isinf
ISINF(3) Linux Programmer's Manual ISINF(3)
NAME
isinf, isnan, finite - test for infinity or not-a-number (NaN)
SYNOPSIS
#include <math.h>
int isinf(double value);
int isnan(double value);
int finite(double value);
DESCRIPTION
The isinf() function returns -1 if value represents negative infinity,
1 if value represents positive infinity, and 0 otherwise.
The isnan() function returns a non-zero value if value is "not-a-num-
ber" (NaN), and 0 otherwise.
The finite() function returns a non-zero value if value is neither
infinite nor a "not-a-number" (NaN) value, and 0 otherwise.
CONFORMING TO
BSD 4.3
GNU 1993-06-02 ISINF(3)