|MBLEN(3)||Library Functions Manual||MBLEN(3)|
mblen — get number
of bytes in a multibyte character
char *s, size_t
mblen() function usually determines
the number of bytes in a multibyte character pointed to by
s and returns it. This function shall only examine max
n bytes of the array beginning from s.
In state-dependent encodings, s may point
the special sequence bytes to change the shift-state. Although such sequence
bytes corresponds to no individual wide-character code, the
mblen() changes the own state by them and treats
them as if they are a part of the subsequent multibyte character.
Unlike mbrlen(3), the first n bytes pointed to by s need to form an entire multibyte character. Otherwise, this function causes an error.
mblen() is equivalent to the following
call, except the internal state of the
mbtowc(3) function is not affected:
mbtowc(NULL, s, n);
Calling any other functions in libc never change
the internal state of the
mblen(), except for
calling setlocale(3) with the
LC_CTYPE category changed to that of the current
locale. Such setlocale(3) calls cause
the internal state of this function to be indeterminate.
The behaviour of
mblen() is affected by
LC_CTYPE category of the current locale.
There are special cases:
mblen() initializes its own internal state to an initial state, and determines whether the current encoding is state-dependent. This function returns 0 if the encoding is state-independent, otherwise non-zero.
mblen() always fails.
mblen() also sets errno to indicate the error.
When s is equal to
mblen() may causes an error in the
mblen() function conforms to
|June 5, 2013||OpenBSD-current|