std_sstream.h (basic_stringbuf(ios_base::openmode)): Don't use _M_stringbuf_init, keep the pointers null, per 27.7.1.1.

2004-09-29  Paolo Carlini  <pcarlini@suse.de>

	* include/std/std_sstream.h (basic_stringbuf(ios_base::openmode)):
	Don't use _M_stringbuf_init, keep the pointers null, per 27.7.1.1.
	(str()): Slightly tweak, protect from pptr() == 0.
	(_M_update_egptr()): Likewise.
	* include/bits/sstream.tcc (ssekoff, seekpos): In order to check
	for an empty buffer use __beg instead of _M_string.capacity().
	* testsuite/27_io/basic_stringbuf/cons/char/1.cc: New.
	* testsuite/27_io/basic_stringbuf/cons/wchar_t/1.cc: Likewise.

	* testsuite/27_io/basic_filebuf/cons/char/1.cc: New.
	* testsuite/27_io/basic_filebuf/cons/wchar_t/1.cc: Likewise.
	* testsuite/27_io/basic_streambuf/cons/char/1.cc: Update.
	* testsuite/27_io/basic_streambuf/cons/wchar_t/1.cc: Likewise.

2004-09-29  Paolo Carlini  <pcarlini@suse.de>
	    Benjamin Kosnik  <bkoz@redhat.com>

	* testsuite/testsuite_io.h (class constraint_buf): New, extended
	and templatized version of constraint_filebuf; add typedefs for
	streambuf/stringbuf/filebuf and wchar_t counterparts.

Co-Authored-By: Benjamin Kosnik <bkoz@redhat.com>

From-SVN: r88307