The
mbsnrtowcs()
function is like the
mbsrtowcs(3)
function, except that
the number of bytes to be converted, starting at *src, is limited to
nms.
If dest is not a NULL pointer, the
mbsnrtowcs()
function converts at
most nms bytes from 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:
1.
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.
2.
The nms limit forces a stop,
or len non-Laq\0aq 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.
3.
The multibyte string has been completely converted, including the
terminating aq\0aq
(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 Laq\0aq 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 destination length limit exists.
In both of the above cases, if ps is a NULL pointer, a static anonymous
state only known to the mbsnrtowcs function is used instead.
The programmer must ensure that there is room for at least len wide
characters at dest.
RETURN VALUE
The
mbsnrtowcs()
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, and errno set to EILSEQ.
CONFORMING TO
This function is a GNU extension.
NOTES
The behavior of
mbsnrtowcs()
depends on the
LC_CTYPE
category of the
current locale.
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/.
