NAME

       mblen - determine number of bytes in next multibyte character

LIBRARY

       Standard C library (libc, -lc)

SYNOPSIS

       #include <stdlib.h>

       int mblen(const char s[.n], 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 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

       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 character.

ATTRIBUTES

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

       ┌────────────────────────────────────────────────────────┬───────────────┬────────────────┐
       │Interface                                               │ Attribute     │ Value          │
       ├────────────────────────────────────────────────────────┼───────────────┼────────────────┤
       │mblen()                                                 │ Thread safety │ MT-Unsafe race │
       └────────────────────────────────────────────────────────┴───────────────┴────────────────┘

VERSIONS

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

STANDARDS

       C11, POSIX.1-2008.

HISTORY

       POSIX.1-2001, C99.

NOTES

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

SEE ALSO

       mbrlen(3)