Defined in header <ctype.h> int isalpha( int ch ); Checks if the given character is an alphabetic character, i.e. either an uppercase letter (ABCDEFGHIJKLMNOPQRSTUVWXYZ), or a lowercase letter (abcdefghijklmnopqrstuvwxyz). In locales other than "C", an alphabetic character is a character for which isupper() or islower() returns true or any other character considered alphabetic by the locale. In any case, iscntrl(), isdigit(), ispunct() and isspace() will return false for th

Defined in header <locale.h> lconv* localeconv(); The localeconv function obtains a pointer to a static object of type lconv, which represents numeric and monetary formatting rules of the current C locale. Parameters (none). Return value pointer to the current lconv object. Notes Modifying the object references through the returned pointer is undefined behavior. localeconv modifies a static object, calling it from different threads without synchronization is undefi

Defined in header <stddef.h> Defined in header <string.h> Defined in header <wchar.h> Defined in header <time.h> Defined in header <locale.h> Defined in header <stdio.h> #define NULL /*implementation-defined*/ Expands into implementation-defined null-pointer constant. Example #include <stdlib.h> struct S; void(*f)() = NULL; int main(void) { char *ptr = malloc(sizeof(char)*10); if (pt

Defined in header <wchar.h> size_t wcscspn( const wchar_t* dest, const wchar_t* src ); (since C95) Returns the length of the maximum initial segment of the wide string pointed to by dest, that consists of only the characters not found in wide string pointed to by src. Parameters dest - pointer to the null-terminated wide string to be analyzed src - pointer to the null-terminated wide string that contains the characters to search for Return value The leng

Defined in header <stdio.h> int puts( const char *str ); Writes character string str and a newline to stdout. Parameters str - character string to be written Return value non-negative number on success or EOF otherwise. Example puts() with error checking. #include <stdio.h> #include <stdlib.h> int main(void) { int ret_code = puts("Hello World"); if ((ret_code == EOF) && (ferror(stdout))) /* test whether EOF was reached */

Defined in header <wchar.h> (1) wchar_t *wcsncat( wchar_t *dest, const wchar_t *src, size_t count ); (since C95) (until C99) wchar_t *wcsncat( wchar_t *restrict dest, const wchar_t *restrict src, size_t count ); (since C99) errno_t wcsncat_s( wchar_t *restrict dest, rsize_t destsz, const wchar_t *restrict src, rsize_t count ); (2) (since C11) 1) Appends at most count wide characters from the wide string pointed to by src, st

Defined in header <stddef.h> Defined in header <stdio.h> Defined in header <string.h> Defined in header <time.h> typedef /*implementation-defined*/ size_t; size_t is the unsigned integer type of the result of sizeof , alignof (since C11) and offsetof. Notes size_t can store the maximum size of a theoretically possible object of any type (including array). size_t is commonly used for array indexing and loop counting. Programs that us

Usage conditionally-supported type specifier for Fortran language linkage. May be used with function declarations and other external declarations to indicate that the calling convention and name mangling is suitable for linking with translation units written in the Fortran programming language.

Defined in header <string.h> char* strpbrk( const char* dest, const char* breakset ); Scans the null-terminated byte string pointed to by dest for any character from the null-terminated byte string pointed to by breakset, and returns a pointer to that character. The behavior is undefined if either dest or breakset is not a pointer to a null-terminated byte string. Parameters dest - pointer to the null-terminated byte string to be analyzed breakset - pointer to

Defined in header <wchar.h> struct mbstate_t; (since C95) The type mbstate_t is a trivial non-array type that can represent any of the conversion states that can occur in an implementation-defined set of supported multibyte character encoding rules. Zero-initialized value of mbstate_t represents the initial conversion state, although other values of mbstate_t may exist that also represent the initial conversion state. Possible implementation of mbstate_t is a struct type ho