DESCRIPTION

If s is not a NULL pointer, the mblen() function inspects at most n bytes of the multibyte string starting at s and extracts the next complete multibyte character. It uses a static anonymous shift state only known to the mblen() function. If the multibyte character is not the null wide character, it returns the number of bytes that were consumed from s. If the multibyte character is the null wide character, it returns 0.

If the n bytes starting at s do not contain a complete multibyte character, mblen() returns −1. This can happen even if n is greater than or equal to MB_CUR_MAX, if the multibyte string contains redundant shift sequences.

If the multibyte string starting at s contains an invalid multibyte sequence before the next complete character, mblen() also returns −1.

If s is a NULL pointer, the mblen() function resets the shift state, only known to this function, to the initial state, and returns nonzero if the encoding has nontrivial shift state, or zero if the encoding is stateless.

RETURN VALUE

The mblen() function returns the number of bytes parsed from the multibyte sequence starting at s, if a non-null wide character was recognized. It returns 0, if a null wide character was recognized. It returns −1, if an invalid multibyte sequence was encountered or if it couldn't parse a complete multibyte character.

CONFORMING TO

C99.

NOTES

The behavior of mblen() depends on the LC_CTYPE category of the current locale.

The function mbrlen(3) provides a better interface to the same functionality.

SEE ALSO

mbrlen(3)