1.\"	$OpenBSD: isalnum.3,v 1.12 2017/09/05 03:16:13 schwarze Exp $
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35.Dd $Mdocdate: September 5 2017 $
36.Dt ISALNUM 3
37.Os
38.Sh NAME
39.Nm isalnum ,
40.Nm isalnum_l
41.Nd alphanumeric single-byte character test
42.Sh SYNOPSIS
43.In ctype.h
44.Ft int
45.Fn isalnum "int c"
46.Ft int
47.Fn isalnum_l "int c" "locale_t locale"
48.Sh DESCRIPTION
49The
50.Fn isalnum
51function tests for any character for which
52.Xr isalpha 3
53or
54.Xr isdigit 3
55is true, and
56.Fn isalnum_l
57tests for any character for which
58.Xr isalpha_l 3
59or
60.Xr isdigit_l 3
61is true.
62.Pp
63In the C locale, the complete list of alphanumeric characters
64is A\(enZ, a\(enz, 0, and 1\(en9.
65.Ox
66always uses the C locale for these functions,
67ignoring the global locale, the thread-specific locale, and the
68.Fa locale
69argument.
70.Sh RETURN VALUES
71These functions return zero if the character tests false or
72non-zero if the character tests true.
73.Sh ENVIRONMENT
74On systems supporting non-ASCII single-byte character encodings,
75these functions may return non-zero for additional characters,
76and the results of
77.Fn isalnum
78may depend on the
79.Ev LC_CTYPE
80.Xr locale 1 .
81.Sh SEE ALSO
82.Xr isalpha 3 ,
83.Xr isascii 3 ,
84.Xr isblank 3 ,
85.Xr iscntrl 3 ,
86.Xr isdigit 3 ,
87.Xr isgraph 3 ,
88.Xr islower 3 ,
89.Xr isprint 3 ,
90.Xr ispunct 3 ,
91.Xr isspace 3 ,
92.Xr isupper 3 ,
93.Xr iswalnum 3 ,
94.Xr isxdigit 3 ,
95.Xr stdio 3 ,
96.Xr toascii 3 ,
97.Xr tolower 3 ,
98.Xr toupper 3 ,
99.Xr ascii 7
100.Sh STANDARDS
101The
102.Fn isalnum
103function conforms to
104.St -ansiC ,
105and
106.Fn isalnum_l
107to
108.St -p1003.1-2008 .
109.Sh HISTORY
110The
111.Fn isalnum
112function first appeared in
113.At v7 ,
114and
115.Fn isalnum_l
116has been available since
117.Ox 6.2 .
118.Sh CAVEATS
119The argument
120.Fa c
121must be
122.Dv EOF
123or representable as an
124.Li unsigned char ;
125otherwise, the result is undefined.
126