re PR libstdc++/9533 (Can't read from tty with ifstream)

re PR libstdc++/9533 (Can't read from tty with ifstream)

2003-03-28  Paolo Carlini  <pcarlini@unitus.it>
	    Nathan Myers  <ncm@cantrip.org>

	PR libstdc++/9533
	* include/bits/fstream.tcc (basic_filebuf<>::open): Don't
	call underflow().
	(basic_filebuf<>::showmanyc): Use the information provided
	by codecvt and __basic_file<>::showmanyc_helper to implement
	a non-trivial showmanyc.
	* config/io/basic_file_stdio.h
	(__basic_file<>::showmanyc_helper): New, declare.
	* config/io/basic_file_stdio.cc
	(__basic_file<>::showmanyc_helper): Define.
	(__basic_file<>::_M_open_mode): Don't set O_NONBLOCK.
	(__basic_file<char>::open): Don't call fcntl().
	* acinclude.m4 (GLIBCPP_CHECK_S_ISREG_OR_S_IFREG,
	GLIBCPP_CHECK_POLL): New macros.
	* configure.in: Call here.
	* acconfig.h: Add #undefs for the corresponding symbols.
	* aclocal.m4: Regenerate.
	* configure: Regenerate.
	* config.h.in: Regenerate.

Co-Authored-By: Nathan Myers <ncm@cantrip.org>
From-SVN: r64978