mblen(3) — Linux manual page


mblen(3)                Library Functions Manual                mblen(3)

NAME         top

       mblen - determine number of bytes in next multibyte character

LIBRARY         top

       Standard C library (libc, -lc)

SYNOPSIS         top

       #include <stdlib.h>

       int mblen(const char s[.n], size_t n);

DESCRIPTION         top

       If s is not NULL, the mblen() function inspects at most n bytes
       of the multibyte string starting at s and extracts the next
       complete multibyte character.  It uses a static anonymous shift
       state known only to the mblen() function.  If the multibyte
       character is not the null wide character, it returns the number
       of bytes that were consumed from s.  If the multibyte character
       is the null wide character, it returns 0.

       If the n bytes starting at s do not contain a complete multibyte
       character, mblen() returns -1.  This can happen even if n is
       greater than or equal to MB_CUR_MAX, if the multibyte string
       contains redundant shift sequences.

       If the multibyte string starting at s contains an invalid
       multibyte sequence before the next complete character, mblen()
       also returns -1.

       If s is NULL, the mblen() function 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.

RETURN VALUE         top

       The mblen() function returns the number of bytes parsed from the
       multibyte sequence starting at 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

ATTRIBUTES         top

       For an explanation of the terms used in this section, see
       │ Interface                    Attribute     Value          │
       │ mblen()                      │ Thread safety │ MT-Unsafe race │

VERSIONS         top

       The function mbrlen(3) provides a better interface to the same

STANDARDS         top

       C11, POSIX.1-2008.

HISTORY         top

       POSIX.1-2001, C99.

NOTES         top

       The behavior of mblen() depends on the LC_CTYPE category of the
       current locale.

SEE ALSO         top


COLOPHON         top

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Linux man-pages 6.9.1          2024-05-02                       mblen(3)

Pages that refer to this page: MB_CUR_MAX(3)mbstowcs(3)mbtowc(3)wcstombs(3)wctomb(3)locale(7)