isinf() — Determines if X is ± infinity
Standards
Standards / Extensions | C or C++ | Dependencies |
---|---|---|
C99 |
both |
z/OS V1R8 |
Format
#define _ISOC99_SOURCE
#include <math.h>
int isinf(real-floating x);
#define __STDC_WANT_DEC_FP__
#include <math.h>
int isinf(real-floating x); /* C only */
int isinf(decimal-floating x); /* C only */
bool isinf(real-floating x); /* C++ only */
#define _TR1_C99
#include <math.h>
bool isinf(real-floating x); /* C++ only */
General description
The isinf() macro or function template determines if its argument is plus or minus infinity.
Function | Hex | IEEE |
---|---|---|
isinf | 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 isinf() macro returns 1 if the argument is plus or minus infinity, else returns 0. The C++ function template returns true if the argument is plus or minus infinity, else returns false.
Special behavior in hex: The isinf() macro returns zero. The C++ function template returns false.