ISINF(F) Linux Programmer's Manual ISINF(F) 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 nega- tive infinity, 1 if value represents positive infinity, and 0 otherwise. The isnan() function returns a non-zero value if value is "not-a-number" (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(F)