1.\"	$OpenBSD: isblank.3,v 1.13 2017/09/05 03:16:13 schwarze Exp $
2.\"
3.\" Copyright (c) 1991 The Regents of the University of California.
4.\" Copyright (c) 2017 Ingo Schwarze <schwarze@openbsd.org>
5.\" All rights reserved.
6.\"
7.\" This code is derived from software contributed to Berkeley by
8.\" the American National Standards Committee X3, on Information
9.\" Processing Systems.
10.\"
11.\" Redistribution and use in source and binary forms, with or without
12.\" modification, are permitted provided that the following conditions
13.\" are met:
14.\" 1. Redistributions of source code must retain the above copyright
15.\"    notice, this list of conditions and the following disclaimer.
16.\" 2. Redistributions in binary form must reproduce the above copyright
17.\"    notice, this list of conditions and the following disclaimer in the
18.\"    documentation and/or other materials provided with the distribution.
19.\" 3. Neither the name of the University nor the names of its contributors
20.\"    may be used to endorse or promote products derived from this software
21.\"    without specific prior written permission.
22.\"
23.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
24.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
25.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
26.\" ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
27.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
28.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
29.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
30.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
31.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
32.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
33.\" SUCH DAMAGE.
34.\"
35.Dd $Mdocdate: September 5 2017 $
36.Dt ISBLANK 3
37.Os
38.Sh NAME
39.Nm isblank ,
40.Nm isblank_l
41.Nd blank-space single-byte character test
42.Sh SYNOPSIS
43.In ctype.h
44.Ft int
45.Fn isblank "int c"
46.Ft int
47.Fn isblank_l "int c" "locale_t locale"
48.Sh DESCRIPTION
49The
50.Fn isblank
51and
52.Fn isblank_l
53functions test for blank-space characters.
54In the C locale, the complete list of blank-space characters is:
55.Pp
56.Bl -tag -width xxxxx -offset indent -compact
57.It Sq \0
58Space character.
59.It Li \et
60Horizontal tab.
61.El
62.Pp
63.Ox
64always uses the C locale for these functions,
65ignoring the global locale, the thread-specific locale, and the
66.Fa locale
67argument.
68.Sh RETURN VALUES
69These functions return zero if the character tests false or
70non-zero if the character tests true.
71.Sh ENVIRONMENT
72On systems supporting non-ASCII single-byte character encodings,
73these functions may return non-zero for additional characters,
74and the results of
75.Fn isblank
76may depend on the
77.Ev LC_CTYPE
78.Xr locale 1 .
79.Sh SEE ALSO
80.Xr isalnum 3 ,
81.Xr isalpha 3 ,
82.Xr isascii 3 ,
83.Xr iscntrl 3 ,
84.Xr isdigit 3 ,
85.Xr isgraph 3 ,
86.Xr islower 3 ,
87.Xr isprint 3 ,
88.Xr ispunct 3 ,
89.Xr isspace 3 ,
90.Xr isupper 3 ,
91.Xr iswblank 3 ,
92.Xr isxdigit 3 ,
93.Xr stdio 3 ,
94.Xr toascii 3 ,
95.Xr tolower 3 ,
96.Xr toupper 3 ,
97.Xr ascii 7
98.Sh STANDARDS
99The
100.Fn isblank
101function conforms to
102.St -isoC-99 ,
103and
104.Fn isblank_l
105to
106.St -p1003.1-2008 .
107.Sh HISTORY
108The
109.Fn isblank
110function has been available since
111.Bx 4.4 ,
112and
113.Fn isblank_l
114since
115.Ox 6.2 .
116.Sh CAVEATS
117The argument
118.Fa c
119must be
120.Dv EOF
121or representable as an
122.Li unsigned char ;
123otherwise, the result is undefined.
124