------- Comment #10 from pcarlini at suse dot de 2008-02-25 13:11 ------- Note, anyway, that there is a serious blocker to any enhancement in this area (and of course it explains the current behavior): if wcin & co are converting, they deal with the underlying stream as a narrow-character oriented stream. But when the stream is synced it must be possible to mix char-by-char with wchar_t C stdio operations, which require a wide-character orientation of the stream, whereas, per C99 7.19.2, the orientation of a stream cannot be changed after opening.
-- http://gcc.gnu.org/bugzilla/show_bug.cgi?id=35353