If dest is not a NULL pointer,
the
mbstowcs()
function converts the
multibyte string src to a wide-character string starting at dest.
At most n wide characters are written to dest.
The conversion starts
in the initial state.
The conversion can stop for three reasons:
1.
An invalid multibyte sequence has been encountered.
In this case
(size_t) -1
is returned.
2.
n non-Laq\0aq wide characters have been stored at dest.
#include <this>
case the number of wide characters written to dest is returned, but the
shift state at this point is lost.
3.
The multibyte string has been completely converted, including the
terminating aq\0aq.
In this case the number of wide characters written to
dest, excluding the terminating Laq\0aq character, is returned.
The programmer must ensure that there is room for at least n wide
characters at dest.
If dest is NULL, n 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 order to avoid the case 2 above, the programmer should make sure n is
greater or equal to mbstowcs(NULL,src,0)+1.
RETURN VALUE
The
mbstowcs()
function returns the number of wide characters that make
up the converted part of the wide-character string, not including the
terminating null wide character.
If an invalid multibyte sequence was
encountered,
(size_t) -1
is returned.
CONFORMING TO
C99.
NOTES
The behavior of
mbstowcs()
depends on the
LC_CTYPE
category of the
current locale.
The function
mbsrtowcs(3)
provides a better interface to the same
functionality.
This page is part of release 3.14 of the Linux
man-pages
project.
A description of the project,
and information about reporting bugs,
can be found at
http://www.kernel.org/doc/man-pages/.
