ISINF(3) BSD Library Functions Manual ISINF(3)NAME
isinf, isnan — test for infinity or not-a-number
SYNOPSIS
int
isinf(double);
int
isnan(double);
DESCRIPTION
The isninf() function returns 1 if the number is “∞”, otherwise 0.
The isnan() function returns 1 if the number is “not-a-number”, otherwise
0.
SEE ALSOmath(3)
IEEE Standard for Binary Floating-Point Arithmetic, Std 754-1985, ANSI.
BUGS
Neither the VAX nor the Tahoe floating point have distinguished values
for either infinity or not-a-number. These routines always return 0 on
those architectures.
BSD January 29, 1994 BSD