xref: /freebsd/lib/libc/locale/isdigit.3 (revision 39ee7a7a6bdd1557b1c3532abf60d139798ac88b)
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32.\"     @(#)isdigit.3	8.1 (Berkeley) 6/4/93
33.\" $FreeBSD$
34.\"
35.Dd May 4, 2007
36.Dt ISDIGIT 3
37.Os
38.Sh NAME
39.Nm isdigit, isnumber
40.Nd decimal-digit character test
41.Sh LIBRARY
42.Lb libc
43.Sh SYNOPSIS
44.In ctype.h
45.Ft int
46.Fn isdigit "int c"
47.Ft int
48.Fn isnumber "int c"
49.Ft int
50.Fn isdigit_l "int c" "locale_t loc"
51.Ft int
52.Fn isnumber_l "int c" "locale_t loc"
53.Sh DESCRIPTION
54The
55.Fn isdigit
56function tests for a decimal digit character.
57Regardless of locale, this includes the following characters only:
58.Bl -column \&``0''______ \&``0''______ \&``0''______ \&``0''______ \&``0''______
59.It "\&``0''" Ta "``1''" Ta "``2''" Ta "``3''" Ta "``4''"
60.It "\&``5''" Ta "``6''" Ta "``7''" Ta "``8''" Ta "``9''"
61.El
62.Pp
63The
64.Fn isnumber
65function behaves similarly to
66.Fn isdigit ,
67but may recognize additional characters, depending on the current locale
68setting.
69.Pp
70The value of the argument must be representable as an
71.Vt "unsigned char"
72or the value of
73.Dv EOF .
74.Pp
75The _l-suffixed versions take an explicit locale argument, whereas the
76non-suffixed versions use the current global or per-thread locale.
77.Sh RETURN VALUES
78The
79.Fn isdigit
80and
81.Fn isnumber
82functions return zero if the character tests false and
83return non-zero if the character tests true.
84.Sh COMPATIBILITY
85The
86.Bx 4.4
87extension of accepting arguments outside of the range of the
88.Vt "unsigned char"
89type in locales with large character sets is considered obsolete
90and may not be supported in future releases.
91The
92.Fn iswdigit
93function should be used instead.
94.Sh SEE ALSO
95.Xr ctype 3 ,
96.Xr iswdigit 3 ,
97.Xr multibyte 3 ,
98.Xr xlocale 3 ,
99.Xr ascii 7
100.Sh STANDARDS
101The
102.Fn isdigit
103function conforms to
104.St -isoC .
105The
106.Fn isdigit_l
107function conforms to
108.St -p1003.1-2008 .
109.Sh HISTORY
110The
111.Fn isnumber
112function appeared in
113.Bx 4.4 .
114