Manual pages for the C standard library, the C POSIX library, and the CS50 Library for those less comfortable.

frequently used in CS50

aio.h

• aio_cancel - cancel an outstanding asynchronous I/O request
• aio_error - get error status of asynchronous I/O operation
• aio_fsync - asynchronous file synchronization
• aio_init - asynchronous I/O initialization
• aio_read - asynchronous read
• aio_return - get return status of asynchronous I/O operation
• aio_suspend - wait for asynchronous I/O operation or timeout
• aio_write - asynchronous write
• lio_listio - initiate a list of I/O requests

arpa/inet.h

• byteorder - convert values between host and network byte order
• htonl - convert values between host and network byte order
• htons - convert values between host and network byte order
• inet_net_ntop - Internet network number conversion
• inet_net_pton - Internet network number conversion
• inet_ntop - convert IPv4 and IPv6 addresses from binary to text form
• inet_pton - convert IPv4 and IPv6 addresses from text to binary form
• ntohl - convert values between host and network byte order
• ntohs - convert values between host and network byte order

assert.h

• assert - abort the program if assertion is false
• assert_perror - test errnum and abort

complex.h

• cabs - absolute value of a complex number
• cabsf - absolute value of a complex number
• cabsl - absolute value of a complex number
• cacos - complex arc cosine
• cacosf - complex arc cosine
• cacosh - complex arc hyperbolic cosine
• cacoshf - complex arc hyperbolic cosine
• cacoshl - complex arc hyperbolic cosine
• cacosl - complex arc cosine
• carg - calculate the complex argument
• cargf - calculate the complex argument
• cargl - calculate the complex argument
• casin - complex arc sine
• casinf - complex arc sine
• casinh - complex arc sine hyperbolic
• casinhf - complex arc sine hyperbolic
• casinhl - complex arc sine hyperbolic
• casinl - complex arc sine
• catan - complex arc tangents
• catanf - complex arc tangents
• catanh - complex arc tangents hyperbolic
• catanhf - complex arc tangents hyperbolic
• catanhl - complex arc tangents hyperbolic
• catanl - complex arc tangents
• ccos - complex cosine function
• ccosf - complex cosine function
• ccosh - complex hyperbolic cosine
• ccoshf - complex hyperbolic cosine
• ccoshl - complex hyperbolic cosine
• ccosl - complex cosine function
• cexp - complex exponential function
• cexp2 - base-2 exponent of a complex number
• cexp2f - base-2 exponent of a complex number
• cexp2l - base-2 exponent of a complex number
• cexpf - complex exponential function
• cexpl - complex exponential function
• cimag - get imaginary part of a complex number
• cimagf - get imaginary part of a complex number
• cimagl - get imaginary part of a complex number
• clog - natural logarithm of a complex number
• clog10 - base-10 logarithm of a complex number
• clog10f - base-10 logarithm of a complex number
• clog10l - base-10 logarithm of a complex number
• clog2 - base-2 logarithm of a complex number
• clog2f - base-2 logarithm of a complex number
• clog2l - base-2 logarithm of a complex number
• clogf - natural logarithm of a complex number
• clogl - natural logarithm of a complex number
• complex - basics of complex mathematics
• conj - calculate the complex conjugate
• conjf - calculate the complex conjugate
• conjl - calculate the complex conjugate
• cpow - complex power function
• cpowf - complex power function
• cpowl - complex power function
• cproj - project into Riemann Sphere
• cprojf - project into Riemann Sphere
• cprojl - project into Riemann Sphere
• creal - get real part of a complex number
• crealf - get real part of a complex number
• creall - get real part of a complex number
• csin - complex sine function
• csinf - complex sine function
• csinh - complex hyperbolic sine
• csinhf - complex hyperbolic sine
• csinhl - complex hyperbolic sine
• csinl - complex sine function
• csqrt - complex square root
• csqrtf - complex square root
• csqrtl - complex square root
• ctan - complex tangent function
• ctanf - complex tangent function
• ctanh - complex hyperbolic tangent
• ctanhf - complex hyperbolic tangent
• ctanhl - complex hyperbolic tangent
• ctanl - complex tangent function

cs50.h

• get_char - prompts user for a line of text from stdin and returns... prompt a user for a char
• get_double - prompts user for a line of text from stdin and returns... prompt a user for a double
• get_float - prompts user for a line of text from stdin and returns... prompt a user for a float
• get_int - prompts user for a line of text from stdin and returns... prompt a user for an int
• get_long - prompts user for a line of text from stdin and returns... prompt a user for an long
• get_long_long - prompts user for a line of text from stdin and returns...
• get_string - prompts user for a line of text from stdin and returns... prompt a user for a string

ctype.h

• isalnum - character classification functions check whether a character is alphanumeric
• isalnum_l - character classification functions
• isalpha - character classification functions check whether a character is alphabetical
• isalpha_l - character classification functions
• isascii - character classification functions
• isascii_l - character classification functions
• isblank - character classification functions check whether a character is blank (i.e., a space or tab)
• isblank_l - character classification functions
• iscntrl - character classification functions
• iscntrl_l - character classification functions
• isdigit - character classification functions check whether a character is a digit
• isdigit_l - character classification functions
• isgraph - character classification functions
• isgraph_l - character classification functions
• islower - character classification functions check whether a character is lowercase
• islower_l - character classification functions
• isprint - character classification functions
• isprint_l - character classification functions
• ispunct - character classification functions check whether a character is punctuation
• ispunct_l - character classification functions
• isspace - character classification functions check whether a character is whitespace (e.g., a newline, space, or tab)
• isspace_l - character classification functions
• isupper - character classification functions check whether a character is uppercase
• isupper_l - character classification functions
• isxdigit - character classification functions
• isxdigit_l - character classification functions
• toascii - convert character to ASCII
• tolower - convert uppercase or lowercase convert a char to lowercase
• tolower_l - convert uppercase or lowercase
• toupper - convert uppercase or lowercase convert a char to uppercase
• toupper_l - convert uppercase or lowercase

dirent.h

• alphasort - scan a directory for matching entries
• getdirentries - get directory entries in a filesystem-independent format
• readdir - read a directory
• readdir_r - read a directory
• scandir - scan a directory for matching entries
• scandirat - scan a directory for matching entries
• seekdir - set the position of the next readdir() call in the dir...
• telldir - return current location in directory stream
• versionsort - scan a directory for matching entries

dlfcn.h

• dladdr - translate address to symbolic information
• dladdr1 - translate address to symbolic information
• dlclose - open and close a shared object
• dlerror - obtain error diagnostic for functions in the dlopen API
• dlmopen - open and close a shared object
• dlopen - open and close a shared object
• dlsym - obtain address of a symbol in a shared object or execu...
• dlvsym - obtain address of a symbol in a shared object or execu...

errno.h

• errno - number of last error
• program_invocation_name - obtain name used to invoke calling program
• program_invocation_short_name - obtain name used to invoke calling program

fcntl.h

• arm_fadvise - predeclare an access pattern for file data
• arm_fadvise64_64 - predeclare an access pattern for file data
• arm_sync_file_range - sync a file segment with disk
• fadvise64 - predeclare an access pattern for file data
• fadvise64_64 - predeclare an access pattern for file data
• fallocate - manipulate file space
• fanotify_init - create and initialize fanotify group
• futimens - change file timestamps with nanosecond precision
• futimesat - change timestamps of a file relative to a directory fi...
• posix_fadvise - predeclare an access pattern for file data
• posix_fallocate - allocate file space
• readahead - initiate file readahead into page cache
• splice - splice data to/from a pipe
• sync_file_range - sync a file segment with disk
• sync_file_range2 - sync a file segment with disk
• tee - duplicating pipe content
• utimensat - change file timestamps with nanosecond precision
• vmsplice - splice user pages to/from a pipe

fenv.h

• feclearexcept - floating-point rounding and exception handling
• fedisableexcept - floating-point rounding and exception handling
• feenableexcept - floating-point rounding and exception handling
• fegetenv - floating-point rounding and exception handling
• fegetexcept - floating-point rounding and exception handling
• fegetexceptflag - floating-point rounding and exception handling
• fegetround - floating-point rounding and exception handling
• feholdexcept - floating-point rounding and exception handling
• fenv - floating-point rounding and exception handling
• feraiseexcept - floating-point rounding and exception handling
• fesetenv - floating-point rounding and exception handling
• fesetexceptflag - floating-point rounding and exception handling
• fesetround - floating-point rounding and exception handling
• fetestexcept - floating-point rounding and exception handling
• feupdateenv - floating-point rounding and exception handling

fmtmsg.h

• addseverity - introduce new severity classes
• fmtmsg - print formatted error messages

fnmatch.h

• fnmatch - match filename or pathname

ftw.h

• ftw - file tree walk
• nftw - file tree walk

glob.h

• glob - find pathnames matching a pattern, free memory from gl...
• globfree - find pathnames matching a pattern, free memory from gl...

grp.h

• fgetgrent_r - get group file entry reentrantly
• getgrent_r - get group file entry reentrantly
• getgrouplist - get list of groups to which a user belongs
• putgrent - write a group database entry to a file

iconv.h

• iconv - perform character set conversion
• iconv_close - deallocate descriptor for character set conversion
• iconv_open - allocate descriptor for character set conversion

inttypes.h

• strtoimax - convert string to integer
• strtoumax - convert string to integer

langinfo.h

• nl_langinfo - query language and locale information
• nl_langinfo_l - query language and locale information

libgen.h

• basename - parse pathname components
• dirname - parse pathname components

limits.h

• MB_LEN_MAX - maximum multibyte length of a character across all loc...
• realpath - return the canonicalized absolute pathname

locale.h

• duplocale - duplicate a locale object
• freelocale - create, modify, and free a locale object
• locale - description of multilanguage support
• localeconv - get numeric formatting information
• newlocale - create, modify, and free a locale object
• setlocale - set the current locale
• uselocale - set/get the locale for the calling thread

math.h

• acos - arc cosine function
• acosf - arc cosine function
• acosh - inverse hyperbolic cosine function
• acoshf - inverse hyperbolic cosine function
• acoshl - inverse hyperbolic cosine function
• acosl - arc cosine function
• asin - arc sine function
• asinf - arc sine function
• asinh - inverse hyperbolic sine function
• asinhf - inverse hyperbolic sine function
• asinhl - inverse hyperbolic sine function
• asinl - arc sine function
• atan - arc tangent function
• atan2 - arc tangent function of two variables
• atan2f - arc tangent function of two variables
• atan2l - arc tangent function of two variables
• atanf - arc tangent function
• atanh - inverse hyperbolic tangent function
• atanhf - inverse hyperbolic tangent function
• atanhl - inverse hyperbolic tangent function
• atanl - arc tangent function
• cbrt - cube root function
• cbrtf - cube root function
• cbrtl - cube root function
• ceil - ceiling function: smallest integral value not less tha... calculate the ceiling of a number
• ceilf - ceiling function: smallest integral value not less tha...
• ceill - ceiling function: smallest integral value not less tha...
• copysign - copy sign of a number
• copysignf - copy sign of a number
• copysignl - copy sign of a number
• cos - cosine function
• cosf - cosine function
• cosh - hyperbolic cosine function
• coshf - hyperbolic cosine function
• coshl - hyperbolic cosine function
• cosl - cosine function
• drem - floating-point remainder function
• dremf - floating-point remainder function
• dreml - floating-point remainder function
• erf - error function
• erfc - complementary error function
• erfcf - complementary error function
• erfcl - complementary error function
• erff - error function
• erfl - error function
• exp - base-e exponential function
• exp10 - base-10 exponential function
• exp10f - base-10 exponential function
• exp10l - base-10 exponential function
• exp2 - base-2 exponential function
• exp2f - base-2 exponential function
• exp2l - base-2 exponential function
• expf - base-e exponential function
• expl - base-e exponential function
• expm1 - exponential minus 1
• expm1f - exponential minus 1
• expm1l - exponential minus 1
• fabs - absolute value of floating-point number
• fabsf - absolute value of floating-point number
• fabsl - absolute value of floating-point number
• fdim - positive difference
• fdimf - positive difference
• fdiml - positive difference
• finite - BSD floating-point classification functions
• finitef - BSD floating-point classification functions
• finitel - BSD floating-point classification functions
• floor - largest integral value not greater than argument calculate the floor of a number
• floorf - largest integral value not greater than argument
• floorl - largest integral value not greater than argument
• fma - floating-point multiply and add
• fmaf - floating-point multiply and add
• fmal - floating-point multiply and add
• fmax - determine maximum of two floating-point numbers
• fmaxf - determine maximum of two floating-point numbers
• fmaxl - determine maximum of two floating-point numbers
• fmin - determine minimum of two floating-point numbers
• fminf - determine minimum of two floating-point numbers
• fminl - determine minimum of two floating-point numbers
• fmod - floating-point remainder function
• fmodf - floating-point remainder function
• fmodl - floating-point remainder function
• fpclassify - floating-point classification macros
• frexp - convert floating-point number to fractional and integr...
• frexpf - convert floating-point number to fractional and integr...
• frexpl - convert floating-point number to fractional and integr...
• gamma - (logarithm of the) gamma function
• gammaf - (logarithm of the) gamma function
• gammal - (logarithm of the) gamma function
• HUGE_VAL - floating-point constants
• HUGE_VALF - floating-point constants
• HUGE_VALL - floating-point constants
• hypot - Euclidean distance function
• hypotf - Euclidean distance function
• hypotl - Euclidean distance function
• ilogb - get integer exponent of a floating-point value
• ilogbf - get integer exponent of a floating-point value
• ilogbl - get integer exponent of a floating-point value
• INFINITY - floating-point constants
• isfinite - floating-point classification macros
• isgreater - floating-point relational tests without exception for NaN
• isgreaterequal - floating-point relational tests without exception for NaN
• isinf - floating-point classification macros
• isinff - BSD floating-point classification functions
• isinfl - BSD floating-point classification functions
• isless - floating-point relational tests without exception for NaN
• islessequal - floating-point relational tests without exception for NaN
• islessgreater - floating-point relational tests without exception for NaN
• isnan - floating-point classification macros
• isnanf - BSD floating-point classification functions
• isnanl - BSD floating-point classification functions
• isnormal - floating-point classification macros
• isunordered - floating-point relational tests without exception for NaN
• j0 - Bessel functions of the first kind
• j0f - Bessel functions of the first kind
• j0l - Bessel functions of the first kind
• j1 - Bessel functions of the first kind
• j1f - Bessel functions of the first kind
• j1l - Bessel functions of the first kind
• jn - Bessel functions of the first kind
• jnf - Bessel functions of the first kind
• jnl - Bessel functions of the first kind
• ldexp - multiply floating-point number by integral power of 2
• ldexpf - multiply floating-point number by integral power of 2
• ldexpl - multiply floating-point number by integral power of 2
• lgamma - log gamma function
• lgamma_r - log gamma function
• lgammaf - log gamma function
• lgammaf_r - log gamma function
• lgammal - log gamma function
• lgammal_r - log gamma function
• llrint - round to nearest integer
• llrintf - round to nearest integer
• llrintl - round to nearest integer
• llround - round to nearest integer
• llroundf - round to nearest integer
• llroundl - round to nearest integer
• log - natural logarithmic function
• log10 - base-10 logarithmic function
• log10f - base-10 logarithmic function
• log10l - base-10 logarithmic function
• log1p - logarithm of 1 plus argument
• log1pf - logarithm of 1 plus argument
• log1pl - logarithm of 1 plus argument
• log2 - base-2 logarithmic function calculate the base-2 logarithm of a number
• log2f - base-2 logarithmic function
• log2l - base-2 logarithmic function
• logb - get exponent of a floating-point value
• logbf - get exponent of a floating-point value
• logbl - get exponent of a floating-point value
• logf - natural logarithmic function
• logl - natural logarithmic function
• lrint - round to nearest integer
• lrintf - round to nearest integer
• lrintl - round to nearest integer
• lround - round to nearest integer
• lroundf - round to nearest integer
• lroundl - round to nearest integer
• math_error - detecting errors from mathematical functions
• matherr - SVID math library exception handling
• modf - extract signed integral and fractional values from flo...
• modff - extract signed integral and fractional values from flo...
• modfl - extract signed integral and fractional values from flo...
• NAN - floating-point constants
• nan - return 'Not a Number'
• nanf - return 'Not a Number'
• nanl - return 'Not a Number'
• nearbyint - round to nearest integer
• nearbyintf - round to nearest integer
• nearbyintl - round to nearest integer
• nextafter - floating-point number manipulation
• nextafterf - floating-point number manipulation
• nextafterl - floating-point number manipulation
• nextdown - return next floating-point number toward positive/nega...
• nextdownf - return next floating-point number toward positive/nega...
• nextdownl - return next floating-point number toward positive/nega...
• nexttoward - floating-point number manipulation
• nexttowardf - floating-point number manipulation
• nexttowardl - floating-point number manipulation
• nextup - return next floating-point number toward positive/nega...
• nextupf - return next floating-point number toward positive/nega...
• nextupl - return next floating-point number toward positive/nega...
• pow - power functions raise a number to a power
• pow10 - base-10 power functions
• pow10f - base-10 power functions
• pow10l - base-10 power functions
• powf - power functions
• powl - power functions
• remainder - floating-point remainder function
• remainderf - floating-point remainder function
• remainderl - floating-point remainder function
• remquo - remainder and part of quotient
• remquof - remainder and part of quotient
• remquol - remainder and part of quotient
• rint - round to nearest integer
• rintf - round to nearest integer
• rintl - round to nearest integer
• round - round to nearest integer, away from zero round a number to the nearest integer
• roundf - round to nearest integer, away from zero
• roundl - round to nearest integer, away from zero
• scalb - multiply floating-point number by integral power of ra...
• scalbf - multiply floating-point number by integral power of ra...
• scalbl - multiply floating-point number by integral power of ra...
• scalbln - multiply floating-point number by integral power of radix
• scalblnf - multiply floating-point number by integral power of radix
• scalblnl - multiply floating-point number by integral power of radix
• scalbn - multiply floating-point number by integral power of radix
• scalbnf - multiply floating-point number by integral power of radix
• scalbnl - multiply floating-point number by integral power of radix
• signbit - test sign of a real floating-point number
• signgam - log gamma function
• significand - get mantissa of floating-point number
• significandf - get mantissa of floating-point number
• significandl - get mantissa of floating-point number
• sin - sine function
• sincos - calculate sin and cos simultaneously
• sincosf - calculate sin and cos simultaneously
• sincosl - calculate sin and cos simultaneously
• sinf - sine function
• sinh - hyperbolic sine function
• sinhf - hyperbolic sine function
• sinhl - hyperbolic sine function
• sinl - sine function
• sqrt - square root function calculate the square root of a number
• sqrtf - square root function
• sqrtl - square root function
• tan - tangent function
• tanf - tangent function
• tanh - hyperbolic tangent function
• tanhf - hyperbolic tangent function
• tanhl - hyperbolic tangent function
• tanl - tangent function
• tgamma - true gamma function
• tgammaf - true gamma function
• tgammal - true gamma function
• trunc - round to integer, toward zero
• truncf - round to integer, toward zero
• truncl - round to integer, toward zero
• y0 - Bessel functions of the second kind
• y0f - Bessel functions of the second kind
• y0l - Bessel functions of the second kind
• y1 - Bessel functions of the second kind
• y1f - Bessel functions of the second kind
• y1l - Bessel functions of the second kind
• yn - Bessel functions of the second kind
• ynf - Bessel functions of the second kind
• ynl - Bessel functions of the second kind

monetary.h

• strfmon - convert monetary value to a string
• strfmon_l - convert monetary value to a string

mqueue.h

• mq_close - close a message queue descriptor
• mq_getattr - get/set message queue attributes
• mq_notify - register for notification when a message is available
• mq_notify - register for notification when a message is available
• mq_open - open a message queue
• mq_open - open a message queue
• mq_receive - receive a message from a message queue
• mq_send - send a message to a message queue
• mq_setattr - get/set message queue attributes
• mq_timedreceive - receive a message from a message queue
• mq_timedreceive - receive a message from a message queue
• mq_timedsend - send a message to a message queue
• mq_timedsend - send a message to a message queue
• mq_unlink - remove a message queue
• mq_unlink - remove a message queue

net/if.h

• if_freenameindex - get network interface names and indexes
• if_indextoname - mappings between network interface names and indexes
• if_nameindex - get network interface names and indexes
• if_nametoindex - mappings between network interface names and indexes

netdb.h

• endhostent - get network host entry
• endnetent - get network entry
• endnetgrent - handle network group entries
• endprotoent - get protocol entry
• endrpcent - get RPC entry
• endservent - get service entry
• gai_cancel - asynchronous network address and service translation
• gai_error - asynchronous network address and service translation
• gai_suspend - asynchronous network address and service translation
• getaddrinfo_a - asynchronous network address and service translation
• gethostbyaddr - get network host entry
• gethostbyaddr_r - get network host entry
• gethostbyname - get network host entry
• gethostbyname2 - get network host entry
• gethostbyname2_r - get network host entry
• gethostbyname_r - get network host entry
• gethostent - get network host entry
• gethostent_r - get network host entry
• getnetbyaddr - get network entry
• getnetbyaddr_r - get network entry (reentrant)
• getnetbyname - get network entry
• getnetbyname_r - get network entry (reentrant)
• getnetent - get network entry
• getnetent_r - get network entry (reentrant)
• getnetgrent - handle network group entries
• getnetgrent_r - handle network group entries
• getprotobyname - get protocol entry
• getprotobyname_r - get protocol entry (reentrant)
• getprotobynumber - get protocol entry
• getprotobynumber_r - get protocol entry (reentrant)
• getprotoent - get protocol entry
• getprotoent_r - get protocol entry (reentrant)
• getrpcbyname - get RPC entry
• getrpcbyname_r - get RPC entry (reentrant)
• getrpcbynumber - get RPC entry
• getrpcbynumber_r - get RPC entry (reentrant)
• getrpcent - get RPC entry
• getrpcent_r - get RPC entry (reentrant)
• getservbyname - get service entry
• getservbyname_r - get service entry (reentrant)
• getservbyport - get service entry
• getservbyport_r - get service entry (reentrant)
• getservent - get service entry
• getservent_r - get service entry (reentrant)
• h_errno - get network host entry
• herror - get network host entry
• hstrerror - get network host entry
• innetgr - handle network group entries
• iruserok - routines for returning a stream to a remote command
• iruserok_af - routines for returning a stream to a remote command
• rcmd - routines for returning a stream to a remote command
• rcmd_af - routines for returning a stream to a remote command
• rexec - return stream to a remote command
• rexec_af - return stream to a remote command
• rresvport - routines for returning a stream to a remote command
• rresvport_af - routines for returning a stream to a remote command
• ruserok - routines for returning a stream to a remote command
• ruserok_af - routines for returning a stream to a remote command
• sethostent - get network host entry
• setnetent - get network entry
• setnetgrent - handle network group entries
• setprotoent - get protocol entry
• setrpcent - get RPC entry
• setservent - get service entry

netinet/in.h

• dn_comp - resolver routines
• dn_expand - resolver routines
• res_init - resolver routines
• res_mkquery - resolver routines
• res_nclose - resolver routines
• res_ninit - resolver routines
• res_nmkquery - resolver routines
• res_nquery - resolver routines
• res_nquerydomain - resolver routines
• res_nsearch - resolver routines
• res_nsend - resolver routines
• res_query - resolver routines
• res_querydomain - resolver routines
• res_search - resolver routines
• res_send - resolver routines
• resolver - resolver routines

nl_types.h

• catclose - open/close a message catalog
• catgets - get message from a message catalog
• catopen - open/close a message catalog

poll.h

• poll - wait for some event on a file descriptor
• ppoll - wait for some event on a file descriptor

pthread.h

• pthread_attr_destroy - initialize and destroy thread attributes object
• pthread_attr_getaffinity_np - set/get CPU affinity attribute in thread at...
• pthread_attr_getdetachstate - set/get detach state attribute in thread at...
• pthread_attr_getguardsize - set/get guard size attribute in thread attrib...
• pthread_attr_getinheritsched - set/get inherit-scheduler attribute in thr...
• pthread_attr_getschedparam - set/get scheduling parameter attributes in t...
• pthread_attr_getschedpolicy - set/get scheduling policy attribute in thre...
• pthread_attr_getscope - set/get contention scope attribute in thread attr...
• pthread_attr_getsigmask_np - set/get signal mask attribute in thread attr...
• pthread_attr_getstack - set/get stack attributes in thread attributes object
• pthread_attr_getstackaddr - set/get stack address attribute in thread att...
• pthread_attr_getstacksize - set/get stack size attribute in thread attrib...
• pthread_attr_init - initialize and destroy thread attributes object
• pthread_attr_setaffinity_np - set/get CPU affinity attribute in thread at...
• pthread_attr_setdetachstate - set/get detach state attribute in thread at...
• pthread_attr_setguardsize - set/get guard size attribute in thread attrib...
• pthread_attr_setinheritsched - set/get inherit-scheduler attribute in thr...
• pthread_attr_setschedparam - set/get scheduling parameter attributes in t...
• pthread_attr_setschedpolicy - set/get scheduling policy attribute in thre...
• pthread_attr_setscope - set/get contention scope attribute in thread attr...
• pthread_attr_setsigmask_np - set/get signal mask attribute in thread attr...
• pthread_attr_setstack - set/get stack attributes in thread attributes object
• pthread_attr_setstackaddr - set/get stack address attribute in thread att...
• pthread_attr_setstacksize - set/get stack size attribute in thread attrib...
• pthread_cancel - send a cancellation request to a thread
• pthread_cleanup_pop - push and pop thread cancellation clean-up handlers
• pthread_cleanup_pop_restore_np - push and pop thread cancellation clean-u...
• pthread_cleanup_push - push and pop thread cancellation clean-up handlers
• pthread_cleanup_push_defer_np - push and pop thread cancellation clean-up...
• pthread_create - create a new thread
• pthread_detach - detach a thread
• pthread_equal - compare thread IDs
• pthread_exit - terminate calling thread
• pthread_getaffinity_np - set/get CPU affinity of a thread
• pthread_getattr_default_np - get or set default thread-creation attributes
• pthread_getattr_np - get attributes of created thread
• pthread_getconcurrency - set/get the concurrency level
• pthread_getcpuclockid - retrieve ID of a thread's CPU time clock
• pthread_getname_np - set/get the name of a thread
• pthread_getschedparam - set/get scheduling policy and parameters of a thread
• pthread_join - join with a terminated thread
• pthread_kill_other_threads_np - terminate all other threads in process
• pthread_mutex_consistent - make a robust mutex consistent
• pthread_mutex_consistent_np - make a robust mutex consistent
• pthread_mutexattr_getpshared - get/set process-shared mutex attribute
• pthread_mutexattr_getrobust - get and set the robustness attribute of a m...
• pthread_mutexattr_getrobust_np - get and set the robustness attribute of ...
• pthread_mutexattr_setpshared - get/set process-shared mutex attribute
• pthread_mutexattr_setrobust - get and set the robustness attribute of a m...
• pthread_mutexattr_setrobust_np - get and set the robustness attribute of ...
• pthread_rwlockattr_getkind_np - set/get the read-write lock kind of the t...
• pthread_rwlockattr_setkind_np - set/get the read-write lock kind of the t...
• pthread_self - obtain ID of the calling thread
• pthread_setaffinity_np - set/get CPU affinity of a thread
• pthread_setattr_default_np - get or set default thread-creation attributes
• pthread_setcancelstate - set cancelability state and type
• pthread_setcanceltype - set cancelability state and type
• pthread_setconcurrency - set/get the concurrency level
• pthread_setname_np - set/get the name of a thread
• pthread_setschedparam - set/get scheduling policy and parameters of a thread
• pthread_setschedprio - set scheduling priority of a thread
• pthread_spin_destroy - initialize or destroy a spin lock
• pthread_spin_init - initialize or destroy a spin lock
• pthread_spin_lock - lock and unlock a spin lock
• pthread_spin_trylock - lock and unlock a spin lock
• pthread_spin_unlock - lock and unlock a spin lock
• pthread_testcancel - request delivery of any pending cancellation request
• pthread_timedjoin_np - try to join with a terminated thread
• pthread_tryjoin_np - try to join with a terminated thread
• pthread_yield - yield the processor

pwd.h

• fgetpwent_r - get passwd file entry reentrantly
• getpwent_r - get passwd file entry reentrantly

regex.h

• regcomp - POSIX regex functions
• regerror - POSIX regex functions
• regex - POSIX regex functions
• regexec - POSIX regex functions
• regfree - POSIX regex functions

sched.h

• __clone2 - create a child process
• clone - create a child process
• clone2 - create a child process
• clone3 - create a child process
• CPU_ALLOC - macros for manipulating CPU sets
• CPU_ALLOC_SIZE - macros for manipulating CPU sets
• CPU_AND - macros for manipulating CPU sets
• CPU_AND_S - macros for manipulating CPU sets
• CPU_CLR - macros for manipulating CPU sets
• CPU_CLR_S - macros for manipulating CPU sets
• CPU_COUNT - macros for manipulating CPU sets
• CPU_COUNT_S - macros for manipulating CPU sets
• CPU_EQUAL - macros for manipulating CPU sets
• CPU_EQUAL_S - macros for manipulating CPU sets
• CPU_FREE - macros for manipulating CPU sets
• CPU_ISSET - macros for manipulating CPU sets
• CPU_ISSET_S - macros for manipulating CPU sets
• CPU_OR - macros for manipulating CPU sets
• CPU_OR_S - macros for manipulating CPU sets
• CPU_SET - macros for manipulating CPU sets
• CPU_SET_S - macros for manipulating CPU sets
• CPU_XOR - macros for manipulating CPU sets
• CPU_XOR_S - macros for manipulating CPU sets
• CPU_ZERO - macros for manipulating CPU sets
• CPU_ZERO_S - macros for manipulating CPU sets
• sched_get_priority_max - get static priority range
• sched_get_priority_min - get static priority range
• sched_getaffinity - set and get a thread's CPU affinity mask
• sched_getattr - set and get scheduling policy and attributes
• sched_getcpu - determine CPU on which the calling thread is running
• sched_getparam - set and get scheduling parameters
• sched_getscheduler - set and get scheduling policy/parameters
• sched_rr_get_interval - get the SCHED_RR interval for the named process
• sched_setaffinity - set and get a thread's CPU affinity mask
• sched_setattr - set and get scheduling policy and attributes
• sched_setparam - set and get scheduling parameters
• sched_setscheduler - set and get scheduling policy/parameters
• sched_yield - yield the processor
• setns - reassociate thread with a namespace
• unshare - disassociate parts of the process execution context

search.h

• hcreate - hash table management
• hcreate_r - hash table management
• hdestroy - hash table management
• hdestroy_r - hash table management
• hsearch - hash table management
• hsearch_r - hash table management
• insque - insert/remove an item from a queue
• lfind - linear search of an array
• lsearch - linear search of an array
• remque - insert/remove an item from a queue
• tdelete - manage a binary search tree
• tdestroy - manage a binary search tree
• tfind - manage a binary search tree
• tsearch - manage a binary search tree
• twalk - manage a binary search tree
• twalk_r - manage a binary search tree

semaphore.h

• sem_close - close a named semaphore
• sem_destroy - destroy an unnamed semaphore
• sem_getvalue - get the value of a semaphore
• sem_init - initialize an unnamed semaphore
• sem_open - initialize and open a named semaphore
• sem_post - unlock a semaphore
• sem_timedwait - lock a semaphore
• sem_trywait - lock a semaphore
• sem_unlink - remove a named semaphore
• sem_wait - lock a semaphore

setjmp.h

• longjmp - performing a nonlocal goto
• setjmp - performing a nonlocal goto
• siglongjmp - performing a nonlocal goto
• sigsetjmp - performing a nonlocal goto

signal.h

• bsd_signal - signal handling with BSD semantics
• gsignal - software signal facility
• killpg - send signal to a process group
• pidfd_send_signal - send a signal to a process specified by a file descri...
• psiginfo - print signal description
• psignal - print signal description
• pthread_kill - send a signal to a thread
• pthread_sigmask - examine and change mask of blocked signals
• pthread_sigqueue - queue a signal and data to a thread
• raise - send a signal to the caller
• rt_sigaction - examine and change a signal action
• rt_sigpending - examine pending signals
• rt_sigprocmask - examine and change blocked signals
• rt_sigsuspend - wait for a signal
• rt_sigtimedwait - synchronously wait for queued signals
• sigaction - examine and change a signal action
• sigaddset - POSIX signal set operations
• sigaltstack - set and/or get signal stack context
• sigandset - POSIX signal set operations
• sigblock - BSD signal API
• sigdelset - POSIX signal set operations
• sigemptyset - POSIX signal set operations
• sigfillset - POSIX signal set operations
• siggetmask - BSD signal API
• sighold - System V signal API
• sigignore - System V signal API
• siginterrupt - allow signals to interrupt system calls
• sigisemptyset - POSIX signal set operations
• sigismember - POSIX signal set operations
• sigmask - BSD signal API
• signal - ANSI C signal handling
• sigorset - POSIX signal set operations
• sigpause - atomically release blocked signals and wait for interrupt
• sigpending - examine pending signals
• sigprocmask - examine and change blocked signals
• sigqueue - queue a signal and data to a process
• sigrelse - System V signal API
• sigset - System V signal API
• sigsetmask - BSD signal API
• sigsetops - POSIX signal set operations
• sigstack - set and/or get signal stack context
• sigsuspend - wait for a signal
• sigtimedwait - synchronously wait for queued signals
• sigvec - BSD signal API
• sigwait - wait for a signal
• sigwaitinfo - synchronously wait for queued signals
• ssignal - software signal facility
• sysv_signal - signal handling with System V semantics
• timer_create - create a POSIX per-process timer

spawn.h

• posix_spawn - spawn a process
• posix_spawnp - spawn a process

stdarg.h

• stdarg - variable argument lists
• va_arg - variable argument lists
• va_copy - variable argument lists
• va_end - variable argument lists
• va_start - variable argument lists

stddef.h

• offsetof - offset of a structure member
• wcstoimax - convert wide-character string to integer
• wcstoumax - convert wide-character string to integer

stdio.h

• __fbufsize - interfaces to stdio FILE structure
• __flbf - interfaces to stdio FILE structure
• __fpending - interfaces to stdio FILE structure
• __fpurge - purge a stream
• __freadable - interfaces to stdio FILE structure
• __freading - interfaces to stdio FILE structure
• __fsetlocking - interfaces to stdio FILE structure
• __fwritable - interfaces to stdio FILE structure
• __fwriting - interfaces to stdio FILE structure
• _flushlbf - interfaces to stdio FILE structure
• addmntent - get filesystem descriptor file entry
• asprintf - print to allocated string
• clearerr - check and reset stream status
• clearerr_unlocked - nonlocking stdio functions
• ctermid - get controlling terminal name
• dprintf - formatted output conversion
• endmntent - get filesystem descriptor file entry
• fclose - close a stream close a file
• fcloseall - close all open streams
• fdopen - stream open functions
• feof - check and reset stream status
• feof_unlocked - nonlocking stdio functions
• ferror - check and reset stream status
• ferror_unlocked - nonlocking stdio functions
• fflush - flush a stream
• fflush_unlocked - nonlocking stdio functions
• fgetc - input of characters and strings
• fgetc_unlocked - nonlocking stdio functions
• fgetgrent - get group file entry
• fgetpos - reposition a stream
• fgetpwent - get password file entry
• fgets - input of characters and strings
• fgets_unlocked - nonlocking stdio functions
• fgetwc - read a wide character from a FILE stream
• fgetwc_unlocked - nonlocking stdio functions
• fgetws_unlocked - nonlocking stdio functions
• fileno - check and reset stream status
• fileno_unlocked - nonlocking stdio functions
• flockfile - lock FILE for stdio
• fmemopen - open memory as stream
• fopen - stream open functions open a file
• fopencookie - opening a custom stream
• fprintf - formatted output conversion print to a file
• fpurge - purge a stream
• fputc - output of characters and strings
• fputc_unlocked - nonlocking stdio functions
• fputs - output of characters and strings
• fputs_unlocked - nonlocking stdio functions
• fputwc - write a wide character to a FILE stream
• fputwc_unlocked - nonlocking stdio functions
• fputws_unlocked - nonlocking stdio functions
• fread - binary stream input/output read bytes from a file
• fread_unlocked - nonlocking stdio functions
• freopen - stream open functions
• fscanf - input format conversion get input from a file
• fseek - reposition a stream
• fseeko - seek to or report file position
• fsetpos - reposition a stream
• ftell - reposition a stream
• ftello - seek to or report file position
• ftrylockfile - lock FILE for stdio
• funlockfile - lock FILE for stdio
• fwprintf - formatted wide-character output conversion
• fwrite - binary stream input/output write bytes to a file
• fwrite_unlocked - nonlocking stdio functions
• getc - input of characters and strings
• getc_unlocked - nonlocking stdio functions
• getchar - input of characters and strings
• getchar_unlocked - nonlocking stdio functions
• getdelim - delimited string input
• getline - delimited string input
• getmntent - get filesystem descriptor file entry
• getmntent_r - get filesystem descriptor file entry
• gets - get a string from standard input (DEPRECATED)
• getw - input and output of words (ints)
• getwc - read a wide character from a FILE stream
• getwc_unlocked - nonlocking stdio functions
• getwchar_unlocked - nonlocking stdio functions
• hasmntopt - get filesystem descriptor file entry
• open_memstream - open a dynamic memory buffer stream
• open_wmemstream - open a dynamic memory buffer stream
• pclose - pipe stream to or from a process
• perror - print a system error message
• popen - pipe stream to or from a process
• printf - formatted output conversion print to the screen
• putc - output of characters and strings
• putc_unlocked - nonlocking stdio functions
• putchar - output of characters and strings
• putchar_unlocked - nonlocking stdio functions
• putpwent - write a password file entry
• puts - output of characters and strings
• putw - input and output of words (ints)
• putwc - write a wide character to a FILE stream
• putwc_unlocked - nonlocking stdio functions
• putwchar_unlocked - nonlocking stdio functions
• remove - remove a file or directory
• rename - change the name or location of a file
• renameat - change the name or location of a file
• renameat2 - change the name or location of a file
• rewind - reposition a stream
• scanf - input format conversion get input from a user
• setbuf - stream buffering operations
• setbuffer - stream buffering operations
• setlinebuf - stream buffering operations
• setmntent - get filesystem descriptor file entry
• setvbuf - stream buffering operations
• snprintf - formatted output conversion
• sprintf - formatted output conversion print to a string
• sscanf - input format conversion
• stderr - standard I/O streams
• stdin - standard I/O streams
• stdio - standard input/output library functions
• stdio_ext - interfaces to stdio FILE structure
• stdout - standard I/O streams
• swprintf - formatted wide-character output conversion
• sys_errlist - print a system error message
• sys_nerr - print a system error message
• tempnam - create a name for a temporary file
• tmpfile - create a temporary file
• tmpnam - create a name for a temporary file
• tmpnam_r - create a name for a temporary file
• ungetc - input of characters and strings
• unlocked_stdio - nonlocking stdio functions
• vasprintf - print to allocated string
• vdprintf - formatted output conversion
• vfprintf - formatted output conversion
• vfscanf - input format conversion
• vfwprintf - formatted wide-character output conversion
• vprintf - formatted output conversion
• vscanf - input format conversion
• vsnprintf - formatted output conversion
• vsprintf - formatted output conversion
• vsscanf - input format conversion
• vswprintf - formatted wide-character output conversion
• vwprintf - formatted wide-character output conversion
• wprintf - formatted wide-character output conversion

stdlib.h

• a64l - convert between long and base-64
• abort - cause abnormal process termination
• abs - compute the absolute value of an integer
• aligned_alloc - allocate aligned memory
• atexit - register a function to be called at normal process ter...
• atof - convert a string to a double convert a string to a float
• atoi - convert a string to an integer convert a string to an int
• atol - convert a string to an integer convert a string to a long
• atoll - convert a string to an integer
• atoq - convert a string to an integer
• bsearch - binary search of a sorted array
• calloc - allocate and free dynamic memory
• canonicalize_file_name - return the canonicalized absolute pathname
• cfree - free allocated memory
• clearenv - clear the environment
• div - compute quotient and remainder of an integer division
• drand48 - generate uniformly distributed pseudo-random numbers
• drand48_r - generate uniformly distributed pseudo-random numbers r...
• ecvt - convert a floating-point number to a string
• ecvt_r - convert a floating-point number to a string
• erand48 - generate uniformly distributed pseudo-random numbers
• erand48_r - generate uniformly distributed pseudo-random numbers r...
• exit - cause normal process termination
• fcvt - convert a floating-point number to a string
• fcvt_r - convert a floating-point number to a string
• free - allocate and free dynamic memory free dynamically allocated memory
• gcvt - convert a floating-point number to a string
• getenv - get an environment variable
• getloadavg - get system load averages
• getpt - open a new pseudoterminal master
• getsubopt - parse suboption arguments from a string
• grantpt - grant access to the slave pseudoterminal
• imaxabs - compute the absolute value of an integer
• imaxdiv - compute quotient and remainder of an integer division
• initstate - random number generator
• initstate_r - reentrant random number generator
• jrand48 - generate uniformly distributed pseudo-random numbers
• jrand48_r - generate uniformly distributed pseudo-random numbers r...
• l64a - convert between long and base-64
• labs - compute the absolute value of an integer
• lcong48 - generate uniformly distributed pseudo-random numbers
• lcong48_r - generate uniformly distributed pseudo-random numbers r...
• ldiv - compute quotient and remainder of an integer division
• llabs - compute the absolute value of an integer
• lldiv - compute quotient and remainder of an integer division
• lrand48 - generate uniformly distributed pseudo-random numbers
• lrand48_r - generate uniformly distributed pseudo-random numbers r...
• malloc - allocate and free dynamic memory allocate memory dynamically
• MB_CUR_MAX - maximum length of a multibyte character in the current...
• mblen - determine number of bytes in next multibyte character
• mbstowcs - convert a multibyte string to a wide-character string
• mbtowc - convert a multibyte sequence to a wide character
• memalign - allocate aligned memory
• mkdtemp - create a unique temporary directory
• mkostemp - create a unique temporary file
• mkostemps - create a unique temporary file
• mkstemp - create a unique temporary file
• mkstemps - create a unique temporary file
• mktemp - make a unique temporary filename
• mrand48 - generate uniformly distributed pseudo-random numbers
• mrand48_r - generate uniformly distributed pseudo-random numbers r...
• nrand48 - generate uniformly distributed pseudo-random numbers
• nrand48_r - generate uniformly distributed pseudo-random numbers r...
• on_exit - register a function to be called at normal process ter...
• posix_memalign - allocate aligned memory
• posix_openpt - open a pseudoterminal device
• ptsname - get the name of the slave pseudoterminal
• ptsname_r - get the name of the slave pseudoterminal
• putenv - change or add an environment variable
• pvalloc - allocate aligned memory
• qecvt - convert a floating-point number to a string
• qecvt_r - convert a floating-point number to a string
• qfcvt - convert a floating-point number to a string
• qfcvt_r - convert a floating-point number to a string
• qgcvt - convert a floating-point number to a string
• qsort - sort an array
• qsort_r - sort an array
• rand - pseudo-random number generator
• rand_r - pseudo-random number generator
• random - random number generator generate a pseudorandom number
• random_r - reentrant random number generator
• realloc - allocate and free dynamic memory reallocate memory dynamically
• reallocarray - allocate and free dynamic memory
• rpmatch - determine if the answer to a question is affirmative o...
• secure_getenv - get an environment variable
• seed48 - generate uniformly distributed pseudo-random numbers
• seed48_r - generate uniformly distributed pseudo-random numbers r...
• setenv - change or add an environment variable
• setstate - random number generator
• setstate_r - reentrant random number generator
• srand - pseudo-random number generator
• srand48 - generate uniformly distributed pseudo-random numbers
• srand48_r - generate uniformly distributed pseudo-random numbers r...
• srandom - random number generator seed pseudorandom number generation
• srandom_r - reentrant random number generator
• strfromd - convert a floating-point value into a string
• strfromf - convert a floating-point value into a string
• strfroml - convert a floating-point value into a string
• strtod - convert ASCII string to floating-point number
• strtof - convert ASCII string to floating-point number
• strtol - convert a string to a long integer
• strtold - convert ASCII string to floating-point number
• strtoll - convert a string to a long integer
• strtoq - convert a string to a long integer
• strtoul - convert a string to an unsigned long integer
• strtoull - convert a string to an unsigned long integer
• strtouq - convert a string to an unsigned long integer
• system - execute a shell command
• unlockpt - unlock a pseudoterminal master/slave pair
• unsetenv - change or add an environment variable
• valloc - allocate aligned memory
• wcstombs - convert a wide-character string to a multibyte string
• wctomb - convert a wide character to a multibyte sequence

string.h

• bstring - byte string operations
• memccpy - copy memory area
• memchr - scan memory for a character
• memcmp - compare memory areas
• memcpy - copy memory area
• memfrob - frobnicate (encrypt) a memory area
• memmem - locate a substring
• memmove - copy memory area
• mempcpy - copy memory area
• memrchr - scan memory for a character
• memset - fill memory with a constant byte
• rawmemchr - scan memory for a character
• sigabbrev_np - return string describing signal
• sigdescr_np - return string describing signal
• stpcpy - copy a string returning a pointer to its end
• stpncpy - copy a fixed-size string, returning a pointer to its end
• strcasestr - locate a substring locate a substring
• strcat - concatenate two strings
• strchr - locate character in string
• strchrnul - locate character in string
• strcmp - compare two strings compare two strings
• strcoll - compare two strings using the current locale
• strcpy - copy a string copy a string
• strcspn - get length of a prefix substring
• strdup - duplicate a string
• strdupa - duplicate a string
• strerror - return string describing error number
• strerror_l - return string describing error number
• strerror_r - return string describing error number
• strerrordesc_np - return string describing error number
• strerrorname_np - return string describing error number
• strfry - randomize a string
• strlen - calculate the length of a string calculate the length of a string
• strncat - concatenate two strings
• strncmp - compare two strings
• strncpy - copy a string
• strndup - duplicate a string
• strndupa - duplicate a string
• strnlen - determine the length of a fixed-size string
• strpbrk - search a string for any of a set of bytes
• strrchr - locate character in string
• strsep - extract token from string
• strsignal - return string describing signal
• strspn - get length of a prefix substring
• strstr - locate a substring locate a substring
• strtok - extract tokens from strings
• strtok_r - extract tokens from strings
• strverscmp - compare two version strings
• strxfrm - string transformation
• sys_siglist - return string describing signal
• wmempcpy - copy memory area

strings.h

• bcmp - compare byte sequences
• bcopy - copy byte sequence
• bzero - zero a byte string
• explicit_bzero - zero a byte string
• ffs - find first bit set in a word
• ffsl - find first bit set in a word
• ffsll - find first bit set in a word
• index - locate character in string
• rindex - locate character in string
• strcasecmp - compare two strings ignoring case compare two strings ignoring case
• string - string operations
• strncasecmp - compare two strings ignoring case

sys/ipc.h

• shmctl - System V shared memory control
• shmget - allocates a System V shared memory segment

sys/mman.h

• madvise - give advice about use of memory
• memfd_create - create an anonymous file
• mlock - lock and unlock memory
• mlock2 - lock and unlock memory
• mlockall - lock and unlock memory
• mmap - map or unmap files or devices into memory
• mmap2 - map files or devices into memory
• mmap64 - map or unmap files or devices into memory
• mprotect - set protection on a region of memory
• mremap - remap a virtual memory address
• msync - synchronize a file with a memory map
• munlock - lock and unlock memory
• munlockall - lock and unlock memory
• munmap - map or unmap files or devices into memory
• pkey_alloc - allocate or free a protection key
• pkey_free - allocate or free a protection key
• pkey_mprotect - set protection on a region of memory
• posix_madvise - give advice about patterns of memory usage
• remap_file_pages - create a nonlinear file mapping
• shm_open - create/open or unlink POSIX shared memory objects
• shm_unlink - create/open or unlink POSIX shared memory objects

sys/select.h

• _newselect - synchronous I/O multiplexing
• FD_CLR - synchronous I/O multiplexing
• FD_ISSET - synchronous I/O multiplexing
• FD_SET - synchronous I/O multiplexing
• FD_ZERO - synchronous I/O multiplexing
• pselect - synchronous I/O multiplexing
• pselect6 - synchronous I/O multiplexing
• select - synchronous I/O multiplexing

sys/socket.h

• accept - accept a connection on a socket
• accept4 - accept a connection on a socket
• address_families - socket address families (domains)
• bind - bind a name to a socket
• cmsg - access ancillary data
• CMSG_ALIGN - access ancillary data
• CMSG_DATA - access ancillary data
• CMSG_FIRSTHDR - access ancillary data
• CMSG_LEN - access ancillary data
• CMSG_NXTHDR - access ancillary data
• CMSG_SPACE - access ancillary data
• connect - initiate a connection on a socket
• ddp - Linux AppleTalk protocol implementation
• getnameinfo - address-to-name translation in protocol-independent ma...
• getpeername - get name of connected peer socket
• getsockname - get socket name
• getsockopt - get and set options on sockets
• inet - Internet address manipulation routines
• inet_addr - Internet address manipulation routines
• inet_aton - Internet address manipulation routines
• inet_lnaof - Internet address manipulation routines
• inet_makeaddr - Internet address manipulation routines
• inet_netof - Internet address manipulation routines
• inet_network - Internet address manipulation routines
• inet_ntoa - Internet address manipulation routines
• ip - Linux IPv4 protocol implementation
• ipv6 - Linux IPv6 protocol implementation
• listen - listen for connections on a socket
• packet - packet interface on device level
• raw - Linux IPv4 raw sockets
• setsockopt - get and set options on sockets
• shutdown - shut down part of a full-duplex connection
• sock_diag - obtaining information about sockets
• sockatmark - determine whether socket is at out-of-band mark
• socket - create an endpoint for communication
• socket - Linux socket interface
• socketpair - create a pair of connected sockets
• tcp - TCP protocol
• udp - User Datagram Protocol for IPv4
• udplite - Lightweight User Datagram Protocol
• unix - sockets for local interprocess communication
• vsock - Linux VSOCK address family
• x25 - ITU-T X.25 / ISO-8208 protocol interface

sys/stat.h

• chmod - change permissions of a file
• fchmod - change permissions of a file
• fchmodat - change permissions of a file
• isfdtype - test file type of a file descriptor
• mkdir - create a directory
• mkdirat - create a directory

sys/statvfs.h

• fstatvfs - get filesystem statistics
• statvfs - get filesystem statistics

sys/time.h

• adjtime - correct the time to synchronize the system clock
• futimes - change file timestamps
• getitimer - get or set value of an interval timer
• getpriority - get/set program scheduling priority
• getrlimit - get/set resource limits
• getrusage - get resource usage
• gettimeofday - get / set time
• lutimes - change file timestamps
• prlimit - get/set resource limits
• prlimit64 - get/set resource limits
• setitimer - get or set value of an interval timer
• setpriority - get/set program scheduling priority
• setrlimit - get/set resource limits
• settimeofday - get / set time
• timeradd - timeval operations
• timerclear - timeval operations
• timercmp - timeval operations
• timerisset - timeval operations
• timersub - timeval operations
• ugetrlimit - get/set resource limits
• vlimit - get/set resource limits
• vtimes - get resource usage

sys/times.h

• times - get process times

sys/types.h

• _llseek - reposition read/write file offset
• add_key - add a key to the kernel's key management facility
• bindresvport - bind a socket to a privileged IP port
• closedir - close a directory
• creat - open and possibly create a file
• db - database access methods
• dbopen - database access methods
• dirfd - get directory stream file descriptor
• endgrent - get group file entry
• endpwent - get password file entry
• fdopendir - open a directory
• fgetxattr - retrieve an extended attribute value
• flistxattr - list extended attribute names
• fork - create a child process
• freeaddrinfo - network address and service translation
• freehostent - get network hostnames and addresses
• freeifaddrs - get interface addresses
• fremovexattr - remove an extended attribute
• fsetxattr - set an extended attribute value
• fstat - get file status
• fstat64 - get file status
• fstatat - get file status
• fstatat64 - get file status
• ftok - convert a pathname and a project identifier to a Syste...
• fts - traverse a file hierarchy
• fts_children - traverse a file hierarchy
• fts_close - traverse a file hierarchy
• fts_open - traverse a file hierarchy
• fts_read - traverse a file hierarchy
• fts_set - traverse a file hierarchy
• gai_strerror - network address and service translation
• getaddrinfo - network address and service translation
• getgrent - get group file entry
• getgrgid - get group file entry
• getgrgid_r - get group file entry
• getgrnam - get group file entry
• getgrnam_r - get group file entry
• getgroups - get/set list of supplementary group IDs
• getgroups32 - get/set list of supplementary group IDs
• getifaddrs - get interface addresses
• getipnodebyaddr - get network hostnames and addresses
• getipnodebyname - get network hostnames and addresses
• getpgid - set/get process group
• getpgrp - set/get process group
• getpid - get process identification
• getppid - get process identification
• getpw - reconstruct password line entry
• getpwent - get password file entry
• getpwnam - get password file entry
• getpwnam_r - get password file entry
• getpwuid - get password file entry
• getpwuid_r - get password file entry
• getsid - get session ID
• getumask - get file creation mask
• getxattr - retrieve an extended attribute value
• initgroups - initialize the supplementary group access list
• keyctl - manipulate the kernel's key management facility
• kill - send signal to a process
• lgetxattr - retrieve an extended attribute value
• listxattr - list extended attribute names
• llistxattr - list extended attribute names
• llseek - reposition read/write file offset
• lremovexattr - remove an extended attribute
• lseek - reposition read/write file offset
• lseek64 - reposition 64-bit read/write file offset
• lsetxattr - set an extended attribute value
• lstat - get file status
• lstat64 - get file status
• mkfifo - make a FIFO special file (a named pipe)
• mkfifoat - make a FIFO special file (a named pipe)
• mknod - create a special or ordinary file
• mknodat - create a special or ordinary file
• modify_ldt - get or set a per-process LDT entry
• mq_getsetattr - get/set message queue attributes
• msgctl - System V message control operations
• msgget - get a System V message queue identifier
• msgop - System V message queue operations
• msgrcv - System V message queue operations
• msgsnd - System V message queue operations
• name_to_handle_at - obtain handle for a pathname and open file via a handle
• newfstatat - get file status
• oldfstat - get file status
• oldlstat - get file status
• oldstat - get file status
• open - open and possibly create a file
• open_by_handle_at - obtain handle for a pathname and open file via a handle
• openat - open and possibly create a file
• openat2 - open and possibly create a file (extended)
• opendir - open a directory
• pidfd_open - obtain a file descriptor that refers to a process
• re_comp - BSD regex functions
• re_exec - BSD regex functions
• recv - receive a message from a socket
• recvfrom - receive a message from a socket
• recvmsg - receive a message from a socket
• removexattr - remove an extended attribute
• request_key - request a key from the kernel's key management facility
• rewinddir - reset directory stream
• semctl - System V semaphore control operations
• semget - get a System V semaphore set identifier
• semop - System V semaphore operations
• semtimedop - System V semaphore operations
• send - send a message on a socket
• sendmsg - send a message on a socket
• sendto - send a message on a socket
• setegid - set effective user or group ID
• seteuid - set effective user or group ID
• setgid - set group identity
• setgid32 - set group identity
• setgrent - get group file entry
• setgroups - get/set list of supplementary group IDs
• setgroups32 - get/set list of supplementary group IDs
• setpgid - set/get process group
• setpgrp - set/get process group
• setpwent - get password file entry
• setregid - set real and/or effective user or group ID
• setregid32 - set real and/or effective user or group ID
• setreuid - set real and/or effective user or group ID
• setreuid32 - set real and/or effective user or group ID
• setsid - creates a session and sets the process group ID
• setuid - set user identity
• setuid32 - set user identity
• setxattr - set an extended attribute value
• shmat - System V shared memory operations
• shmdt - System V shared memory operations
• shmop - System V shared memory operations
• spu_create - create a new spu context
• stat - get file status
• stat64 - get file status
• statx - get file status (extended)
• umask - set file mode creation mask
• userfaultfd - create a file descriptor for handling page faults in u...
• ustat - get filesystem statistics
• utime - change file last access and modification times
• utimes - change file last access and modification times
• vfork - create a child process and block parent
• wait - wait for process to change state
• wait3 - wait for process to change state, BSD style
• wait4 - wait for process to change state, BSD style
• waitid - wait for process to change state
• waitpid - wait for process to change state

sys/uio.h

• preadv - read or write data into multiple buffers
• preadv2 - read or write data into multiple buffers
• process_vm_readv - transfer data between process address spaces
• process_vm_writev - transfer data between process address spaces
• pwritev - read or write data into multiple buffers
• pwritev2 - read or write data into multiple buffers
• readv - read or write data into multiple buffers
• writev - read or write data into multiple buffers

sys/utsname.h

• oldolduname - get name and information about current kernel
• olduname - get name and information about current kernel
• uname - get name and information about current kernel

syslog.h

• closelog - send messages to the system logger
• openlog - send messages to the system logger
• setlogmask - set log priority mask
• syslog - send messages to the system logger
• vsyslog - send messages to the system logger

termios.h

• cfgetispeed - get and set terminal attributes, line control, get and...
• cfgetospeed - get and set terminal attributes, line control, get and...
• cfmakeraw - get and set terminal attributes, line control, get and...
• cfsetispeed - get and set terminal attributes, line control, get and...
• cfsetospeed - get and set terminal attributes, line control, get and...
• cfsetspeed - get and set terminal attributes, line control, get and...
• ioctl_tty - ioctls for terminals and serial lines
• tcdrain - get and set terminal attributes, line control, get and...
• tcflow - get and set terminal attributes, line control, get and...
• tcflush - get and set terminal attributes, line control, get and...
• tcgetattr - get and set terminal attributes, line control, get and...
• tcgetsid - get session ID
• tcsendbreak - get and set terminal attributes, line control, get and...
• tcsetattr - get and set terminal attributes, line control, get and...
• termios - get and set terminal attributes, line control, get and...
• tty_ioctl - ioctls for terminals and serial lines

time.h

• asctime - transform date and time to broken-down time or ASCII
• asctime_r - transform date and time to broken-down time or ASCII
• clock - determine processor time
• clock_getcpuclockid - obtain ID of a process CPU-time clock
• clock_getres - clock and time functions
• clock_gettime - clock and time functions
• clock_nanosleep - high-resolution sleep with specifiable clock
• clock_settime - clock and time functions
• ctime - transform date and time to broken-down time or ASCII
• ctime_r - transform date and time to broken-down time or ASCII
• daylight - initialize time conversion information
• difftime - calculate time difference
• dysize - get number of days for a given year
• getdate - convert a date-plus-time string to broken-down time
• getdate_err - convert a date-plus-time string to broken-down time
• getdate_r - convert a date-plus-time string to broken-down time
• gmtime - transform date and time to broken-down time or ASCII
• gmtime_r - transform date and time to broken-down time or ASCII
• localtime - transform date and time to broken-down time or ASCII
• localtime_r - transform date and time to broken-down time or ASCII
• mktime - transform date and time to broken-down time or ASCII
• nanosleep - high-resolution sleep
• stime - set time
• strftime - format date and time
• strptime - convert a string representation of time to a time tm s...
• time - get time in seconds get time in seconds
• timegm - inverses of gmtime and localtime
• timelocal - inverses of gmtime and localtime
• timer_delete - delete a POSIX per-process timer
• timer_getoverrun - get overrun count for a POSIX per-process timer
• timer_gettime - arm/disarm and fetch state of POSIX per-process timer
• timer_settime - arm/disarm and fetch state of POSIX per-process timer
• timezone - initialize time conversion information
• tzname - initialize time conversion information
• tzset - initialize time conversion information

ulimit.h

• ulimit - get and set user limits

unistd.h

• _Exit - terminate the calling process
• _exit - terminate the calling process
• _sysctl - read/write system parameters
• access - check user's permissions for a file
• acct - switch process accounting on or off
• alarm - set an alarm clock for delivery of a signal
• brk - change data segment size
• chdir - change working directory
• chown - change ownership of a file
• chown32 - change ownership of a file
• chroot - change root directory
• close - close a file descriptor
• confstr - get configuration dependent string variables
• copy_file_range - Copy a range of data from one file to another
• cuserid - get username
• daemon - run in the background
• dup - duplicate a file descriptor
• dup2 - duplicate a file descriptor
• dup3 - duplicate a file descriptor
• eaccess - check effective user's permissions for a file
• encrypt - encrypt 64-bit messages
• encrypt_r - encrypt 64-bit messages
• endusershell - get permitted user shells
• euidaccess - check effective user's permissions for a file
• exec - execute a file
• execl - execute a file
• execle - execute a file
• execlp - execute a file
• execv - execute a file
• execve - execute program
• execveat - execute program relative to a directory file descriptor
• execvp - execute a file
• execvpe - execute a file
• exit - terminate the calling process
• faccessat - check user's permissions for a file
• faccessat2 - check user's permissions for a file
• fchdir - change working directory
• fchown - change ownership of a file
• fchown32 - change ownership of a file
• fchownat - change ownership of a file
• fcntl - manipulate file descriptor
• fcntl64 - manipulate file descriptor
• fdatasync - synchronize a file's in-core state with storage device
• fexecve - execute program specified via file descriptor
• fpathconf - get configuration values for files
• fsync - synchronize a file's in-core state with storage device
• ftruncate - truncate a file to a specified length
• ftruncate64 - truncate a file to a specified length
• get_current_dir_name - get current working directory
• getcwd - get current working directory
• getcwd - get current working directory
• getdomainname - get/set NIS domain name
• getdtablesize - get file descriptor table size
• getegid - get group identity
• getegid32 - get group identity
• getentropy - fill a buffer with random bytes
• geteuid - get user identity
• geteuid32 - get user identity
• getgid - get group identity
• getgid32 - get group identity
• gethostid - get or set the unique identifier of the current host
• gethostname - get/set hostname
• getlogin - get username
• getlogin_r - get username
• getopt - Parse command-line options
• getopt_long - Parse command-line options
• getopt_long_only - Parse command-line options
• getpagesize - get memory page size
• getpass - get a password
• getresgid - get real, effective and saved user/group IDs
• getresgid32 - get real, effective and saved user/group IDs
• getresuid - get real, effective and saved user/group IDs
• getresuid32 - get real, effective and saved user/group IDs
• gettid - get thread identification
• getuid - get user identity
• getuid32 - get user identity
• getusershell - get permitted user shells
• getwd - get current working directory
• group_member - test whether a process is in a group
• idle - make process 0 idle
• isatty - test whether a file descriptor refers to a terminal
• lchown - change ownership of a file
• lchown32 - change ownership of a file
• link - make a new name for a file
• linkat - make a new name for a file
• lockf - apply, test or remove a POSIX lock on an open file
• mincore - determine whether pages are resident in memory
• nice - change process priority
• optarg - Parse command-line options
• opterr - Parse command-line options
• optind - Parse command-line options
• optopt - Parse command-line options
• pathconf - get configuration values for files
• pause - wait for signal
• pipe - create pipe
• pipe2 - create pipe
• pread - read from or write to a file descriptor at a given offset
• pread64 - read from or write to a file descriptor at a given offset
• profil - execution time profile
• pwrite - read from or write to a file descriptor at a given offset
• pwrite64 - read from or write to a file descriptor at a given offset
• read - read from a file descriptor
• readlink - read value of a symbolic link
• readlinkat - read value of a symbolic link
• reboot - reboot or enable/disable Ctrl-Alt-Del
• rmdir - delete a directory
• sbrk - change data segment size
• setdomainname - get/set NIS domain name
• sethostid - get or set the unique identifier of the current host
• sethostname - get/set hostname
• setkey - encrypt 64-bit messages
• setkey_r - encrypt 64-bit messages
• setresgid - set real, effective and saved user or group ID
• setresgid32 - set real, effective and saved user or group ID
• setresuid - set real, effective and saved user or group ID
• setresuid32 - set real, effective and saved user or group ID
• setup - setup devices and filesystems, mount root filesystem
• setusershell - get permitted user shells
• sleep - sleep for a specified number of seconds
• swab - swap adjacent bytes
• swapoff - start/stop swapping to file/device
• swapon - start/stop swapping to file/device
• symlink - make a new name for a file
• symlinkat - make a new name for a file
• sync - commit filesystem caches to disk
• syncfs - commit filesystem caches to disk
• syscall - indirect system call
• sysconf - get configuration information at run time
• sysctl - read/write system parameters
• tcgetpgrp - get and set terminal foreground process group
• tcsetpgrp - get and set terminal foreground process group
• truncate - truncate a file to a specified length
• truncate64 - truncate a file to a specified length
• ttyname - return name of a terminal
• ttyname_r - return name of a terminal
• ualarm - schedule signal after given number of microseconds
• unlink - delete a name and possibly the file it refers to
• unlinkat - delete a name and possibly the file it refers to
• uselib - load shared library
• usleep - suspend execution for microsecond intervals
• vhangup - virtually hangup the current terminal
• write - write to a file descriptor

utmpx.h

• getutmp - copy utmp structure to utmpx, and vice versa
• getutmpx - copy utmp structure to utmpx, and vice versa

wchar.h

• btowc - convert single byte to wide character
• fgetws - read a wide-character string from a FILE stream
• fputws - write a wide-character string to a FILE stream
• fwide - set and determine the orientation of a FILE stream
• getwchar - read a wide character from standard input
• mbrlen - determine number of bytes in next multibyte character
• mbrtowc - convert a multibyte sequence to a wide character
• mbsinit - test for initial shift state
• mbsnrtowcs - convert a multibyte string to a wide-character string
• mbsrtowcs - convert a multibyte string to a wide-character string
• putwchar - write a wide character to standard output
• ungetwc - push back a wide character onto a FILE stream
• wcpcpy - copy a wide-character string, returning a pointer to i...
• wcpncpy - copy a fixed-size string of wide characters, returning...
• wcrtomb - convert a wide character to a multibyte sequence
• wcscasecmp - compare two wide-character strings, ignoring case
• wcscat - concatenate two wide-character strings
• wcschr - search a wide character in a wide-character string
• wcscmp - compare two wide-character strings
• wcscpy - copy a wide-character string
• wcscspn - search a wide-character string for any of a set of wid...
• wcsdup - duplicate a wide-character string
• wcslen - determine the length of a wide-character string
• wcsncasecmp - compare two fixed-size wide-character strings, ignorin...
• wcsncat - concatenate two wide-character strings
• wcsncmp - compare two fixed-size wide-character strings
• wcsncpy - copy a fixed-size string of wide characters
• wcsnlen - determine the length of a fixed-size wide-character st...
• wcsnrtombs - convert a wide-character string to a multibyte string
• wcspbrk - search a wide-character string for any of a set of wid...
• wcsrchr - search a wide character in a wide-character string
• wcsrtombs - convert a wide-character string to a multibyte string
• wcsspn - advance in a wide-character string, skipping any of a ...
• wcsstr - locate a substring in a wide-character string
• wcstok - split wide-character string into tokens
• wcswidth - determine columns needed for a fixed-size wide-charact...
• wctob - try to represent a wide character as a single byte
• wcwidth - determine columns needed for a wide character
• wmemchr - search a wide character in a wide-character array
• wmemcmp - compare two arrays of wide-characters
• wmemcpy - copy an array of wide-characters
• wmemmove - copy an array of wide-characters
• wmemset - fill an array of wide-characters with a constant wide ...

wctype.h

• iswalnum - test for alphanumeric wide character
• iswalpha - test for alphabetic wide character
• iswblank - test for whitespace wide character
• iswcntrl - test for control wide character
• iswctype - wide-character classification
• iswdigit - test for decimal digit wide character
• iswgraph - test for graphic wide character
• iswlower - test for lowercase wide character
• iswprint - test for printing wide character
• iswpunct - test for punctuation or symbolic wide character
• iswspace - test for whitespace wide character
• iswupper - test for uppercase wide character
• iswxdigit - test for hexadecimal digit wide character
• towctrans - wide-character transliteration
• towlower - convert a wide character to lowercase
• towlower_l - convert a wide character to lowercase
• towupper - convert a wide character to uppercase
• towupper_l - convert a wide character to uppercase
• wctrans - wide-character translation mapping
• wctype - wide-character classification

wordexp.h

• wordexp - perform word expansion like a posix-shell
• wordfree - perform word expansion like a posix-shell