freebsd-dev/lib/libc/gen/fpclassify.3

128 lines
3.0 KiB
Groff
Raw Normal View History

.\" 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.
.\"
.\" $FreeBSD$
.\"
.Dd July 8, 2004
.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
2003-06-01 19:19:59 +00:00
.Fa x
and returns one of the following manifest constants.
.Bl -tag -width ".Dv FP_SUBNORMAL"
.It Dv FP_INFINITE
Indicates that
2003-06-01 19:19:59 +00:00
.Fa x
is an infinite number.
.It Dv FP_NAN
Indicates that
2003-06-01 19:19:59 +00:00
.Fa x
is not a number (NaN).
.It Dv FP_NORMAL
Indicates that
2003-06-01 19:19:59 +00:00
.Fa x
is a normalized number.
.It Dv FP_SUBNORMAL
Indicates that
2003-06-01 19:19:59 +00:00
.Fa x
is a denormalized number.
.It Dv FP_ZERO
Indicates that
2003-06-01 19:19:59 +00:00
.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
2003-06-01 19:19:59 +00:00
a finite (zero, subnormal, or normal) value.
The
.Fn isinf ,
.Fn isnan ,
and
.Fn isnormal
macros return non-zero if and only if
2003-06-01 19:19:59 +00:00
.Fa x
is an infinity, NaN,
or a non-zero normalized number, respectively.
.Pp
The symbol
.Fn isnanf
is provided as an alias to
.Fn isnan
for compatibility, and its use is deprecated.
.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
The
.Fn fpclassify ,
.Fn isfinite ,
.Fn isinf ,
.Fn isnan ,
and
.Fn isnormal
macros were added in
.Fx 5.1 .
.Bx 3
introduced
.Fn isinf
and
.Fn isnan
functions, which accepted
2003-06-01 19:19:59 +00:00
.Vt double
arguments; these have been superseded by the macros
described above.