Name

isnand, isnanf − test for floating point NaN (Not-A-Number)

Syntax

#include <ieeefp.h>

int isnand (dsrc)
double dsrc;

int isnanf (fsrc)
float fsrc;

Description

The isnand and isnanf routines return the value 1 for true if the argument dsrc or fsrc is a NaN; otherwise they return the value 0 for false.

Neither routine generates any exception, even for signaling NaNs. 

The isnan function is implemented as a macro included in <ieeefp.h>.