Determines whether its argument value is an infinity.

[Classification]

Mathematical library

[Syntax]

#include <math.h>

int isinf(real-floating x); (C99)

[Return value]

If the argument is positive or negative infinite, a value other than 0 is returned.

In other cases, 0 is returned.

[Description]

This macro determines whether its argument value is an infinity (positive or negative).

If a type other than the floating-point type is passed to the argument, correct operation is not guaranteed.