.\"	$OpenBSD: isgreater.3,v 1.3 2011/07/07 13:30:28 jmc Exp $
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.\" Copyright (c) 2003 David Schultz <das@FreeBSD.ORG>
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.\" $FreeBSD: src/lib/libc/gen/isgreater.3,v 1.3 2005/02/06 03:23:31 das Exp $
.\"
.Dd $Mdocdate: July 7 2011 $
.Dt ISGREATER 3
.Os
.Sh NAME
.Nm isgreater ,
.Nm isgreaterequal ,
.Nm isless ,
.Nm islessequal ,
.Nm islessgreater ,
.Nm isunordered
.Nd compare two floating-point numbers
.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
.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
.Ox 4.4 .