function is like the
function, except that
the number of bytes to be converted, starting at *src, is limited to
If dest is not a NULL pointer, the
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
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.
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,
and errno is set to EILSEQ.
The nms limit forces a stop,
or 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
(which has the side effect of bringing back *ps to the
In this case *src is set to NULL, and the number of wide
characters written to dest,
excluding the terminating L'\0' character,
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.
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
is returned, and errno set to EILSEQ.
This function is a GNU extension.
The behavior of
depends on the
category of the