MBTOWC
Section: Linux Programmer's Manual (3)
Updated: 2016-10-08
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NAME
mbtowc - convert a multibyte sequence to a wide character
SYNOPSIS
#include <stdlib.h>
int mbtowc(wchar_t *pwc, const char *s, size_t n);
DESCRIPTION
The main case for this function is when
s
is not NULL and
pwc
is
not NULL.
In this case, the
mbtowc()
function inspects at most
n
bytes of the multibyte string starting at
s,
extracts the next complete
multibyte character, converts it to a wide character and stores it at
*pwc.
It updates an internal shift state known only to the
mbtowc()
function.
If
s
does not point to a null byte (aq\0aq), it returns the number
of bytes that were consumed from
s,
otherwise it returns 0.
If the
n
bytes starting at
s
do not contain a complete multibyte
character, or if they contain an invalid multibyte sequence,
mbtowc()
returns -1.
This can happen even if
n
>=
MB_CUR_MAX,
if the multibyte string contains redundant shift sequences.
A different case is when
s
is not NULL but
pwc
is NULL.
In this case, the
mbtowc()
function behaves as above, except that it does not
store the converted wide character in memory.
A third case is when
s
is NULL.
In this case,
pwc
and
n
are
ignored.
The
mbtowc()
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
If
s
is not NULL, the
mbtowc()
function returns the number of
consumed bytes starting at
s,
or 0 if
s
points to a null byte,
or -1 upon failure.
If
s
is NULL, the
mbtowc()
function
returns nonzero if the encoding
has nontrivial shift state, or zero if the encoding is stateless.
ATTRIBUTES
For an explanation of the terms used in this section, see
attributes(7).
| Interface | Attribute | Value
|
|
mbtowc()
| Thread safety | MT-Unsafe race
|
CONFORMING TO
POSIX.1-2001, POSIX.1-2008, C99.
NOTES
The behavior of
mbtowc()
depends on the
LC_CTYPE
category of the
current locale.
This function is not multithread safe.
The function
mbrtowc(3)
provides
a better interface to the same functionality.
SEE ALSO
MB_CUR_MAX(3),
mblen(3),
mbrtowc(3),
mbstowcs(3),
wcstombs(3),
wctomb(3)
COLOPHON
This page is part of release 4.13 of the Linux
man-pages
project.
A description of the project,
information about reporting bugs,
and the latest version of this page,
can be found at
https://www.kernel.org/doc/man-pages/.
Index
- NAME
-
- SYNOPSIS
-
- DESCRIPTION
-
- RETURN VALUE
-
- ATTRIBUTES
-
- CONFORMING TO
-
- NOTES
-
- SEE ALSO
-
- COLOPHON
-
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