MBLEN(3) | Library Functions Manual | MBLEN(3) |
mblen
— get number
of bytes in a multibyte character
#include
<stdlib.h>
int
mblen
(const
char *s, size_t
n);
The
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 the 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.Normally, mblen
() returns:
MB_CUR_MAX
macro.mblen
() function also sets
errno to indicate the error.When s is equal to
NULL
, mblen
() returns:
The mblen
() function may cause an error in
the following case:
EILSEQ
]The mblen
() function conforms to
ANSI X3.159-1989
(“ANSI C89”).
March 29, 2022 | OpenBSD-current |