113 lines
3.4 KiB
Groff
113 lines
3.4 KiB
Groff
.\" Copyright (c) 1991, 1993
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.\" The Regents of the University of California. All rights reserved.
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.\"
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.\" This code is derived from software contributed to Berkeley by
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.\" the American National Standards Committee X3, on Information
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.\" Processing Systems.
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.\"
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.\" Redistribution and use in source and binary forms, with or without
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.\" modification, are permitted provided that the following conditions
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.\" are met:
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.\" 1. Redistributions of source code must retain the above copyright
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.\" notice, this list of conditions and the following disclaimer.
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.\" 2. Redistributions in binary form must reproduce the above copyright
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.\" notice, this list of conditions and the following disclaimer in the
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.\" documentation and/or other materials provided with the distribution.
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.\" 3. All advertising materials mentioning features or use of this software
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.\" must display the following acknowledgement:
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.\" This product includes software developed by the University of
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.\" California, Berkeley and its contributors.
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.\" 4. Neither the name of the University nor the names of its contributors
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.\" may be used to endorse or promote products derived from this software
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.\" without specific prior written permission.
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.\"
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.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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.\" SUCH DAMAGE.
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.\"
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.\" @(#)isdigit.3 8.1 (Berkeley) 6/4/93
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.\" $FreeBSD$
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.\"
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.Dd March 30, 2004
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.Dt ISDIGIT 3
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.Os
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.Sh NAME
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.Nm isdigit, isnumber
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.Nd decimal-digit character test
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.Sh LIBRARY
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.Lb libc
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.Sh SYNOPSIS
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.In ctype.h
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.Ft int
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.Fn isdigit "int c"
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.Ft int
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.Fn isnumber "int c"
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.Sh DESCRIPTION
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The
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.Fn isdigit
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function tests for a decimal digit character.
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Regardless of locale, this includes the following characters only:
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.Pp
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.Bl -column \&``0''______ \&``0''______ \&``0''______ \&``0''______ \&``0''______
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.It "\&``0''\t``1''\t``2''\t``3''\t``4''"
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.It "\&``5''\t``6''\t``7''\t``8''\t``9''"
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.El
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.Pp
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The
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.Fn isnumber
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function behaves similarly to
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.Fn isdigit ,
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but may recognize additional characters, depending on the current locale
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setting.
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.Pp
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For single C
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.Va char Ns s
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locales (see
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.Xr multibyte 3 )
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the value of the argument is
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representable as an
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.Li unsigned char
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or the value of
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.Dv EOF .
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.Sh RETURN VALUES
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The
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.Fn isdigit
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and
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.Fn isnumber
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functions return zero if the character tests false and
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returns non-zero if the character tests true.
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.Sh COMPATIBILITY
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Although
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.Fn isdigit
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accepts arguments outside of the range of the
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.Vt "unsigned char"
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type in locales with large character sets,
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this is a
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.Bx 4.4
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extension and the
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.Fn iswdigit
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function should be used instead for maximum portability.
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.Sh SEE ALSO
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.Xr ctype 3 ,
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.Xr iswdigit 3 ,
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.Xr multibyte 3 ,
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.Xr ascii 7
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.Sh STANDARDS
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The
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.Fn isdigit
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function conforms to
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.St -isoC .
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.Sh HISTORY
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The
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.Fn isnumber
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function appeared in
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.Bx 4.4 .
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