialized. An implementation may cause...
pthread_mutexattr_getprioceiling
The pthread_mutexattr_getprioceiling() and pthread_mutexattr_setprioceiling() functions, respectively, shall get and set the priority ceiling attribute of a...
pthread_mutexattr_getprotocol
The pthread_mutexattr_getprotocol() and pthread_mutexattr_setprotocol() functions, respectively, shall get and set the protocol attribute of a mutex attributes...
pthread_mutexattr_getpshared
The pthread_mutexattr_getpshared() function shall obtain the value of the process-shared attribute from the attributes object referenced by attr. The...
pthread_mutexattr_getrobust
The pthread_mutexattr_getrobust() and pthread_mutexattr_setrobust() functions, respectively, shall get and set the mutex robust attribute. This attribute is set...
pthread_mutexattr_gettype
The pthread_mutexattr_gettype() and pthread_mutexattr_settype() functions, respectively, shall get and set the mutex type attribute. This attribute is set in...
pthread_mutexattr_init
Refer to pthread_mutexattr_destroy().
pthread_mutexattr_setprioceiling
Refer to pthread_mutexattr_getprioceiling().
pthread_mutexattr_setprotocol
Refer to pthread_mutexattr_getprotocol().
pthread_mutexattr_setpshared
Refer to pthread_mutexattr_getpshared().
pthread_mutexattr_setrobust
Refer to pthread_mutexattr_getrobust().
pthread_mutexattr_settype
Refer to pthread_mutexattr_gettype().
pthread_mutex_consistent
If mutex is a robust mutex in an inconsistent state, the pthread_mutex_consistent() function can be used to mark the state protected by the mutex referenced by...
pthread_mutex_destroy
The pthread_mutex_destroy() function shall destroy the mutex object referenced by mutex; the mutex object becomes, in effect, uninitialized. An implementation...
pthread_mutex_getprioceiling
The pthread_mutex_getprioceiling() function shall return the current priority ceiling of the mutex. The pthread_mutex_setprioceiling() function shall attempt to...
pthread_mutex_init
Refer to pthread_mutex_destroy().
pthread_mutex_lock
The mutex object referenced by mutex shall be locked by a call to pthread_mutex_lock() that returns zero or [EOWNERDEAD]. If the mutex is already locked by...
pthread_mutex_setprioceiling
Refer to pthread_mutex_getprioceiling().
pthread_mutex_timedlock
The pthread_mutex_timedlock() function shall lock the mutex object referenced by mutex. If the mutex is already locked, the calling thread shall block until the...
pthread_mutex_trylock
Refer to pthread_mutex_lock().
pthread_once
The first call to pthread_once() by any thread in a process, with a given once_control, shall call the init_routine with no arguments. Subsequent calls of...
pthread_rwlockattr_destroy
The pthread_rwlockattr_destroy() function shall destroy a read-write lock attributes object. A destroyed attr attributes object can be reinitialized using...
pthread_rwlockattr_getpshared
The pthread_rwlockattr_getpshared() function shall obtain the value of the process-shared attribute from the initialized attributes object referenced by attr...
pthread_rwlockattr_init
Refer to pthread_rwlockattr_destroy().
pthread_rwlockattr_setpshared
Refer to pthread_rwlockattr_getpshared().
pthread_rwlock_destroy
The pthread_rwlock_destroy() function shall destroy the read-write lock object referenced by rwlock and release any resources used by the lock. The effect of...
pthread_rwlock_rdlock
The pthread_rwlock_rdlock() function shall apply a read lock to the read-write lock referenced by rwlock. The calling thread acquires the read lock if a writer...
pthread_rwlock_timedrdlock
The pthread_rwlock_timedrdlock() function shall apply a read lock to the read-write lock referenced by rwlock as in the pthread_rwlock_rdlock() function...
pthread_rwlock_timedwrlock
The pthread_rwlock_timedwrlock() function shall apply a write lock to the read-write lock referenced by rwlock as in the pthread_rwlock_wrlock() function...
pthread_rwlock_tryrdlock
Refer to pthread_rwlock_rdlock().
pthread_rwlock_trywrlock
The pthread_rwlock_trywrlock() function shall apply a write lock like the pthread_rwlock_wrlock() function, with the exception that the function shall fail if...
pthread_rwlock_unlock
The pthread_rwlock_unlock() function shall release a lock held on the read-write lock object referenced by rwlock. Results are undefined if the read-write lock...
pthread_rwlock_wrlock
Refer to pthread_rwlock_trywrlock().
pthread_self
The pthread_self() function shall return the thread ID of the calling thread.
pthread_setcancelstate
The pthread_setcancelstate() function shall atomically both set the calling thread's cancelability state to the indicated state and return the previous...
pthread_setconcurrency
Refer to pthread_getconcurrency().
pthread_setschedparam
Refer to pthread_getschedparam().
pthread_setschedprio
The pthread_setschedprio() function shall set the scheduling priority for the thread whose thread ID is given by thread to the value given by prio. See...
pthread_setspecific
Refer to pthread_getspecific().
pthread_sigmask
The pthread_sigmask() function shall examine or change (or both) the calling thread's signal mask, regardless of the number of threads in the process. The...
pthread_spin_destroy
The pthread_spin_destroy() function shall destroy the spin lock referenced by lock and release any resources used by the lock. The effect of subsequent use of...
pthread_spin_lock
The pthread_spin_lock() function shall lock the spin lock referenced by lock. The calling thread shall acquire the lock if it is not held by another thread...
pthread_spin_unlock
The pthread_spin_unlock() function shall release the spin lock referenced by lock which was locked via the pthread_spin_lock() or pthread_spin_trylock()...
pthread_testcancel
Refer to pthread_setcancelstate().
ptsname
The ptsname() function shall return the name of the slave pseudo-terminal device associated with a master pseudo-terminal device. The fildes argument is a file...
putc
The putc() function shall be equivalent to fputc(), except that if it is implemented as a macro it may evaluate stream more than once, so the argument should...
putchar
The function call putchar(c) shall be equivalent to putc(c,stdout).
putchar_unlocked
Refer to getc_unlocked().
putc_unlocked
Refer to getc_unlocked().
putenv
The putenv() function shall use the string argument to set environment variable values. The string argument should point to a string of the form "name=value"...
putmsg
The putmsg() function shall create a message from a process buffer(s) and send the message to a STREAMS file. The message may contain either a data part, a...
puts
The puts() function shall write the string pointed to by s, followed by a <newline>, to the standard output stream stdout. The terminating null byte shall not...
pututxline
put an entry into the user accounting database
putwc
The putwc() function shall be equivalent to fputwc(), except that if it is implemented as a macro it may evaluate stream more than once, so the argument should...
putwchar
The function call putwchar(wc) shall be equivalent to putwc(wc,stdout).
pwrite
write on a file
qsort
The qsort() function shall sort an array of nel objects, the initial element of which is pointed to by base. The size of each object, in bytes, is specified by...
raise
The raise() function shall send the signal sig to the executing thread or process. If a signal handler is called, the raise() function shall not return until...
rand
For rand() and srand(): The rand() function shall compute a sequence of pseudo-random integers in the range [0,{RAND_MAX}] with a period of at least 232. The...
random
generate pseudo-random number
read
The read() function shall attempt to read nbyte bytes from the file associated with the open file descriptor, fildes, into the buffer pointed to by buf. The...
readdir
The type DIR, which is defined in the <dirent.h> header, represents a directory stream, which is an ordered sequence of all the directory entries in a...
readlink
The readlink() function shall place the contents of the symbolic link referred to by path in the buffer buf which has size bufsize. If the number of bytes in...
readv
The readv() function shall be equivalent to read(), except as described below. The readv() function shall place the input data into the iovcnt buffers specified...
realloc
The realloc() function shall deallocate the old object pointed to by ptr and return a pointer to a new object that has the size specified by size. The contents...
realpath
The realpath() function shall derive, from the pathname pointed to by file_name, an absolute pathname that resolves to the same directory entry, whose...
recv
The recv() function shall receive a message from a connection-mode or connectionless-mode socket. It is normally used with connected sockets because it does not...
recvfrom
The recvfrom() function shall receive a message from a connection-mode or connectionless-mode socket. It is normally used with connectionless-mode sockets...
recvmsg
The recvmsg() function shall receive a message from a connection-mode or connectionless-mode socket. It is normally used with connectionless-mode sockets...
regcomp
These functions interpret basic and extended regular expressions as described in the Base Definitions volume of POSIX.1‐2008, Chapter 9, Regular Expressions.
remainder
These functions shall return the floating-point remainder r=x-ny when y is non-zero. The value n is the integral value nearest the exact value x/y. When...
remove
The remove() function shall cause the file named by the pathname pointed to by path to be no longer accessible by that name. A subsequent attempt to open that...
remque
remove an element from a queue
remquo
The remquo(), remquof(), and remquol() functions shall compute the same remainder as the remainder(), remainderf(), and remainderl() functions, respectively. In...
rename
For rename(): The rename() function shall change the name of a file. The old argument points to the pathname of the file to be renamed. The new argument points...
rewind
reset the file position indicator in a stream
rewinddir
The rewinddir() function shall reset the position of the directory stream to which dirp refers to the beginning of the directory. It shall also cause the...
rint
These functions shall return the integral value (represented as a double) nearest x in the direction of the current rounding mode. The current rounding mode is...
rmdir
The rmdir() function shall remove a directory whose name is given by path. The directory shall be removed only if it is an empty directory. If the directory is...
round
These functions shall round their argument to the nearest integer value in floating-point format, rounding halfway cases away from zero, regardless of the...
scalbln
These functions shall compute x * FLT_RADIXn efficiently, not normally by computing FLT_RADIXn explicitly. An application wishing to check for error situations...
scandir
scan a directory
scanf
convert formatted input
sched_getparam
The sched_getparam() function shall return the scheduling parameters of a process specified by pid in the sched_param structure pointed to by param. If a...
sched_get_priority_max
The sched_get_priority_max() and sched_get_priority_min() functions shall return the appropriate maximum or minimum, respectively, for the scheduling policy...
sched_getscheduler
The sched_getscheduler() function shall return the scheduling policy of the process specified by pid. If the value of pid is negative, the behavior of the...
sched_rr_get_interval
The sched_rr_get_interval() function shall update the timespec structure referenced by the interval argument to contain the current execution time limit (that...
sched_setparam
The sched_setparam() function shall set the scheduling parameters of the process specified by pid to the values specified by the sched_param structure pointed...
sched_setscheduler
The sched_setscheduler() function shall set the scheduling policy and scheduling parameters of the process specified by pid to policy and the parameters...
sched_yield
The sched_yield() function shall force the running thread to relinquish the processor until it again becomes the head of its thread list. It takes no arguments.
seed48
seed a uniformly distributed pseudo-random non-negative long integer generator
seekdir
The seekdir() function shall set the position of the next readdir() operation on the directory stream specified by dirp to the position specified by loc. The...
select
synchronous I/O multiplexing
sem_close
The sem_close() function shall indicate that the calling process is finished using the named semaphore indicated by sem. The effects of calling sem_close() for...
semctl
The semctl() function operates on XSI semaphores (see the Base Definitions volume of POSIX.1‐2008, Section 4.16, Semaphore). It is unspecified whether this...
sem_destroy
The sem_destroy() function shall destroy the unnamed semaphore indicated by sem. Only a semaphore that was created using sem_init() may be destroyed using...
semget
The semget() function operates on XSI semaphores (see the Base Definitions volume of POSIX.1‐2008, Section 4.16, Semaphore). It is unspecified whether this...
sem_getvalue
The sem_getvalue() function shall update the location referenced by the sval argument to have the value of the semaphore referenced by sem without affecting the...
sem_init
The sem_init() function shall initialize the unnamed semaphore referred to by sem. The value of the initialized semaphore shall be value. Following a successful...
semop
The semop() function operates on XSI semaphores (see the Base Definitions volume of POSIX.1‐2008, Section 4.16, Semaphore). It is unspecified whether this...
sem_open
The sem_open() function shall establish a connection between a named semaphore and a process. Following a call to sem_open() with semaphore name name, the...
sem_post
The sem_post() function shall unlock the semaphore referenced by sem by performing a semaphore unlock operation on that semaphore. If the semaphore value...
sem_timedwait
The sem_timedwait() function shall lock the semaphore referenced by sem as in the sem_wait() function. However, if the semaphore cannot be locked without...
sem_trywait
The sem_trywait() function shall lock the semaphore referenced by sem only if the semaphore is currently not locked; that is, if the semaphore value is...
sem_unlink
The sem_unlink() function shall remove the semaphore named by the string name. If the semaphore named by name is currently referenced by other processes, then...
sem_wait
lock a semaphore
send
The send() function shall initiate transmission of a message from the specified socket to its peer. The send() function shall send a message only when the...
sendmsg
The sendmsg() function shall send a message through a connection-mode or connectionless-mode socket. If the socket is a connectionless-mode socket, the message...
sendto
The sendto() function shall send a message through a connection-mode or connectionless-mode socket. If the socket is a connectionless-mode socket, the message...
setbuf
assign buffering to a stream
setegid
If gid is equal to the real group ID or the saved set-group-ID, or if the process has appropriate privileges, setegid() shall set the effective group ID of the...
setenv
The setenv() function shall update or add a variable in the environment of the calling process. The envname argument points to a string containing the name of...
seteuid
If uid is equal to the real user ID or the saved set-user-ID, or if the process has appropriate privileges, seteuid() shall set the effective user ID of the...
setgid
If the process has appropriate privileges, setgid() shall set the real group ID, effective group ID, and the saved set-group-ID of the calling process to gid...
setgrent
reset the group database to the first entry
sethostent
network host database functions
setitimer
set the value of an interval timer
setjmp
A call to setjmp() shall save the calling environment in its env argument for later use by longjmp(). It is unspecified whether setjmp() is a macro or a...
setkey
The setkey() function provides access to an implementation-defined encoding algorithm. The argument of setkey() is an array of length 64 bytes containing only...
setlocale
The setlocale() function selects the appropriate piece of the global locale, as specified by the category and locale arguments, and can be used to change or...
setlogmask
set the log priority mask
setnetent
network database function
setpgid
The setpgid() function shall either join an existing process group or create a new process group within the session of the calling process. The process group ID...
setpgrp
If the calling process is not already a session leader, setpgrp() sets the process group ID of the calling process to the process ID of the calling process. If...
setpriority
set the nice value
setprotoent
network protocol database functions
setpwent
user database function
setregid
The setregid() function shall set the real and effective group IDs of the calling process. If rgid is -1, the real group ID shall not be changed; if egid is -1...
setreuid
The setreuid() function shall set the real and effective user IDs of the current process to the values specified by the ruid and euid arguments. If ruid or euid...
setrlimit
control maximum resource consumption
setservent
network services database functions
setsid
The setsid() function shall create a new session, if the calling process is not a process group leader. Upon return the calling process shall be the session...
setsockopt
The setsockopt() function shall set the option specified by the option_name argument, at the protocol level specified by the level argument, to the value...
setstate
switch pseudo-random number generator state arrays
setuid
If the process has appropriate privileges, setuid() shall set the real user ID, effective user ID, and the saved set-user-ID of the calling process to uid. If...
setutxent
reset the user accounting database to the first entry
setvbuf
The setvbuf() function may be used after the stream pointed to by stream is associated with an open file but before any other operation (other than an...
shmat
The shmat() function operates on XSI shared memory (see the Base Definitions volume of POSIX.1‐2008, Section 3.342, Shared Memory Object). It is unspecified...
shmctl
The shmctl() function operates on XSI shared memory (see the Base Definitions volume of POSIX.1‐2008, Section 3.342, Shared Memory Object). It is unspecified...
shmdt
The shmdt() function operates on XSI shared memory (see the Base Definitions volume of POSIX.1‐2008, Section 3.342, Shared Memory Object). It is unspecified...
shmget
The shmget() function operates on XSI shared memory (see the Base Definitions volume of POSIX.1‐2008, Section 3.342, Shared Memory Object). It is unspecified...
shm_open
The shm_open() function shall establish a connection between a shared memory object and a file descriptor. It shall create an open file description that refers...
shm_unlink
The shm_unlink() function shall remove the name of the shared memory object named by the string pointed to by name. If one or more references to the shared...
shutdown
The shutdown() function shall cause all or part of a full-duplex connection on the socket associated with the file descriptor socket to be shut down.
sigaction
The sigaction() function allows the calling process to examine and/or specify the action to be associated with a specific signal. The argument sig specifies the...
sigaddset
The sigaddset() function adds the individual signal specified by the signo to the signal set pointed to by set. Applications shall call either sigemptyset() or...
sigaltstack
The sigaltstack() function allows a process to define and examine the state of an alternate stack for signal handlers for the current thread. Signals that have...
sigdelset
The sigdelset() function deletes the individual signal specified by signo from the signal set pointed to by set. Applications should call either sigemptyset()...
sigemptyset
The sigemptyset() function initializes the signal set pointed to by set, such that all signals defined in POSIX.1‐2008 are excluded.
sigfillset
The sigfillset() function shall initialize the signal set pointed to by set, such that all signals defined in this volume of POSIX.1‐2008 are included.
sighold
Use of any of these functions is unspecified in a multi-threaded process. The sighold(), sigignore(), sigpause(), sigrelse(), and sigset() functions provide...
siginterrupt
The siginterrupt() function shall change the restart behavior when a function is interrupted by the specified signal.
sigismember
The sigismember() function shall test whether the signal specified by signo is a member of the set pointed to by set. Applications should call either...
siglongjmp
non-local goto with signal handling
signal
Use of this function is unspecified in a multi-threaded process. The signal() function chooses one of three ways in which receipt of the signal number sig is to...
signbit
The signbit() macro shall determine whether the sign of its argument value is negative. NaNs, zeros, and infinities have a sign bit.
signgam
log gamma function
sigpause
remove a signal from the signal mask and suspend the thread
sigpending
The sigpending() function shall store, in the location referenced by the set argument, the set of signals that are blocked from delivery to the calling thread...
sigprocmask
Refer to pthread_sigmask().
sigqueue
The sigqueue() function shall cause the signal specified by signo to be sent with the value specified by value to the process specified by pid. If signo is zero...
sigrelse
signal management
sigsetjmp
set jump point for a non-local goto
sigsuspend
The sigsuspend() function shall replace the current signal mask of the calling thread with the set of signals pointed to by sigmask and then suspend the thread...
sigtimedwait
The sigtimedwait() function shall be equivalent to sigwaitinfo() except that if none of the signals specified by set are pending, sigtimedwait() shall wait for...
sigwait
The sigwait() function shall select a pending signal from set, atomically clear it from the system's set of pending signals, and return that signal number in...
sigwaitinfo
wait for queued signals
sin
These functions shall compute the sine of their argument x, measured in radians. An application wishing to check for error situations should set errno to zero...
sinh
These functions shall compute the hyperbolic sine of their argument x. An application wishing to check for error situations should set errno to zero and call...
sinl
sine function
sleep
The sleep() function shall cause the calling thread to be suspended from execution until either the number of realtime seconds specified by the argument seconds...
snprintf
print formatted output
sockatmark
The sockatmark() function shall determine whether the socket specified by the descriptor s is at the out-of-band data mark (see Section 2.10.12, Socket...
socket
The socket() function shall create an unbound socket in a communications domain, and return a file descriptor that can be used in later function calls that...
socketpair
The socketpair() function shall create an unbound pair of connected sockets in a specified domain, of a specified type, under the protocol optionally specified...
sprintf
print formatted output
sqrt
These functions shall compute the square root of their argument x, x. An application wishing to check for error situations should set errno to zero and call...
srand
pseudo-random number generator
srand48
seed the uniformly distributed double-precision pseudo-random number generator
srandom
seed pseudo-random number generator
sscanf
convert formatted input
stat
get file status
statvfs
get file system information
stdin
A file with associated buffering is called a stream and is declared to be a pointer to a defined type FILE. The fopen() function shall create certain...
stpcpy
copy a string and return a pointer to the end of the result
stpncpy
copy fixed length string, returning a pointer to the array end
strcasecmp
The strcasecmp() and strcasecmp_l() functions shall compare, while ignoring differences in case, the string pointed to by s1 to the string pointed to by s2. The...
strcat
The strcat() function shall append a copy of the string pointed to by s2 (including the terminating NUL character) to the end of the string pointed to by s1...
strchr
The strchr() function shall locate the first occurrence of c (converted to a char) in the string pointed to by s. The terminating NUL character is considered to...
strcmp
The strcmp() function shall compare the string pointed to by s1 to the string pointed to by s2. The sign of a non-zero return value shall be determined by the...
strcoll
For strcoll(): The strcoll() and strcoll_l() functions shall compare the string pointed to by s1 to the string pointed to by s2, both interpreted as appropriate...
strcpy
For strcpy(): The stpcpy() and strcpy() functions shall copy the string pointed to by s2 (including the terminating NUL character) into the array pointed to by...
strcspn
The strcspn() function shall compute the length (in bytes) of the maximum initial segment of the string pointed to by s1 which consists entirely of bytes not...
strdup
The strdup() function shall return a pointer to a new string, which is a duplicate of the string pointed to by s. The returned pointer can be passed to free()...
strerror
For strerror(): The strerror() function shall map the error number in errnum to a locale-dependent error message string and shall return a pointer to it...
strfmon
The strfmon() function shall place characters into the array pointed to by s as controlled by the string pointed to by format. No more than maxsize bytes are...
strftime
For strftime(): The strftime() function shall place bytes into the array pointed to by s as controlled by the string pointed to by format. The format is a...
strlen
For strlen(): The strlen() function shall compute the number of bytes in the string to which s points, not including the terminating NUL character. The...
strncasecmp
case-insensitive string comparisons
strncat
The strncat() function shall append not more than n bytes (a NUL character and bytes that follow it are not appended) from the array pointed to by s2 to the end...
strncmp
The strncmp() function shall compare not more than n bytes (bytes that follow a NUL character are not compared) from the array pointed to by s1 to the array...
strncpy
For strncpy(): The stpncpy() and strncpy() functions shall copy not more than n bytes (bytes that follow a NUL character are not copied) from the array pointed...
strndup
duplicate a specific number of bytes from a string
strnlen
get length of fixed size string
strpbrk
The strpbrk() function shall locate the first occurrence in the string pointed to by s1 of any byte from the string pointed to by s2.
strptime
The strptime() function shall convert the character string pointed to by buf to values which are stored in the tm structure pointed to by tm, using the format...
strrchr
The strrchr() function shall locate the last occurrence of c (converted to a char) in the string pointed to by s. The terminating NUL character is considered to...
strsignal
The strsignal() function shall map the signal number in signum to an implementation-defined string and shall return a pointer to it. It shall use the same set...
strspn
The strspn() function shall compute the length (in bytes) of the maximum initial segment of the string pointed to by s1 which consists entirely of bytes from...
strstr
The strstr() function shall locate the first occurrence in the string pointed to by s1 of the sequence of bytes (excluding the terminating NUL character) in the...
strtod
These functions shall convert the initial portion of the string pointed to by nptr to double, float, and long double representation, respectively.
strtoimax
These functions shall be equivalent to the strtol(), strtoll(), strtoul(), and strtoull() functions, except that the initial portion of the string shall be...
strtok
For strtok(): A sequence of calls to strtok() breaks the string pointed to by s1 into a sequence of tokens, each of which is delimited by a byte from the string...
strtol
These functions shall convert the initial portion of the string pointed to by str to a type long and long long representation, respectively.
strtold
convert a string to a double-precision number
strtoll
convert a string to a long integer
strtoul
These functions shall convert the initial portion of the string pointed to by str to a type unsigned long and unsigned long long representation, respectively.
strtoumax
convert a string to an integer type
strxfrm
For strxfrm(): The strxfrm() and strxfrm_l() functions shall transform the string pointed to by s2 and place the resulting string into the array pointed to by...
swab
The swab() function shall copy nbytes bytes, which are pointed to by src, to the object pointed to by dest, exchanging adjacent bytes. The nbytes argument...
swprintf
print formatted wide-character output
swscanf
convert formatted wide-character input
symlink
The symlink() function shall create a symbolic link called path2 that contains the string pointed to by path1 (path2 is the name of the symbolic link created...
sync
The sync() function shall cause all information in memory that updates file systems to be scheduled for writing out to all file systems. The writing, although...
sysconf
The sysconf() function provides a method for the application to determine the current value of a configurable system limit or option (variable). The...
syslog
log a message
system
If command is a null pointer, the system() function shall determine whether the host environment has a command processor. If command is not a null pointer, the...
tan
These functions shall compute the tangent of their argument x, measured in radians. An application wishing to check for error situations should set errno to...
tanh
These functions shall compute the hyperbolic tangent of their argument x. An application wishing to check for error situations should set errno to zero and call...
tanl
tangent function
tcdrain
The tcdrain() function shall block until all output written to the object referred to by fildes is transmitted. The fildes argument is an open file descriptor...
tcflow
The tcflow() function shall suspend or restart transmission or reception of data on the object referred to by fildes, depending on the value of action. The...
tcflush
flush non-transmitted output data, non-read input data, or both
tcgetattr
The tcgetattr() function shall get the parameters associated with the terminal referred to by fildes and store them in the termios structure referenced by...
tcgetpgrp
The tcgetpgrp() function shall return the value of the process group ID of the foreground process group associated with the terminal. If there is no foreground...
tcgetsid
The tcgetsid() function shall obtain the process group ID of the session for which the terminal specified by fildes is the controlling terminal.
tcsendbreak
If the terminal is using asynchronous serial data transmission, tcsendbreak() shall cause transmission of a continuous stream of zero-valued bits for a specific...
tcsetattr
set the parameters associated with the terminal
tcsetpgrp
If the process has a controlling terminal, tcsetpgrp() shall set the foreground process group ID associated with the terminal to pgid_id. The application shall...
tdelete
The tdelete(), tfind(), tsearch(), and twalk() functions manipulate binary search trees. Comparisons are made with a user-supplied routine, the address of which...
telldir
The telldir() function shall obtain the current location associated with the directory stream specified by dirp. If the most recent operation on the directory...
tempnam
The tempnam() function shall generate a pathname that may be used for a temporary file. The tempnam() function allows the user to control the choice of a...
tfind
search binary search tree
tgamma
These functions shall compute the gamma function of x. An application wishing to check for error situations should set errno to zero and call...
time
The time() function shall return the value of time in seconds since the Epoch. The tloc argument points to an area where the return value is also stored. If...
timer_create
The timer_create() function shall create a per-process timer using the specified clock, clock_id, as the timing base. The timer_create() function shall return...
timer_delete
The timer_delete() function deletes the specified timer, timerid, previously created by the timer_create() function. If the timer is armed when timer_delete()...
timer_getoverrun
The timer_gettime() function shall store the amount of time until the specified timer, timerid, expires and the reload value of the timer into the space pointed...
times
The times() function shall fill the tms structure pointed to by buffer with time-accounting information. The tms structure is defined in <sys/times.h>. All...
timezone
difference from UTC and local standard time
tmpfile
The tmpfile() function shall create a temporary file and open a corresponding stream. The file shall be automatically deleted when all references to the file...
tmpnam
The tmpnam() function shall generate a string that is a valid pathname that does not name an existing file. The function is potentially capable of generating...
toascii
The toascii() function shall convert its argument into a 7-bit ASCII character.
tolower
For tolower(): The tolower() and tolower_l() functions have as a domain a type int, the value of which is representable as an unsigned char or the value of EOF...
_tolower
The _tolower() macro shall be equivalent to tolower(c) except that the application shall ensure that the argument c is an uppercase letter.
toupper
For toupper(): The toupper() and toupper_l() functions have as a domain a type int, the value of which is representable as an unsigned char or the value of EOF...
_toupper
The _toupper() macro shall be equivalent to toupper() except that the application shall ensure that the argument c is a lowercase letter.
towctrans
For towctrans(): The towctrans() and towctrans_l() functions shall transliterate the wide-character code wc using the mapping described by desc. The current...
towlower
For towlower(): The towlower() and towlower_l() functions have as a domain a type wint_t, the value of which the application shall ensure is a character...
towupper
For towupper(): The towupper() and towupper_l() functions have as a domain a type wint_t, the value of which the application shall ensure is a character...
trunc
These functions shall round their argument to the integer value, in floating format, nearest to but no larger in magnitude than the argument.
truncate
The truncate() function shall cause the regular file named by path to have a size which shall be equal to length bytes. If the file previously was larger than...
truncf
round to truncated integer value
tsearch
search a binary search tree
ttyname
The ttyname() function shall return a pointer to a string containing a null-terminated pathname of the terminal associated with file descriptor fildes. The...
twalk
traverse a binary search tree
tzset
The tzset() function shall use the value of the environment variable TZ to set time conversion information used by ctime(), localtime(), mktime(), and...
ulimit
The ulimit() function shall control process limits. The process limits that can be controlled by this function include the maximum size of a single file that...
umask
The umask() function shall set the file mode creation mask of the process to cmask and return the previous value of the mask. Only the file permission bits of...
uname
The uname() function shall store information identifying the current system in the structure pointed to by name. The uname() function uses the utsname structure...
ungetc
The ungetc() function shall push the byte specified by c (converted to an unsigned char) back onto the input stream pointed to by stream. The pushed-back bytes...
ungetwc
The ungetwc() function shall push the character corresponding to the wide-character code specified by wc back onto the input stream pointed to by stream. The...
unlink
The unlink() function shall remove a link to a file. If path names a symbolic link, unlink() shall remove the symbolic link named by path and shall not affect...
unlockpt
The unlockpt() function shall unlock the slave pseudo-terminal device associated with the master to which fildes refers. Conforming applications shall ensure...
unsetenv
The unsetenv() function shall remove an environment variable from the environment of the calling process. The name argument points to a string, which is the...
uselocale
The uselocale() function shall set the current locale for the current thread to the locale represented by newloc.
utime
The utime() function shall set the access and modification times of the file named by the path argument. If times is a null pointer, the access and modification...
utimensat
set file access and modification times relative to directory file descriptor
va_arg
Refer to the Base Definitions volume of POSIX.1‐2008, <stdarg.h>
vfprintf
The vdprintf(), vfprintf(), vprintf(), vsnprintf(), and vsprintf() functions shall be equivalent to the dprintf(), fprintf(), printf(), snprintf(), and...
vfscanf
The vscanf(), vfscanf(), and vsscanf() functions shall be equivalent to the scanf(), fscanf(), and sscanf() functions, respectively, except that instead of...
vfwprintf
The vfwprintf(), vswprintf(), and vwprintf() functions shall be equivalent to fwprintf(), swprintf(), and wprintf() respectively, except that instead of being...
vfwscanf
The vfwscanf(), vswscanf(), and vwscanf() functions shall be equivalent to the fwscanf(), swscanf(), and wscanf() functions, respectively, except that instead...
vprintf
format the output of a stdarg argument list
vscanf
format input of a stdarg argument list
vsnprintf
format output of a stdarg argument list
vsscanf
format input of a stdarg argument list
vswprintf
wide-character formatted output of a stdarg argument list
vswscanf
wide-character formatted input of a stdarg argument list
vwprintf
wide-character formatted output of a stdarg argument list
vwscanf
wide-character formatted input of a stdarg argument list
wait
The wait() and waitpid() functions shall obtain status information pertaining to one of the caller's child processes. Various options permit status information...
waitid
The waitid() function shall suspend the calling thread until one child of the process containing the calling thread changes state. It records the current state...
waitpid
wait for a child process to stop or terminate
wcpcpy
copy a wide-character string, returning a pointer to its end
wcpncpy
copy a fixed-size wide-character string, returning a pointer to its end
wcrtomb
convert a wide-character code to a character (restartable)
wcscasecmp
The wcscasecmp() and wcsncasecmp() functions are the wide-character equivalent of the strcasecmp() and strncasecmp() functions, respectively. The wcscasecmp()...
wcscat
The wcscat() function shall append a copy of the wide-character string pointed to by ws2 (including the terminating null wide-character code) to the end of the...
wcschr
The wcschr() function shall locate the first occurrence of wc in the wide-character string pointed to by ws. The application shall ensure that the value of wc...
wcscmp
The wcscmp() function shall compare the wide-character string pointed to by ws1 to the wide-character string pointed to by ws2. The sign of a non-zero return...
wcscoll
For wcscoll(): The wcscoll() and wcscoll_l() functions shall compare the wide-character string pointed to by ws1 to the wide-character string pointed to by ws2...
wcscpy
For wcscpy(): The wcpcpy() and wcscpy() functions shall copy the wide-character string pointed to by ws2 (including the terminating null wide-character code)...
wcscspn
The wcscspn() function shall compute the length (in wide characters) of the maximum initial segment of the wide-character string pointed to by ws1 which...
wcsdup
The wcsdup() function is the wide-character equivalent of the strdup() function. The wcsdup() function shall return a pointer to a new wide-character string...
wcsftime
convert date and time to a wide-character string
wcslen
For wcslen(): The wcslen() function shall compute the number of wide-character codes in the wide-character string to which ws points, not including the...
wcsncasecmp
case-insensitive wide-character string comparison
wcsncat
The wcsncat() function shall append not more than n wide-character codes (a null wide-character code and wide-character codes that follow it are not appended)...
wcsncmp
The wcsncmp() function shall compare not more than n wide-character codes (wide-character codes that follow a null wide-character code are not compared) from...
wcsncpy
For wcsncpy(): The wcpncpy() and wcsncpy() functions shall copy not more than n wide-character codes (wide-character codes that follow a null wide-character...
wcsnlen
get length of a fixed-sized wide-character string
wcsnrtombs
convert wide-character string to multi-byte string
wcspbrk
The wcspbrk() function shall locate the first occurrence in the wide-character string pointed to by ws1 of any wide-character code from the wide-character...
wcsrchr
The wcsrchr() function shall locate the last occurrence of wc in the wide-character string pointed to by ws. The application shall ensure that the value of wc...
wcsrtombs
For wcsrtombs(): The wcsrtombs() function shall convert a sequence of wide characters from the array indirectly pointed to by src into a sequence of...
wcsspn
The wcsspn() function shall compute the length (in wide characters) of the maximum initial segment of the wide-character string pointed to by ws1 which consists...
wcsstr
The wcsstr() function shall locate the first occurrence in the wide-character string pointed to by ws1 of the sequence of wide characters (excluding the...
wcstod
These functions shall convert the initial portion of the wide-character string pointed to by nptr to double, float, and long double representation...
wcstoimax
These functions shall be equivalent to the wcstol(), wcstoll(), wcstoul(), and wcstoull() functions, respectively, except that the initial portion of the wide...
wcstok
A sequence of calls to wcstok() shall break the wide-character string pointed to by ws1 into a sequence of tokens, each of which shall be delimited by a...
wcstol
These functions shall convert the initial portion of the wide-character string pointed to by nptr to long and long long, respectively.
wcstold
convert a wide-character string to a double-precision number
wcstoll
convert a wide-character string to a long integer
wcstombs
The wcstombs() function shall convert the sequence of wide-character codes that are in the array pointed to by pwcs into a sequence of characters that begins in...
wcstoul
The wcstoul() and wcstoull() functions shall convert the initial portion of the wide-character string pointed to by nptr to unsigned long and unsigned long long...
wcstoumax
convert a wide-character string to an integer type
wcswidth
The wcswidth() function shall determine the number of column positions required for n wide-character codes (or fewer than n wide-character codes if a null...
wcsxfrm
For wcsxfrm(): The wcsxfrm() and wcsxfrm_l() functions shall transform the wide-character string pointed to by ws2 and place the resulting wide-character string...
wctob
The wctob() function shall determine whether c corresponds to a member of the extended character set whose character representation is a single byte when in the...
wctomb
The wctomb() function shall determine the number of bytes needed to represent the character corresponding to the wide-character code whose value is wchar...
wctrans
For wctrans(): The wctrans() and wctrans_l() functions are defined for valid character mapping names identified in the current locale. The charclass is a string...
wctype
For wctype(): The wctype() and wctype_l() functions are defined for valid character class names as defined in the current locale or in the locale represented by...
wcwidth
The wcwidth() function shall determine the number of column positions required for the wide character wc. The application shall ensure that the value of wc is a...
wmemchr
The wmemchr() function shall locate the first occurrence of wc in the initial n wide characters of the object pointed to by ws. This function shall not be...
wmemcmp
The wmemcmp() function shall compare the first n wide characters of the object pointed to by ws1 to the first n wide characters of the object pointed to by ws2...
wmemcpy
The wmemcpy() function shall copy n wide characters from the object pointed to by ws2 to the object pointed to by ws1. This function shall not be affected by...
wmemmove
The wmemmove() function shall copy n wide characters from the object pointed to by ws2 to the object pointed to by ws1. Copying shall take place as if the n...
wmemset
The wmemset() function shall copy the value of wc into each of the first n wide characters of the object pointed to by ws. This function shall not be affected...
wordexp
The wordexp() function shall perform word expansions as described in the Shell and Utilities volume of POSIX.1‐2008, Section 2.6, Word Expansions, subject to...
wprintf
print formatted wide-character output
write
The write() function shall attempt to write nbyte bytes from the buffer pointed to by buf to the file associated with the open file descriptor, fildes. Before...
writev
The writev() function shall be equivalent to write(), except as described below. The writev() function shall gather output data from the iovcnt buffers...
wscanf
convert formatted wide-character input
y0
The y0(), y1(), and yn() functions shall compute Bessel functions of x of the second kind of orders 0, 1, and n, respectively. An application wishing to check...