NAME

isinf, isnan − test for indeterminate floating point values

SYNOPSIS

int isinf(value)
double value;

int isnan(value)
double value;

DESCRIPTION

Isinf returns a value of 1 if its value is an IEEE format infinity (0x7ff000000x00000000) or negative infinity, and returns a zero otherwise. Isnan returns a value of 1 if its value is an IEEE format ‘not-a-number’ (0x7ffnnnnn0xnnnnnnnn, where n is not zero) or its negative, and returns a zero otherwise. 

Some library routines such as ecvt(3) do not handle indeterminate floating point values gracefully. Prospective arguments to such routines should be checked with isinf or isnan before calling these routines. 

Sun System Release 0.3  —  26 April 1983