_isnan
Checks a given double-precision floating-point value for not a number (NAN).
int _isnan(
double x
);
Parameters
- x
Double-precision floating-point value.
Return Value
_isnan returns a nonzero value if the argument x is a NAN; otherwise it returns 0.
Remarks
The _isnan function tests a given double-precision floating-point value x, returning a nonzero value if x is a not a number (NAN). A NAN is generated when the result of a floating-point operation cannot be represented in Institute of Electrical and Electronics Engineers (IEEE) format. For information about how a NAN is represented for output, see printf.
Requirements
Routine |
Required header |
|---|---|
_isnan |
<float.h> |
For more compatibility information, see Compatibility in the Introduction.
Libraries
All versions of the C run-time libraries.