2003-04-12  Paolo Carlini  <pcarlini at unitus dot it>

	* include/ext/stdio_filebuf.h
	(stdio_filebuf::stdio_filebuf(int, openmode, bool, size_t),
	stdio_filebuf::stdio_filebuf(__c_file*, openmode, size_t):
	_M_buf_size_opt == 0 means only "not to use an allocated buffer"
	since a stack-based buffer is used for small values of the size_t
	parameter.
	* include/bits/fstream.tcc (basic_filebuf::_M_really_overflow).
	If _M_buf_size != 0 flush out the buffer (any kind, stack-based too).
	* testsuite/ext/stdio_filebuf_2.cc: New testfile.

From-SVN: r65513