| '\" t |
| .\" Copyright (c) Bruno Haible <haible@clisp.cons.org> |
| .\" |
| .\" SPDX-License-Identifier: GPL-2.0-or-later |
| .\" |
| .\" 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 (date) "Linux man-pages (unreleased)" |
| .SH NAME |
| mblen \- determine number of bytes in next multibyte character |
| .SH LIBRARY |
| Standard C library |
| .RI ( libc ,\~ \-lc ) |
| .SH SYNOPSIS |
| .nf |
| .B #include <stdlib.h> |
| .P |
| .BI "int mblen(const char " s [. n "], 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. |
| .P |
| If the |
| .I 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. |
| .P |
| If the multibyte string starting at |
| .I s |
| contains an invalid multibyte |
| sequence before the next complete character, |
| .BR mblen () |
| also returns \-1. |
| .P |
| 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; |
| lbx lb lb |
| l l l. |
| Interface Attribute Value |
| T{ |
| .na |
| .nh |
| .BR mblen () |
| T} Thread safety MT-Unsafe race |
| .TE |
| .SH VERSIONS |
| The function |
| .BR mbrlen (3) |
| provides a better interface to the same |
| functionality. |
| .SH STANDARDS |
| C11, POSIX.1-2008. |
| .SH HISTORY |
| POSIX.1-2001, C99. |
| .SH NOTES |
| The behavior of |
| .BR mblen () |
| depends on the |
| .B LC_CTYPE |
| category of the |
| current locale. |
| .SH SEE ALSO |
| .BR mbrlen (3) |
