.\" Copyright (c) 2003 David Schultz <das@FreeBSD.org>
.\" All rights reserved.
.\"
.\" Redistribution and use in source and binary forms, with or without
.\" modification, are permitted provided that the following conditions
.\" are met:
.\" 1. Redistributions of source code must retain the above copyright
.\"    notice, this list of conditions and the following disclaimer.
.\" 2. Redistributions in binary form must reproduce the above copyright
.\"    notice, this list of conditions and the following disclaimer in the
.\"    documentation and/or other materials provided with the distribution.
.\"
.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
.\" ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
.\" SUCH DAMAGE.
.\"
.\" $FreeBSD: head/lib/libc/gen/isgreater.3 208291 2010-05-19 08:57:53Z uqs $
.\"
.Dd February 12, 2003
.Dt ISGREATER 3
.Os
.Sh NAME
.Nm isgreater , isgreaterequal , isless , islessequal ,
.Nm islessgreater , isunordered
.Nd "compare two floating-point numbers"
.Sh LIBRARY
.Lb libc
.Sh SYNOPSIS
.In math.h
.Ft int
.Fn isgreater "real-floating x" "real-floating y"
.Ft int
.Fn isgreaterequal "real-floating x" "real-floating y"
.Ft int
.Fn isless "real-floating x" "real-floating y"
.Ft int
.Fn islessequal "real-floating x" "real-floating y"
.Ft int
.Fn islessgreater "real-floating x" "real-floating y"
.Ft int
.Fn isunordered "real-floating x" "real-floating y"
.Sh DESCRIPTION
Each of the macros
.Fn isgreater ,
.Fn isgreaterequal ,
.Fn isless ,
.Fn islessequal ,
and
.Fn islessgreater
take arguments
.Fa x
and
.Fa y
and return a non-zero value if and only if its nominal
relation on
.Fa x
and
.Fa y
is true.
These macros always return zero if either
argument is not a number (NaN), but unlike the corresponding C
operators, they never raise a floating point exception.
.Pp
The
.Fn isunordered
macro takes arguments
.Fa x
and
.Fa y
and returns non-zero if and only if neither
.Fa x
nor
.Fa y
are NaNs.
For any pair of floating-point values, one
of the relationships (less, greater, equal, unordered) holds.
.Sh SEE ALSO
.Xr fpclassify 3 ,
.Xr math 3 ,
.Xr signbit 3
.Sh STANDARDS
The
.Fn isgreater ,
.Fn isgreaterequal ,
.Fn isless ,
.Fn islessequal ,
.Fn islessgreater ,
and
.Fn isunordered
macros conform to
.St -isoC-99 .
.Sh HISTORY
The relational macros described above first appeared in
.Fx 5.1 .