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MBRLEN(3)                BSD Library Functions Manual                MBRLEN(3)

NAME
     mbrlen, mbrlen_l -- get number of bytes in a character (restartable)

LIBRARY
     Standard C Library (libc, -lc)

SYNOPSIS
     #include <wchar.h>

     size_t
     mbrlen(const char *restrict s, size_t n, mbstate_t *restrict ps);

     #include <wchar.h>
     #include <xlocale.h>

     size_t
     mbrlen_l(const char *restrict s, size_t n, mbstate_t *restrict ps, locale_t loc);

DESCRIPTION
     The mbrlen() function inspects at most n bytes, pointed to by s, to determine the number of bytes
     needed to complete the next multibyte character.

     The mbstate_t argument, ps, is used to keep track of the shift state.  If it is NULL, mbrlen() uses an
     internal, static mbstate_t object, which is initialized to the initial conversion state at program
     startup.

     It is equivalent to:

           mbrtowc(NULL, s, n, ps);

     Except that, when ps is a NULL pointer, mbrlen() uses its own static, internal mbstate_t object to keep
     track of the shift state.

     Although the mbrlen() function uses the current locale, the mbrlen_l() function may be passed a locale
     directly. See xlocale(3) for more information.

RETURN VALUES
     The mbrlen() functions returns:

     0       The next n or fewer bytes represent the null wide character (L'\0').

     >0      The next n or fewer bytes represent a valid character, mbrlen() returns the number of bytes
             used to complete the multibyte character.

     (size_t)-2
             The next n contribute to, but do not complete, a valid multibyte character sequence, and all n
             bytes have been processed.

     (size_t)-1
             An encoding error has occurred.  The next n or fewer bytes do not contribute to a valid multi-byte multibyte
             byte character.

EXAMPLES
     A function that calculates the number of characters in a multibyte character string:

           size_t
           nchars(const char *s)
           {
                   size_t charlen, chars;
                   mbstate_t mbs;

                   chars = 0;
                   memset(&mbs, 0, sizeof(mbs));
                   while ((charlen = mbrlen(s, MB_CUR_MAX, &mbs)) != 0 &&
                       charlen != (size_t)-1 && charlen != (size_t)-2) {
                           s += charlen;
                           chars++;
                   }

                   return (chars);
           }

ERRORS
     The mbrlen() function will fail if:

     [EILSEQ]           An invalid multibyte sequence was detected.

     [EINVAL]           The conversion state is invalid.

SEE ALSO
     mblen(3), mbrtowc(3), multibyte(3), xlocale(3)

STANDARDS
     The mbrlen() function conforms to ISO/IEC 9899:1999 (``ISO C99'').

BSD                              April 7, 2004                             BSD