Defined in header <<fenv.h>> int fegetexceptflag( fexcept_t* flagp, int excepts ); (1) (since C99) int fesetexceptflag( const fexcept_t* flagp, int excepts ); (2) (since C99) 1) Attempts to obtain the full contents of the floating-point exception flags that are listed in the bitmask argument excepts, which is a bitwise OR of the floating point exception macros. 2) Attempts to copy the full contents of the floating-point exception flags that are listed in excepts

Usage if statement: as the declaration of the if statement

Defined in header <math.h> float frexpf( float arg, int* exp ); (1) (since C99) double frexp( double arg, int* exp ); (2) long double frexpl( long double arg, int* exp ); (3) (since C99) Defined in header <tgmath.h> #define frexp( arg, exp ) (4) (since C99) 1-3) Decomposes given floating point value x into a normalized fraction and an integral power of two. 4) Type-generic macro: If arg has type long double, frexpl is called. Othe

An enumerated type is a distinct type whose value is restricted to one of several explicitly named constants (enumeration constants). Syntax Enumerated type is declared using the following enumeration specifier as the type specifier in the declaration grammar: enum identifier(optional) { enumerator-list } where enumerator-list is a comma-separated list (with trailing comma permitted) (since C99) of enumerators, each of which has the form: enumerator (1) enumerator = constant-e

Usage short type modifier

Defined in header <ctype.h> int isspace( int ch ); Checks if the given character is a whitespace character, i.e. either space (0x20), form feed (0x0c), line feed (0x0a), carriage return (0x0d), horizontal tab (0x09) or vertical tab (0x0b). The behavior is undefined if the value of ch is not representable as unsigned char and is not equal to EOF. Parameters ch - character to classify Return value Non-zero value if the character is a whitespace character, zero o

Defined in header <string.h> (1) void* memcpy( void *dest, const void *src, size_t count ); (until C99) void* memcpy( void *restrict dest, const void *restrict src, size_t count ); (since C99) errno_t memcpy_s( void *restrict dest, rsize_t destsz, const void *restrict src, rsize_t count ); (2) (since C11) 1) Copies count characters from the object pointed to by src to the object pointed to by dest. Both objects are interpreted as arrays of uns

Declares a member with explicit width, in bits. Adjacent bit field members may be packed to share and straddle the individual bytes. A bit field declaration is a struct or union member declaration which uses the following declarator: identifier(optional) : width identifier - the name of the bit field that is being declared. The name is optional: nameless bitfields introduce the specified number of bits of padding width - an integer constant expression with a value greater or

When initializing an object of scalar type, the initializer must be a single expression. The initializer for a scalar (an object of integer type including booleans and enumerated types, floating type including complex and imaginary, and pointer type including pointer to function) must be a single expression, optionally enclosed in braces: = expression (1) = { expression } (2) The expression is evaluated, and its value, after conversion as if by assignment to the type of the obje

Executes code according to the value of an integral argument. Used where one or several out of many branches of code need to be executed according to an integral value. Syntax switch ( expression ) statement expression - any expression of integer type (char, signed or unsigned integer, or enumeration) statement - any statement (typically a compound statement). case: and default: labels are permitted in statement, and break; statement has special meaning. case constant_