xref: /freebsd/lib/libc/locale/isdigit.3 (revision 3642298923e528d795e3a30ec165d2b469e28b40)
1.\" Copyright (c) 1991, 1993
2.\"	The Regents of the University of California.  All rights reserved.
3.\"
4.\" This code is derived from software contributed to Berkeley by
5.\" the American National Standards Committee X3, on Information
6.\" Processing Systems.
7.\"
8.\" Redistribution and use in source and binary forms, with or without
9.\" modification, are permitted provided that the following conditions
10.\" are met:
11.\" 1. Redistributions of source code must retain the above copyright
12.\"    notice, this list of conditions and the following disclaimer.
13.\" 2. Redistributions in binary form must reproduce the above copyright
14.\"    notice, this list of conditions and the following disclaimer in the
15.\"    documentation and/or other materials provided with the distribution.
16.\" 3. All advertising materials mentioning features or use of this software
17.\"    must display the following acknowledgement:
18.\"	This product includes software developed by the University of
19.\"	California, Berkeley and its contributors.
20.\" 4. Neither the name of the University nor the names of its contributors
21.\"    may be used to endorse or promote products derived from this software
22.\"    without specific prior written permission.
23.\"
24.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
25.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
26.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
27.\" ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
28.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
29.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
30.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
31.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
32.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
33.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
34.\" SUCH DAMAGE.
35.\"
36.\"     @(#)isdigit.3	8.1 (Berkeley) 6/4/93
37.\" $FreeBSD$
38.\"
39.Dd July 17, 2005
40.Dt ISDIGIT 3
41.Os
42.Sh NAME
43.Nm isdigit, isnumber
44.Nd decimal-digit character test
45.Sh LIBRARY
46.Lb libc
47.Sh SYNOPSIS
48.In ctype.h
49.Ft int
50.Fn isdigit "int c"
51.Ft int
52.Fn isnumber "int c"
53.Sh DESCRIPTION
54The
55.Fn isdigit
56function tests for a decimal digit character.
57Regardless of locale, this includes the following characters only:
58.Pp
59.Bl -column \&``0''______ \&``0''______ \&``0''______ \&``0''______ \&``0''______
60.It "\&``0''\t``1''\t``2''\t``3''\t``4''"
61.It "\&``5''\t``6''\t``7''\t``8''\t``9''"
62.El
63.Pp
64The
65.Fn isnumber
66function behaves similarly to
67.Fn isdigit ,
68but may recognize additional characters, depending on the current locale
69setting.
70.Pp
71The value of the argument must be representable as an
72.Vt unsigned char
73or the value of
74.Dv EOF .
75.Sh RETURN VALUES
76The
77.Fn isdigit
78and
79.Fn isnumber
80functions return zero if the character tests false and
81returns non-zero if the character tests true.
82.Sh COMPATIBILITY
83The
84.Bx 4.4
85extension of accepting arguments outside of the range of the
86.Vt "unsigned char"
87type in locales with large character sets is considered obsolete
88and may not be supported in future releases.
89The
90.Fn iswdigit
91function should be used instead.
92.Sh SEE ALSO
93.Xr ctype 3 ,
94.Xr iswdigit 3 ,
95.Xr multibyte 3 ,
96.Xr ascii 7
97.Sh STANDARDS
98The
99.Fn isdigit
100function conforms to
101.St -isoC .
102.Sh HISTORY
103The
104.Fn isnumber
105function appeared in
106.Bx 4.4 .
107