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 char-
acter.
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 infor-
mation.
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 char-
acter.
(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 multibyte character.
EXAMPLES
A function that calculates the number of characters in a multibyte char-
acter 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
Mac OS X 10.5 - Generated Sun Oct 28 21:34:56 EDT 2007