1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
|
.\" $OpenBSD: tolower.3,v 1.14 2017/09/05 03:16:13 schwarze Exp $
.\"
.\" Copyright (c) 1989, 1991 The Regents of the University of California.
.\" Copyright (c) 2017 Ingo Schwarze <schwarze@openbsd.org>
.\" All rights reserved.
.\"
.\" This code is derived from software contributed to Berkeley by
.\" the American National Standards Committee X3, on Information
.\" Processing Systems.
.\"
.\" Redistribution and use in source and binary forms, with or without
.\" modification, are permitted provided that the following conditions
.\" are met:
.\" 1. Redistributions of source code must retain the above copyright
.\" notice, this list of conditions and the following disclaimer.
.\" 2. Redistributions in binary form must reproduce the above copyright
.\" notice, this list of conditions and the following disclaimer in the
.\" documentation and/or other materials provided with the distribution.
.\" 3. Neither the name of the University nor the names of its contributors
.\" may be used to endorse or promote products derived from this software
.\" without specific prior written permission.
.\"
.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
.\" SUCH DAMAGE.
.\"
.Dd $Mdocdate: September 5 2017 $
.Dt TOLOWER 3
.Os
.Sh NAME
.Nm tolower ,
.Nm tolower_l ,
.Nm _tolower
.Nd upper case to lower case letter conversion
.Sh SYNOPSIS
.In ctype.h
.Ft int
.Fn tolower "int c"
.Ft int
.Fn tolower_l "int c" "locale_t locale"
.Ft int
.Fn _tolower "int c"
.Sh DESCRIPTION
The
.Fn tolower
and
.Fn tolower_l
functions convert an upper-case letter to the corresponding lower-case
letter.
The
.Fn _tolower
function is identical to
.Fn tolower
except that
.Fa c
must be an upper-case letter.
.Pp
.Ox
always uses the C locale for these functions,
ignoring the global locale, the thread-specific locale, and the
.Fa locale
argument.
.Sh RETURN VALUES
If the argument to the
.Fn tolower
or
.Fn tolower_l
function is an upper-case letter, the corresponding lower-case letter
is returned if there is one; otherwise the argument is returned unchanged.
If the argument to the
.Fn _tolower
function is an upper-case letter, the corresponding lower-case letter
is returned; otherwise the output is undefined.
.Sh ENVIRONMENT
On systems supporting non-ASCII single-byte character encodings,
the results of
.Fn tolower
and
.Fn _tolower
may depend on the
.Ev LC_CTYPE
.Xr locale 1 .
.Sh SEE ALSO
.Xr isalnum 3 ,
.Xr isalpha 3 ,
.Xr isascii 3 ,
.Xr isblank 3 ,
.Xr iscntrl 3 ,
.Xr isdigit 3 ,
.Xr isgraph 3 ,
.Xr islower 3 ,
.Xr isprint 3 ,
.Xr ispunct 3 ,
.Xr isspace 3 ,
.Xr isupper 3 ,
.Xr isxdigit 3 ,
.Xr stdio 3 ,
.Xr toascii 3 ,
.Xr toupper 3 ,
.Xr towlower 3 ,
.Xr ascii 7
.Sh STANDARDS
The
.Fn tolower
and
.Fn _tolower
functions conform to
.St -ansiC ,
and
.Fn tolower_l
to
.St -p1003.1-2008 .
.Sh HISTORY
The
.Fn tolower
function first appeared in
.At v7
and acquired the current semantics in
.At III ,
where
.Fn _tolower
first appeared.
.Pp
The
.Fn tolower_l
function has been available since
.Ox 6.2 .
.Sh CAVEATS
The argument
.Fa c
must be
.Dv EOF
or representable as an
.Li unsigned char ;
otherwise, the result is undefined.
|
