mbsrtowcs - convert a multibyte string to a wide-character string
#include <wchar.h>
size_t mbsrtowcs(wchar_t *dest, const char **src,
size_t len, mbstate_t *ps);
If dest
is not NULL, the mbsrtowcs()
function converts the multibyte string *src
to a wide-character
string starting at dest
. At most len
wide characters
are written to dest
. The shift state *ps
is updated.
The conversion is effectively performed by repeatedly calling
mbrtowc(dest, *src, n, ps)
where n
is some positive
number, as long as this call succeeds, and then incrementing
dest
by one and *src
by the number of bytes consumed.
The conversion can stop for three reasons:
An invalid multibyte sequence has been encountered. In this case,
*src
is left pointing to the invalid multibyte sequence,
(size_t) -1
is returned, and errno
is set to
EILSEQ.
len
non-L'\0' wide characters have been stored at
dest
. In this case, *src
is left pointing to the next
multibyte sequence to be converted, and the number of wide characters
written to dest
is returned.
The multibyte string has been completely converted, including the
terminating null wide character ('\0'), which has the side effect of
bringing back *ps
to the initial state. In this case,
*src
is set to NULL, and the number of wide characters written
to dest
, excluding the terminating null wide character, is
returned.
If dest
is NULL, len
is ignored, and the conversion
proceeds as above, except that the converted wide characters are not
written out to memory, and that no length limit exists.
In both of the above cases, if ps
is NULL, a static
anonymous state known only to the mbsrtowcs() function
is used instead.
The programmer must ensure that there is room for at least
len
wide characters at dest
.
For an explanation of the terms used in this section, see attributes(7).
Interface | Attribute | Value |
mbsrtowcs() | Thread safety | MT-Unsafe race:mbsrtowcs/!ps |
POSIX.1-2001, POSIX.1-2008, C99.
The behavior of mbsrtowcs() depends on the LC_CTYPE category of the current locale.
Passing NULL as ps
is not multithread safe.
iconv(3), mbrtowc(3), mbsinit(3), mbsnrtowcs(3), mbstowcs(3)
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and the latest version of this page, can be found at
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