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 (two words 0x7ff00000 0x00000000) or an IEEE negative infinity, and returns a zero otherwise. 

Isnan returns a value of 1 if its value is an IEEE format ‘not-a-number’ (two words 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. 

The FORTRAN Programmer’s Guide for the Sun Workstation describes in detail the format of IEEE standard floating point. 

Sun Release 3.0β  —  Last change: 8 August 1985