.\" Copyright (c) 1991, 1993
.\"	The Regents of the University of California.  All rights reserved.
.\"
.\" %sccs.include.redist.man%
.\"
.\"     @(#)isinf.3	8.1 (Berkeley) 06/04/93
.\"
.Dd 
.Dt ISINF 3
.Os
.Sh NAME
.Nm isinf ,
.Nm isnan
.Nd test for infinity or not-a-number (\*(Na)
.Sh SYNOPSIS
.Ft int 
.Fn isinf double
.Ft int 
.Fn isnan double
.Sh DESCRIPTION
The
.Fn isninf
function
returns 1 if the number is
.Dq \\*(If ,
otherwise 0.
.Pp
The
.Fn isnan
function
returns 1 if the number is
.Dq \\*(Na ,
otherwise 0.
.Sh SEE ALSO
.Xr math 3
.Rs
.%T "IEEE Standard for Binary Floating-Point Arithmetic"
.%Q ANSI
.%R Std 754-1985
.Re
.Sh BUGS
Neither the
.Tn VAX
nor the Tahoe floating point have distinguished values
for either infinity or not-a-number.
These routines always return 0 on those architectures.