mblen - determine number of bytes in next multibyte character
int mblen(const char *s, size_t n);
If s is not NULL, 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 known
only 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
If s is NULL, the mblen() function resets the shift
state, known to only this function, to the initial state, and returns
nonzero if the encoding has nontrivial shift state, or zero if the encoding
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.
For an explanation of the terms used in this section, see attributes(7).
POSIX.1-2001, POSIX.1-2008, C99.
The behavior of mblen() depends on the LC_CTYPE category of the
The function mbrlen(3) provides a better interface to the
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