obtained gcc-4.6.4.tar.bz2 from upstream website;upstream

verified gcc-4.6.4.tar.bz2.sig;
imported gcc-4.6.4 source tree from verified upstream tarball.

downloading a git-generated archive based on the 'upstream' tag
should provide you with a source tree that is binary identical
to the one extracted from the above tarball.

if you have obtained the source via the command 'git clone',
however, do note that line-endings of files in your working
directory might differ from line-endings of the respective
files in the upstream repository.

34 files changed, 3148 insertions, 0 deletions

diff --git a/libstdc++-v3/testsuite/27_io/basic_filebuf/seekoff/10132-2.cc b/libstdc++-v3/testsuite/27_io/basic_filebuf/seekoff/10132-2.cc
new file mode 100644
index 000000000..008b56d21
--- /dev/null
+++ b/libstdc++-v3/testsuite/27_io/basic_filebuf/seekoff/10132-2.cc
@@ -0,0 +1,54 @@
+// 2003-04-24 bkoz
+
+// Copyright (C) 2003, 2004, 2005, 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/>.
+
+// 27.8.1.1 - Template class basic_filebuf 
+// NB: This file is for testing basic_filebuf with NO OTHER INCLUDES.
+
+#include <fstream>
+#include <testsuite_hooks.h>
+#include <testsuite_character.h>
+
+// libstdc++/10132, add on
+void test07()
+{
+  bool test __attribute__((unused)) = true;
+  typedef std::basic_filebuf<__gnu_test::pod_ushort> gnu_filebuf;
+  
+  try
+    { 
+      // Need codecvt facet for width argument in seekoff.
+      gnu_filebuf obj;
+      obj.pubseekoff(2, std::ios_base::beg);
+    }
+  catch(std::exception& obj)
+    { 
+      test = false; 
+      VERIFY( test );
+    }
+}
+
+int main() 
+{
+  test07();
+  return 0;
+}
+
+
+
+// more surf!!!
diff --git a/libstdc++-v3/testsuite/27_io/basic_filebuf/seekoff/12790-1.cc b/libstdc++-v3/testsuite/27_io/basic_filebuf/seekoff/12790-1.cc
new file mode 100644
index 000000000..14e0b0a3a
--- /dev/null
+++ b/libstdc++-v3/testsuite/27_io/basic_filebuf/seekoff/12790-1.cc
@@ -0,0 +1,83 @@
+// Copyright (C) 2003, 2005, 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 <locale>
+#include <fstream>
+#include <testsuite_hooks.h>
+#include <testsuite_character.h>
+
+// libstdc++/12790
+void test01()
+{
+  using namespace std;
+  using __gnu_test::pod_uchar;
+  typedef basic_filebuf<pod_uchar>::traits_type traits_type;
+
+  bool test __attribute__((unused)) = true;
+  const char* name = "tmp_seekoff_12790";
+
+  locale loc(locale::classic(),
+	     new codecvt<traits_type::char_type, char,
+	     traits_type::state_type>);
+
+  basic_filebuf<pod_uchar> fb;
+  fb.pubimbue(loc);
+
+  fb.open(name, ios_base::out);
+  fb.sputc(pod_uchar::from<char>(0xff));
+  fb.sputc(pod_uchar::from<char>(0));
+  fb.sputc(pod_uchar::from<char>(0));
+  fb.sputc(pod_uchar::from<char>('a'));
+  fb.sputc(pod_uchar::from<char>('a'));
+  fb.sputc(pod_uchar::from<char>('a'));
+  fb.sputc(pod_uchar::from<char>('a'));
+  fb.close();
+
+  fb.open(name, ios_base::in);
+  fb.sbumpc();
+  fb.sbumpc();
+  fb.sbumpc();
+
+  // Check that seekoff calls codecvt::length with the correct state.
+  traits_type::pos_type pos = fb.pubseekoff(0, ios_base::cur);
+  VERIFY( pos != traits_type::pos_type(traits_type::off_type(-1)) );
+
+  traits_type::int_type c = fb.sbumpc();
+  VERIFY( c != traits_type::eof() );
+  VERIFY( traits_type::eq(traits_type::to_char_type(c),
+			  pod_uchar::from<char>('a')) );
+  fb.sbumpc();
+  fb.sbumpc();
+  c = fb.sbumpc();
+  VERIFY( c != traits_type::eof() );
+  VERIFY( traits_type::eq(traits_type::to_char_type(c),
+			  pod_uchar::from<char>('a')) );
+  c = fb.sbumpc();
+  VERIFY( c == traits_type::eof() );
+
+  fb.close();
+}
+
+int main()
+{
+  test01();
+  return 0;
+}
diff --git a/libstdc++-v3/testsuite/27_io/basic_filebuf/seekoff/12790-2.cc b/libstdc++-v3/testsuite/27_io/basic_filebuf/seekoff/12790-2.cc
new file mode 100644
index 000000000..64ada570c
--- /dev/null
+++ b/libstdc++-v3/testsuite/27_io/basic_filebuf/seekoff/12790-2.cc
@@ -0,0 +1,86 @@
+// Copyright (C) 2003, 2005, 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 <locale>
+#include <fstream>
+#include <testsuite_hooks.h>
+#include <testsuite_character.h>
+
+// libstdc++/12790
+void test01()
+{
+  using namespace std;
+  using __gnu_test::pod_uchar;
+  typedef basic_filebuf<pod_uchar>::traits_type traits_type;
+
+  bool test __attribute__((unused)) = true;
+  const char* name = "tmp_seekoff_12790";
+
+  locale loc(locale::classic(),
+	     new codecvt<traits_type::char_type, char,
+	     traits_type::state_type>);
+
+  basic_filebuf<pod_uchar> fb;
+  fb.pubimbue(loc);
+
+  fb.open(name, ios_base::out);
+  fb.sputc(pod_uchar::from<char>(0xff));
+  fb.sputc(pod_uchar::from<char>(0));
+  fb.sputc(pod_uchar::from<char>(0));
+  fb.sputc(pod_uchar::from<char>('a'));
+  fb.sputc(pod_uchar::from<char>('a'));
+  fb.sputc(pod_uchar::from<char>('a'));
+  fb.sputc(pod_uchar::from<char>('a'));
+  fb.close();
+
+  fb.open(name, ios_base::in);
+  fb.sbumpc();
+  fb.sbumpc();
+  fb.sbumpc();
+
+  // Check that seekoff resets the state when seeking to beginning.
+  traits_type::pos_type pos = fb.pubseekoff(0, ios_base::beg);
+  VERIFY( pos != traits_type::pos_type(traits_type::off_type(-1)) );
+
+  traits_type::int_type c = fb.sbumpc();
+  VERIFY( c != traits_type::eof() );
+  VERIFY( traits_type::eq(traits_type::to_char_type(c),
+			  pod_uchar::from<char>(0xff)) );
+  fb.sbumpc();
+  fb.sbumpc();
+  fb.sbumpc();
+  fb.sbumpc();
+  fb.sbumpc();
+  c = fb.sbumpc();
+  VERIFY( c != traits_type::eof() );
+  VERIFY( traits_type::eq(traits_type::to_char_type(c),
+			  pod_uchar::from<char>('a')) );
+  c = fb.sbumpc();
+  VERIFY( c == traits_type::eof() );
+
+  fb.close();
+}
+
+int main()
+{
+  test01();
+  return 0;
+}
diff --git a/libstdc++-v3/testsuite/27_io/basic_filebuf/seekoff/12790-3.cc b/libstdc++-v3/testsuite/27_io/basic_filebuf/seekoff/12790-3.cc
new file mode 100644
index 000000000..79cda63fe
--- /dev/null
+++ b/libstdc++-v3/testsuite/27_io/basic_filebuf/seekoff/12790-3.cc
@@ -0,0 +1,81 @@
+// Copyright (C) 2003, 2005, 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 <locale>
+#include <fstream>
+#include <testsuite_hooks.h>
+#include <testsuite_character.h>
+
+// libstdc++/12790
+void test01()
+{
+  using namespace std;
+  using __gnu_test::pod_uchar;
+  typedef basic_filebuf<pod_uchar>::traits_type traits_type;
+
+  bool test __attribute__((unused)) = true;
+  const char* name = "tmp_seekoff_12790";
+
+  locale loc(locale::classic(),
+	     new codecvt<traits_type::char_type, char,
+	     traits_type::state_type>);
+
+  basic_filebuf<pod_uchar> fb;
+  fb.pubimbue(loc);
+
+  fb.open(name, ios_base::out | ios_base::trunc);
+  fb.sputc(pod_uchar::from<char>('b'));
+  fb.sputc(pod_uchar::from<char>(0xff));
+  fb.sputc(pod_uchar::from<char>('a'));
+  fb.sputc(pod_uchar::from<char>(0xfc));
+  fb.sputc(pod_uchar::from<char>(0));
+  fb.sputc(pod_uchar::from<char>(0));
+
+  fb.close();
+  fb.open(name, ios_base::in);
+
+  fb.sbumpc();
+  fb.sbumpc();
+
+  // Check that seekoff returns the correct state
+  traits_type::pos_type pos = fb.pubseekoff(0, ios_base::cur);
+
+  traits_type::int_type c = fb.sbumpc();
+  VERIFY( c != traits_type::eof() );
+  VERIFY( traits_type::eq(traits_type::to_char_type(c),
+			  pod_uchar::from<char>('a')) );
+  fb.sbumpc();
+
+  fb.pubseekpos(pos);
+
+  c = fb.sbumpc();
+  VERIFY( c != traits_type::eof() );
+  VERIFY( traits_type::eq(traits_type::to_char_type(c),
+			  pod_uchar::from<char>('a')) );
+
+  fb.close();
+}
+
+int main()
+{
+  test01();
+  return 0;
+}
diff --git a/libstdc++-v3/testsuite/27_io/basic_filebuf/seekoff/12790-4.cc b/libstdc++-v3/testsuite/27_io/basic_filebuf/seekoff/12790-4.cc
new file mode 100644
index 000000000..3bf4353d7
--- /dev/null
+++ b/libstdc++-v3/testsuite/27_io/basic_filebuf/seekoff/12790-4.cc
@@ -0,0 +1,72 @@
+// Copyright (C) 2003, 2005, 2009, 2010 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 <locale>
+#include <fstream>
+#include <testsuite_hooks.h>
+#include <testsuite_character.h>
+
+// libstdc++/12790
+void test01()
+{
+  using namespace std;
+  using __gnu_test::pod_uchar;
+  typedef basic_filebuf<pod_uchar>::traits_type traits_type;
+
+  bool test __attribute__((unused)) = true;
+  const char* name = "tmp_seekoff_12790";
+
+  locale loc(locale::classic(),
+	     new codecvt<traits_type::char_type, char,
+	     traits_type::state_type>);
+
+  basic_filebuf<pod_uchar> fb;
+  fb.pubsetbuf(0, 0);
+  fb.pubimbue(loc);
+
+  fb.open(name, ios_base::in | ios_base::out | ios_base::trunc);
+  fb.sputc(pod_uchar::from<char>('b'));
+  fb.sputc(pod_uchar::from<char>(0xff));
+
+  // Check that seekoff sets the current state during output
+  fb.pubseekoff(0, ios_base::cur);
+  fb.sputc(pod_uchar::from<char>('a'));
+  fb.sputc(pod_uchar::from<char>(0xff));
+  fb.sputc(pod_uchar::from<char>(0));
+  fb.sputc(pod_uchar::from<char>(0));
+
+  fb.pubseekoff(0, ios_base::beg);
+  fb.sbumpc();
+  fb.sbumpc();
+
+  traits_type::int_type c = fb.sbumpc();
+  VERIFY( c != traits_type::eof() );
+  VERIFY( traits_type::eq(traits_type::to_char_type(c),
+			  pod_uchar::from<char>('a')) );
+
+  fb.close();
+}
+
+int main()
+{
+  test01();
+  return 0;
+}
diff --git a/libstdc++-v3/testsuite/27_io/basic_filebuf/seekoff/45628-2.cc b/libstdc++-v3/testsuite/27_io/basic_filebuf/seekoff/45628-2.cc
new file mode 100644
index 000000000..6e40a89aa
--- /dev/null
+++ b/libstdc++-v3/testsuite/27_io/basic_filebuf/seekoff/45628-2.cc
@@ -0,0 +1,103 @@
+// Copyright (C) 2010 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/>.
+
+// { dg-require-fileio "" }
+
+#include <fstream>
+#include <testsuite_hooks.h>
+#include <testsuite_character.h>
+
+const char name_01[] = "tmp_seekoff_45628.tst";
+
+unsigned underflows, overflows;
+
+class my_filebuf
+: public std::basic_filebuf<__gnu_test::pod_uchar>
+{
+  virtual int_type
+  underflow()
+  {
+    ++underflows;
+    return std::basic_filebuf<__gnu_test::pod_uchar>::underflow();
+  }
+  virtual int_type
+  overflow(int_type c)
+  {
+    ++overflows;
+    return std::basic_filebuf<__gnu_test::pod_uchar>::overflow(c);
+  }
+};
+
+// libstdc++/45628
+void test01()
+{
+  bool test __attribute__((unused)) = true;
+
+  using __gnu_test::pod_uchar;
+  std::locale loc(std::locale::classic(),
+	     new std::codecvt<my_filebuf::traits_type::char_type, char,
+	     my_filebuf::traits_type::state_type>);
+
+  my_filebuf::pos_type opos[3], ipos[3];
+  my_filebuf q;
+  q.pubimbue(loc);
+   
+  q.open(name_01, std::ios_base::in | std::ios_base::out 
+	 | std::ios_base::trunc); 
+
+  q.sputc(pod_uchar::from<char>('a'));
+  opos[0] = q.pubseekoff(0, std::ios_base::cur);
+  q.sputc(pod_uchar::from<char>('b'));
+  opos[1] = q.pubseekoff(0, std::ios_base::cur);
+  q.sputc(pod_uchar::from<char>('c'));
+  opos[2] = q.pubseekoff(0, std::ios_base::cur);
+
+  VERIFY( overflows <= 9 ); // pubseekoff calls overflow twice if converting.
+  // NB: checking opos==ipos is not very rigorous as long as it flushes, since
+  // all positions will be at initial state.
+  q.pubseekoff(0, std::ios_base::beg);
+
+  q.sbumpc();
+  VERIFY( underflows == 1 );
+
+  ipos[0] = q.pubseekoff(0, std::ios_base::cur);
+  VERIFY( ipos[0] == opos[0] );
+  q.sbumpc();
+  ipos[1] = q.pubseekoff(0, std::ios_base::cur);
+  VERIFY( ipos[1] == opos[1] );
+  q.sbumpc();
+  ipos[2] = q.pubseekoff(0, std::ios_base::cur);
+  VERIFY( ipos[2] == opos[2] );
+
+  VERIFY( underflows == 1 ); // pubseekoff never flushes get area
+  
+  // Bonus test: check automatic mode switches.
+  q.sputc(pod_uchar::from<char>('d'));
+  
+  q.pubseekpos( ipos[1] );
+  q.sputc(pod_uchar::from<char>('e'));
+  
+  VERIFY( my_filebuf::traits_type::eq(
+			my_filebuf::traits_type::to_char_type(q.sgetc()),
+			pod_uchar::from<char>('d')) );
+}
+
+int main()
+{
+  test01();
+  return 0;
+}
diff --git a/libstdc++-v3/testsuite/27_io/basic_filebuf/seekoff/char/1-in.cc b/libstdc++-v3/testsuite/27_io/basic_filebuf/seekoff/char/1-in.cc
new file mode 100644
index 000000000..248874617
--- /dev/null
+++ b/libstdc++-v3/testsuite/27_io/basic_filebuf/seekoff/char/1-in.cc
@@ -0,0 +1,124 @@
+// 2001-05-21 Benjamin Kosnik  <bkoz@redhat.com>
+
+// Copyright (C) 2001, 2002, 2003, 2009, 2010 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[] = "seekoff.txt";
+
+void test05() 
+{
+  using namespace std;
+  using namespace __gnu_test;
+
+  typedef filebuf::int_type 	int_type;
+  typedef filebuf::pos_type 	pos_type;
+  typedef filebuf::off_type 	off_type;
+  typedef filebuf::traits_type 	traits_type;
+
+  bool test __attribute__((unused)) = true;
+  streamsize 			strmsz_1;
+
+  int_type c1;
+  int_type c2;
+  int_type c3;
+
+  pos_type pt_1(off_type(-1));
+  pos_type pt_2(off_type(0));
+  off_type off_1 = 0;
+  off_type off_2 = 0;
+
+  // seekoff
+  // pubseekoff(off_type off, ios_base::seekdir way, ios_base::openmode which)
+  // alters the stream position to off
+
+  // in
+  {
+    constraint_filebuf fb;
+    fb.open(name_01, ios_base::in);
+    VERIFY( !fb.write_position() );
+
+    //beg
+    strmsz_1 = fb.in_avail(); 
+    pt_1 = fb.pubseekoff(2, ios_base::beg);
+    fb.in_avail(); 
+    off_1 = off_type(pt_1);
+    VERIFY( off_1 > 0 );
+    c1 = fb.snextc(); //current in pointer +1
+    VERIFY( c1 == '9' );
+    fb.pubseekoff(3, ios_base::beg);
+    c2 = fb.sputc('\n');  //current in pointer +1
+    fb.pubseekoff(4, ios_base::beg);
+    c3 = fb.sgetc();
+    VERIFY( c2 == traits_type::eof() ); 
+    VERIFY( c3 == '9' );
+    fb.pubsync(); 
+    c1 = fb.sgetc();
+    VERIFY( c1 == c3 );
+
+    //cur
+    pt_2 = fb.pubseekoff(2, ios_base::cur);
+    off_2 = off_type(pt_2);
+    VERIFY( (off_2 == (off_1 + 2 + 1 + 1)) );
+    c1 = fb.snextc(); //current in pointer +1
+    VERIFY( c1 == '1' );
+    fb.pubseekoff(0, ios_base::cur);
+    c2 = fb.sputc('x');  //test current out pointer
+    c3 = fb.sputc('\n');
+    VERIFY( c2 == traits_type::eof() );
+    VERIFY( c3 == traits_type::eof() );
+    fb.pubseekoff(0, ios_base::cur);
+    c1 = fb.sgetc();
+    fb.pubsync(); 
+    c3 = fb.sgetc();
+    VERIFY( c1 == c3 );
+
+    //end
+    pt_2 = fb.pubseekoff(0, ios_base::end);
+    off_1 = off_type(pt_2);
+    VERIFY( off_1 > off_2 ); //weak, but don't know exactly where it ends
+    c3 = fb.sputc('\n');
+    strmsz_1 = fb.sputn("because because because. . .", 28);  
+    VERIFY( strmsz_1 == 0 );
+    fb.pubseekoff(-1, ios_base::end);
+    fb.sgetc();
+    c1 = fb.sungetc();
+    // Defect?  retval of sungetc is not necessarily the character ungotten.
+    // So re-get it.
+    c1 = fb.sgetc();
+    fb.pubsync(); 
+    c3 = fb.sgetc();
+    VERIFY( c1 == c3 );
+    VERIFY( !fb.write_position() );
+  }
+}
+
+int main() 
+{
+  test05();
+  return 0;
+}
diff --git a/libstdc++-v3/testsuite/27_io/basic_filebuf/seekoff/char/1-io.cc b/libstdc++-v3/testsuite/27_io/basic_filebuf/seekoff/char/1-io.cc
new file mode 100644
index 000000000..4dc6d8648
--- /dev/null
+++ b/libstdc++-v3/testsuite/27_io/basic_filebuf/seekoff/char/1-io.cc
@@ -0,0 +1,124 @@
+// 2001-05-21 Benjamin Kosnik  <bkoz@redhat.com>
+
+// Copyright (C) 2001, 2002, 2003, 2009, 2010 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 "" }
+// { dg-require-binary-io "" }
+
+#include <fstream>
+#include <testsuite_hooks.h>
+#include <testsuite_io.h>
+
+// @require@ %-*.tst %-*.txt
+// @diff@ %-*.tst %*.txt
+
+const char name_01[] = "seekoff-1io.tst";
+
+void test05() 
+{
+  using namespace std;
+  using namespace __gnu_test;
+
+  typedef filebuf::int_type 	int_type;
+  typedef filebuf::pos_type 	pos_type;
+  typedef filebuf::off_type 	off_type;
+
+  bool test __attribute__((unused)) = true;
+  streamsize 			strmsz_1;
+
+  int_type c1;
+  int_type c2;
+  int_type c3;
+
+  pos_type pt_1(off_type(-1));
+  pos_type pt_2(off_type(0));
+  off_type off_1 = 0;
+  off_type off_2 = 0;
+
+  // seekoff
+  // pubseekoff(off_type off, ios_base::seekdir way, ios_base::openmode which)
+  // alters the stream position to off
+
+  // in | out
+  {
+    constraint_filebuf fb;
+    fb.open(name_01, ios_base::out | ios_base::in);
+    VERIFY( !fb.write_position() );
+    VERIFY( !fb.read_position() );
+
+    //beg
+    strmsz_1 = fb.in_avail(); 
+    pt_1 = fb.pubseekoff(2, ios_base::beg);
+    fb.in_avail(); 
+    off_1 = off_type(pt_1);
+    VERIFY( off_1 > 0 );
+    c1 = fb.snextc(); //current in pointer +1
+    VERIFY( c1 == '9' );
+    fb.pubseekoff(3, ios_base::beg);
+    c2 = fb.sputc('\n');  //current in pointer +1
+    fb.pubseekoff(4, ios_base::beg);
+    c3 = fb.sgetc();
+    VERIFY( c2 != c3 ); 
+    VERIFY( c3 == '9' );
+    fb.pubsync(); 
+    c1 = fb.sgetc();
+    VERIFY( c1 == c3 );
+
+    //cur
+    pt_2 = fb.pubseekoff(2, ios_base::cur);
+    off_2 = off_type(pt_2);
+    VERIFY( (off_2 == (off_1 + 2 + 1 + 1)) );
+    c1 = fb.snextc(); //current in pointer +1
+    VERIFY( c1 == '1' );
+    fb.pubseekoff(0, ios_base::cur);
+    c2 = fb.sputc('x');  //test current out pointer
+    c3 = fb.sputc('\n');
+    fb.pubseekoff(0, ios_base::cur);
+    c1 = fb.sgetc();
+    fb.pubsync(); 
+    c3 = fb.sgetc();
+    VERIFY( c1 == c3 );
+
+    //end
+    pt_2 = fb.pubseekoff(0, ios_base::end);
+    off_1 = off_type(pt_2);
+    VERIFY( off_1 > off_2 ); //weak, but don't know exactly where it ends
+    c3 = fb.sputc('\n');
+    strmsz_1 = fb.sputn("because because because. . .", 28);  
+    VERIFY( strmsz_1 == 28 );
+    fb.pubseekoff(-1, ios_base::end);
+    fb.sgetc();
+    c1 = fb.sungetc();
+    // Defect?  retval of sungetc is not necessarily the character ungotten.
+    // So re-get it.
+    c1 = fb.sgetc();
+    fb.pubsync(); 
+    c3 = fb.sgetc();
+    VERIFY( c1 == c3 );
+    VERIFY( !fb.write_position() );
+    VERIFY( fb.read_position() );
+  }
+}
+
+int main() 
+{
+  test05();
+  return 0;
+}
diff --git a/libstdc++-v3/testsuite/27_io/basic_filebuf/seekoff/char/1-out.cc b/libstdc++-v3/testsuite/27_io/basic_filebuf/seekoff/char/1-out.cc
new file mode 100644
index 000000000..8d7ab1dfc
--- /dev/null
+++ b/libstdc++-v3/testsuite/27_io/basic_filebuf/seekoff/char/1-out.cc
@@ -0,0 +1,124 @@
+// 2001-05-21 Benjamin Kosnik  <bkoz@redhat.com>
+
+// Copyright (C) 2001, 2002, 2003, 2009, 2010 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[] = "seekoff-1out.tst";
+
+void test05() 
+{
+  using namespace std;
+  using namespace __gnu_test;
+
+  typedef filebuf::int_type 	int_type;
+  typedef filebuf::pos_type 	pos_type;
+  typedef filebuf::off_type 	off_type;
+  typedef filebuf::traits_type 	traits_type;
+
+  bool test __attribute__((unused)) = true;
+  streamsize 			strmsz_1;
+
+  int_type c1;
+  int_type c2;
+  int_type c3;
+
+  pos_type pt_1(off_type(-1));
+  pos_type pt_2(off_type(0));
+  off_type off_1 = 0;
+  off_type off_2 = 0;
+
+  // seekoff
+  // pubseekoff(off_type off, ios_base::seekdir way, ios_base::openmode which)
+  // alters the stream position to off
+
+  // out
+  {
+    constraint_filebuf fb;
+    fb.open(name_01, ios_base::out);
+    VERIFY( !fb.write_position() );
+    VERIFY( !fb.read_position() );
+
+    //beg
+    strmsz_1 = fb.in_avail(); 
+    pt_1 = fb.pubseekoff(2, ios_base::beg);
+    fb.in_avail(); 
+    off_1 = off_type(pt_1);
+    VERIFY( off_1 > 0 );
+    c1 = fb.snextc(); //current in pointer +1
+    VERIFY( c1 == traits_type::eof() );
+    fb.pubseekoff(3, ios_base::beg);
+    c2 = fb.sputc('\n');  //current in pointer +1
+    fb.pubseekoff(4, ios_base::beg);
+    c3 = fb.sgetc();
+    VERIFY( c2 != c3 ); 
+    VERIFY( c3 == traits_type::eof() );
+    fb.pubsync(); 
+    c1 = fb.sgetc();
+    VERIFY( c1 == c3 );
+
+    //cur
+    pt_2 = fb.pubseekoff(2, ios_base::cur);
+    off_2 = off_type(pt_2);
+    VERIFY( (off_2 == (off_1 + 2 + 1 + 1)) );
+    c1 = fb.snextc(); //current in pointer +1
+    VERIFY( c1 == traits_type::eof() );
+    fb.pubseekoff(0, ios_base::cur);
+    c2 = fb.sputc('x');  //test current out pointer
+    c3 = fb.sputc('\n');
+    fb.pubseekoff(0, ios_base::cur);
+    c1 = fb.sgetc();
+    fb.pubsync(); 
+    c3 = fb.sgetc();
+    VERIFY( c1 == c3 );
+
+    //end
+    pt_2 = fb.pubseekoff(0, ios_base::end);
+    off_1 = off_type(pt_2);
+    VERIFY( off_1 > off_2 ); //weak, but don't know exactly where it ends
+    c3 = fb.sputc('\n');
+    strmsz_1 = fb.sputn("because because because. . .", 28);  
+    VERIFY( strmsz_1 == 28 );
+    fb.pubseekoff(-1, ios_base::end);
+    fb.sgetc();
+    c1 = fb.sungetc();
+    // Defect?  retval of sungetc is not necessarily the character ungotten.
+    // So re-get it.
+    c1 = fb.sgetc();
+    fb.pubsync(); 
+    c3 = fb.sgetc();
+    VERIFY( c1 == c3 );
+    VERIFY( !fb.write_position() );
+    VERIFY( !fb.read_position() );
+  }
+}
+
+int main() 
+{
+  test05();
+  return 0;
+}
diff --git a/libstdc++-v3/testsuite/27_io/basic_filebuf/seekoff/char/11543.cc b/libstdc++-v3/testsuite/27_io/basic_filebuf/seekoff/char/11543.cc
new file mode 100644
index 000000000..2f6cf2988
--- /dev/null
+++ b/libstdc++-v3/testsuite/27_io/basic_filebuf/seekoff/char/11543.cc
@@ -0,0 +1,153 @@
+// 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 <locale>
+#include <testsuite_hooks.h>
+
+struct MyState
+{
+};
+
+struct MyCharTraits : std::char_traits<char>
+{
+  typedef std::fpos<MyState> pos_type;
+  typedef MyState state_type;
+};
+
+namespace std
+{
+  template <>
+    class codecvt<char, char, MyState> :
+      public locale::facet, public codecvt_base
+    {
+    public:
+      typedef char intern_type;
+      typedef char extern_type;
+      typedef MyState state_type;
+    
+      explicit codecvt(size_t refs = 0)
+      : locale::facet(refs) { }
+    
+      result out(state_type& state, const intern_type* from,
+		 const intern_type* from_end,  const intern_type*& from_next,
+		 extern_type* to, extern_type* to_limit,
+		 extern_type*& to_next) const
+      { return do_out(state, from, from_end, from_next,
+		      to, to_limit, to_next); }
+
+      result unshift(state_type& state, extern_type* to, extern_type* to_limit,
+		     extern_type*& to_next) const
+      { return do_unshift(state, to, to_limit, to_next); }
+
+      result in(state_type& state, const extern_type* from,
+		const extern_type* from_end, const extern_type*& from_next,
+		intern_type* to, intern_type* to_limit,
+		intern_type*& to_next) const
+      { return do_in(state, from, from_end, from_next,
+		     to, to_limit, to_next); }
+
+      int encoding() const throw()
+      { return do_encoding(); }
+      
+      bool always_noconv() const throw()
+      { return do_always_noconv(); }
+
+      int length(state_type& state, const extern_type* from,
+		 const extern_type* end, size_t max) const
+      { return do_length(state, from, end, max); }
+
+      int max_length() const throw()
+      { return do_max_length(); }
+    
+      static locale::id id;
+    
+    protected:
+      virtual ~codecvt();
+
+      virtual result do_out(state_type&, const intern_type* from,
+			    const intern_type*, const intern_type*& from_next,
+			    extern_type* to, extern_type*,
+			    extern_type*& to_next) const
+      {
+	from_next = from;
+	to_next = to;
+	return noconv;
+      }
+
+      virtual result do_in(state_type&, const extern_type* from,
+			   const extern_type*, const extern_type*& from_next,
+			   intern_type* to, intern_type*,
+			   intern_type*& to_next) const
+      {
+	from_next = from;
+	to_next = to;
+	return noconv;
+      }
+
+      virtual result do_unshift(state_type&, extern_type*, extern_type*,
+				extern_type*&) const
+      { return noconv; }
+
+      virtual int do_encoding() const throw()
+      { return 1; }
+
+      virtual bool do_always_noconv() const throw()
+      { return true; }
+
+      virtual int do_length(state_type&, const extern_type* from,
+			    const extern_type* end, size_t max) const
+      {
+	size_t len = end - from;
+	return std::min(max, len);
+      }
+
+      virtual int do_max_length() const throw()
+      { return 1; }
+    };
+  
+  locale::id codecvt<char, char, MyState>::id;
+
+  codecvt<char, char, MyState>::~codecvt()
+  { }
+}
+
+void test01()
+{
+  bool test __attribute__((unused)) = true;
+
+  std::locale loc(std::locale::classic(),
+		  new std::codecvt<char, char, MyState>);
+  std::basic_filebuf<char, MyCharTraits> fb;
+  fb.pubimbue(loc);
+  fb.open("tmp_11543", std::ios_base::out);
+  VERIFY( fb.is_open() );
+  MyCharTraits::pos_type pos = fb.pubseekoff(0, std::ios_base::beg);
+  VERIFY( pos != MyCharTraits::pos_type(MyCharTraits::off_type(-1)) );
+  fb.close();
+}
+
+int main()
+{
+  test01();
+  return 0;
+}
diff --git a/libstdc++-v3/testsuite/27_io/basic_filebuf/seekoff/char/12232.cc b/libstdc++-v3/testsuite/27_io/basic_filebuf/seekoff/char/12232.cc
new file mode 100644
index 000000000..a60293274
--- /dev/null
+++ b/libstdc++-v3/testsuite/27_io/basic_filebuf/seekoff/char/12232.cc
@@ -0,0 +1,71 @@
+// 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
+
+#include <fstream>
+#include <testsuite_hooks.h>
+
+const char name[] = "tmp_12232";
+
+// libstdc++/12232
+void test01()
+{
+  using namespace std;
+  bool test __attribute__((unused)) = true;
+
+  filebuf fbout;
+  fbout.open(name, ios_base::out);
+  fbout.sputn("abc", 3);
+  
+  streampos p1 = fbout.pubseekoff(0, ios_base::cur, ios_base::in);
+  VERIFY( p1 != streampos(-1) );
+  fbout.sputn("de", 2);
+  
+  streampos p2 = fbout.pubseekpos(p1, ios_base::openmode());
+  VERIFY( p2 != streampos(-1) );
+  fbout.sputn("34", 2);
+  
+  streampos p3 = fbout.pubseekoff(0, ios_base::beg, ios_base::ate);
+  VERIFY( p3 != streampos(-1) );
+  fbout.sputn("012", 3);
+  
+  fbout.close();
+  
+  filebuf fbin;
+  fbin.open(name, ios_base::in);
+  
+  streampos p4 = fbin.pubseekoff(0, ios_base::beg, ios_base::ate);
+  VERIFY( p4 != streampos(-1) );
+  VERIFY( fbin.sgetc() == '0' );
+  
+  streampos p5 = fbin.pubseekoff(-1, ios_base::end, ios_base::out);
+  VERIFY( p5 != streampos(-1) );
+  VERIFY( fbin.sbumpc() == '4' );
+  
+  streampos p6 = fbin.pubseekpos(p4, ios_base::binary);
+  VERIFY( p6 != streampos(-1) );
+  VERIFY( fbin.sbumpc() == '0' );
+  
+  fbin.close();
+}
+
+int main()
+{
+  void test01();
+  return 0;
+}
diff --git a/libstdc++-v3/testsuite/27_io/basic_filebuf/seekoff/char/12790-1.cc b/libstdc++-v3/testsuite/27_io/basic_filebuf/seekoff/char/12790-1.cc
new file mode 100644
index 000000000..d2860cbf5
--- /dev/null
+++ b/libstdc++-v3/testsuite/27_io/basic_filebuf/seekoff/char/12790-1.cc
@@ -0,0 +1,80 @@
+// 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 <locale>
+#include <fstream>
+#include <testsuite_hooks.h>
+
+class Cvt : public std::codecvt<char, char, std::mbstate_t>
+{
+public:
+  mutable bool unshift_called;
+
+  Cvt()
+  : unshift_called(false)
+  { }
+
+protected:
+  bool
+  do_always_noconv() const throw()
+  { return false; }
+
+  int
+  do_encoding() const throw()
+  { return -1; }
+
+  std::codecvt_base::result
+  do_unshift(std::mbstate_t&, char* to, char*, char*& to_next) const
+  {
+    unshift_called = true;
+    to_next = to;
+    return std::codecvt_base::ok;
+  }
+};
+
+// libstdc++/12790
+// basic_filebuf::seekoff() should call codecvt::unshift()
+void test01()
+{
+  using namespace std;
+
+  bool test __attribute__((unused)) = true;
+  const char* name = "tmp_seekoff_12790";
+
+  Cvt* cvt = new Cvt;
+  locale loc(locale::classic(), cvt);
+
+  filebuf fb;
+  fb.pubimbue(loc);
+
+  fb.open(name, ios_base::out);
+  fb.sputc('a');
+
+  VERIFY( !cvt->unshift_called );
+  fb.pubseekoff(0, ios_base::cur);
+  VERIFY( cvt->unshift_called );
+}
+
+int main()
+{
+  test01();
+  return 0;
+}
diff --git a/libstdc++-v3/testsuite/27_io/basic_filebuf/seekoff/char/12790-2.cc b/libstdc++-v3/testsuite/27_io/basic_filebuf/seekoff/char/12790-2.cc
new file mode 100644
index 000000000..f0f1b9938
--- /dev/null
+++ b/libstdc++-v3/testsuite/27_io/basic_filebuf/seekoff/char/12790-2.cc
@@ -0,0 +1,81 @@
+// 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 <locale>
+#include <fstream>
+#include <testsuite_hooks.h>
+
+class Cvt : public std::codecvt<char, char, std::mbstate_t>
+{
+public:
+  mutable bool unshift_called;
+
+  Cvt()
+  : unshift_called(false)
+  { }
+
+protected:
+  bool
+  do_always_noconv() const throw()
+  { return false; }
+
+  int
+  do_encoding() const throw()
+  { return -1; }
+
+  std::codecvt_base::result
+  do_unshift(std::mbstate_t&, char* to, char*, char*& to_next) const
+  {
+    unshift_called = true;
+    to_next = to;
+    return std::codecvt_base::ok;
+  }
+};
+
+// libstdc++/12790
+// basic_filebuf::seekoff() should call codecvt::unshift()
+void test01()
+{
+  using namespace std;
+
+  bool test __attribute__((unused)) = true;
+  const char* name = "tmp_seekoff_12790";
+
+  Cvt* cvt = new Cvt;
+  locale loc(locale::classic(), cvt);
+
+  filebuf fb;
+  fb.pubsetbuf(0, 0);
+  fb.pubimbue(loc);
+
+  fb.open(name, ios_base::out);
+  fb.sputc('a');
+
+  VERIFY( !cvt->unshift_called );
+  fb.pubseekoff(0, ios_base::cur);
+  VERIFY( cvt->unshift_called );
+}
+
+int main()
+{
+  test01();
+  return 0;
+}
diff --git a/libstdc++-v3/testsuite/27_io/basic_filebuf/seekoff/char/12790-3.cc b/libstdc++-v3/testsuite/27_io/basic_filebuf/seekoff/char/12790-3.cc
new file mode 100644
index 000000000..026d75029
--- /dev/null
+++ b/libstdc++-v3/testsuite/27_io/basic_filebuf/seekoff/char/12790-3.cc
@@ -0,0 +1,80 @@
+// 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 <locale>
+#include <fstream>
+#include <testsuite_hooks.h>
+
+class Cvt : public std::codecvt<char, char, std::mbstate_t>
+{
+public:
+  mutable bool unshift_called;
+
+  Cvt()
+  : unshift_called(false)
+  { }
+
+protected:
+  bool
+  do_always_noconv() const throw()
+  { return false; }
+
+  int
+  do_encoding() const throw()
+  { return -1; }
+
+  std::codecvt_base::result
+  do_unshift(std::mbstate_t&, char* to, char*, char*& to_next) const
+  {
+    unshift_called = true;
+    to_next = to;
+    return std::codecvt_base::ok;
+  }
+};
+
+// libstdc++/12790
+// basic_filebuf::seekoff() should call codecvt::unshift(),
+// but only if writing
+void test01()
+{
+  using namespace std;
+
+  bool test __attribute__((unused)) = true;
+  const char* name = "tmp_seekoff_12790";
+
+  Cvt* cvt = new Cvt;
+  locale loc(locale::classic(), cvt);
+
+  filebuf fb;
+  fb.pubimbue(loc);
+
+  fb.open(name, ios_base::out);
+
+  VERIFY( !cvt->unshift_called );
+  fb.pubseekoff(0, ios_base::cur);
+  VERIFY( !cvt->unshift_called );
+}
+
+int main()
+{
+  test01();
+  return 0;
+}
diff --git a/libstdc++-v3/testsuite/27_io/basic_filebuf/seekoff/char/12790-4.cc b/libstdc++-v3/testsuite/27_io/basic_filebuf/seekoff/char/12790-4.cc
new file mode 100644
index 000000000..60813c899
--- /dev/null
+++ b/libstdc++-v3/testsuite/27_io/basic_filebuf/seekoff/char/12790-4.cc
@@ -0,0 +1,81 @@
+// 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 <locale>
+#include <fstream>
+#include <testsuite_hooks.h>
+
+class Cvt : public std::codecvt<char, char, std::mbstate_t>
+{
+public:
+  mutable bool unshift_called;
+
+  Cvt()
+  : unshift_called(false)
+  { }
+
+protected:
+  bool
+  do_always_noconv() const throw()
+  { return false; }
+
+  int
+  do_encoding() const throw()
+  { return -1; }
+
+  std::codecvt_base::result
+  do_unshift(std::mbstate_t&, char* to, char*, char*& to_next) const
+  {
+    unshift_called = true;
+    to_next = to;
+    return std::codecvt_base::ok;
+  }
+};
+
+// libstdc++/12790
+// basic_filebuf::seekoff() should call codecvt::unshift()
+void test01()
+{
+  using namespace std;
+
+  bool test __attribute__((unused)) = true;
+  const char* name = "tmp_seekoff_12790";
+
+  Cvt* cvt = new Cvt;
+  locale loc(locale::classic(), cvt);
+
+  filebuf fb;
+  fb.pubimbue(loc);
+
+  fb.open(name, ios_base::out);
+  fb.sputc('a');
+  fb.pubsync(); // Does not call unshift()
+
+  VERIFY( !cvt->unshift_called );
+  fb.pubseekoff(0, ios_base::cur);
+  VERIFY( cvt->unshift_called );
+}
+
+int main()
+{
+  test01();
+  return 0;
+}
diff --git a/libstdc++-v3/testsuite/27_io/basic_filebuf/seekoff/char/2-in.cc b/libstdc++-v3/testsuite/27_io/basic_filebuf/seekoff/char/2-in.cc
new file mode 100644
index 000000000..3a8809da2
--- /dev/null
+++ b/libstdc++-v3/testsuite/27_io/basic_filebuf/seekoff/char/2-in.cc
@@ -0,0 +1,125 @@
+// 2001-05-21 Benjamin Kosnik  <bkoz@redhat.com>
+
+// Copyright (C) 2001, 2002, 2003, 2009, 2010 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[] = "seekoff.txt";
+
+void test05() 
+{
+  using namespace std;
+  using namespace __gnu_test;
+
+  typedef filebuf::int_type 	int_type;
+  typedef filebuf::pos_type 	pos_type;
+  typedef filebuf::off_type 	off_type;
+  typedef filebuf::traits_type 	traits_type;
+
+  bool test __attribute__((unused)) = true;
+  streamsize 			strmsz_1;
+
+  int_type c1;
+  int_type c2;
+  int_type c3;
+
+  pos_type pt_1(off_type(-1));
+  pos_type pt_2(off_type(0));
+  off_type off_1 = 0;
+  off_type off_2 = 0;
+
+  // seekoff
+  // pubseekoff(off_type off, ios_base::seekdir way, ios_base::openmode which)
+  // alters the stream position to off
+
+  // in
+  {
+    constraint_filebuf fb;
+    fb.pubsetbuf(0, 0);
+    fb.open(name_01, ios_base::in);
+    VERIFY( fb.unbuffered() );
+
+    //beg
+    strmsz_1 = fb.in_avail(); 
+    pt_1 = fb.pubseekoff(2, ios_base::beg);
+    fb.in_avail(); 
+    off_1 = off_type(pt_1);
+    VERIFY( off_1 > 0 );
+    c1 = fb.snextc(); //current in pointer +1
+    VERIFY( c1 == '9' );
+    fb.pubseekoff(3, ios_base::beg);
+    c2 = fb.sputc('\n');  //current in pointer +1
+    fb.pubseekoff(4, ios_base::beg);
+    c3 = fb.sgetc();
+    VERIFY( c2 == traits_type::eof() ); 
+    VERIFY( c3 == '9' );
+    fb.pubsync(); 
+    c1 = fb.sgetc();
+    VERIFY( c1 == c3 );
+
+    //cur
+    pt_2 = fb.pubseekoff(2, ios_base::cur);
+    off_2 = off_type(pt_2);
+    VERIFY( (off_2 == (off_1 + 2 + 1 + 1)) );
+    c1 = fb.snextc(); //current in pointer +1
+    VERIFY( c1 == '1' );
+    fb.pubseekoff(0, ios_base::cur);
+    c2 = fb.sputc('x');  //test current out pointer
+    c3 = fb.sputc('\n');
+    VERIFY( c2 == traits_type::eof() );
+    VERIFY( c3 == traits_type::eof() );
+    fb.pubseekoff(0, ios_base::cur);
+    c1 = fb.sgetc();
+    fb.pubsync(); 
+    c3 = fb.sgetc();
+    VERIFY( c1 == c3 );
+
+    //end
+    pt_2 = fb.pubseekoff(0, ios_base::end);
+    off_1 = off_type(pt_2);
+    VERIFY( off_1 > off_2 ); //weak, but don't know exactly where it ends
+    c3 = fb.sputc('\n');
+    strmsz_1 = fb.sputn("because because because. . .", 28);  
+    VERIFY( strmsz_1 == 0 );
+    fb.pubseekoff(-1, ios_base::end);
+    fb.sgetc();
+    c1 = fb.sungetc();
+    // Defect?  retval of sungetc is not necessarily the character ungotten.
+    // So re-get it.
+    c1 = fb.sgetc();
+    fb.pubsync(); 
+    c3 = fb.sgetc();
+    VERIFY( c1 == c3 );
+    VERIFY( fb.unbuffered() );
+  }
+}
+
+int main() 
+{
+  test05();
+  return 0;
+}
diff --git a/libstdc++-v3/testsuite/27_io/basic_filebuf/seekoff/char/2-io.cc b/libstdc++-v3/testsuite/27_io/basic_filebuf/seekoff/char/2-io.cc
new file mode 100644
index 000000000..89fab2aed
--- /dev/null
+++ b/libstdc++-v3/testsuite/27_io/basic_filebuf/seekoff/char/2-io.cc
@@ -0,0 +1,123 @@
+// 2001-05-21 Benjamin Kosnik  <bkoz@redhat.com>
+
+// Copyright (C) 2001, 2002, 2003, 2009, 2010 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 "" }
+// { dg-require-binary-io "" }
+
+#include <fstream>
+#include <testsuite_hooks.h>
+#include <testsuite_io.h>
+
+// @require@ %-*.tst %-*.txt
+// @diff@ %-*.tst %*.txt
+
+const char name_01[] = "seekoff-2io.tst";
+
+void test05() 
+{
+  using namespace std;
+  using namespace __gnu_test;
+
+  typedef filebuf::int_type 	int_type;
+  typedef filebuf::pos_type 	pos_type;
+  typedef filebuf::off_type 	off_type;
+
+  bool test __attribute__((unused)) = true;
+  streamsize 			strmsz_1;
+
+  int_type c1;
+  int_type c2;
+  int_type c3;
+
+  pos_type pt_1(off_type(-1));
+  pos_type pt_2(off_type(0));
+  off_type off_1 = 0;
+  off_type off_2 = 0;
+
+  // seekoff
+  // pubseekoff(off_type off, ios_base::seekdir way, ios_base::openmode which)
+  // alters the stream position to off
+
+  // in | out
+  {
+    constraint_filebuf fb;
+    fb.pubsetbuf(0, 0);
+    fb.open(name_01, ios_base::out | ios_base::in);
+    VERIFY( fb.unbuffered() );
+
+    //beg
+    strmsz_1 = fb.in_avail(); 
+    pt_1 = fb.pubseekoff(2, ios_base::beg);
+    fb.in_avail(); 
+    off_1 = off_type(pt_1);
+    VERIFY( off_1 > 0 );
+    c1 = fb.snextc(); //current in pointer +1
+    VERIFY( c1 == '9' );
+    fb.pubseekoff(3, ios_base::beg);
+    c2 = fb.sputc('\n');  //current in pointer +1
+    fb.pubseekoff(4, ios_base::beg);
+    c3 = fb.sgetc();
+    VERIFY( c2 != c3 ); 
+    VERIFY( c3 == '9' );
+    fb.pubsync(); 
+    c1 = fb.sgetc();
+    VERIFY( c1 == c3 );
+
+    //cur
+    pt_2 = fb.pubseekoff(2, ios_base::cur);
+    off_2 = off_type(pt_2);
+    VERIFY( (off_2 == (off_1 + 2 + 1 + 1)) );
+    c1 = fb.snextc(); //current in pointer +1
+    VERIFY( c1 == '1' );
+    fb.pubseekoff(0, ios_base::cur);
+    c2 = fb.sputc('x');  //test current out pointer
+    c3 = fb.sputc('\n');
+    fb.pubseekoff(0, ios_base::cur);
+    c1 = fb.sgetc();
+    fb.pubsync(); 
+    c3 = fb.sgetc();
+    VERIFY( c1 == c3 );
+
+    //end
+    pt_2 = fb.pubseekoff(0, ios_base::end);
+    off_1 = off_type(pt_2);
+    VERIFY( off_1 > off_2 ); //weak, but don't know exactly where it ends
+    c3 = fb.sputc('\n');
+    strmsz_1 = fb.sputn("because because because. . .", 28);  
+    VERIFY( strmsz_1 == 28 );
+    fb.pubseekoff(-1, ios_base::end);
+    fb.sgetc();
+    c1 = fb.sungetc();
+    // Defect?  retval of sungetc is not necessarily the character ungotten.
+    // So re-get it.
+    c1 = fb.sgetc();
+    fb.pubsync(); 
+    c3 = fb.sgetc();
+    VERIFY( c1 == c3 );
+    VERIFY( fb.unbuffered() );
+  }
+}
+
+int main() 
+{
+  test05();
+  return 0;
+}
diff --git a/libstdc++-v3/testsuite/27_io/basic_filebuf/seekoff/char/2-out.cc b/libstdc++-v3/testsuite/27_io/basic_filebuf/seekoff/char/2-out.cc
new file mode 100644
index 000000000..b1ad66e89
--- /dev/null
+++ b/libstdc++-v3/testsuite/27_io/basic_filebuf/seekoff/char/2-out.cc
@@ -0,0 +1,123 @@
+// 2001-05-21 Benjamin Kosnik  <bkoz@redhat.com>
+
+// Copyright (C) 2001, 2002, 2003, 2009, 2010 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[] = "seekoff-2out.tst";
+
+void test05() 
+{
+  using namespace std;
+  using namespace __gnu_test;
+
+  typedef filebuf::int_type 	int_type;
+  typedef filebuf::pos_type 	pos_type;
+  typedef filebuf::off_type 	off_type;
+  typedef filebuf::traits_type 	traits_type;
+
+  bool test __attribute__((unused)) = true;
+  streamsize 			strmsz_1;
+
+  int_type c1;
+  int_type c2;
+  int_type c3;
+
+  pos_type pt_1(off_type(-1));
+  pos_type pt_2(off_type(0));
+  off_type off_1 = 0;
+  off_type off_2 = 0;
+
+  // seekoff
+  // pubseekoff(off_type off, ios_base::seekdir way, ios_base::openmode which)
+  // alters the stream position to off
+
+  // out
+  {
+    constraint_filebuf fb;
+    fb.pubsetbuf(0, 0);
+    fb.open(name_01, ios_base::out);
+    VERIFY( fb.unbuffered() );
+
+    //beg
+    strmsz_1 = fb.in_avail(); 
+    pt_1 = fb.pubseekoff(2, ios_base::beg);
+    fb.in_avail(); 
+    off_1 = off_type(pt_1);
+    VERIFY( off_1 > 0 );
+    c1 = fb.snextc(); //current in pointer +1
+    VERIFY( c1 == traits_type::eof() );
+    fb.pubseekoff(3, ios_base::beg);
+    c2 = fb.sputc('\n');  //current in pointer +1
+    fb.pubseekoff(4, ios_base::beg);
+    c3 = fb.sgetc();
+    VERIFY( c2 != c3 ); 
+    VERIFY( c3 == traits_type::eof() );
+    fb.pubsync(); 
+    c1 = fb.sgetc();
+    VERIFY( c1 == c3 );
+
+    //cur
+    pt_2 = fb.pubseekoff(2, ios_base::cur);
+    off_2 = off_type(pt_2);
+    VERIFY( (off_2 == (off_1 + 2 + 1 + 1)) );
+    c1 = fb.snextc(); //current in pointer +1
+    VERIFY( c1 == traits_type::eof() );
+    fb.pubseekoff(0, ios_base::cur);
+    c2 = fb.sputc('x');  //test current out pointer
+    c3 = fb.sputc('\n');
+    fb.pubseekoff(0, ios_base::cur);
+    c1 = fb.sgetc();
+    fb.pubsync(); 
+    c3 = fb.sgetc();
+    VERIFY( c1 == c3 );
+
+    //end
+    pt_2 = fb.pubseekoff(0, ios_base::end);
+    off_1 = off_type(pt_2);
+    VERIFY( off_1 > off_2 ); //weak, but don't know exactly where it ends
+    c3 = fb.sputc('\n');
+    strmsz_1 = fb.sputn("because because because. . .", 28);  
+    VERIFY( strmsz_1 == 28 );
+    fb.pubseekoff(-1, ios_base::end);
+    fb.sgetc();
+    c1 = fb.sungetc();
+    // Defect?  retval of sungetc is not necessarily the character ungotten.
+    // So re-get it.
+    c1 = fb.sgetc();
+    fb.pubsync(); 
+    c3 = fb.sgetc();
+    VERIFY( c1 == c3 );
+    VERIFY( fb.unbuffered() );
+  }
+}
+
+int main() 
+{
+  test05();
+  return 0;
+}
diff --git a/libstdc++-v3/testsuite/27_io/basic_filebuf/seekoff/char/26777.cc b/libstdc++-v3/testsuite/27_io/basic_filebuf/seekoff/char/26777.cc
new file mode 100644
index 000000000..d98234bab
--- /dev/null
+++ b/libstdc++-v3/testsuite/27_io/basic_filebuf/seekoff/char/26777.cc
@@ -0,0 +1,90 @@
+// { dg-require-fork "" }
+// { dg-require-mkfifo "" }
+
+// 2006-03-22  Paolo Carlini  <pcarlini@suse.de>
+
+// Copyright (C) 2006, 2007, 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/>.
+
+// No asserts, avoid leaking the semaphores if a VERIFY fails.
+#undef _GLIBCXX_ASSERT
+
+#include <testsuite_hooks.h>
+#include <fstream>
+#include <sstream>
+#include <cstdlib>
+#include <unistd.h>
+#include <signal.h>
+#include <fcntl.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+
+// libstdc++/26777
+bool test01()
+{
+  using namespace std;
+  using namespace __gnu_test;
+
+  bool test __attribute__((unused)) = true;
+
+  const char* name = "tmp_fifo6";
+
+  signal(SIGPIPE, SIG_IGN);
+
+  unlink(name);  
+  mkfifo(name, S_IRWXU);
+  semaphore s1, s2;
+
+  int child = fork();
+  VERIFY( child != -1 );
+
+  if (child == 0)
+    {
+      filebuf fbout;
+      fbout.open(name, ios_base::in | ios_base::out);
+      VERIFY( fbout.is_open() );
+      fbout.sputn("Whatever", 8);
+      fbout.pubsync();
+      s1.signal();
+      s2.wait();
+      fbout.close();
+      s1.signal();
+      exit(0);
+    }
+
+  filebuf fbin;
+  fbin.open(name, ios::in);
+  s1.wait();
+
+  fbin.sgetc();
+  fbin.pubseekoff(0, ios::cur, ios::in);
+  s2.signal();
+  s1.wait();
+
+  ostringstream oss;
+  oss << &fbin;
+  fbin.close();
+
+  VERIFY( oss.str() == "Whatever" );
+
+  return test;
+}
+
+int main()
+{
+  return !test01();
+}
diff --git a/libstdc++-v3/testsuite/27_io/basic_filebuf/seekoff/char/3-in.cc b/libstdc++-v3/testsuite/27_io/basic_filebuf/seekoff/char/3-in.cc
new file mode 100644
index 000000000..a0c4d5a86
--- /dev/null
+++ b/libstdc++-v3/testsuite/27_io/basic_filebuf/seekoff/char/3-in.cc
@@ -0,0 +1,63 @@
+// 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/>.
+
+// 27.7.1.3 Overridden virtual functions
+
+// { dg-require-fileio "" }
+
+#include <fstream>
+#include <testsuite_hooks.h>
+
+void test02(std::filebuf& in, bool pass)
+{
+  bool test __attribute__((unused)) = true;
+  using namespace std;
+  typedef streambuf::pos_type pos_type;
+  typedef streambuf::off_type off_type;
+  pos_type bad = pos_type(off_type(-1));
+  pos_type p = 0;
+
+  // seekoff
+  p = in.pubseekoff(0, ios_base::beg, ios_base::in);
+  VERIFY( pass == (p != bad) );
+
+  p = in.pubseekoff(0, ios_base::beg, ios_base::out);
+  VERIFY( pass == (p != bad) );  // See libstdc++/12232
+
+  p = in.pubseekoff(0, ios_base::beg); 
+  VERIFY( pass == (p != bad) );
+}
+
+const char name_01[] = "filebuf_virtuals-1.tst"; // file with data in it
+const char name_03[] = "filebuf_members-1.tst"; // empty file
+
+int main() 
+{
+  using namespace std;
+
+  filebuf in1;
+  in1.open(name_01, ios_base::in);
+  filebuf in2;
+  filebuf in3;
+  in3.open(name_03, ios_base::in);
+  test02(in1, true);
+  test02(in2, false);
+  test02(in3, true);
+  return 0;
+}
diff --git a/libstdc++-v3/testsuite/27_io/basic_filebuf/seekoff/char/3-io.cc b/libstdc++-v3/testsuite/27_io/basic_filebuf/seekoff/char/3-io.cc
new file mode 100644
index 000000000..803a81f27
--- /dev/null
+++ b/libstdc++-v3/testsuite/27_io/basic_filebuf/seekoff/char/3-io.cc
@@ -0,0 +1,66 @@
+// 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/>.
+
+// 27.7.1.3 Overridden virtual functions
+
+// { dg-require-fileio "" }
+
+#include <fstream>
+#include <testsuite_hooks.h>
+
+void test02(std::filebuf& in, bool pass)
+{
+  bool test __attribute__((unused)) = true;
+  using namespace std;
+  typedef streambuf::pos_type pos_type;
+  typedef streambuf::off_type off_type;
+  pos_type bad = pos_type(off_type(-1));
+  pos_type p = 0;
+
+  // seekoff
+  p = in.pubseekoff(0, ios_base::beg, ios_base::in);
+  if (pass)
+    VERIFY( p != bad );
+
+  p = in.pubseekoff(0, ios_base::beg, ios_base::out); 
+  if (pass)
+    VERIFY( p != bad );
+
+  p = in.pubseekoff(0, ios_base::beg); 
+  if (pass)
+    VERIFY( p != bad );
+}
+
+const char name_01[] = "filebuf_virtuals-1.tst"; // file with data in it
+const char name_03[] = "filebuf_members-1.tst"; // empty file
+
+int main() 
+{
+  using namespace std;
+
+  filebuf in1;
+  in1.open(name_01, ios_base::in | ios_base::out);
+  filebuf in2;
+  filebuf in3;
+  in3.open(name_03, ios_base::in | ios_base::out);
+  test02(in1, true);
+  test02(in2, false);
+  test02(in3, true);
+  return 0;
+}
diff --git a/libstdc++-v3/testsuite/27_io/basic_filebuf/seekoff/char/3-out.cc b/libstdc++-v3/testsuite/27_io/basic_filebuf/seekoff/char/3-out.cc
new file mode 100644
index 000000000..08eac2933
--- /dev/null
+++ b/libstdc++-v3/testsuite/27_io/basic_filebuf/seekoff/char/3-out.cc
@@ -0,0 +1,63 @@
+// 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/>.
+
+// 27.7.1.3 Overridden virtual functions
+
+// { dg-require-fileio "" }
+
+#include <fstream>
+#include <testsuite_hooks.h>
+
+void test02(std::filebuf& in, bool pass)
+{
+  bool test __attribute__((unused)) = true;
+  using namespace std;
+  typedef streambuf::pos_type pos_type;
+  typedef streambuf::off_type off_type;
+  pos_type bad = pos_type(off_type(-1));
+  pos_type p = 0;
+
+  // seekoff
+  p = in.pubseekoff(0, ios_base::beg, ios_base::in);
+  VERIFY( pass == (p != bad) );  // See libstdc++/12232
+
+  p = in.pubseekoff(0, ios_base::beg, ios_base::out); 
+  VERIFY( pass == (p != bad) );
+
+  p = in.pubseekoff(0, ios_base::beg); 
+  VERIFY( pass == (p != bad) );
+}
+
+const char name_01[] = "filebuf_virtuals-1.tst"; // file with data in it
+const char name_03[] = "filebuf_members-1.tst"; // empty file
+
+int main() 
+{
+  using namespace std;
+
+  filebuf out1;
+  out1.open(name_01, ios_base::out);
+  filebuf out2;
+  filebuf out3;
+  out3.open(name_03, ios_base::out);
+  test02(out1, true);
+  test02(out2, false);
+  test02(out3, true);
+  return 0;
+}
diff --git a/libstdc++-v3/testsuite/27_io/basic_filebuf/seekoff/char/4.cc b/libstdc++-v3/testsuite/27_io/basic_filebuf/seekoff/char/4.cc
new file mode 100644
index 000000000..fe21b3a88
--- /dev/null
+++ b/libstdc++-v3/testsuite/27_io/basic_filebuf/seekoff/char/4.cc
@@ -0,0 +1,93 @@
+// { dg-require-fileio "" }
+
+// Copyright (C) 2010 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
+
+#include <fstream>
+#include <cstring>
+#include <testsuite_hooks.h>
+
+void test01()
+{
+  using namespace std;
+  bool test __attribute__((unused)) = true;
+
+  typedef filebuf::pos_type pos_type;
+  const char name[] = "tmp_seekoff-4.tst";
+
+  const size_t size = 12;
+  char buf[size];
+  streamsize n;
+
+  filebuf fb;
+  fb.open(name, ios_base::in | ios_base::out | ios_base::trunc);
+
+  n = fb.sputn("abcd", 4);
+  VERIFY( n == 4 );
+
+  fb.pubseekoff(0, ios_base::beg);
+  n = fb.sgetn(buf, 3);
+  VERIFY( n == 3 );
+  VERIFY( !memcmp(buf, "abc", 3) );
+
+  // Check read => write without pubseekoff(0, ios_base::cur)
+
+  n = fb.sputn("ef", 2);
+  VERIFY( n == 2 );
+
+  fb.pubseekoff(0, ios_base::beg);
+
+  n = fb.sgetn(buf, size);
+  VERIFY( n == 5 );
+  VERIFY( !memcmp(buf, "abcef", 5) );
+
+  fb.pubseekoff(0, ios_base::beg);
+  n = fb.sputn("gh", 2);
+  VERIFY( n == 2 );
+  
+  // Check write => read without pubseekoff(0, ios_base::cur)
+
+  n = fb.sgetn( buf, 3 );
+  VERIFY( !memcmp(buf, "cef", 3) );
+
+  n = fb.sputn("ijkl", 4);
+  VERIFY( n == 4 );
+  
+  fb.pubseekoff(0, ios_base::beg);
+  n = fb.sgetn(buf, 2);
+  VERIFY( n == 2 );
+  VERIFY( !memcmp(buf, "gh", 2) );
+
+  fb.pubseekoff(0, ios_base::end);
+  n = fb.sputn("mno", 3);
+  VERIFY( n == 3 );
+
+  fb.pubseekoff(0, ios_base::beg);
+  n = fb.sgetn(buf, size);
+  VERIFY( n == 12 );
+  VERIFY( !memcmp(buf, "ghcefijklmno", 12) );
+
+  fb.close();
+}
+
+int main()
+{
+  test01();
+  return 0;
+}
diff --git a/libstdc++-v3/testsuite/27_io/basic_filebuf/seekoff/char/45628-1.cc b/libstdc++-v3/testsuite/27_io/basic_filebuf/seekoff/char/45628-1.cc
new file mode 100644
index 000000000..a80a33876
--- /dev/null
+++ b/libstdc++-v3/testsuite/27_io/basic_filebuf/seekoff/char/45628-1.cc
@@ -0,0 +1,79 @@
+// Copyright (C) 2010 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/>.
+
+// { dg-require-fileio "" }
+
+#include <fstream>
+#include <testsuite_hooks.h>
+
+const char name_01[] = "tmp_seekoff_45628.tst";
+
+unsigned underflows, overflows;
+
+class my_filebuf
+: public std::filebuf
+{
+  virtual int_type
+  underflow()
+  {
+    ++underflows;
+    return std::filebuf::underflow();
+  }
+  virtual int_type
+  overflow(int_type c)
+  {
+    ++overflows;
+    return std::filebuf::overflow(c);
+  }
+};
+
+// libstdc++/45628
+void test01()
+{
+  bool test __attribute__((unused)) = true;
+
+  my_filebuf q;
+  q.open(name_01, std::ios_base::in | std::ios_base::out 
+	 | std::ios_base::trunc); 
+
+  q.sputc('a');
+  q.pubseekoff(0, std::ios_base::cur);
+  q.sputc('b');
+  q.pubseekoff(0, std::ios_base::cur);
+  q.sputc('c');
+  q.pubseekoff(0, std::ios_base::cur);
+
+  VERIFY( overflows <= 1 ); // only initial sputc allowed to overflow
+  q.pubseekoff(0, std::ios_base::beg);
+
+  q.sbumpc();
+  VERIFY( underflows == 1 );
+
+  q.pubseekoff(0, std::ios_base::cur);
+  q.sbumpc();
+  q.pubseekoff(0, std::ios_base::cur);
+  q.sbumpc();
+  q.pubseekoff(0, std::ios_base::cur);
+
+  VERIFY( underflows == 1 );
+}
+
+int main()
+{
+  test01();
+  return 0;
+}
diff --git a/libstdc++-v3/testsuite/27_io/basic_filebuf/seekoff/wchar_t/1.cc b/libstdc++-v3/testsuite/27_io/basic_filebuf/seekoff/wchar_t/1.cc
new file mode 100644
index 000000000..c6f13dcd0
--- /dev/null
+++ b/libstdc++-v3/testsuite/27_io/basic_filebuf/seekoff/wchar_t/1.cc
@@ -0,0 +1,137 @@
+// { dg-require-namedlocale "se_NO.UTF-8" }
+
+// 2003-09-08  Petur Runolfsson  <peturr02@ru.is>
+
+// Copyright (C) 2003, 2005, 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
+
+#include <fstream>
+#include <locale>
+#include <cstdio>
+#include <testsuite_hooks.h>
+
+// Check that basic_filebuf::seekoff handles UTF-8 when open for input.
+void test01()
+{
+  using namespace std;
+  typedef wfilebuf::pos_type pos_type;
+  typedef wfilebuf::int_type int_type;
+
+  bool test __attribute__((unused)) = true;
+  const char name[] = "tmp_seekoff-1.tst";
+  const int_type eof = wfilebuf::traits_type::eof();
+
+  const char cstr[] =
+    "\x1\x2\x3\x4\x5\x6\x7\x8\x9\xa\xb\xc\xd\xe\xf\x10\x11\x12\x13"
+    "\x14\x15\x16\x17\x18\x19\x1a\x1b\x1c\x1d\x1e\x1f\x20!\"#$%&"
+    "'()*+,-./0123456789:;<=>?@}~\x7f\xc2\x80\xc2\x81\xc2\x82\xc2"
+    "\x83\xc2\x84\xc2\x85\xc2\x86\xc2\x87\xc2\x88\xc2\x89\xc2\x8a"
+    "\xc2\x8b\xc2\x8c\xc2\x8d\xc2\x8e\xc2\x8f\xc2\x90\xc2\x91\xc2"
+    "\x92\xc2\x93\xc2\x94\xc2\x95\xc2\x96\xc2\x97\xc2\x98\xc2\x99"
+    "\xc2\x9a\xc2\x9b\xc2\x9c\xc3\xba\xc3\xbb\xc3\xbc\xc3\xbd\xc3"
+    "\xbe\xc3\xbf\xc4\x80\xc4\x81\xc4\x82\xc4\x83\xc4\x84\xc4\x85"
+    "\xc4\x86\xc4\x87\xc4\x88\xc4\x89\xc4\x8a\xc4\x8b\xc4\x8c\xc4"
+    "\x8d\xc4\x8e\xc4\x8f\xc4\x90\xc4\x91\xc4\x92\xc4\x93\xc4\x94"
+    "\xc4\x95\xc4\x96\xc4\x97\xc4\x98\xc4\x99\xdf\xb8\xdf\xb9\xdf"
+    "\xba\xdf\xbb\xdf\xbc\xdf\xbd\xdf\xbe\xdf\xbf\xe0\xa0\x80\xe0"
+    "\xa0\x81\xe0\xa0\x82\xe0\xa0\x83\xe0\xa0\x84\xe0\xa0\x85\xe0"
+    "\xa0\x86\xe0\xa0\x87\xe0\xa0\x88\xe0\xa0\x89\xe0\xa0\x8a\xe0"
+    "\xa0\x8b\xe0\xa0\x8c\xe0\xa0\x8d\xe0\xa0\x8e\xe0\xa0\x8f\xe0"
+    "\xa0\x90\xe0\xa0\x91\xe0\xa0\x92\xe0\xa0\x93\xe0\xa0\x94\xe0"
+    "\xa0\x95\xe0\xa0\x96\xe0\xa0\x97\x1\x2\x4\x8\x10\x20@\xc2\x80"
+    "\xc4\x80\xc8\x80\xd0\x80\xe0\xa0\x80\xe1\x80\x80\xe2\x80\x80"
+    "\xe4\x80\x80\xe8\x80\x80\xf0\x90\x80\x80\xf0\xa0\x80\x80\xf1"
+    "\x80\x80\x80\xf2\x80\x80\x80\xf4\x80\x80\x80\xf8\x88\x80\x80"
+    "\x80\xf8\x90\x80\x80\x80\xf8\xa0\x80\x80\x80\xf9\x80\x80\x80"
+    "\x80\xfa\x80\x80\x80\x80\xfc\x84\x80\x80\x80\x80\xfc\x88\x80"
+    "\x80\x80\x80\xfc\x90\x80\x80\x80\x80\xfc\xa0\x80\x80\x80\x80"
+    "\xfd\x80\x80\x80\x80\x80";
+
+  const wchar_t wstr[] = {
+    0x1, 0x2, 0x3, 0x4, 0x5, 0x6, 0x7, 0x8, 0x9, 0xa, 0xb, 0xc,
+    0xd, 0xe, 0xf, 0x10, 0x11, 0x12, 0x13, 0x14, 0x15, 0x16, 0x17,
+    0x18, 0x19, 0x1a, 0x1b, 0x1c, 0x1d, 0x1e, 0x1f, 0x20, L'!',
+    L'"', L'#', L'$', L'%', L'&', L'\'', L'(', L')', L'*', L'+',
+    L',', L'-', L'.', L'/', L'0', L'1', L'2', L'3', L'4', L'5',
+    L'6', L'7', L'8', L'9', L':', L';', L'<', L'=', L'>', L'?',
+    L'@', L'}', L'~', 0x7f, 0x80, 0x81, 0x82, 0x83, 0x84, 0x85,
+    0x86, 0x87, 0x88, 0x89, 0x8a, 0x8b, 0x8c, 0x8d, 0x8e, 0x8f,
+    0x90, 0x91, 0x92, 0x93, 0x94, 0x95, 0x96, 0x97, 0x98, 0x99,
+    0x9a, 0x9b, 0x9c, 0xfa, 0xfb, 0xfc, 0xfd, 0xfe, 0xff, 0x100,
+    0x101, 0x102, 0x103, 0x104, 0x105, 0x106, 0x107, 0x108, 0x109,
+    0x10a, 0x10b, 0x10c, 0x10d, 0x10e, 0x10f, 0x110, 0x111, 0x112,
+    0x113, 0x114, 0x115, 0x116, 0x117, 0x118, 0x119, 0x7f8, 0x7f9,
+    0x7fa, 0x7fb, 0x7fc, 0x7fd, 0x7fe, 0x7ff, 0x800, 0x801, 0x802,
+    0x803, 0x804, 0x805, 0x806, 0x807, 0x808, 0x809, 0x80a, 0x80b,
+    0x80c, 0x80d, 0x80e, 0x80f, 0x810, 0x811, 0x812, 0x813, 0x814,
+    0x815, 0x816, 0x817, 0x1, 0x2, 0x4, 0x8, 0x10, 0x20, L'@',
+    0x80, 0x100, 0x200, 0x400, 0x800, 0x1000, 0x2000, 0x4000, 0x8000,
+    0x10000, 0x20000, 0x40000, 0x80000, 0x100000, 0x200000, 0x400000,
+    0x800000, 0x1000000, 0x2000000, 0x4000000, 0x8000000, 0x10000000,
+    0x20000000, 0x40000000, 0x0
+  };
+
+  const size_t clen = sizeof(cstr) / sizeof(cstr[0]);
+  const size_t wlen = sizeof(wstr) / sizeof(wstr[0]);
+
+  const int loops = 2 * BUFSIZ / wlen;
+  locale loc = locale("se_NO.UTF-8");
+
+  FILE* file = fopen(name, "w");
+  for (int i = 0; i < loops; ++i)
+    fwrite(cstr, 1, clen, file);
+  fclose(file);
+
+  wfilebuf fb;
+  fb.pubimbue(loc);
+  fb.open(name, ios_base::in);
+
+  pos_type p1 = fb.pubseekoff(0, ios_base::cur);
+  pos_type end = fb.pubseekoff(0, ios_base::end);
+  pos_type beg = fb.pubseekoff(0, ios_base::beg);
+  VERIFY( p1 == beg );
+
+  const size_t limit = wlen * loops;
+  for (size_t index = 0; index < limit; ++index)
+    {
+      // Call seekoff at pseudo-random intervals.
+      if (index % 5 == 0 || index % 7 == 0)
+	{
+	  pos_type p2 = fb.pubseekoff(0, ios_base::cur);
+	  VERIFY( p2 != pos_type(-1) );
+	}
+      int_type c1 = fb.sbumpc();
+      VERIFY( c1 != eof );
+      VERIFY( static_cast<wchar_t>(c1) == wstr[index % wlen] );
+    }
+
+  pos_type p3 = fb.pubseekoff(0, ios_base::cur);
+  VERIFY( p3 == end );
+
+  int_type c2 = fb.sbumpc();
+  VERIFY( c2 == eof );
+
+  fb.close();
+}
+
+int main()
+{
+  test01();
+  return 0;
+}
diff --git a/libstdc++-v3/testsuite/27_io/basic_filebuf/seekoff/wchar_t/11543.cc b/libstdc++-v3/testsuite/27_io/basic_filebuf/seekoff/wchar_t/11543.cc
new file mode 100644
index 000000000..fd0c19ea3
--- /dev/null
+++ b/libstdc++-v3/testsuite/27_io/basic_filebuf/seekoff/wchar_t/11543.cc
@@ -0,0 +1,141 @@
+// 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
+
+#include <fstream>
+#include <locale>
+#include <testsuite_hooks.h>
+
+struct MyState
+{
+};
+
+struct MyCharTraits : std::char_traits<wchar_t>
+{
+  typedef std::fpos<MyState> pos_type;
+  typedef MyState state_type;
+};
+
+namespace std
+{
+  template <>
+    class codecvt<wchar_t, char, MyState> :
+      public locale::facet, public codecvt_base
+    {
+    public:
+      typedef wchar_t intern_type;
+      typedef char extern_type;
+      typedef MyState state_type;
+    
+      explicit codecvt(size_t refs = 0)
+      : locale::facet(refs) { }
+    
+      result out(state_type& state, const intern_type* from,
+		 const intern_type* from_end,  const intern_type*& from_next,
+		 extern_type* to, extern_type* to_limit,
+		 extern_type*& to_next) const
+      { return do_out(state, from, from_end, from_next,
+		      to, to_limit, to_next); }
+
+      result unshift(state_type& state, extern_type* to, extern_type* to_limit,
+		     extern_type*& to_next) const
+      { return do_unshift(state, to, to_limit, to_next); }
+
+      result in(state_type& state, const extern_type* from,
+		const extern_type* from_end, const extern_type*& from_next,
+		intern_type* to, intern_type* to_limit,
+		intern_type*& to_next) const
+      { return do_in(state, from, from_end, from_next,
+		     to, to_limit, to_next); }
+
+      int encoding() const throw()
+      { return do_encoding(); }
+      
+      bool always_noconv() const throw()
+      { return do_always_noconv(); }
+
+      int length(state_type& state, const extern_type* from,
+		 const extern_type* end, size_t max) const
+      { return do_length(state, from, end, max); }
+
+      int max_length() const throw()
+      { return do_max_length(); }
+    
+      static locale::id id;
+    
+    protected:
+      virtual ~codecvt();
+
+      virtual result do_out(state_type&, const intern_type*,
+			    const intern_type*, const intern_type*&,
+			    extern_type*, extern_type*, extern_type*&) const
+      { return error; }
+
+      virtual result do_in(state_type&, const extern_type*, const extern_type*,
+			   const extern_type*&, intern_type*, intern_type*,
+			   intern_type*&) const
+      { return error; }
+
+      virtual result do_unshift(state_type&, extern_type*, extern_type*,
+				extern_type*&) const
+      { return noconv; }
+
+      virtual int do_encoding() const throw()
+      { return 1; }
+
+      virtual bool do_always_noconv() const throw()
+      { return false; }
+
+      virtual int do_length(state_type&, const extern_type* from,
+			    const extern_type* end, size_t max) const
+      {
+	size_t len = end - from;
+	return std::min(max, len);
+      }
+
+      virtual int do_max_length() const throw()
+      { return 1; }
+    };
+  
+  locale::id codecvt<wchar_t, char, MyState>::id;
+
+  codecvt<wchar_t, char, MyState>::~codecvt()
+  { }
+}
+
+void test01()
+{
+  bool test __attribute__((unused)) = true;
+
+  std::locale loc(std::locale::classic(),
+		  new std::codecvt<wchar_t, char, MyState>);
+  std::basic_filebuf<wchar_t, MyCharTraits> fb;
+  fb.pubimbue(loc);
+  fb.open("tmp_11543", std::ios_base::out);
+  VERIFY( fb.is_open() );
+  MyCharTraits::pos_type pos = fb.pubseekoff(0, std::ios_base::beg);
+  VERIFY( pos != MyCharTraits::pos_type(MyCharTraits::off_type(-1)) );
+  fb.close();
+}
+
+int main()
+{
+  test01();
+  return 0;
+}
diff --git a/libstdc++-v3/testsuite/27_io/basic_filebuf/seekoff/wchar_t/12790-1.cc b/libstdc++-v3/testsuite/27_io/basic_filebuf/seekoff/wchar_t/12790-1.cc
new file mode 100644
index 000000000..b889f1bf5
--- /dev/null
+++ b/libstdc++-v3/testsuite/27_io/basic_filebuf/seekoff/wchar_t/12790-1.cc
@@ -0,0 +1,78 @@
+// 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
+
+#include <locale>
+#include <fstream>
+#include <testsuite_hooks.h>
+
+class Cvt : public std::codecvt<wchar_t, char, std::mbstate_t>
+{
+public:
+  mutable bool unshift_called;
+
+  Cvt()
+  : unshift_called(false)
+  { }
+
+protected:
+  bool
+  do_always_noconv() const throw()
+  { return false; }
+
+  int
+  do_encoding() const throw()
+  { return -1; }
+
+  std::codecvt_base::result
+  do_unshift(std::mbstate_t&, char* to, char*, char*& to_next) const
+  {
+    unshift_called = true;
+    to_next = to;
+    return std::codecvt_base::ok;
+  }
+};
+
+// libstdc++/12790
+// basic_filebuf::seekoff() should call codecvt::unshift()
+void test01()
+{
+  using namespace std;
+
+  bool test __attribute__((unused)) = true;
+  const char* name = "tmp_seekoff_12790";
+
+  Cvt* cvt = new Cvt;
+  locale loc(locale::classic(), cvt);
+
+  wfilebuf fb;
+  fb.pubimbue(loc);
+
+  fb.open(name, ios_base::out);
+  fb.sputc(L'a');
+
+  VERIFY( !cvt->unshift_called );
+  fb.pubseekoff(0, ios_base::cur);
+  VERIFY( cvt->unshift_called );
+}
+
+int main()
+{
+  test01();
+  return 0;
+}
diff --git a/libstdc++-v3/testsuite/27_io/basic_filebuf/seekoff/wchar_t/12790-2.cc b/libstdc++-v3/testsuite/27_io/basic_filebuf/seekoff/wchar_t/12790-2.cc
new file mode 100644
index 000000000..d38952586
--- /dev/null
+++ b/libstdc++-v3/testsuite/27_io/basic_filebuf/seekoff/wchar_t/12790-2.cc
@@ -0,0 +1,79 @@
+// 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
+
+#include <locale>
+#include <fstream>
+#include <testsuite_hooks.h>
+
+class Cvt : public std::codecvt<wchar_t, char, std::mbstate_t>
+{
+public:
+  mutable bool unshift_called;
+
+  Cvt()
+  : unshift_called(false)
+  { }
+
+protected:
+  bool
+  do_always_noconv() const throw()
+  { return false; }
+
+  int
+  do_encoding() const throw()
+  { return -1; }
+
+  std::codecvt_base::result
+  do_unshift(std::mbstate_t&, char* to, char*, char*& to_next) const
+  {
+    unshift_called = true;
+    to_next = to;
+    return std::codecvt_base::ok;
+  }
+};
+
+// libstdc++/12790
+// basic_filebuf::seekoff() should call codecvt::unshift()
+void test01()
+{
+  using namespace std;
+
+  bool test __attribute__((unused)) = true;
+  const char* name = "tmp_seekoff_12790";
+
+  Cvt* cvt = new Cvt;
+  locale loc(locale::classic(), cvt);
+
+  wfilebuf fb;
+  fb.pubsetbuf(0, 0);
+  fb.pubimbue(loc);
+
+  fb.open(name, ios_base::out);
+  fb.sputc(L'a');
+
+  VERIFY( !cvt->unshift_called );
+  fb.pubseekoff(0, ios_base::cur);
+  VERIFY( cvt->unshift_called );
+}
+
+int main()
+{
+  test01();
+  return 0;
+}
diff --git a/libstdc++-v3/testsuite/27_io/basic_filebuf/seekoff/wchar_t/12790-3.cc b/libstdc++-v3/testsuite/27_io/basic_filebuf/seekoff/wchar_t/12790-3.cc
new file mode 100644
index 000000000..4057cd418
--- /dev/null
+++ b/libstdc++-v3/testsuite/27_io/basic_filebuf/seekoff/wchar_t/12790-3.cc
@@ -0,0 +1,78 @@
+// 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
+
+#include <locale>
+#include <fstream>
+#include <testsuite_hooks.h>
+
+class Cvt : public std::codecvt<wchar_t, char, std::mbstate_t>
+{
+public:
+  mutable bool unshift_called;
+
+  Cvt()
+  : unshift_called(false)
+  { }
+
+protected:
+  bool
+  do_always_noconv() const throw()
+  { return false; }
+
+  int
+  do_encoding() const throw()
+  { return -1; }
+
+  std::codecvt_base::result
+  do_unshift(std::mbstate_t&, char* to, char*, char*& to_next) const
+  {
+    unshift_called = true;
+    to_next = to;
+    return std::codecvt_base::ok;
+  }
+};
+
+// libstdc++/12790
+// basic_filebuf::seekoff() should call codecvt::unshift(),
+// but only if writing
+void test01()
+{
+  using namespace std;
+
+  bool test __attribute__((unused)) = true;
+  const char* name = "tmp_seekoff_12790";
+
+  Cvt* cvt = new Cvt;
+  locale loc(locale::classic(), cvt);
+
+  wfilebuf fb;
+  fb.pubimbue(loc);
+
+  fb.open(name, ios_base::out);
+
+  VERIFY( !cvt->unshift_called );
+  fb.pubseekoff(0, ios_base::cur);
+  VERIFY( !cvt->unshift_called );
+}
+
+int main()
+{
+  test01();
+  return 0;
+}
diff --git a/libstdc++-v3/testsuite/27_io/basic_filebuf/seekoff/wchar_t/12790-4.cc b/libstdc++-v3/testsuite/27_io/basic_filebuf/seekoff/wchar_t/12790-4.cc
new file mode 100644
index 000000000..c04b4e79b
--- /dev/null
+++ b/libstdc++-v3/testsuite/27_io/basic_filebuf/seekoff/wchar_t/12790-4.cc
@@ -0,0 +1,79 @@
+// 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
+
+#include <locale>
+#include <fstream>
+#include <testsuite_hooks.h>
+
+class Cvt : public std::codecvt<wchar_t, char, std::mbstate_t>
+{
+public:
+  mutable bool unshift_called;
+
+  Cvt()
+  : unshift_called(false)
+  { }
+
+protected:
+  bool
+  do_always_noconv() const throw()
+  { return false; }
+
+  int
+  do_encoding() const throw()
+  { return -1; }
+
+  std::codecvt_base::result
+  do_unshift(std::mbstate_t&, char* to, char*, char*& to_next) const
+  {
+    unshift_called = true;
+    to_next = to;
+    return std::codecvt_base::ok;
+  }
+};
+
+// libstdc++/12790
+// basic_filebuf::seekoff() should call codecvt::unshift()
+void test01()
+{
+  using namespace std;
+
+  bool test __attribute__((unused)) = true;
+  const char* name = "tmp_seekoff_12790";
+
+  Cvt* cvt = new Cvt;
+  locale loc(locale::classic(), cvt);
+
+  wfilebuf fb;
+  fb.pubimbue(loc);
+
+  fb.open(name, ios_base::out);
+  fb.sputc(L'a');
+  fb.pubsync(); // Does not call unshift()
+
+  VERIFY( !cvt->unshift_called );
+  fb.pubseekoff(0, ios_base::cur);
+  VERIFY( cvt->unshift_called );
+}
+
+int main()
+{
+  test01();
+  return 0;
+}
diff --git a/libstdc++-v3/testsuite/27_io/basic_filebuf/seekoff/wchar_t/2.cc b/libstdc++-v3/testsuite/27_io/basic_filebuf/seekoff/wchar_t/2.cc
new file mode 100644
index 000000000..cc9c4e22a
--- /dev/null
+++ b/libstdc++-v3/testsuite/27_io/basic_filebuf/seekoff/wchar_t/2.cc
@@ -0,0 +1,90 @@
+// { dg-require-namedlocale "se_NO.UTF-8" }
+
+// 2003-09-08  Petur Runolfsson  <peturr02@ru.is>
+
+// Copyright (C) 2003, 2005, 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
+
+#include <fstream>
+#include <locale>
+#include <cstdio>
+#include <testsuite_hooks.h>
+
+// Check that basic_filebuf::seekoff handles UTF-8 when open for input and
+// output.
+void test02()
+{
+  using namespace std;
+  typedef wfilebuf::int_type int_type;
+  bool test __attribute__((unused)) = true;
+  const char name[] = "tmp_seekoff-2.tst";
+
+  locale loc = locale("se_NO.UTF-8");
+
+  const size_t size = 10;
+  wchar_t buf[size];
+  streamsize n;
+
+  wfilebuf fb;
+  fb.pubimbue(loc);
+  fb.open(name, ios_base::in | ios_base::out | ios_base::trunc);
+
+  n = fb.sputn(L"\xa0st", 3);
+  VERIFY( n == 3 );
+  
+  fb.pubseekoff(0, ios_base::beg);
+  n = fb.sgetn(buf, 2);
+  VERIFY( n == 2 );
+  VERIFY( !wmemcmp(buf, L"\xa0s", 2) );
+
+  fb.pubseekoff(0, ios_base::cur);
+  n = fb.sputn(L"\xb2R", 2);
+  VERIFY( n == 2 );
+
+  fb.pubseekoff(0, ios_base::beg);
+  n = fb.sgetn(buf, size);
+  VERIFY( n == 4 );
+  VERIFY( !wmemcmp(buf, L"\xa0s\xb2R", 4) );
+
+  fb.pubseekoff(0, ios_base::beg);
+  n = fb.sputn(L"\x90m\x92n\x94", 5);
+  VERIFY( n == 5 );
+
+  fb.pubseekoff(0, ios_base::beg);
+  n = fb.sgetn(buf, 2);
+  VERIFY( n == 2 );
+  VERIFY( !wmemcmp(buf, L"\x90m", 2) );
+
+  fb.pubseekoff(0, ios_base::end);
+  n = fb.sputn(L"I\xbfJ", 3);
+  VERIFY( n == 3 );
+
+  fb.pubseekoff(0, ios_base::beg);
+  n = fb.sgetn(buf, size);
+  VERIFY( n == 8 );
+  VERIFY( !wmemcmp(buf, L"\x90m\x92n\x94I\xbfJ", 8) );
+
+  fb.close();
+}
+
+int main()
+{
+  test02();
+  return 0;
+}
diff --git a/libstdc++-v3/testsuite/27_io/basic_filebuf/seekoff/wchar_t/3.cc b/libstdc++-v3/testsuite/27_io/basic_filebuf/seekoff/wchar_t/3.cc
new file mode 100644
index 000000000..435ebcc3e
--- /dev/null
+++ b/libstdc++-v3/testsuite/27_io/basic_filebuf/seekoff/wchar_t/3.cc
@@ -0,0 +1,51 @@
+// Copyright (C) 2003, 2004, 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
+
+#include <fstream>
+#include <testsuite_hooks.h>
+
+void test03()
+{
+  using namespace std;
+  bool test __attribute__((unused)) = true;
+
+  const char* name = "tmp_seekoff_3";
+
+  wfilebuf fb;
+
+  fb.open(name, ios_base::out);
+  fb.sputc(0xf001);
+
+  try
+    {
+      // seekoff should flush the output sequence, which will fail
+      // if the output buffer contains illegal characters.
+      fb.pubseekoff(0, ios_base::cur);
+      VERIFY( false );
+    }
+  catch (std::exception&)
+    {
+    }
+}
+
+int main()
+{
+  test03();
+  return 0;
+}
diff --git a/libstdc++-v3/testsuite/27_io/basic_filebuf/seekoff/wchar_t/4.cc b/libstdc++-v3/testsuite/27_io/basic_filebuf/seekoff/wchar_t/4.cc
new file mode 100644
index 000000000..245f18f48
--- /dev/null
+++ b/libstdc++-v3/testsuite/27_io/basic_filebuf/seekoff/wchar_t/4.cc
@@ -0,0 +1,94 @@
+// { dg-require-fileio "" }
+
+// Copyright (C) 2010, 2011 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
+
+#include <fstream>
+#include <cwchar>
+#include <cstring>
+#include <testsuite_hooks.h>
+
+void test01()
+{
+  using namespace std;
+  bool test __attribute__((unused)) = true;
+
+  typedef wfilebuf::pos_type pos_type;
+  const char name[] = "tmp_seekoff-4.tst";
+
+  const size_t size = 12;
+  wchar_t buf[size];
+  streamsize n;
+
+  wfilebuf fb;
+  fb.open(name, ios_base::in | ios_base::out | ios_base::trunc);
+
+  n = fb.sputn(L"abcd", 4);
+  VERIFY( n == 4 );
+
+  fb.pubseekoff(0, ios_base::beg);
+  n = fb.sgetn(buf, 3);
+  VERIFY( n == 3 );
+  VERIFY( !wmemcmp(buf, L"abc", 3) );
+
+  // Check read => write without pubseekoff(0, ios_base::cur)
+
+  n = fb.sputn(L"ef", 2);
+  VERIFY( n == 2 );
+
+  fb.pubseekoff(0, ios_base::beg);
+
+  n = fb.sgetn(buf, size);
+  VERIFY( n == 5 );
+  VERIFY( !wmemcmp(buf, L"abcef", 5) );
+
+  fb.pubseekoff(0, ios_base::beg);
+  n = fb.sputn(L"gh", 2);
+  VERIFY( n == 2 );
+  
+  // Check write => read without pubseekoff(0, ios_base::cur)
+
+  n = fb.sgetn( buf, 3 );
+  VERIFY( !memcmp(buf, L"cef", 3) );
+
+  n = fb.sputn(L"ijkl", 4);
+  VERIFY( n == 4 );
+
+  fb.pubseekoff(0, ios_base::beg);
+  n = fb.sgetn(buf, 2);
+  VERIFY( n == 2 );
+  VERIFY( !wmemcmp(buf, L"gh", 2) );
+
+  fb.pubseekoff(0, ios_base::end);
+  n = fb.sputn(L"mno", 3);
+  VERIFY( n == 3 );
+
+  fb.pubseekoff(0, ios_base::beg);
+  n = fb.sgetn(buf, size);
+  VERIFY( n == 12 );
+  VERIFY( !wmemcmp(buf, L"ghcefijklmno", 12) );
+
+  fb.close();
+}
+
+int main()
+{
+  test01();
+  return 0;
+}
diff --git a/libstdc++-v3/testsuite/27_io/basic_filebuf/seekoff/wchar_t/9875_seekoff.cc b/libstdc++-v3/testsuite/27_io/basic_filebuf/seekoff/wchar_t/9875_seekoff.cc
new file mode 100644
index 000000000..312386a24
--- /dev/null
+++ b/libstdc++-v3/testsuite/27_io/basic_filebuf/seekoff/wchar_t/9875_seekoff.cc
@@ -0,0 +1,99 @@
+// 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
+
+#include <fstream>
+#include <locale>
+#include <algorithm>
+#include <cstring>
+#include <testsuite_hooks.h>
+
+class Cvt : public std::codecvt<wchar_t, char, mbstate_t>
+{
+protected:
+  virtual std::codecvt_base::result
+  do_out(std::mbstate_t&, const wchar_t* from, const wchar_t* from_end,
+	 const wchar_t*& from_next, char* to, char* to_end,
+	 char*& to_next) const
+  {
+    std::size_t from_len = from_end - from;
+    std::size_t to_len = (to_end - to) / sizeof(wchar_t);
+    std::size_t len = std::min(from_len, to_len);
+    std::memcpy(to, from, len * sizeof(wchar_t));
+    from_next = from + len;
+    to_next = to + len * sizeof(wchar_t);
+    return from_next == from_end ? std::codecvt_base::ok :
+           std::codecvt_base::partial;
+  }
+
+  virtual std::codecvt_base::result
+  do_in(std::mbstate_t&, const char* from, const char* from_end,
+	const char*& from_next, wchar_t* to, wchar_t* to_end,
+	wchar_t*& to_next) const
+  {
+    std::size_t from_len =
+      (from_end - from) / sizeof(wchar_t);
+    std::size_t to_len = to_end - to;
+    std::size_t len = std::min(from_len, to_len);
+    std::memcpy(to, from, len * sizeof(wchar_t));
+    from_next = from + len * sizeof(wchar_t);
+    to_next = to + len;
+    return from_next == from_end ? std::codecvt_base::ok :
+           std::codecvt_base::partial;
+  }
+  
+  virtual std::codecvt_base::result
+  do_unshift(std::mbstate_t&, char*, char*, char*&) const
+  { return std::codecvt_base::noconv; }
+  
+  virtual int do_encoding() const throw() { return sizeof(wchar_t); }
+  virtual bool do_always_noconv() const throw() { return false; }
+  
+  virtual int
+  do_length(std::mbstate_t&, const char* from, const char* end,
+	    std::size_t max)
+  {
+    std::size_t len = (end - from) / sizeof(wchar_t);
+    return std::min(len, max) * sizeof(wchar_t);
+  }
+  
+  virtual int do_max_length() const throw() { return sizeof(wchar_t); }
+};
+
+void test01()
+{
+  using namespace std;
+  bool test __attribute__((unused)) = true;
+  
+  // seekoff
+  wfilebuf fb;
+  fb.pubimbue(locale(locale::classic(), new Cvt));
+  fb.open("tmp_9875_seekoff", ios_base::out | ios_base::in | ios_base::trunc);
+  fb.sputn(L"0123456789", 10);
+  fb.pubseekoff(-3, ios_base::cur);
+  VERIFY( fb.sgetc() == L'7' );
+  fb.pubseekoff(-3, ios_base::cur);
+  VERIFY( fb.sgetc() == L'4' );
+  fb.close();
+}
+
+int main()
+{
+  test01();
+  return 0;
+}