isfinite() — Determines if its argument has a finite value

Standards

Standards / Extensions	C or C++	Dependencies
C99 Single UNIX Specification, Version 3 C/C++ DFP C++ TR1 C99	both	z/OS V1R8

Format

#define _ISOC99_SOURCE
#include <math.h>

int isfinite(real-floating x);

#define __STDC_WANT_DEC_FP__
#include <math.h>

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

#define _TR1_C99
#include <math.h>

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

General description

The isfinite() macro or function template determines if its argument has a finite value.

Function	Hex	IEEE
isfinite	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 isfinite() macro returns 1 if and only if its argument value is finite, else returns 0. The C++ function template returns true if and only if its argument value is finite, else returns false.

Special behavior in hex: The isfinite() macro always returns 1. The C++ function template always returns true.

Related information

math.h