Defined in header <stdlib.h> void ignore_handler_s( const char * restrict msg, void * restrict ptr, errno_t error ); (since C11) The function simply returns to the caller without performing any other action. A pointer to this function can be passed to set_constraint_handler_s to establish a runtime constraints violation handler that does nothing. As with all bounds-checked functions, ignore_handler_s is onl

Usage declaration of a compound type

A struct is a type consisting of a sequence of members whose storage is allocated in an ordered sequence (as opposed to union, which is a type consisting of a sequence of members whose storage overlaps). The type specifier for a struct is identical to the union type specifier except for the keyword used: Syntax struct name(optional) { struct-declaration-list } (1) struct name (2) 1) Struct definition: introduces the new type struct name and defines its meaning 2) If used o

A null-terminated byte string (NTBS) is a sequence of nonzero bytes followed by a byte with value zero (the terminating null character). Each byte in a byte string encodes one character of some character set. For example, the character array {'\x63','\x61','\x74','\0'} is an NTBS holding the string "cat" in ASCII encoding. Functions Character classification Defined in header <ctype.h> isalnum checks if a character is alphanumeric (function) isalpha checks if a charact

Defined in header <wchar.h> int wcscoll( const wchar_t *lhs, const wchar_t *rhs ); (since C95) Compares two null-terminated wide strings according to the collation order defined by the LC_COLLATE category of the currently installed locale. Parameters lhs, rhs - pointers to the null-terminated wide strings to compare Return value Negative value if lhs is less than (precedes) rhs. ​0​ if lhs is equal to rhs. Positive value if lhs is greater than (follows) rhs.

Defined in header <stdlib.h> void free( void* ptr ); Deallocates the space previously allocated by malloc(), calloc(), aligned_alloc, (since C11) or realloc(). If ptr is a null pointer, the function does nothing. The behavior is undefined if the value of ptr does not equal a value returned earlier by malloc(), calloc(), realloc(), or aligned_alloc() (since C11). The behavior is undefined if the memory area referred to by ptr has already been deallocated, that is, free() or

Defined in header <uchar.h> size_t mbrtoc16( char16_t* pc16, const char* s, size_t n, mbstate_t* ps ); (since C11) Converts a narrow multibyte character to 16-bit character representation (typically, UTF-16). If s is not a null pointer, inspects at most n bytes of the multibyte character string, beginning with the byte pointed to by s to determine the number of bytes necessary to complete the next multibyte character (including any shift sequences). If the function determin

Defined in header <<fenv.h>> int feholdexcept( fenv_t* envp ); (since C99) First, saves the current floating-point environment to the object pointed to by envp (similar to fegetenv), then clears all floating-point status flags, and then installs the non-stop mode: future floating-point exceptions will not interrupt execution (will not trap), until the floating-point environment is restored by feupdateenv or fesetenv. This function may be used in the beginning of a sub

Defined in header <stdlib.h> void abort_handler_s( const char * restrict msg, void * restrict ptr, errno_t error ); (since C11) Writes an implementation-defined message to stderr which must include the string pointed to by msg and calls abort(). A pointer to this function can be passed to set_constraint_handler_s to establish a runtime constraints violation handler. As with all bounds-checked functions, abort_

Defined in header <math.h> float lgammaf( float arg ); (1) (since C99) double lgamma( double arg ); (2) (since C99) long double lgammal( long double arg ); (3) (since C99) Defined in header <tgmath.h> #define lgamma( arg ) (4) (since C99) 1-3) Computes the natural logarithm of the absolute value of the gamma function of arg. 4) Type-generic macro: If arg has type long double, lgammal is called. Otherwise, if arg has integer type o