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The mysterious _M_output_unshift
- From: Paolo Carlini <pcarlini at unitus dot it>
- To: libstdc++ at gcc dot gnu dot org
- Cc: Benjamin Kosnik <bkoz at redhat dot com>, Nathan Myers <ncm at cantrip dot org>
- Date: Mon, 21 Apr 2003 11:34:14 +0200
- Subject: The mysterious _M_output_unshift
Hi,
I'm currently trying to understand in better detail basic_filebuf
(in particular seekoff) in order to simplify _M_*_cur_move, the
last remaining CPU hog in the implementation of sputc(), sbumpc(),
etc.
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:
#if 0
// XXX not done
if (_M_last_overflowed)
{
_M_output_unshift();
_M_really_overflow(__eof);
}
#endif
Thank you very much in advance!
Paolo.