.\" Copyright (c) 2003 Mike Barcroft <mike@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: src/lib/libc/gen/fpclassify.3,v 1.5 2004/07/09 06:37:44 das Exp $ .\" .Dd December 11, 2006 .Dt FPCLASSIFY 3 .Os .Sh NAME .Nm fpclassify , isfinite , isinf , isnan , isnormal .Nd "classify a floating-point number" .Sh LIBRARY .Lb libm .Sh SYNOPSIS .In math.h .Ft int .Fn fpclassify "real-floating x" .Ft int .Fn isfinite "real-floating x" .Ft int .Fn isinf "real-floating x" .Ft int .Fn isnan "real-floating x" .Ft int .Fn isnormal "real-floating x" .Sh DESCRIPTION The .Fn fpclassify macro takes an argument of .Fa x and returns one of the following manifest constants. .Bl -tag -width ".Dv FP_SUBNORMAL" .It Dv FP_INFINITE Indicates that .Fa x is an infinite number. .It Dv FP_NAN Indicates that .Fa x is not a number (NaN). .It Dv FP_NORMAL Indicates that .Fa x is a normalized number. .It Dv FP_SUBNORMAL Indicates that .Fa x is a denormalized number. .It Dv FP_ZERO Indicates that .Fa x is zero (0 or \-0). .El .Pp The .Fn isfinite macro returns a non-zero value if and only if its argument has a finite (zero, subnormal, or normal) value. The .Fn isinf , .Fn isnan , and .Fn isnormal macros return non-zero if and only if .Fa x is an infinity, NaN, or a non-zero normalized number, respectively. .Sh SEE ALSO .Xr isgreater 3 , .Xr math 3 , .Xr signbit 3 .Sh STANDARDS The .Fn fpclassify , .Fn isfinite , .Fn isinf , .Fn isnan , and .Fn isnormal macros conform to .St -isoC-99 . .Sh HISTORY .Bx 3 introduced .Fn isinf and .Fn isnan functions, which accepted .Vt double arguments; these have been superseded by the macros described above.