2010-10-05  David Krauss  <potswa@mac.com>

	PR libstdc++/45841
	* include/bits/fstream.h (basic_filebuf::underflow): Overflow
	success does not preclude returning failure.
	(basic_filebuf::pbackfail): Likewise.
	(basic_filebuf::xsputn): Fix indentation problem.
	(basic_filebuf::xsgetn): Likewise. Also, add similar overflow
	call to enable optimized case from write mode.
	* testsuite/27_io/basic_filebuf/underflow/char/45841.cc: New.
	* testsuite/27_io/basic_filebuf/underflow/wchar_t/45841.cc: Likewise.

From-SVN: r165009