Defined in header <wchar.h> wchar_t *wmemchr( const wchar_t *ptr, wchar_t ch, size_t count ); (since C95) Locates the first occurrence of wide character ch in the initial count wide characters of the wide character array or integer array of compatible type, pointed to by ptr. If count is zero, the function returns a null pointer. Parameters ptr - pointer to the wide character array to be examined ch - wide character to search for count - number of wide c

Defined in header <wctype.h> wctype_t wctype( const char* str ); (since C95) Constructs a value of type wctype_t that describes a LC_CTYPE category of wide character classification. It may be one of the standard classification categories, or a locale-specific category, such as "jkanji". Parameters str - C string holding the name of the desired category The following values of str are supported in all C locales: value of str effect "alnum" identifies the ca

Defined in header <wchar.h> wchar_t *wmemset( wchar_t *dest, wchar_t ch, size_t count ); (since C95) Copies the wide character ch into each of the first count wide characters of the wide character array (or integer array of compatible type) pointed to by dest. If overflow occurs, the behavior is undefined. If count is zero, the function does nothing. Parameters dest - pointer to the wide character array to fill ch - fill wide character count - number of

Conditionally executes code. Used where code needs to be executed only if some condition is true. Syntax if ( expression ) statement_true (1) if ( expression ) statement_true else statement_false (2) Explanation expression must be an expression of any scalar type. If expression compares not equal to the integer zero, statement_true is executed. In the form (2), if expression compares equal to the integer zero, statement_false is executed. As with all other selection and ite

Defined in header <math.h> #define islessequal(x, y) /* implementation defined */ (since C99) Determines if the floating point number x is less than or equal to the floating-point number y, without setting floating-point exceptions. Parameters x - floating point value y - floating point value Return value Nonzero integral value if x <= y, ​0​ otherwise. Notes The built-in operator<= for floating-point numbers may raise FE_INVALID if one or both

Defined in header <math.h> #define signbit(arg) /* implementation defined */ (since C99) Determines if the given floating point number arg is negative. The macro returns an integral value. Parameters arg - floating point value Return value Nonzero integral value if arg is negative, ​0​ otherwise. Notes This macro detects the sign bit of zeroes, infinities, and NaNs. Along with copysign, this macro is one of the only two portable ways to examine the sign of

Defined in header <stdlib.h> int mbtowc( wchar_t *pwc, const char *s, size_t n ) (until C99) int mbtowc( wchar_t *restrict pwc, const char *restrict s, size_t n ) (since C99) Converts a multibyte character whose first byte is pointed to by s to a wide character, written to *pwc if pwc is not null. If s is a null pointer, resets the global conversion state and determines whether shift sequences are used. Notes Each call to mbtowc updates the intern

Defined in header <stdatomic.h> C atomic_fetch_xor( volatile A* obj, M arg ); (1) (since C11) C atomic_fetch_xor_explicit( volatile A* obj, M arg, memory_order order ); (2) (since C11) Atomically replaces the value pointed by obj with the result of bitwise XOR between the old value of obj and arg, and returns the value obj held previously. The operation is read-modify-write operation. The first version orders memory accesses according to memory_order_seq_cst, the seco

Defined in header <string.h> size_t strcspn( const char *dest, const char *src ); Returns the length of the maximum initial segment of the null-terminated byte string pointed to by dest, that consists of only the characters not found in the null-terminated byte string pointed to by src. The behavior is undefined if either dest or src is not a pointer to a null-terminated byte string. Parameters dest - pointer to the null-terminated byte string to be analyzed src

The preprocessor is executed at translation phase 4, before the compilation. The result of preprocessing is single file which is then passed to the actual compiler. Directives The preprocessing directives control the behavior of the preprocessor. Each directive occupies one line and has the following format: # character preprocessing instruction (one of define, undef, include, if, ifdef, ifndef, else, elif, endif, line, error, pragma) [1] arguments (depends on the instruction) line bre