The mysterious _M_output_unshift

[Benjamin Kosnik]

>As part of this I would really appreciate some help about the
>rationale behind basic_filebuf::_M_output_unshift, currently
>completely empty, and also about this code in basic_filebuf::close:

It's a placeholder. See:

27.8.1.3 - Member functions p 6

"calls a_codecvt.unshift (possibly several times) to determine a
termination sequence, inserts those characters and calls overflow(EOF)
again"

-benjamin