--- /dev/null
+// 2001-05-21 Benjamin Kosnik <bkoz@redhat.com>
+
+// Copyright (C) 2001, 2002, 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>
+#include <testsuite_io.h>
+
+// @require@ %-*.tst %-*.txt
+// @diff@ %-*.tst %*.txt
+
+const char name_01[] = "tmp_sputbackc_2out.tst"; // empty file, need to create
+
+// Test overloaded virtual functions.
+void test01()
+{
+ using namespace std;
+ using namespace __gnu_test;
+ typedef std::filebuf::int_type int_type;
+ typedef filebuf::traits_type traits_type;
+
+ bool test __attribute__((unused)) = true;
+ int_type c1, c2;
+
+ // int_type sputbackc(char_type c)
+ // if in_cur not avail || ! traits::eq(c, gptr() [-1]), return pbfail
+ // otherwise decrements in_cur and returns *gptr()
+
+ // out
+ {
+ constraint_filebuf fb_01; // out
+ fb_01.pubsetbuf(0, 0);
+ fb_01.open(name_01, ios::out | ios::trunc);
+ VERIFY( fb_01.unbuffered() );
+ VERIFY( !fb_01.read_position() );
+ c1 = fb_01.sgetc();
+ VERIFY( c1 == traits_type::eof() );
+ c2 = fb_01.sputbackc('a');
+ VERIFY( c2 == traits_type::eof() );
+ fb_01.sbumpc();
+ c1 = fb_01.sbumpc();
+ c2 = fb_01.sputbackc('a');
+ VERIFY( c1 == c2 );
+ VERIFY( fb_01.unbuffered() );
+ VERIFY( !fb_01.read_position() );
+ }
+}
+
+int main()
+{
+ test01();
+ return 0;
+}