MBLEN(3C) Standard C Library Functions MBLEN(3C)

NAME

mblen, mblen_l - get number of bytes in a character

SYNOPSIS

#include <stdlib.h>

int mblen(const char *s, size_t n);

#include <stdlib.h>
#include <xlocale.h>

int mblen_l(const char *s, size_t n, locale_t loc);

DESCRIPTION

If s is not a null pointer, mblen() and mblen_l() determine the number of
bytes constituting the character pointed to by s. The call

mblen(s, n);

is equivalent to:

mbtowc((wchar_t *)0, s, n);

A call with s as a null pointer causes this function to return 0.

Whereas the behavior of the mblen() function is affected by the LC_CTYPE
category of the current locale, the behavior of mblen_l() is affected by
the LC_CTYPE category of the locale specified by loc.

RETURN VALUES

If s is a null pointer, mblen() and mblen_l() returns 0. It s is not a
null pointer, mblen() and mblen_l() returns 0 (if s points to the null
byte), the number of bytes that constitute the character (if the next n
or fewer bytes form a valid character), or -1 (if they do not form a
valid character) and may set errno to indicate the error. In no case will
the value returned be greater than n or the value of the MB_CUR_MAX
macro.

ERRORS

The mblen() and mblen_l() functions may fail if:

EILSEQ
Invalid character sequence is detected.

ATTRIBUTES

See attributes(7) for descriptions of the following attributes:


+--------------------+-----------------+
| ATTRIBUTE TYPE | ATTRIBUTE VALUE |
+--------------------+-----------------+
|CSI | Enabled |
+--------------------+-----------------+
|Interface Stability | See below. |
+--------------------+-----------------+
|MT-Level | MT-Safe |
+--------------------+-----------------+

The mblen() function is Standard. The mblen_l() function is Uncommitted.

SEE ALSO

mbstowcs(3C), mbtowc(3C), newlocale(3C), setlocale(3C), wcstombs(3C),
wctomb(3C), uselocale(3C) attributes(7), standards(7)

June 24, 2014 MBLEN(3C)