diff --git a/libstdc++-v3/ChangeLog b/libstdc++-v3/ChangeLog
index 48059ebe044..8e0014aad75 100644
--- a/libstdc++-v3/ChangeLog
+++ b/libstdc++-v3/ChangeLog
@@ -1,3 +1,13 @@
+2006-09-21  Paolo Carlini  <pcarlini@suse.de>
+
+	PR libstdc++/29134 (ext/vstring bits)
+	* include/ext/sso_string_base.h (__sso_string_base<>::_S_max_size):
+	Remove.
+	(__sso_string_base<>::_M_max_size): Use allocator' max_size.
+	(__sso_string_base<>::_M_create): Adjust.
+	* include/ext/vstring.h: Minor comment tweak.
+	* testsuite/ext/vstring/capacity/29134.cc: New.
+
 2006-09-20  Paolo Carlini  <pcarlini@suse.de>
 
 	PR libstdc++/29134
diff --git a/libstdc++-v3/include/ext/sso_string_base.h b/libstdc++-v3/include/ext/sso_string_base.h
index 30988260dd7..24cd160be11 100644
--- a/libstdc++-v3/include/ext/sso_string_base.h
+++ b/libstdc++-v3/include/ext/sso_string_base.h
@@ -51,21 +51,7 @@ _GLIBCXX_BEGIN_NAMESPACE(__gnu_cxx)
       typedef typename _CharT_alloc_type::size_type	    size_type;
       
     private:
-      // The maximum number of individual char_type elements of an
-      // individual string is determined by _S_max_size. This is the
-      // value that will be returned by max_size().  (Whereas npos
-      // is the maximum number of bytes the allocator can allocate.)
-      // If one was to divvy up the theoretical largest size string,
-      // with a terminating character and m _CharT elements, it'd
-      // look like this:
-      // npos = m * sizeof(_CharT) + sizeof(_CharT)
-      // Solving for m:
-      // m = npos / sizeof(_CharT) - 1
-      // In addition, this implementation halfs this amount.
-      enum { _S_max_size = (((static_cast<size_type>(-1)
-			      / sizeof(_CharT)) - 1) / 2) };
-
-      // Data Members (private):
+      // Data Members:
       typename _Util_Base::template _Alloc_hider<_CharT_alloc_type>
                                                             _M_dataplus;
       size_type                                             _M_string_length;
@@ -151,7 +137,7 @@ _GLIBCXX_BEGIN_NAMESPACE(__gnu_cxx)
     public:
       size_type
       _M_max_size() const
-      { return size_type(_S_max_size); }
+      { return (_M_dataplus._CharT_alloc_type::max_size() - 1) / 2; }
 
       _CharT*
       _M_data() const
@@ -322,7 +308,7 @@ _GLIBCXX_BEGIN_NAMESPACE(__gnu_cxx)
     {
       // _GLIBCXX_RESOLVE_LIB_DEFECTS
       // 83.  String::npos vs. string::max_size()
-      if (__capacity > size_type(_S_max_size))
+      if (__capacity > _M_max_size())
 	std::__throw_length_error(__N("__sso_string_base::_M_create"));
 
       // The below implements an exponential growth policy, necessary to
@@ -331,9 +317,9 @@ _GLIBCXX_BEGIN_NAMESPACE(__gnu_cxx)
       if (__capacity > __old_capacity && __capacity < 2 * __old_capacity)
 	{
 	  __capacity = 2 * __old_capacity;
-	  // Never allocate a string bigger than _S_max_size.
-	  if (__capacity > size_type(_S_max_size))
-	    __capacity = size_type(_S_max_size);
+	  // Never allocate a string bigger than max_size.
+	  if (__capacity > _M_max_size())
+	    __capacity = _M_max_size();
 	}
 
       // NB: Need an array of char_type[__capacity], plus a terminating
diff --git a/libstdc++-v3/include/ext/vstring.h b/libstdc++-v3/include/ext/vstring.h
index d858949db46..62e9673d3ef 100644
--- a/libstdc++-v3/include/ext/vstring.h
+++ b/libstdc++-v3/include/ext/vstring.h
@@ -74,8 +74,6 @@ _GLIBCXX_BEGIN_NAMESPACE(__gnu_cxx)
       typedef std::reverse_iterator<iterator>		    reverse_iterator;
 
       // Data Member (public):
-      // NB: This is an unsigned type, and thus represents the maximum
-      // size that the allocator can hold.
       ///  Value returned by various member functions when they fail.
       static const size_type	npos = static_cast<size_type>(-1);
 
diff --git a/libstdc++-v3/testsuite/ext/vstring/capacity/29134.cc b/libstdc++-v3/testsuite/ext/vstring/capacity/29134.cc
new file mode 100644
index 00000000000..41658ee0ae9
--- /dev/null
+++ b/libstdc++-v3/testsuite/ext/vstring/capacity/29134.cc
@@ -0,0 +1,38 @@
+// Copyright (C) 2006 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 2, or (at your option)
+// any later version.
+
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without Pred 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 COPYING.  If not, write to the Free
+// Software Foundation, 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301,
+// USA.
+
+// 21.3.3 basic_string capacity [lib.string.capacity]
+
+#include <ext/vstring.h>
+#include <testsuite_hooks.h>
+
+// libstdc++/29134
+void test01()
+{
+  bool test __attribute__((unused)) = true;
+
+  __gnu_cxx::__vstring vs;
+
+  VERIFY( vs.max_size() <= vs.get_allocator().max_size() );
+}
+
+int main()
+{
+  test01();
+  return 0;
+}