.\" Copyright (c) Bruno Haible <haible@clisp.cons.org>

.\"

.\" %%%LICENSE_START(GPLv2+_DOC_ONEPARA)

.\" This is free documentation; you can redistribute it and/or

.\" modify it under the terms of the GNU General Public License as

.\" published by the Free Software Foundation; either version 2 of

.\" the License, or (at your option) any later version.

.\" %%%LICENSE_END

.\"

.\" References consulted:

.\"   GNU glibc-2 source code and manual

.\"   Dinkumware C library reference http://www.dinkumware.com/

.\"   OpenGroup's Single UNIX specification http://www.UNIX-systems.org/online.html

.\"   ISO/IEC 9899:1999

.\"

.TH MBLEN 3  2015-08-08 "GNU" "Linux Programmer's Manual"

.SH NAME

mblen \- determine number of bytes in next multibyte character

.SH SYNOPSIS

.nf

.B #include <stdlib.h>

.PP

.BI "int mblen(const char *" s ", size_t " n );

.fi

.SH DESCRIPTION

If

.I s

is not NULL, the

.BR mblen ()

function inspects at most

.I n

bytes of the multibyte string starting at

.I s

and extracts the

next complete multibyte character.

It uses a static anonymous shift state known only to the

.BR mblen ()

function.

If the multibyte character is not the null wide

character, it returns the number of bytes that were consumed from

.IR s .

If the multibyte character is the null wide character, it returns 0.

.PP

If the

.IR n

bytes starting at

.I s

do not contain a complete multibyte

character,

.BR mblen ()

returns \-1.

This can happen even if

.I n

is greater than or equal to

.IR MB_CUR_MAX ,

if the multibyte string contains redundant shift sequences.

.PP

If the multibyte string starting at

.I s

contains an invalid multibyte

sequence before the next complete character,

.BR mblen ()

also returns \-1.

.PP

If

.I s

is NULL, the

.BR mblen ()

function

.\" The Dinkumware doc and the Single UNIX specification say this, but

.\" glibc doesn't implement this.

resets the shift state, known to only this function, to the initial state, and

returns nonzero if the encoding has nontrivial shift state, or zero if the

encoding is stateless.

.SH RETURN VALUE

The

.BR mblen ()

function returns the number of

bytes parsed from the multibyte

sequence starting at

.IR s ,

if a non-null wide character was recognized.

It returns 0, if a null wide character was recognized.

It returns \-1, if an

invalid multibyte sequence was encountered or if it couldn't parse a complete

multibyte character.

.SH ATTRIBUTES

For an explanation of the terms used in this section, see

.BR attributes (7).

.TS

allbox;

lb lb lb

l l l.

Interface	Attribute	Value

T{

.BR mblen ()

T}	Thread safety	MT-Unsafe race

.TE

.SH CONFORMING TO

POSIX.1-2001, POSIX.1-2008, C99.

.SH NOTES

The behavior of

.BR mblen ()

depends on the

.B LC_CTYPE

category of the

current locale.

.PP

The function

.BR mbrlen (3)

provides a better interface to the same

functionality.

.SH SEE ALSO

.BR mbrlen (3)

.SH COLOPHON

This page is part of release 4.15 of the Linux

.I man-pages

project.

A description of the project,

information about reporting bugs,

and the latest version of this page,

can be found at

\%https://www.kernel.org/doc/man\-pages/.