diff --git a/libstdc++-v3/ChangeLog b/libstdc++-v3/ChangeLog
index 7585153ed1d891cc70d52192692ef1cc6ffe509d..3bdd2c830a77f14b57d6f5f8eb9be817151c8494 100644
--- a/libstdc++-v3/ChangeLog
+++ b/libstdc++-v3/ChangeLog
@@ -1,3 +1,15 @@
+2009-12-03  Paolo Carlini  <paolo.carlini@oracle.com>
+
+	PR libstdc++/42261
+	* include/bits/basic_string.h (_S_construct_aux(_Integer, _Integer,
+	const _Alloc&, __true_type)): Cast the second argument to value_type.
+	* include/ext/sso_string_base.h (_M_construct_aux(_Integer, _Integer,
+	std::__true_type)): Likewise.
+	* include/ext/rc_string_base.h (_S_construct_aux(_Integer, _Integer,
+	const _Alloc&, std::__true_type)): Likewise.
+	* testsuite/21_strings/basic_string/cons/char/42261.cc: New.
+	* testsuite/21_strings/basic_string/cons/wchar_t/42261.cc: Likewise.
+
 2009-12-03  Paolo Carlini  <paolo.carlini@oracle.com>
 
 	* testsuite/20_util/bind/ref.cc: Add.
diff --git a/libstdc++-v3/include/bits/basic_string.h b/libstdc++-v3/include/bits/basic_string.h
index 269a75ed46817a51f9701d14f05db4b1ecf67eae..a574bf62f8789490d5090116d0a9d200e6ee5e76 100644
--- a/libstdc++-v3/include/bits/basic_string.h
+++ b/libstdc++-v3/include/bits/basic_string.h
@@ -1588,7 +1588,8 @@ _GLIBCXX_BEGIN_NAMESPACE(std)
         static _CharT*
         _S_construct_aux(_Integer __beg, _Integer __end,
 			 const _Alloc& __a, __true_type)
-        { return _S_construct(static_cast<size_type>(__beg), __end, __a); }
+        { return _S_construct(static_cast<size_type>(__beg),
+			      static_cast<value_type>(__end), __a); }
 
       template<class _InIterator>
         static _CharT*
diff --git a/libstdc++-v3/include/ext/rc_string_base.h b/libstdc++-v3/include/ext/rc_string_base.h
index 6d8c430d57503e718a0958fea04cadb291c7baab..c9fdb25317d38ea2d963d57873e960ad9b2b5be8 100644
--- a/libstdc++-v3/include/ext/rc_string_base.h
+++ b/libstdc++-v3/include/ext/rc_string_base.h
@@ -231,7 +231,8 @@ _GLIBCXX_BEGIN_NAMESPACE(__gnu_cxx)
         static _CharT*
         _S_construct_aux(_Integer __beg, _Integer __end,
 			 const _Alloc& __a, std::__true_type)
-	{ return _S_construct(static_cast<size_type>(__beg), __end, __a); }
+	{ return _S_construct(static_cast<size_type>(__beg),
+			      static_cast<value_type>(__end), __a); }
 
       template<typename _InIterator>
         static _CharT*
diff --git a/libstdc++-v3/include/ext/sso_string_base.h b/libstdc++-v3/include/ext/sso_string_base.h
index d88297fc36e55ba249ef92fb793e7fe78100245b..264e862e96ae9a3953c37b2b61229526e170992e 100644
--- a/libstdc++-v3/include/ext/sso_string_base.h
+++ b/libstdc++-v3/include/ext/sso_string_base.h
@@ -106,7 +106,8 @@ _GLIBCXX_BEGIN_NAMESPACE(__gnu_cxx)
       template<typename _Integer>
         void
         _M_construct_aux(_Integer __beg, _Integer __end, std::__true_type)
-	{ _M_construct(static_cast<size_type>(__beg), __end); }
+      { _M_construct(static_cast<size_type>(__beg),
+		     static_cast<value_type>(__end)); }
 
       template<typename _InIterator>
         void
diff --git a/libstdc++-v3/testsuite/21_strings/basic_string/cons/char/42261.cc b/libstdc++-v3/testsuite/21_strings/basic_string/cons/char/42261.cc
new file mode 100644
index 0000000000000000000000000000000000000000..a83b74ac73599631c7f4923db9fa737b43c3963b
--- /dev/null
+++ b/libstdc++-v3/testsuite/21_strings/basic_string/cons/char/42261.cc
@@ -0,0 +1,35 @@
+// Copyright (C) 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/>.
+
+#include <string>
+#include <testsuite_hooks.h>
+
+// libstdc++/42261
+void test01()
+{
+  bool test __attribute__((unused)) = true;
+  using namespace std;
+
+  const string s(string::size_type(6), string::size_type('f'));
+  VERIFY( s == "ffffff" );
+}
+
+int main()
+{
+  test01();
+  return 0;
+}
diff --git a/libstdc++-v3/testsuite/21_strings/basic_string/cons/wchar_t/42261.cc b/libstdc++-v3/testsuite/21_strings/basic_string/cons/wchar_t/42261.cc
new file mode 100644
index 0000000000000000000000000000000000000000..8782e8cafe90db7de10d8ddf2a6156a6c6ec01a6
--- /dev/null
+++ b/libstdc++-v3/testsuite/21_strings/basic_string/cons/wchar_t/42261.cc
@@ -0,0 +1,35 @@
+// Copyright (C) 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/>.
+
+#include <string>
+#include <testsuite_hooks.h>
+
+// libstdc++/42261
+void test01()
+{
+  bool test __attribute__((unused)) = true;
+  using namespace std;
+
+  const wstring s(wstring::size_type(6), wstring::size_type(L'f'));
+  VERIFY( s == L"ffffff" );
+}
+
+int main()
+{
+  test01();
+  return 0;
+}