--- /dev/null
+// 2003-06-25 Paolo Carlini <pcarlini@unitus.it>
+
+// Copyright (C) 2003, 2009 Free Software Foundation, Inc.
+//
+// This file is part of the GNU ISO C++ Library. This library is free
+// software; you can redistribute it and/or modify it under the
+// terms of the GNU General Public License as published by the
+// Free Software Foundation; either version 3, or (at your option)
+// any later version.
+
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU General Public License for more details.
+
+// You should have received a copy of the GNU General Public License along
+// with this library; see the file COPYING3. If not see
+// <http://www.gnu.org/licenses/>.
+
+// 27.8.1.4 Overridden virtual functions
+
+// { dg-require-fileio "" }
+
+#include <fstream>
+#include <testsuite_hooks.h>
+
+void test01()
+{
+ bool test __attribute__((unused)) = true;
+ using namespace std;
+
+ filebuf fb_out, fb_in_out;
+
+ fb_out.open("tmp_underflow.tst", ios::out);
+ fb_out.sputc('S');
+ fb_out.sputc('T');
+ fb_out.close();
+
+ fb_in_out.open("tmp_underflow.tst", ios::in | ios::out);
+ while (fb_in_out.sbumpc() != filebuf::traits_type::eof());
+
+ VERIFY( fb_in_out.sputc('x') == 'x' );
+ fb_in_out.close();
+}
+
+int main()
+{
+ test01();
+}