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[dragonfly.git] / lib / libc / gen / isdigit.3
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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.
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36.\" @(#)isdigit.3 8.1 (Berkeley) 6/4/93
37.\" $FreeBSD: src/lib/libc/locale/isdigit.3,v 1.6.2.5 2001/12/14 18:33:54 ru Exp $
38.\"
39.Dd June 4, 1993
40.Dt ISDIGIT 3
41.Os
42.Sh NAME
43.Nm isdigit
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.Sh DESCRIPTION
52The
53.Fn isdigit
54function tests for any decimal-digit character.
55For single C
56.Va char Ns s
57locales (see
58.Xr multibyte 3 )
59the value of the argument is
60representable as an
61.Li unsigned char
62or the value of
63.Dv EOF .
64In the ASCII character set, this includes the following characters
65(with their numeric values shown in octal):
66.Pp
67.Bl -column \&000_``0''__ \&000_``0''__ \&000_``0''__ \&000_``0''__ \&000_``0''__
68.It "\&060\ ``0'' \t061\ ``1'' \t062\ ``2'' \t063\ ``3'' \t064\ ``4''"
69.It "\&065\ ``5'' \t066\ ``6'' \t067\ ``7'' \t070\ ``8'' \t071\ ``9''"
70.El
71.Sh RETURN VALUES
72The
73.Fn isdigit
74function returns zero if the character tests false and
75returns non-zero if the character tests true.
76.Sh SEE ALSO
77.Xr ctype 3 ,
78.Xr multibyte 3 ,
79.Xr ascii 7
80.Sh STANDARDS
81The
82.Fn isdigit
83function conforms to
84.St -isoC .