MBRLEN(3C) Standard C Library Functions MBRLEN(3C)

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

#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);

If s is not a null pointer, mbrlen() and mbrlen_l() determine the number of bytes constituting the character pointed to by s. The call

mbrlen(s, n, ps);

is equivalent to:

mbstate_t internal;
mbrtowc(NULL, s, n, ps != NULL ? ps : &internal);

If ps is a null pointer, the mbrlen() and mbrlen_l() functions use their own internal mbstate_t object, which is initialized at program startup to the initial conversion state. Otherwise, the mbstate_t object pointed to by ps is used to completely describe the current conversion state of the associated character sequence. The implementation will behave as if no function defined in the Reference Manual calls mbrlen().

The behavior of mbrlen() is affected by the LC_CTYPE category of the current locale. See environ(7). The behavior of mbrlen_l() does not use the current environment and instead uses the locale specified by loc.

The mbrlen() and mbrlen_l() functions return the first of the following that applies:

0

If the next n or fewer bytes complete the character that corresponds to the null wide-character.

positive

If the next n or fewer bytes complete a valid character; the value returned is the number of bytes that complete the character.

(size_t)−2

If the next n bytes contribute to an incomplete but potentially valid character, and all n bytes have been processed. When n has at least the value of the MB_CUR_MAX macro, this case can only occur if s points at a sequence of redundant shift sequences (for implementations with state-dependent encodings).

(size_t)−1

If an encoding error occurs, in which case the next n or fewer bytes do not contribute to a complete and valid character. In this case, EILSEQ is stored in errno and the conversion state is undefined.

The mbrlen() and mbrlen_l() functions may fail if:

EINVAL

The ps argument points to an object that contains an invalid conversion state.

EILSEQ

Invalid character sequence is detected.

See attributes(7) for descriptions of the following attributes:

ATTRIBUTE TYPE ATTRIBUTE VALUE
Interface Stability See below.
MT-Level MT-Safe

The mbrlen() function is Standard. The mbrlen_l() function is Uncommitted.

mbrtowc(3C), mbsinit(3C), newlocale(3C), setlocale(3C), attributes(7), environ(7), standards(7)

If ps is not a null pointer, mbrlen() uses the mbstate_t object pointed to by ps and the function can be used safely in multithreaded applications, as long as setlocale(3C) is not being called to change the locale or a per-thread locale has been installed on the calling thread with uselocale(3C). If ps is a null pointer, mbrlen() uses its internal mbstate_t object and the function is Unsafe in multithreaded applications.

February 17, 2023 OmniOS