Defined in header <<fenv.h>> int fegetenv( fenv_t* envp ); (1) (since C99) int fesetenv( const fenv_t* envp ); (2) (since C99) 1) Attempts to store the status of the floating-point environment in the object pointed to by envp. 2) Attempts to establish the floating-point environment from the object pointed to by envp. The value of that object must be previously obtained by a call to feholdexcept or fegetenv or be a floating-point macro constant. If any of the flo

Defined in header <complex.h> #define _Imaginary_I /* unspecified */ (since C99) The _Imaginary_I macro expands to a value of type const float _Imaginary with the value of the imaginary unit. As with any pure imaginary number support in C, this macro is only defined if the imaginary numbers are supported. A compiler that defines __STDC_IEC_559_COMPLEX__ is not required to support imaginary numbers. POSIX recommends checking if the macro _Imaginary_I is defined to identify

If the macro constant __STDC_NO_COMPLEX__ is defined by the implementation, the complex types, the header <complex.h> and all of the names listed here are not provided. (since C11) The C programming language, as of C99, supports complex number math with the three built-in types double _Complex, float _Complex, and long double _Complex (see _Complex). When the header <complex.h> is included, the three complex number types are also accessible as double complex, float complex, long

Defined in header <math.h> float log1pf( float arg ); (1) (since C99) double log1p( double arg ); (2) (since C99) long double log1pl( long double arg ); (3) (since C99) Defined in header <tgmath.h> #define log1p( arg ) (4) (since C99) 1-3) Computes the natural (base e) logarithm of 1+arg. This function is more precise than the expression log(1+arg) if arg is close to zero. 4) Type-generic macro: If arg has type long double, log1pl

Defined in header <wchar.h> int wscanf( const wchar_t *format, ... ); (1) (since C95) int fwscanf( FILE *stream, const wchar_t *format, ... ); (2) (since C95) int swscanf( const wchar_t *buffer, const wchar_t *format, ... ); (3) (since C95) int wscanf_s( const wchar_t *restrict format, ...); (4) (since C11) int fwscanf_s( FILE *restrict stream, const wchar_t *restrict format, ...); (5) (since C11) int swscanf_s( const wchar_t *restrict

Defined in header <ctype.h> int islower( int ch ); Checks if the given character is classified as a lowercase character according to the current C locale. In the default "C" locale, islower returns true only for the lowercase letters (abcdefghijklmnopqrstuvwxyz). If islower returns true, it is guaranteed that iscntrl, isdigit, ispunct, and isspace return false for the same character in the same C locale. The behavior is undefined if the value of ch is not representable as u

Defined in header <math.h> float powf( float base, float exponent ); (1) (since C99) double pow( double base, double exponent ); (2) long double powl( long double base, long double exponent ); (3) (since C99) Defined in header <tgmath.h> #define pow( base, exponent ) (4) (since C99) 1-3) Computes the value of base raised to the power exponent. 4) Type-generic macro: If any argument has type long double, powl is called. Otherwise, if any argu

Escape sequences are used to represent certain special characters within string literals and character constants. The following escape sequences are available. ISO C requires a diagnostic if the backslash is followed by any character not listed here: Escape sequence Description Representation \' single quote byte 0x27 (in ASCII encoding) \" double quote byte 0x22 (in ASCII encoding) \? question mark byte 0x3f (in ASCII encoding) \\ backslash byte 0x5c (in ASCII enco

Defined in header <complex.h> float complex cexpf( float complex z ); (1) (since C99) double complex cexp( double complex z ); (2) (since C99) long double complex cexpl( long double complex z ); (3) (since C99) Defined in header <tgmath.h> #define exp( z ) (4) (since C99) 1-3) Computes the complex base-e exponential of z. 4) Type-generic macro: If z has type long double complex, cexpl is called. if z has type double complex, cexp

Defined in header <fenv.h> int fesetround( int round ); (1) (since C99) int fegetround(); (2) (since C99) 1) Attempts to establish the floating-point rounding direction equal to the argument argument round, which is expected to be one of the floating point rounding macros. 2) Returns the value of the floating point rounding macro that corresponds to the current rounding direction. Parameters round - rounding direction, one of floating point rounding macros