Manual pages for the C standard library and the Noobs Library for those less comfortable.

feeling less comfortable

assert.h

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

ctype.h

• isalnum - character classification functions checks whether a character is alphanumeric
• isalnum_l - character classification functions
• isalpha - character classification functions checks whether a character is alphabetical
• isalpha_l - character classification functions
• isascii - character classification functions
• isascii_l - character classification functions
• isblank - character classification functions
• isblank_l - character classification functions
• iscntrl - character classification functions
• iscntrl_l - character classification functions
• isdigit - character classification functions checks whether a character is a digit
• isdigit_l - character classification functions
• isgraph - character classification functions
• isgraph_l - character classification functions
• islower - character classification functions checks whether a character is lowercase
• islower_l - character classification functions
• isprint - character classification functions
• isprint_l - character classification functions
• ispunct - character classification functions
• ispunct_l - character classification functions
• isspace - character classification functions checks whether a character is whitespace
• isspace_l - character classification functions
• isupper - character classification functions checks 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 uppercase or lowercase
• tolower_l - convert uppercase or lowercase
• toupper - convert uppercase or lowercase convert uppercase or lowercase
• 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 directory stream.
• telldir - return current location in directory stream
• versionsort - scan a directory for matching entries

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

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 glob()
• globfree - find pathnames matching a pattern, free memory from glob()

inttypes.h

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

libgen.h

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

limits.h

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

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 than argument ceiling function: smallest integral value not less than argument
• ceilf - ceiling function: smallest integral value not less than argument
• ceill - ceiling function: smallest integral value not less than argument
• 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 largest integral value not greater than argument
• 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 integral components
• frexpf - convert floating-point number to fractional and integral components
• frexpl - convert floating-point number to fractional and integral components
• 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 base-2 logarithmic function
• 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 floating-point number
• modff - extract signed integral and fractional values from floating-point number
• modfl - extract signed integral and fractional values from floating-point number
• 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/negative infinity
• nextdownf - return next floating-point number toward positive/negative infinity
• nextdownl - return next floating-point number toward positive/negative infinity
• nexttoward - floating-point number manipulation
• nexttowardf - floating-point number manipulation
• nexttowardl - floating-point number manipulation
• nextup - return next floating-point number toward positive/negative infinity
• nextupf - return next floating-point number toward positive/negative infinity
• nextupl - return next floating-point number toward positive/negative infinity
• pow - power functions raises 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 to nearest integer, away from zero
• 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 radix (OBSOLETE)
• scalbf - multiply floating-point number by integral power of radix (OBSOLETE)
• scalbl - multiply floating-point number by integral power of radix (OBSOLETE)
• 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 square root function
• 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

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 tree
• tdestroy - manage a binary tree
• tfind - manage a binary tree
• tsearch - manage a binary tree
• twalk - manage a binary tree

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

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 stream
• fcloseall - close all open streams
• fdopen - stream open functions
• feof - check and reset stream status check and reset stream status
• feof_unlocked - nonlocking stdio functions
• ferror - check and reset stream status 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 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 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 stream open functions
• fopencookie - opening a custom stream
• fprintf - formatted output conversion formatted output conversion
• fpurge - purge a stream
• fputc - output of characters and strings 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 binary stream input/output
• fread_unlocked - nonlocking stdio functions
• freopen - stream open functions
• fscanf - input format conversion
• fseek - reposition a stream 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 binary stream input/output
• 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 formatted output conversion
• 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 input format conversion
• 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 formatted output conversion
• 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 termination
• atof - convert a string to a double convert a string to a double
• atoi - convert a string to an integer convert a string to an integer
• atol - convert a string to an integer convert a string to an integer
• atoll - convert a string to an integer 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 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 reentrantly
• 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 reentrantly
• 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 allocate and free dynamic memory
• gcvt - convert a floating-point number to a string
• getenv - get an environment variable
• getloadavg - get system load averages
• getpt - open the pseudoterminal master (PTM)
• 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 reentrantly
• 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 reentrantly
• 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 reentrantly
• malloc - allocate and free dynamic memory allocate and free dynamic memory
• MB_CUR_MAX - maximum length of a multibyte character in the current locale
• 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 reentrantly
• nrand48 - generate uniformly distributed pseudo-random numbers
• nrand48_r - generate uniformly distributed pseudo-random numbers reentrantly
• on_exit - register a function to be called at normal process termination
• 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 random number generator
• random_r - reentrant random number generator
• realloc - allocate and free dynamic memory allocate and free dynamic memory
• rpmatch - determine if the answer to a question is affirmative or negative
• secure_getenv - get an environment variable
• seed48 - generate uniformly distributed pseudo-random numbers
• seed48_r - generate uniformly distributed pseudo-random numbers reentrantly
• 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 reentrantly
• srandom - random number generator random number generator
• 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
• 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
• 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
• 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/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
• fstatvfs - get filesystem statistics
• statvfs - 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

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_getres - clock and time functions
• clock_gettime - clock and time functions
• clock_gettime - clock and time functions
• clock_nanosleep - high-resolution sleep with specifiable clock
• clock_settime - clock and time functions
• 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 structure
• time - 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