Add section numbers to references and fix .Xr abuse
[dragonfly.git] / lib / libc / gen / isdigit.3
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1.\" Copyright (c) 1991, 1993
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4.\" This code is derived from software contributed to Berkeley by
5.\" the American National Standards Committee X3, on Information
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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 $
1de703da 38.\" $DragonFly: src/lib/libc/gen/isdigit.3,v 1.2 2003/06/17 04:26:44 dillon Exp $
984263bc
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39.\"
40.Dd June 4, 1993
41.Dt ISDIGIT 3
42.Os
43.Sh NAME
44.Nm isdigit
45.Nd decimal-digit character test
46.Sh LIBRARY
47.Lb libc
48.Sh SYNOPSIS
49.In ctype.h
50.Ft int
51.Fn isdigit "int c"
52.Sh DESCRIPTION
53The
54.Fn isdigit
55function tests for any decimal-digit character.
56For single C
57.Va char Ns s
58locales (see
59.Xr multibyte 3 )
60the value of the argument is
61representable as an
62.Li unsigned char
63or the value of
64.Dv EOF .
65In the ASCII character set, this includes the following characters
66(with their numeric values shown in octal):
67.Pp
68.Bl -column \&000_``0''__ \&000_``0''__ \&000_``0''__ \&000_``0''__ \&000_``0''__
69.It "\&060\ ``0'' \t061\ ``1'' \t062\ ``2'' \t063\ ``3'' \t064\ ``4''"
70.It "\&065\ ``5'' \t066\ ``6'' \t067\ ``7'' \t070\ ``8'' \t071\ ``9''"
71.El
72.Sh RETURN VALUES
73The
74.Fn isdigit
75function returns zero if the character tests false and
76returns non-zero if the character tests true.
77.Sh SEE ALSO
78.Xr ctype 3 ,
79.Xr multibyte 3 ,
80.Xr ascii 7
81.Sh STANDARDS
82The
83.Fn isdigit
84function conforms to
85.St -isoC .