signbit() — Determines whether the sign of its argument is negative

Standards

Standards / Extensions	C or C++	Dependencies
C99 Single UNIX Specification, Version 3	both	z/OS V1R8

Format

#define _ISOC99_SOURCE
#include <math.h>

int signbit(real-floating x);

#define __STDC_WANT_DEC_FP__
#include <math.h>

int signbit(real-floating x);  /* C only */
int signbit(decimal-floating x);  /* C only */
bool signbit(real-floating x);  /* C++ only */
bool signbit(decimal-floating x);  /* C++ only */


#define _TR1_C99
#include <math.h>

bool signbit(real-floating x);  /* C++ only */

General description

The signbit() macro or function template determines whether the sign of its argument value is negative.

Function	Hex	IEEE
signbit	X	X

Notes:

To use IEEE decimal floating-point, the hardware must have the Decimal Floating-Point Facility installed.
This function works in IEEE decimal floating-point format. See "IEEE Decimal Floating-Point" for more information.

Returned value

The signbit() macro returns 1 if the sign of its argument value is negative, else returns 0. The C++ function template returns true if the sign of its argument value is negative, else returns false.

Related information

math.h