.\" Copyright 1993 David Metcalfe (david@prism.demon.co.uk)
.\" May be distributed under the GNU General Public License
.\" References consulted:
.\"     Linux libc source code
.\"     Lewine's _POSIX Programmer's Guide_ (O'Reilly & Associates, 1991)
.\"     386BSD man pages
.\" Modified Sat Jul 24 19:07:26 1993 by Rik Faith (faith@cs.unc.edu)
.TH ISINF 3  "June 2, 1993" "GNU" "Linux Programmer's Manual"
.SH NAME
isinf, isnan, finite \- test for infinity or not-a-number (NaN)
.SH SYNOPSIS
.nf
.B #include <math.h>
.sp
.BI "int isinf(double " value );
.sp
.BI "int isnan(double " value );
.sp
.BI "int finite(double " value );
.fi
.SH DESCRIPTION
The \fBisinf()\fP function returns -1 if \fIvalue\fP represents negative
infinity, 1 if \fIvalue\fP represents positive infinity, and 0 otherwise.
.PP
The \fBisnan()\fP function returns a non-zero value if \fIvalue\fP is
"not-a-number" (NaN), and 0 otherwise.
.PP
The \fBfinite()\fP function returns a non-zero value if \fIvalue\fP is
finite or is not a "not-a-number" (NaN) value, and 0 otherwise.
.SH "CONFORMING TO"
BSD 4.3