| MBLEN(3) | Library Functions Manual | MBLEN(3) | 
mblen —
#include <stdlib.h>
int
  
  mblen(const
    char *s, size_t
  n);
mblen() function usually determines the number of
  bytes in a multibyte character pointed to by s and
  returns it. This function shall only examine max n bytes of the array
  beginning from s.
In state-dependent encodings, s may point
    the special sequence bytes to change the shift-state. Although such sequence
    bytes corresponds to no individual wide-character code, the
    mblen() changes the own state by them and treats
    them as if they are a part of the subsequent multibyte character.
Unlike mbrlen(3), the first n bytes pointed to by s need to form an entire multibyte character. Otherwise, this function causes an error.
mblen() is equivalent to the following
    call, except the internal state of the
    mbtowc(3) function is not
    affected:
mbtowc(NULL, s, n);
Calling any other functions in Standard
    C Library (libc, -lc) never changes the internal state of
    mblen(), except for calling
    setlocale(3) with the
    LC_CTYPE category changed to that of the current
    locale. Such setlocale(3)
    calls cause the internal state of this function to be indeterminate.
The behaviour of mblen() is affected by
    the LC_CTYPE category of the current locale.
These are the special cases:
mblen() initializes its own internal state to an
      initial state, and determines whether the current encoding is
      state-dependent. This function returns 0 if the encoding is
      state-independent, otherwise non-zero.mblen() always fails.mblen() returns:
MB_CUR_MAX macro.mblen() also sets
      errno to indicate the error.When s is equal to
    NULL, the mblen()
  returns:
mblen() may cause an error in the following case:
EILSEQ]mblen() function conforms to ANSI
  X3.159-1989 (“ANSI C89”).
| February 3, 2002 | NetBSD 9.3 |