mbrlen(3C)

NAME

mbrlen() — get number of bytes in a character (restartable)

SYNOPSIS

#include <wchar.h>

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

DESCRIPTION

If s is not a null pointer, mbrlen() determines the number of bytes constituting the character pointed to by s. It is equivalent to:

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

If ps is a null pointer, the mbrlen() function uses its 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.

APPLICATION USAGE

The prototype of this function is available to applications if they are:

a.: c99 conformant.
b.: Compiled with -D_XOPEN_SOURCE macro with a value >=500.
c.: Compiled with -D_POSIX_C_SOURCE macro with a value >= 200112.

EXTERNAL INFLUENCES

Environment Variables

The behavior of this function is affected by the LC_CTYPE category of the current locale.

RETURN VALUE

The mbrlen() function returns 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.

ERRORS

The mbrlen() function may fail if:

EILSEQ: Invalid character sequence is detected.
EINVAL: ps points to an object that contains an invalid conversion state.

AUTHOR

mbrlen() was developed by HP and Mitsubishi Electric Corporation.