xref: /freebsd/lib/libc/locale/mblen.3 (revision 13464e4a44fc58490a03bb8bfc7e3c972e9c30b2)
1.\" Copyright (c) 2002-2004 Tim J. Robbins. All rights reserved.
2.\" Copyright (c) 1993
3.\"	The Regents of the University of California.  All rights reserved.
4.\"
5.\" This code is derived from software contributed to Berkeley by
6.\" Donn Seeley of BSDI.
7.\"
8.\" Redistribution and use in source and binary forms, with or without
9.\" modification, are permitted provided that the following conditions
10.\" are met:
11.\" 1. Redistributions of source code must retain the above copyright
12.\"    notice, this list of conditions and the following disclaimer.
13.\" 2. Redistributions in binary form must reproduce the above copyright
14.\"    notice, this list of conditions and the following disclaimer in the
15.\"    documentation and/or other materials provided with the distribution.
16.\" 3. Neither the name of the University nor the names of its contributors
17.\"    may be used to endorse or promote products derived from this software
18.\"    without specific prior written permission.
19.\"
20.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
21.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
22.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
23.\" ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
24.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
25.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
26.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
27.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
28.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
29.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
30.\" SUCH DAMAGE.
31.\"
32.\" From @(#)multibyte.3	8.1 (Berkeley) 6/4/93
33.\" From FreeBSD: src/lib/libc/locale/multibyte.3,v 1.22 2003/11/08 03:23:11 tjr Exp
34.\" $FreeBSD$
35.\"
36.Dd April 11, 2004
37.Dt MBLEN 3
38.Os
39.Sh NAME
40.Nm mblen
41.Nd get number of bytes in a character
42.Sh LIBRARY
43.Lb libc
44.Sh SYNOPSIS
45.In stdlib.h
46.Ft int
47.Fn mblen "const char *mbchar" "size_t nbytes"
48.Sh DESCRIPTION
49The
50.Fn mblen
51function computes the length in bytes
52of a multibyte character
53.Fa mbchar
54according to the current conversion state.
55Up to
56.Fa nbytes
57bytes are examined.
58.Pp
59A call with a null
60.Fa mbchar
61pointer returns nonzero if the current locale requires shift states,
62zero otherwise;
63if shift states are required, the shift state is reset to the initial state.
64.Sh RETURN VALUES
65If
66.Fa mbchar
67is
68.Dv NULL ,
69the
70.Fn mblen
71function returns nonzero if shift states are supported,
72zero otherwise.
73.Pp
74Otherwise, if
75.Fa mbchar
76is not a null pointer,
77.Fn mblen
78either returns 0 if
79.Fa mbchar
80represents the null wide character, or returns
81the number of bytes processed in
82.Fa mbchar ,
83or returns \-1 if no multibyte character
84could be recognized or converted.
85In this case,
86.Fn mblen Ns 's
87internal conversion state is undefined.
88.Sh ERRORS
89The
90.Fn mblen
91function will fail if:
92.Bl -tag -width Er
93.It Bq Er EILSEQ
94An invalid multibyte sequence was detected.
95.It Bq Er EINVAL
96The internal conversion state is not valid.
97.El
98.Sh SEE ALSO
99.Xr mbrlen 3 ,
100.Xr mbtowc 3 ,
101.Xr multibyte 3
102.Sh STANDARDS
103The
104.Fn mblen
105function conforms to
106.St -isoC-99 .
107