isinf
Header: <math.h>
Determines if the given floating-point number arg is positive or negative infinity. The macro returns an integral value.
# Declarations
#define isinf(arg) /* implementation defined */
(since C99)
# Parameters
arg: floating-point value
# Return value
Nonzero integral value if arg has an infinite value, 0 otherwise.
# Example
#include <stdio.h>
#include <math.h>
#include <float.h>
int main(void)
{
printf("isinf(NAN) = %d\n", isinf(NAN));
printf("isinf(INFINITY) = %d\n", isinf(INFINITY));
printf("isinf(0.0) = %d\n", isinf(0.0));
printf("isinf(DBL_MIN/2.0) = %d\n", isinf(DBL_MIN/2.0));
printf("isinf(1.0) = %d\n", isinf(1.0));
printf("isinf(exp(800)) = %d\n", isinf(exp(800)));
}