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.\"     @(#)isinf.3	8.2 (Berkeley) 1/29/94
.\" $FreeBSD: src/lib/libc/gen/isinf.3,v 1.5.2.3 2003/05/04 22:25:22 murray Exp $
.\" $DragonFly: src/lib/libc/gen/isinf.3,v 1.2 2003/06/17 04:26:42 dillon Exp $
.\"
.Dd January 29, 1994
.Dt ISINF 3
.Os
.Sh NAME
.Nm isinf ,
.Nm isnan ,
.Nm isnanf
.Nd test for infinity or not-a-number
.Sh LIBRARY
.Lb libc
.Sh SYNOPSIS
.In math.h
.Ft int
.Fn isinf double
.Ft int
.Fn isnan double
.Ft int
.Fn isnanf float
.Sh DESCRIPTION
The
.Fn isinf
function
returns 1 if the number is
.Dq \\*(If ,
otherwise 0.
.Pp
The
.Fn isnan
and
.Fn isnanf
functions
return 1 if the double or float (respectively) is
.Dq not-a-number ,
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.