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MBLEN(3) Linux Programmer's Manual MBLEN(3)

NAME

     mblen - determine number of bytes in next multibyte character

SYNOPSIS

     #include <stdlib.h>

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

DESCRIPTION

     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  char-
     acter,  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  state-
     less.

RETURN VALUE

     The mblen() function returns the number of bytes parsed from the multi-
     byte sequence starting at s, if a non-null wide  character  was  recog-
     nized.   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.

ATTRIBUTES

     For   an   explanation   of   the  terms  used  in  this  section,  see
     attributes(7).

     +----------+---------------+----------------+
     |Interface | Attribute     | Value          |
     +----------+---------------+----------------+
     |mblen()   | Thread safety | MT-Unsafe race |
     +----------+---------------+----------------+

CONFORMING TO

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

NOTES

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

     The  function  mbrlen(3)  provides a better interface to the same func-
     tionality.