C standard library
The C library is a system library that contains common C language subroutines for file access, string operators, character operations, memory allocation, and other functions.
Library Functions
| Header | Function | Extension | |
|---|---|---|---|
| assert.h | assert | Diagnostic message | |
| complex.h | Complex arithmetics | C99 | |
| cacos, casin, catan, ccos, csin, ctan | Trigonometric | ||
| cacosh, casinh, catanh, ccosh, csinh, ctanh | Hyperbolic | ||
| cexp, clog | Exponential and logarithmic | ||
| cabs, cpow, csqrt | Power and absolute value | ||
| carg, cproj | Manipulation | ||
| conio.h | _cgets | Character read | |
| _cprintf | Character print | ||
| _cputs | String write | ||
| _cscanf | Read from keyboard | ||
| ctype.h | isalnum | ||
| isalpha | |||
| isblank | |||
| iscntrl | |||
| isdigit | |||
| isgraph | |||
| islower | |||
| isprint | |||
| ispunct | |||
| isspace | |||
| isupper | |||
| isxdigit | |||
| tolower | |||
| toupper | |||
| direct.h | chdir | Change directory | |
| _chdrive | Change drive | ||
| errno.h | Errors | ||
| fenv.h | Floating point environment | C99 | |
| iconv.h | iconv_close | Remove conversion description | XPG4 |
| iconv_close | Create conversion description | XPG4 | |
| inttypes.h | Integer types format conversion | C99 | |
| io.h | access | Access mode determination | |
| chmod | Change file permission | ||
| _chsize | Change file length | ||
| close | Close file handle | ||
| creat | Create file | ||
| dup | Duplicate file handle | ||
| dup2 | Second handle for open file | ||
| __eof | End of file determination | ||
| _filelength | File length determination | ||
| isatty, _isatty | Character device determination | X/Open | |
| lseek | File pointer movement | ||
| open | File open | ||
| read | File read | ||
| _tell | File pointer position | ||
| umask | File permission mask setting | ||
| write | Write from buffer to file | ||
| langinfo.h | nl_langinfo | Retrieve locale info | XPG4 |
| locale.h | localeconv | Locale information from environment | |
| math.h | acos | Arccosine | |
| asin | Arcsine | ||
| atan, atan2 | Arctangent | ||
| _j0, j1, _jn _y0, _y1, _yn |
Bessel | ||
| ceil | Find integer greater or equal | ||
| cos | Cosine | ||
| cosh | Cosine hyperbolic | ||
| erf, erfc | Error functions | ||
| exp | Exponential | ||
| fabs | Absolute value of floating-point | ||
| floor | Find integer smaller or equal | ||
| fmod | Remainder of floating-point | ||
| frexp | Floating-point value separation | ||
| gamma | Gamma | SAA | |
| hypot | Hypotenuse | ||
| ldexp | Power of 2 | ||
| log | Natural logarithm | ||
| log10 | Decimal logarithm | ||
| _matherr | Math library error processing | ||
| modf | Floating-point value separation | ||
| pow | Power | ||
| sin | Sine | ||
| sinh | Sine hyperbolic | ||
| sqrt | Square root | ||
| tan | Tangent | ||
| tanh | Tangent hyperbolic | ||
| monetary.h | strfmon | Monetary value format | XPG4 |
| nl_types.h | catclose | Message catalogue close | |
| catgets | Message catalogue retrieval | ||
| catgets | Message catalogue open | ||
| process.h | _cwait | Child process wait | |
| execl | Child process execution | ||
| search.h | lfind | Find key in array | |
| stdio.h | clearerr | Error indicator reset | |
| fclose | Stream close | ||
| _fcloseall | All open streams close | ||
| fdopen | I/O association with file | ||
| feof | EOF indicator test | ||
| ferror | Read/write error test | ||
| fflush | Buffer write to file | ||
| fgets | Byte read | ||
| fgetpos | File position | ||
| fgets | String read | ||
| fgetwc | Wide character read from stream | ||
| fgetws | Wide char string read from stream | ||
| fileno | File handle determination | ||
| _flushall | Buffers write to files | ||
| fopen | File open | ||
| fprintf | Formatted data write to stream | ||
| fputc | Byte write | ||
| fputs | String write | ||
| fputwc | Wide character write | ||
| fputws | Wide char string write | ||
| fread | Stream read | ||
| stdlib.h | abort | stop | |
| abs | Absolute value of integer | ||
| atexit | Record program termination | ||
| atof | Character string to float conversion | ||
| atoi | Character string to integer conversion | ||
| atol | Character string to long integer conversion | ||
| _atold | Character string to long double conversion | ||
| _beginthread | New thread creation | ||
| bsearch | Array search | ||
| calloc | Storage space reservation | ||
| div | Quotient and remainder | ||
| _ecvt | Floating-point to character conversion | ||
| _endthread | Thread termination | ||
| exit | Program exit | ||
| _exit | Process end | ||
| _fcvt | Floating-point to string conversion | ||
| labs | Absolute value of long integer | ||
| ldiv | Long division | ||
| time.h | asctime | Time to character string conversion | |
| clock | Processor time | ||
| ctime | Time to character string conversion | ||
| difftime | Time difference | ||
| gmtime | Time structure | ||
| localtime | Time conversion | ||
| mktime | Time conversion | ||
| strftime | Time conversion | ||
| time | Time determination |
Header files
- C90
- assert.h - assert macro
- ctype.h - character types
- errno.h - error testing
- float.h - floating point
- limits.h - macro constants
- locale.h - localisation
- math.h - mathematical
- setjmp.h - declaration of setjmp & longjmp
- signal.h - signal handling
- stdarg.h - argument handling
- stddef.h - types and macros
- stdio.h - core input/output
- stdlib.h - numeric conversion, memory allocation, process control
- string.h - string handling
- time.h - date and time handling
Normative Addendum 1
- iso646.h - ISO646 charset
- wchar.h - wide character
- wctype.h - wide character types
- C99
- complex.h - complex numbers
- fenv.h - floating-point environment
- inttypes.h - exact width integer types
- stdbool.h - boolean data type
- stdint.h -
- tgmath.h - type-generic mathematical
- C11
- stdalign.h - object alignment
- stdatomic.h - atomic operations
- stdnoreturn.h - non-returning functions
- threads.h - thread management
- uchar.h - Unicode character handling
Publications
- SAA CPI C Reference - Level 2, SC09-1308