List of C functions

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The predefined functions used in the C standard library, and a few of the non-standard functions, include:

• assert.h

assert (macro)

• complex.h

cabs cacos [disambiguation needed] cacosh carg casin [disambiguation needed] casinh catan [disambiguation needed] catanh

ccos ccosh cexp cimag cis (non-standard) clog [disambiguation needed] conj cpow

cproj creal csin csinh csqrt ctan ctanh

• ctype.h

digittoint (non-standard) isalnum isalpha isascii (non-standard) isblank iscntrl

isdigit isgraph islower isprint ispunct isspace

isupper isxdigit toascii (non-standard) tolower toupper

• errno.h

(no functions)

• float.h

(no functions)

• inttypes.h

imaxabs imaxdiv

strtoimax strtoumax

wcstoimax wcstoumax

• iso646.h

(no functions)

• limits.h

(no functions)

• locale.h

localeconv

setlocale

• math.h

acos asin atan atan2 atof ceil cos cosh

exp fabs floor frexp ldexp log log10

modf pow sin sinh sqrt tan tanh

• netdb.h

getaddrinfo

getnameinfo

• setjmp.h

longjmp, setjmp

• signal.h

raise

• stdarg.h

va_arg (macro)

va_copy (macro)

va_end (macro)

va_start (macro)

• stddef.h

offsetof (macro)

• stdio.h

clearerr fclose feof ferror fflush fgetc fgetpos fgets fopen, freopen, fdopen (non-standard) fprintf fputc fputs fread

fscanf fseek fsetpos ftell fwrite getc (macro) getchar (macro) gets perror printf, fprintf, sprintf, snprintf (non-standard) putc (macro) putchar, fputchar (non-standard) (macro)

puts remove rename rewind scanf, fscanf, sscanf, vfscanf (non-standard), vscanf, vsscanf setbuf setvbuf tmpfile tmpnam ungetc vprintf, vfprintf, vsprintf

• stdlib.h

abort abs, labs atexit atof atoi atol bsearch div, ldiv

exit free itoa (non-standard) getenv ldiv ltoa (non-standard) malloc, calloc, and realloc qsort

rand srand strtod strtol strtoul system

• string.h

memchr memcmp memcpy memmove memset strcat, strncat strchr

strcmp, strncmp strcoll strcpy, strncpy strcspn strerror strlen strpbrk

strrchr strspn strstr strtok strxfrm

• time.h

asctime clock ctime difftime gmtime

localtime mktime strftime time

• wchar.h

btowc fgetwc fgetws fputwc fputws fwide fwprintf fwscanf getwc (macro) getwchar (macro) mbrlen mbrtowc mbsinit mbsrtowcs putwc (macro) putwchar (macro) swprintf swscanf

ungetwc vfwprintf vswprintf vwprintf wcrtomb wcscat wcschr wcscmp wcscoll wcscpy wcscspn wcsftime wcslen wcsncat wcsncmp wcsncpy wcspbrk wcsrchr

wcsrtombs wcsspn wcsstr wcstod wcstok wcstol wcstoul wcsxfrm wctob wmemchr wmemcmp wmemcpy wmemmove wmemset wprintf wscanf

• wctype.h

iswalnum iswalpha iswcntrl iswctype iswdigit iswgraph

iswlower iswprint iswpunct iswspace iswupper iswxdigit

towctrans towlower towupper wctrans wctype

Non-standard headers

• alloc.h

farmalloc

• conio.h

getch, getche, gotoxy

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