|
NAME | SYNOPSIS | DESCRIPTION | RETURN VALUE | ATTRIBUTES | CONFORMING TO | NOTES | SEE ALSO | COLOPHON |
MBRTOWC(3) Linux Programmer's Manual MBRTOWC(3)
mbrtowc - convert a multibyte sequence to a wide character
#include <wchar.h>
size_t mbrtowc(wchar_t *pwc, const char *s, size_t n, mbstate_t *ps);
The main case for this function is when s is not NULL and pwc is not
NULL. In this case, the mbrtowc() 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 the shift state *ps. If the converted wide
character is not L'\0' (the null wide character), it returns the
number of bytes that were consumed from s. If the converted wide
character is L'\0', it resets the shift state *ps to the initial
state and returns 0.
If the n bytes starting at s do not contain a complete multibyte
character, mbrtowc() returns (size_t) -2. This can happen even if n
>= 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, mbrtowc() returns
(size_t) -1 and sets errno to EILSEQ. In this case, the effects on
*ps are undefined.
A different case is when s is not NULL but pwc is NULL. In this
case, the mbrtowc() 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.
If the conversion state represented by *ps denotes an incomplete
multibyte character conversion, the mbrtowc() function returns
(size_t) -1, sets errno to EILSEQ, and leaves *ps in an undefined
state. Otherwise, the mbrtowc() function puts *ps in the initial
state and returns 0.
In all of the above cases, if ps is NULL, a static anonymous state
known only to the mbrtowc() function is used instead. Otherwise, *ps
must be a valid mbstate_t object. An mbstate_t object a can be
initialized to the initial state by zeroing it, for example using
memset(&a, 0, sizeof(a));
The mbrtowc() function returns the number of bytes parsed from the
multibyte sequence starting at s, if a non-L'\0' wide character was
recognized. It returns 0, if a L'\0' wide character was recognized.
It returns (size_t) -1 and sets errno to EILSEQ, if an invalid
multibyte sequence was encountered. It returns (size_t) -2 if it
couldn't parse a complete multibyte character, meaning that n should
be increased.
For an explanation of the terms used in this section, see
attributes(7).
┌──────────┬───────────────┬────────────────────────────┐
│Interface │ Attribute │ Value │
├──────────┼───────────────┼────────────────────────────┤
│mbrtowc() │ Thread safety │ MT-Unsafe race:mbrtowc/!ps │
└──────────┴───────────────┴────────────────────────────┘
POSIX.1-2001, POSIX.1-2008, C99.
The behavior of mbrtowc() depends on the LC_CTYPE category of the
current locale.
mbsinit(3), mbsrtowcs(3)
This page is part of release 4.12 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/.
GNU 2015-08-08 MBRTOWC(3)
Pages that refer to this page: btowc(3), mbrlen(3), mbsinit(3), mbsnrtowcs(3), mbsrtowcs(3), mbtowc(3), wprintf(3)