The main case for this function is when s is
not NULL and wc is not
In this case, the
converts the wide character wc
to its multibyte representation and stores it
at the beginning of the character
array pointed to by s.
It updates the shift state *ps, and
returns the length of said multibyte representation,
that is, the number of bytes
written at s.
A different case is when s is not NULL but wc is L'\0'.
function stores at
the character array pointed to by
s the shift sequence needed to
bring *ps back to the initial state,
followed by a '\0' byte.
It updates the shift state *ps (i.e., brings
it into the initial state),
and returns the length of the shift sequence plus
one, that is, the number of bytes written at s.
A third case is when s is NULL.
In this case wc is ignored,
and the function effectively returns wcrtomb(buf,L'\0',ps) where
buf is an internal anonymous buffer.
In all of the above cases, if ps is a NULL pointer, a static anonymous
state only known to the
function is used instead.
function returns the number of
bytes that have been or would
have been written to the byte array at s.
If wc can not be
represented as a multibyte sequence (according to the current locale),
is returned, and errno set to EILSEQ.
The behavior of
depends on the
category of the