FunctionSystem Include FileFunction PrototypeDescription
abortstdlib.hvoid abort(void);Stops a program abnormally.
absstdlib.hint abs(int n);Calculates the absolute value of an integer argument n.
acosmath.hdouble acos(double x);Calculates the arc cosine of x.
asctimetime.hchar *asctime(const struct tm *time);Converts the time that is stored as a structure to a character string.
asctime_rtime.hchar *asctime_r (const struct tm *tm, char *buf);Converts tm that is stored as a structure to a character string. (Restartable version of asctime.)
asinmath.hdouble asin(double x);Calculates the arc sine of x.
assertassert.hvoid assert(int expression);Prints a diagnostic message and ends the program if the expression is false.
atanmath.hdouble atan(double x);Calculates the arc tangent of x.
atan2math.hdouble atan2(double y, double x);Calculates the arc tangent of y/x.
atexitstdlib.hint atexit(void (*func)(void));Registers a function to be called at normal termination.
atofstdlib.hdouble atof(const char *string);Converts string to a double-precision floating-point value.
atoistdlib.hint atoi(const char *string);Converts string to an integer.
atolstdlib.hlong int atol(const char *string);Converts string to a long integer.
bsearchstdlib.hvoid *bsearch(const void *key, const void *base, size_t num, size_t size, int (*compare) (const void *element1, const void *element2));Performs a binary search on an array of num elements, each of size bytes. The array must be sorted in ascending order by the function pointed to by compare.
btowcstdio.h
wchar.h
wint_t btowc(int c);Determines whether c constitues a valid multibyte character in the initial shift state.
callocstdlib.hvoid *calloc(size_t num, size_t size);Reserves storage space for an array of num elements, each of size size, and initializes the values of all elements to 0.
catclose6nl_types.hint catclose (nl_catd catd);Closes a previously opened message catalog.
catgets6nl_types.hchar *catgets(nl_catd catd, int set_id, int msg_id, const char *s);Retrieves a message from an open message catalog.
catopen6nl_types.hnl_catd catopen (const char *name, int oflag);Opens a message catalog, which must be done before a message can be retrieved.
ceilmath.hdouble ceil(double x);Calculates the double value representing the smallest integer that is greater than or equal to x.
clearerrstdio.hvoid clearerr(FILE *stream);Resets the error indicators and the end-of-file indicator for stream.
clocktime.hclock_t clock(void);Returns the processor time that has elapsed since the job was started.
cosmath.hdouble cos(double x);Calculates the cosine of x.
coshmath.hdouble cosh(double x);Calculates the hyperbolic cosine of x.
ctimetime.hchar *ctime(const time_t *time);Converts time to a character string.
ctime64time.hchar *ctime64(const time64_t *time);Converts time to a character string.
ctime_rtime.hchar *ctime_r(const time_t *time, char *buf);Converts time to a character string. (Restartable version of ctime.)
ctime64_rtime.hchar *ctime64_r(const time64_t *time, char *buf);Converts time to a character string. (Restartable version of ctime64.)
difftimetime.hdouble difftime(time_t time2, time_t time1);Computes the difference between time2 and time1.
difftime64time.hdouble difftime64(time64_t time2, time64_t time1);Computes the difference between time2 and time1.
divstdlib.hdiv_t div(int numerator, int denominator);Calculates the quotient and remainder of the division of numerator by denominator.
erfmath.hdouble erf(double x);Calculates the error function of x.
erfcmath.hdouble erfc(double x);Calculates the error function for large values of x.
exitstdlib.hvoid exit(int status);Ends a program normally.
expmath.hdouble exp(double x);Calculates the exponential function of a floating-point argument x.
fabsmath.hdouble fabs(double x);Calculates the absolute value of a floating-point argument x.
fclosestdio.hint fclose(FILE *stream);Closes the specified stream.
fdopen5stdio.hFILE *fdopen(int handle, const char *type);Associates an input or output stream with the file identified by handle.
feofstdio.hint feof(FILE *stream);Tests whether the end-of-file flag is set for a given stream.
ferrorstdio.hint ferror(FILE *stream);Tests for an error indicator in reading from or writing to stream.
fflush1stdio.hint fflush(FILE *stream);Writes the contents of the buffer associated with the output stream.
fgetc1stdio.hint fgetc(FILE *stream);Reads a single unsigned character from the input stream.
fgetpos1stdio.hint fgetpos(FILE *stream, fpos_t *pos);Stores the current position of the file pointer associated with stream into the object pointed to by pos.
fgets1stdio.hchar *fgets(char *string, int n, FILE *stream);Reads a string from the input stream.
fgetwc6stdio.h
wchar.h
wint_t fgetwc(FILE *stream);Reads the next multibyte character from the input stream pointed to by stream.
fgetws6stdio.h
wchar.h
wchar_t *fgetws(wchar_t *wcs, int n, FILE *stream);Reads wide characters from the stream into the array pointed to by wcs.
fileno5stdio.hint fileno(FILE *stream);Determines the file handle currently associated with stream.
floormath.hdouble floor(double x);Calculates the floating-point value representing the largest integer less than or equal to x.
fmodmath.hdouble fmod(double x, double y);Calculates the floating-point remainder of x/y.
fopenstdio.hFILE *fopen(const char *filename, const char *mode);Opens the specified file.
fprintfstdio.hint fprintf(FILE *stream, const char *format-string, arg-list);Formats and prints characters and values to the output stream.
fputc1stdio.hint fputc(int c, FILE *stream);Prints a character to the output stream.
fputs1stdio.hint fputs(const char *string, FILE *stream);Copies a string to the output stream.
fputwc6stdio.h
wchar.h
wint_t fputwc(wchar_t wc, FILE *stream);Converts the wide character wc to a multibyte character and writes it to the output stream pointed to by stream at the current position.
fputws6stdio.h
wchar.h
int fputws(const wchar_t *wcs, FILE *stream);Converts the wide-character string wcs to a multibyte-character string and writes it to stream as a multibyte character string.
freadstdio.hsize_t fread(void *buffer, size_t size, size_t count, FILE *stream);Reads up to count items of size length from the input stream, and stores them in buffer.
freestdlib.hvoid free(void *ptr);Frees a block of storage.
freopenstdio.hFILE *freopen(const char *filename, const char *mode, FILE *stream);Closes stream, and reassigns it to the file specified.
frexpmath.hdouble frexp(double x, int *expptr);Separates a floating-point number into its mantissa and exponent.
fscanfstdio.hint fscanf(FILE *stream, const char *format-string, arg-list);Reads data from stream into locations given by arg-list.
fseek1stdio.hint fseek(FILE *stream, long int offset, int origin);Changes the current file position associated with stream to a new location.
fsetpos1stdio.hint fsetpos(FILE *stream, const fpos_t *pos);Moves the current file position to a new location determined by pos.
ftell1stdio.hlong int ftell(FILE *stream);Gets the current position of the file pointer.
fwide6stdio.h
wchar.h
int fwide(FILE *stream, int mode);Determines the orientation of the stream pointed to by stream.
fwprintf6stdio.h
wchar.h
int fwprintf(FILE *stream, const wchar_t *format, arg-list);Writes output to the stream pointed to by stream.
fwritestdio.hsize_t fwrite(const void *buffer, size_t size,size_t count, FILE *stream);Writes up to count items of size length from buffer to stream.
fwscanf6stdio.h
wchar.h
int fwscanf(FILE *stream, const wchar_t *format, arg-list)Reads input from the stream pointed to by stream.
gammamath.hdouble gamma(double x);Computes the Gamma Function
getc1stdio.hint getc(FILE *stream);Reads a single character from the input stream.
getchar1stdio.hint getchar(void);Reads a single character from stdin.
getenvstdlib.hchar *getenv(const char *varname);Searches environment variables for varname.
getsstdio.hchar *gets(char *buffer);Reads a string from stdin, and stores it in buffer.
getwc6stdio.h
wchar.h
wint_t getwc(FILE *stream);Reads the next multibyte character from stream, converts it to a wide character and advances the associated file position indicator for stream.
getwchar6wchar.hwint_t getwchar(void);Reads the next multibyte character from stdin, converts it to a wide character, and advances the associated file position indicator for stdin.
gmtimetime.hstruct tm *gmtime(const time_t *time);Converts a time value to a structure of type tm.
gmtime64time.hstruct tm *gmtime64(const time64_t *time);Converts a time value to a structure of type tm.
gmtime_rtime.hstruct tm *gmtime_r (const time_t *time, struct tm *result);Converts a time value to a structure of type tm. (Restartable version of gmtime.)
gmtime64_rtime.hstruct tm *gmtime64_r (const time64_t *time, struct tm *result);Converts a time value to a structure of type tm. (Restartable version of gmtime64.)
hypotmath.hdouble hypot(double side1, double side2);Calculates the hypotenuse of a right-angled triangle with sides of length side1 and side2.
isalnumctype.hint isalnum(int c);Tests if c is alphanumeric.
isalphactype.hint isalpha(int c);Tests if c is alphabetic.
isascii4ctype.hint isascii(int c);Tests if c is within the 7-bit US-ASCII range.
isblankctype.hint isblank(int c);Tests if c is a blank or tab character.
iscntrlctype.hint iscntrl(int c);Tests if c is a control character.
isdigitctype.hint isdigit(int c);Tests if c is a decimal digit.
isgraphctype.hint isgraph(int c);Tests if c is a printable character excluding the space.
islowerctype.hint islower(int c);Tests if c is a lowercase letter.
isprintctype.hint isprint(int c);Tests if c is a printable character including the space.
ispunctctype.hint ispunct(int c);Tests if c is a punctuation character.
isspacectype.hint isspace(int c);Tests if c is a whitespace character.
isupperctype.hint isupper(int c);Tests if c is an uppercase letter.
iswalnum4wctype.hint iswalnum (wint_t wc);Checks for any alphanumeric wide character.
iswalpha4wctype.hint iswalpha (wint_t wc);Checks for any alphabetic wide character.
iswblank4wctype.hint iswblank (wint_t wc);Checks for any blank or tab wide character.
iswcntrl4wctype.hint iswcntrl (wint_t wc);Tests for any control wide character.
iswctype4wctype.hint iswctype(wint_t wc, wctype_t wc_prop);Determines whether or not the wide character wc has the property wc_prop.
iswdigit4wctype.hint iswdigit (wint_t wc);Checks for any decimal-digit wide character.
iswgraph4wctype.hint iswgraph (wint_t wc);Checks for any printing wide character except for the wide-character space.
iswlower4wctype.hint iswlower (wint_t wc);Checks for any lowercase wide character.
iswprint4wctype.hint iswprint (wint_t wc);Checks for any printing wide character.
iswpunct4wctype.hint iswpunct (wint_t wc);Test for a wide non-alphanumeric, non-space character.
iswspace4wctype.hint iswspace (wint_t wc);Checks for any wide character that corresponds to an implementation-defined set of wide characters for which iswalnum is false.
iswupper4wctype.hint iswupper (wint_t wc);Checks for any uppercase wide character.
iswxdigit4wctype.hint iswxdigit (wint_t wc);Checks for any hexadecimal digit character.
isxdigit4wctype.hint isxdigit(int c);Tests if c is a hexadecimal digit.
j0math.hdouble j0(double x);Calculates the Bessel function value of the first kind of order 0.
j1math.hdouble j1(double x);Calculates the Bessel function value of the first kind of order 1.
jnmath.hdouble jn(int n, double x);Calculates the Bessel function value of the first kind of order n.
labsstdlib.hlong int labs(long int n);Calculates the absolute value of n.
ldexpmath.hdouble ldexp(double x, int exp);Returns the value of x multiplied by (2 to the power of exp).
ldivstdlib.hldiv_t ldiv(long int numerator, long int denominator);Calculates the quotient and remainder of numerator/denominator.
localeconvlocale.hstruct lconv *localeconv(void);Formats numeric quantities in struct lconv according to the current locale.
localtimetime.hstruct tm *localtime(const time_t *timeval);Converts timeval to a structure of type tm.
localtime64time.hstruct tm *localtime64(const time64_t *timeval);Converts timeval to a structure of type tm.
localtime_rtime.hstruct tm *localtime_r (const time_t *timeval, struct tm *result);Converts a time value to a structure of type tm. (Restartable version of localtime.)
localtime64_rtime.hstruct tm *localtime64_r (const time64_t *timeval, struct tm *result);Converts a time value to a structure of type tm. (Restartable version of localtime64.)
logmath.hdouble log(double x);Calculates the natural logarithm of x.
log10math.hdouble log10(double x);Calculates the base 10 logarithm of x.
longjmpsetjmp.hvoid longjmp(jmp_buf env, int value);Restores a stack environment previously set in env by the setjmp function.
mallocstdlib.hvoid *malloc(size_t size);Reserves a block of storage.
mblenstdlib.hint mblen(const char *string, size_t n);Determines the length of a multibyte character string.
mbrlen4wchar.hint mbrlen (const char *s, size_t n, mbstate_t *ps);Determines the length of a multibyte character. (Restartable version of mblen.)
mbrtowc4wchar.hint mbrtowc (wchar_t *pwc, const char *s, size_t n, mbstate_t *ps);Convert a multibyte character to a wide character (Restartable version of mbtowc.)
mbsinit4wchar.hint mbsinit (const mbstate_t *ps);Test state object *ps for initial state.
mbsrtowcs4wchar.hsize_t mbsrtowc (wchar_t *dst, const char **src, size_t len, mbstate_t *ps);Convert multibyte string to a wide character string. (Restartable version of mbstowcs.)
mbstowcsstdlib.hsize_t mbstowcs(wchar_t *pwc, const char *string, size_t n);Converts the multibyte characters in string to their corresponding wchar_t codes, and stores not more than n codes in pwc.
mbtowcstdlib.hint mbtowc(wchar_t *pwc, const char *string, size_t n);Stores the wchar_t code corresponding to the first n bytes of multibyte character string into the wchar_t character pwc.
memchrstring.hvoid *memchr(const void *buf, int c, size_t count);Searches the first count bytes of buf for the first occurrence of c converted to an unsigned character.
memcmpstring.hint memcmp(const void *buf1, const void *buf2, size_t count);Compares up to count bytes of buf1 and buf2.
memcpystring.hvoid *memcpy(void *dest, const void *src, size_t count);Copies count bytes of src to dest.
memmovestring.hvoid *memmove(void *dest, const void *src, size_t count);Copies count bytes of src to dest. Allows copying between objects that overlap.
memsetstring.hvoid *memset(void *dest, int c, size_t count);Sets count bytes of dest to a value c.
mktimetime.htime_t mktime(struct tm *time);Converts local time into calendar time.
mktime64time.htime64_t mktime64(struct tm *time);Converts local time into calendar time.
modfmath.hdouble modf(double x, double *intptr);Breaks down the floating-point value x into fractional and integral parts.
nextaftermath.hdouble nextafter(double x, double y);Calculates the next representable value after x in the direction of y.
nextafterlmath.hlong double nextafterl(long double x, long double y);Calculates the next representable value after x in the direction of y.
nexttowardmath.hdouble nexttoward(double x, long double y);Calculates the next representable value after x in the direction of y.
nexttowardlmath.hlong double nexttowardl(long double x, long double y);Calculates the next representable value after x in the direction of y.
nl_langinfo4langinfo.hchar *nl_langinfo(nl_item item);Retrieve from the current locale the string that describes the requested information specified by item.
perrorstdio.hvoid perror(const char *string);Prints an error message to stderr.
powmath.hdouble pow(double x, double y);Calculates the value x to the power y.
printfstdio.hint printf(const char *format-string, arg-list);Formats and prints characters and values to stdout.
putc1stdio.hint putc(int c, FILE *stream);Prints c to the output stream.
putchar1stdio.hint putchar(int c);Prints c to stdout.
putenvstdlib.hint *putenv(const char *varname);Sets the value of an environment variable by altering an existing variable or creating a new one.
putsstdio.hint puts(const char *string);Prints a string to stdout.
putwc6stdio.h
wchar.h
wint_t putwchar(wchar_t wc, FILE *stream);Converts the wide character wc to a multibyte character, and writes it to the stream at the current position.
putwchar6wchar.hwint_t putwchar(wchar_t wc);Converts the wide character wc to a multibyte character and writes it to stdout.
qsortstdlib.hvoid qsort(void *base, size_t num, size_t width, int(*compare)(const void *element1, const void *element2));Performs a quick sort of an array of num elements, each of width bytes in size.
quantexpd32math.h_Decimal32 quantized32(_Decimal32 x, _Decimal32 y);Compute the quantum exponent of a single-precision decimal floating-point value.
quantexpd64math.h_Decimal64 quantized64(_Decimal64 x, _Decimal64 y);Compute the quantum exponent of a double-precision decimal floating-point value.
quantexpd128math.h_Decimal128 quantized128(_Decimal128 x, _Decimal128 y);Compute the quantum exponent of a quad-precision decimal floating-point value.
quantized32math.hint quantexpd32(_Decimal32 x);Set the quantum exponent of a single-precision decimal floating-point value to the quantum exponent of another single-precision decimal floating-point value.
quantized64math.hint quantexpd64(_Decimal64 x);Set the quantum exponent of a double-precision decimal floating-point value to the quantum exponent of another double-precision decimal floating-point value.
quantized128math.hint quantexpd128(_Decimal128 x);Set the quantum exponent of a quad-precision decimal floating-point value to the quantum exponent of another quad-precision decimal floating-point value.
samequantumd32math.h__bool__ samequantumd32(_Decimal32 x, _Decimal32 y);Determine if the quantum exponents of two single-precision decimal floating-point values are the same.
samequantumd64math.h__bool__ samequantumd64(_Decimal64 x, _Decimal64 y);Determine if the quantum exponents of two double-precision decimal floating-point values are the same.
samequantumd128math.h__bool__ samequantumd128(_Decimal128 x, _Decimal128 y);Determine if the quantum exponents of two quad-precision decimal floating-point values are the same.
raisesignal.hint raise(int sig);Sends the signal sig to the running program.
randstdlib.hint rand(void);Returns a pseudo-random integer.
rand_rstdlib.hint rand_r(void);Returns a pseudo-random integer. (Restartable version)
reallocstdlib.hvoid *realloc(void *ptr, size_t size);Changes the size of a previously reserved storage block.
regcompregex.hint regcomp(regex_t *preg, const char *pattern, int cflags);Compiles the source regular expression pointed to by pattern into an executable version and stores it in the location pointed to by preg.
regerrorregex.hsize_t regerror(int errcode, const regex_t *preg, char *errbuf, size_t errbuf_size);Finds the description for the error code errcode for the regular expression preg.
regexecregex.hint regexec(const regex_t *preg, const char *string, size_t nmatch, regmatch_t *pmatch, int eflags);Compares the null-ended string string against the compiled regular expression preg to find a match between the two.
regfreeregex.hvoid regfree(regex_t *preg);Frees any memory that was allocated by regcomp to implement the regular expression preg.
removestdio.hint remove(const char *filename);Deletes the file specified by filename.
renamestdio.hint rename(const char *oldname, const char *newname);Renames the specified file.
rewind1stdio.hvoid rewind(FILE *stream);Repositions the file pointer associated with stream to the beginning of the file.
scanfstdio.hint scanf(const char *format-string, arg-list);Reads data from stdin into locations given by arg-list.
setbufstdio.hvoid setbuf(FILE *stream, char *buffer);Controls buffering for stream.
setjmpsetjmp.hint setjmp(jmp_buf env);Saves a stack environment that can be subsequently restored by longjmp.
setlocalelocale.hchar *setlocale(int category, const char *locale);Changes or queries variables defined in the locale.
setvbufstdio.hint setvbuf(FILE *stream, char *buf, int type, size_t size);Controls buffering and buffer size for stream.
signalsignal.hvoid(*signal (int sig, void(*func)(int))) (int);Registers func as a signal handler for the signal sig.
sinmath.hdouble sin(double x);Calculates the sine of x.
sinhmath.hdouble sinh(double x);Calculates the hyperbolic sine of x.
snprintfstdio.hint snprintf(char *outbuf, size_t n, const char*, …)Same as sprintf except that the function will stop after n characters have been written to outbuf.
sprintfstdio.hint sprintf(char *buffer, const char *format-string, arg-list);Formats and stores characters and values in buffer.
sqrtmath.hdouble sqrt(double x);Calculates the square root of x.
srandstdlib.hvoid srand(unsigned int seed);Sets the seed for the pseudo-random number generator.
sscanfstdio.hint sscanf(const char *buffer, const char *format, arg-list);Reads data from buffer into the locations given by arg-list.
strcasecmpstrings.hint srtcasecmp(const char *string1, const char *string2);Compares strings without case sensitivity.
strcatstring.hchar *strcat(char *string1, const char *string2);Concatenates string2 to string1.
strchrstring.hchar *strchr(const char *string, int c);Locates the first occurrence of c in string.
strcmpstring.hint strcmp(const char *string1, const char *string2);Compares the value of string1 to string2.
strcollstring.hint strcoll(const char *string1, const char *string2);Compares two strings using the collating sequence in the current locale.
strcpystring.hchar *strcpy(char *string1, const char *string2);Copies string2 into string1.
strcspnstring.hsize_t strcspn(const char *string1, const char *string2);Returns the length of the initial substring of string1 consisting of characters not contained in string2.
strerrorstring.hchar *strerror(int errnum);Maps the error number in errnum to an error message string.
strfmon4wchar.hint strfmon (char *s, size_t maxsize, const char *format, …);Converts monetary value to string.
strftimetime.hsize_t strftime (char *dest, size_t maxsize, const char *format, const struct tm *timeptr);Stores characters in an array pointed to by dest, according to the string determined by format.
strlenstring.hsize_t strlen(const char *string);Calculates the length of string.
strncasecmpstrings.hint strncasecmp(const char *string1, const char *string2, size_t count);Compares strings without case sensitivity.
strncatstring.hchar *strncat(char *string1, const char *string2, size_t count);Concatenates up to count characters of string2 to string1.
strncmpstring.hint strncmp(const char *string1, const char *string2, size_t count);Compares up to count characters of string1 and string2.
strncpystring.hchar *strncpy(char *string1, const char *string2, size_t count);Copies up to count characters of string2 to string1.
strpbrkstring.hchar *strpbrk(const char *string1, const char *string2);Locates the first occurrence in string1 of any character in string2.
strptime4time.hchar *strptime (const char *buf, const char *format, struct tm *tm);Date and time conversion
strrchrstring.hchar *strrchr(const char *string, int c);Locates the last occurrence of c in string.
strspnstring.hsize_t strspn(const char *string1, const char *string2);Returns the length of the initial substring of string1 consisting of characters contained in string2.
strstrstring.hchar *strstr(const char *string1, const char *string2);Returns a pointer to the first occurrence of string2 in string1.
strtodstdlib.hdouble strtod(const char *nptr, char **endptr);Converts nptr to a double precision value.
strtod32stdlib.h_Decimal32 strtod32(const char *nptr, char **endptr);Converts nptr to a single-precision decimal floating-point value.
strtod64stdlib.h_Decimal64 strtod64(const char *nptr, char **endptr);Converts nptr to a double-precision decimal floating-point value.
strtod128stdlib.h_Decimal128 strtod128(const char *nptr, char **endptr);Converts nptr to a quad-precision decimal floating-point value.
strtofstdlib.hfloat strtof(const char *nptr, char **endptr);Converts nptr to a float value.
strtokstring.hchar *strtok(char *string1, const char *string2);Locates the next token in string1 delimited by the next character in string2.
strtok_rstring.hchar *strtok_r(char *string, const char *seps, char **lasts);Locates the next token in string delimited by the next character in seps. (Restartable version of strtok.)
strtolstdlib.hlong int strtol(const char *nptr, char **endptr, int base);Converts nptr to a signed long integer.
strtoldstdlib.hlong double strtold(const char *nptr, char **endptr);Converts nptr to a long double value.
strtoulstdlib.hunsigned long int strtoul(const char *string1, char **string2, int base);Converts string1 to an unsigned long integer.
strxfrmstring.hsize_t strxfrm(char *string1, const char *string2, size_t count);Converts string2 and places the result in string1. The conversion is determined by the program’s current locale.
swprintfwchar.hint swprintf(wchar_t *wcsbuffer, size_t n, const wchar_t *format, arg-list);Formats and stores a series of wide characters and values into the wide-character buffer wcsbuffer.
swscanfwchar.hint swscanf (const wchar_t *buffer, const wchar_t *format, arg-list)Reads data from buffer into the locations given by arg-list.
systemstdlib.hint system(const char *string);Passes string to the system command analyzer.
tanmath.hdouble tan(double x);Calculates the tangent of x.
tanhmath.hdouble tanh(double x);Calculates the hyperbolic tangent of x.
timetime.htime_t time(time_t *timeptr);Returns the current calendar time.
time64time.htime64_t time64(time64_t *timeptr);Returns the current calendar time.
tmpfilestdio.hFILE *tmpfile(void);Creates a temporary binary file and opens it.
tmpnamstdio.hchar *tmpnam(char *string);Generates a temporary file name.
toasciictype.hint toascii(int c);Converts c to a character in the 7-bit US-ASCII character set.
tolowerctype.hint tolower(int c);Converts c to lowercase.
toupperctype.hint toupper(int c);Converts c to uppercase.
towctranswctype.hwint_t towctrans(wint_t wc, wctrans_t desc);Translates the wide character wc based on the mapping described by desc.
towlower4wctype.hwint_t towlower (wint_t wc);Converts uppercase letter to lowercase letter.
towupper4wctype.hwint_t towupper (wint_t wc);Converts lowercase letter to uppercase letter.
ungetc1stdio.hint ungetc(int c, FILE *stream);Pushes c back onto the input stream.
ungetwc6stdio.h
wchar.h
wint_t ungetwc(wint_t wc, FILE *stream);Pushes the wide character wc back onto the input stream.
va_argstdarg.hvar_type va_arg(va_list arg_ptr, var_type);Returns the value of one argument and modifies arg_ptr to point to the next argument.
va_copystdarg.hvoid va_copy(va_list dest, va_list src);Initializes dest as a copy of src.
va_endstdarg.hvoid va_end(va_list arg_ptr);Facilitates normal return from variable argument list processing.
va_startstdarg.hvoid va_start(va_list arg_ptr, variable_name);Initializes arg_ptr for subsequent use by va_arg and va_end.
vfprintfstdio.h stdarg.hint vfprintf(FILE *stream, const char *format, va_list arg_ptr);Formats and prints characters to the output stream using a variable number of arguments.
vfscanfstdio.h stdarg.hint vfscanf(FILE *stream, const char *format, va_list arg_ptr);Reads data from a specified stream into locations given by a variable number of arguments.
vfwprintf6stdarg.h
stdio.h
wchar.h
int vfwprintf(FILE *stream, const wchar_t *format, va_list arg);Equivalent to fwprintf, except that the variable argument list is replaced by arg.
vfwscanfstdio.h stdarg.hint vfwscanf(FILE *stream, const wchar_t *format, va_list arg_ptr);Reads wide data from a specified stream into locations given by a variable number of arguments.
vprintfstdio.h stdarg.hint vprintf(const char *format, va_list arg_ptr);Formats and prints characters to stdout using a variable number of arguments.
vscanfstdio.h stdarg.hint vscanf(const char *format, va_list arg_ptr);Reads data from stdin into locations given by a variable number of arguments.
vsprintfstdio.h stdarg.hint vsprintf(char *target-string, const char *format, va_list arg_ptr);Formats and stores characters in a buffer using a variable number of arguments.
vsnprintfstdio.hint vsnprintf(char *outbuf, size_t n, const char*, va_list);Same as vsprintf except that the function will stop after n characters have been written to outbuf.
vsscanfstdio.h stdarg.hint vsscanf(const char*buffer, const char *format, va_list arg_ptr);Reads data from a buffer into locations given by a variable number of arguments.
vswprintfstdarg.h
wchar.h
int vswprintf(wchar_t *wcsbuffer, size_t n, const wchar_t *format, va_list arg);Formats and stores a series of wide characters and values in the buffer wcsbuffer.
vswscanfstdio.h wchar.hint vswscanf(const wchar_t *buffer, const wchar_t *format, va_list arg_ptr);Reads wide data from a buffer into locations given by a variable number of arguments.
vwprintf6stdarg.h
wchar.h
int vwprintf(const wchar_t *format, va_list arg);Equivalent to wprintf, except that the variable argument list is replaced by arg.
vwscanfstdio.h wchar.hint vwscanf(const wchar_t *format, va_list arg_ptr);Reads wide data from stdin into locations given by a variable number of arguments.
wcrtomb4wchar.hint wcrtomb (char *s, wchar_t wchar, mbstate_t *pss);Converts a wide character to a multibyte character. (Restartable version of wctomb.)
wcscatwchar.hwchar_t *wcscat(wchar_t *string1, const wchar_t *string2);Appends a copy of the string pointed to by string2 to the end of the string pointed to by string1.
wcschrwchar.hwchar_t *wcschr(const wchar_t *string, wchar_t character);Searches the wide-character string pointed to by string for the occurrence of character.
wcscmpwchar.hint wcscmp(const wchar_t *string1, const wchar_t *string2);Compares two wide-character strings, *string1 and *string2.
wcscoll4wchar.hint wcscoll (const wchar_t *wcs1, const wchar_t *wcs2);Compares two wide-character strings using the collating sequence in the current locale.
wcscpywchar.hwchar_t *wcscpy(wchar_t *string1, const wchar_t *string2);Copies the contents of *string2 (including the ending wchar_t null character) into *string1.
wcscspnwchar.hsize_t wcscspn(const wchar_t *string1, const wchar_t *string2);Determines the number of wchar_t characters in the initial segment of the string pointed to by *string1 that do not appear in the string pointed to by *string2.
wcsftimewchar.hsize_t wcsftime(wchar_t *wdest, size_t maxsize, const wchar_t *format, const struct tm *timeptr);Converts the time and date specification in the timeptr structure into a wide-character string.
wcslenwchar.hsize_t wcslen(const wchar_t *string);Computes the number of wide-characters in the string pointed to by string.
wcslocaleconvlocale.hstruct wcslconv *wcslocaleconv(void);Formats numeric quantities in struct wcslconv according to the current locale.
wcsncatwchar.hwchar_t *wcsncat(wchar_t *string1, const wchar_t *string2, size_t count);Appends up to count wide characters from string2 to the end of string1, and appends a wchar_t null character to the result.
wcsncmpwchar.hint wcsncmp(const wchar_t *string1, const wchar_t *string2, size_t count);Compares up to count wide characters in string1 to string2.
wcsncpywchar.hwchar_t *wcsncpy(wchar_t *string1, const wchar_t *string2, size_t count);Copies up to count wide characters from string2 to string1.
wcspbrkwchar.hwchar_t *wcspbrk(const wchar_t *string1, const wchar_t *string2);Locates the first occurrence in the string pointed to by string1 of any wide characters from the string pointed to by string2.
wcsptimewchar.hwchar_t *wcsptime ( const wchar_t *buf, const wchar_t *format, struct tm *tm );Date and time conversion. Equivalent to strptime(), except that it uses wide characters.
wcsrchrwchar.hwchar_t *wcsrchr(const wchar_t *string, wchar_t character);Locates the last occurrence of character in the string pointed to by string.
wcsrtombs4wchar.hsize_t wcsrtombs (char *dst, const wchar_t **src, size_t len, mbstate_t *ps);Converts wide character string to multibyte string. (Restartable version of wcstombs.)
wcsspnwchar.hsize_t wcsspn(const wchar_t *string1, const wchar_t *string2);Computes the number of wide characters in the initial segment of the string pointed to by string1, which consists entirely of wide characters from the string pointed to by string2.
wcsstrwchar.hwchar_t *wcsstr(const wchar_t *wcs1, const wchar_t *wcs2);Locates the first occurrence of wcs2 in wcs1.
wcstodwchar.hdouble wcstod(const wchar_t *nptr, wchar_t **endptr);Converts the initial portion of the wide-character string pointed to by nptr to a double value.
wcstod32wchar.h_Decimal32 wcstod32(const wchar_t *nptr, wchar_t **endptr);Converts the initial portion of the wide-character string pointed to by nptr to a single-precision decimal floating-point value.
wcstod64wchar.h_Decimal64 wcstod64(const wchar_t *nptr, wchar_t **endptr);Converts the initial portion of the wide-character string pointed to by nptr to a double-precision decimal floating-point value.
wcstod128wchar.h_Decimal128 wcstod128(const wchar_t *nptr, wchar_t **endptr);Converts the initial portion of the wide-character string pointed to by nptr to a quad-precision decimal floating-point value.
wcstofwchar.hfloat wcstof(const wchar_t *nptr, wchar_t **endptr);Converts the initial portion of the wide-character string pointed to by nptr to a float value.
wcstokwchar.hwchar_t *wcstok(wchar_t *wcs1, const wchar_t *wcs2, wchar_t **ptr)Breaks wcs1 into a sequence of tokens, each of which is delimited by a wide character from the wide string pointed to by wcs2.
wcstolwchar.hlong int wcstol(const wchar_t *nptr, wchar_t **endptr, int base);Converts the initial portion of the wide-character string pointed to by nptr to a long integer value.
wcstoldwchar.hlong double wcstold(const wchar_t *nptr, wchar_t **endptr);Converts the initial portion of the wide-character string pointed to by nptr to a long double value.
wcstombsstdlib.hsize_t wcstombs(char *dest, const wchar_t *string, size_t count);Converts the wchar_t string into a multibyte string dest.
wcstoulwchar.hunsigned long int wcstoul(const wchar_t *nptr, wchar_t **endptr, int base);Converts the initial portion of the wide-character string pointed to by nptr to an unsigned long integer value.
wcsxfrm4wchar.hsize_t wcsxfrm (wchar_t *wcs1, const wchar_t *wcs2, size_t n);Transforms a wide-character string to values which represent character collating weights and places the resulting wide-character string into an array.
wctobstdarg.h
wchar.h
int wctob(wint_t wc);Determines whether wc corresponds to a member of the extended character set whose multibyte character representation is a single byte when in the initial shift state.
wctombstdlib.hint wctomb(char *string, wchar_t character);Converts the wchar_t value of character into a multibyte string.
wctranswctype.hwctrans_t wctrans(const char *property);Constructs a value with type wctrans_t that describes a mapping between wide characters identified by the string argument property.
wctype4wchar.hwctype_t wctype (const char *property);Obtains handle for character property classification.
wcwidthwchar.hint wcswidth(const wchar_t *pwcs, size_t n);Determine the display width of a wide character string.
wmemchrwchar.hwchar_t *wmemchr(const wchar_t *s, wchar_t c, size_t n);Locates the first occurrence of c in the initial n wide characters of the object pointed to by s.
wmemcmpwchar.hint wmemcmp(const wchar_t *s1, const wchar_t *s2, size_t n);Compares the first n wide characters of the object pointed to by s1 to the first n characters of the object pointed to by s2.
wmemcpywchar.hwchar_t *wmemcpy(wchar_t *s1, const wchar_t *s2, size_t n);Copies n wide characters from the object pointed to by s2 to the object pointed to by s1.
wmemmovewchar.hwchar_t *wmemmove(wchar_t *s1, const wchar_t *s2, size_t n);Copies n wide characters from the object pointed to by s2 to the object pointed to by s1.
wmemsetwchar.hwchar_t *wmemset(wchar_t *s, wchar_t c, size_t n);Copies the value of c into each of the first n wide characters of the object pointed to by s.
wprintf6wchar.hint wprintf(const wchar_t *format, arg-list);Equivalent to fwprintf with the argument stdout interposed before the arguments to wprintf.
wscanf6wchar.hint wscanf(const wchar_t *format, arg-list);Equivalent to fwscanf with the argument stdin interposed before the arguments of wscanf.
y0math.hdouble y0(double x);Calculates the Bessel function value of the second kind of order 0.
y1math.hdouble y1(double x);Calculates the Bessel function value of the second kind of order 1.
ynmath.hdouble yn(int n, double x);Calculates the Bessel function value of the second kind of order n.
Categories: C language

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