diff --git a/hl_ref.htm b/hl_ref.htm
index 0cb9dff3..44b803a1 100644
--- a/hl_ref.htm
+++ b/hl_ref.htm
@@ -92,10 +92,13 @@ are allowed. </p>
 </i>&nbsp;&nbsp; <i>// 
 </i></font>&nbsp;&nbsp; <b>unsigned</b> <b>int</b> Position(<b>int</b> i = 0)<b>const</b>; 
 &nbsp;&nbsp; <b>unsigned</b> <b>int</b> Length(<b>int</b> i = 0)<b>const</b>; 
+   <strong>bool</strong> Matched(<strong>int</strong> i = 0)<strong>const</strong>;
 &nbsp;&nbsp; <b>unsigned</b> <b>int</b> Line()<b>const</b>; 
 &nbsp;&nbsp; <b>unsigned int</b> Marks() const; 
 &nbsp;&nbsp; std::string What(<b>int</b> i)<b>const</b>; 
 &nbsp;&nbsp; std::string <b>operator</b>[](<b>int</b> i)<b>const</b> ; 
+
+   <strong>static const unsigned int</strong> npos;
 }; &nbsp; &nbsp; </pre>
 
 <p>Member functions for class RegEx are defined as follows: <br>
@@ -495,8 +498,8 @@ are allowed. </p>
         Position(<b>int</b> i = 0)<b>const</b>;</td>
         <td valign="top" width="42%">Returns the position of what
         matched sub-expression <i>i</i>. If <i>i = 0</i> then
-        returns the position of the whole match. Returns -1 if
-        the supplied index is invalid, or if the specified sub-expression
+        returns the position of the whole match. Returns RegEx::npos
+        if the supplied index is invalid, or if the specified sub-expression
         did not participate in the match.</td>
         <td valign="top" width="7%">&nbsp;</td>
     </tr>
@@ -506,18 +509,26 @@ are allowed. </p>
         Length(<b>int</b> i = 0)<b>const</b>;</td>
         <td valign="top" width="42%">Returns the length of what
         matched sub-expression <i>i</i>. If <i>i = 0</i> then
-        returns the length of the whole match. Returns -1 if the
-        supplied index is invalid, or if the specified sub-expression
+        returns the length of the whole match. Returns RegEx::npos
+        if the supplied index is invalid, or if the specified sub-expression
         did not participate in the match.</td>
         <td valign="top" width="7%">&nbsp;</td>
     </tr>
+    <tr>
+        <td>&nbsp;</td>
+        <td><strong>bool</strong> Matched(<strong>int</strong> i
+        = 0)<strong>const</strong>;</td>
+        <td>Returns true if sub-expression <em>i</em> was
+        matched, false otherwise.</td>
+        <td>&nbsp;</td>
+    </tr>
     <tr>
         <td valign="top" width="7%">&nbsp;</td>
         <td valign="top" width="43%"><b>unsigned</b> <b>int</b>
         Line()<b>const</b>;</td>
         <td valign="top" width="42%">Returns the line on which
         the match occurred, indexes start from 1 not zero, if no
-        match occurred then returns (unsigned)-1.</td>
+        match occurred then returns RegEx::npos.</td>
         <td valign="top" width="7%">&nbsp;</td>
     </tr>
     <tr>
diff --git a/src/c_regex_traits.cpp b/src/c_regex_traits.cpp
index a55dc831..c41a0260 100644
--- a/src/c_regex_traits.cpp
+++ b/src/c_regex_traits.cpp
@@ -342,7 +342,14 @@ void BOOST_REGEX_CALL re_message_update()
          message_cat = (nl_catd)-1;
       }
       if(*boost::re_detail::c_traits_base::get_catalogue())
+      {
          message_cat = catopen(boost::re_detail::c_traits_base::get_catalogue(), 0);
+         if(message_cat == (nl_catd)-1)
+         {
+            std::string m("Unable to open message catalog: ");
+            throw std::runtime_error(m + boost::re_detail::c_traits_base::get_catalogue());
+         }
+      }
 #endif
       for(int i = 0; i < boost::REG_E_UNKNOWN; ++i)
       {
diff --git a/src/cpp_regex_traits.cpp b/src/cpp_regex_traits.cpp
index 31a8c756..e5b93163 100644
--- a/src/cpp_regex_traits.cpp
+++ b/src/cpp_regex_traits.cpp
@@ -189,8 +189,19 @@ message_data<char>::message_data(const std::locale& l, const std::string& regex_
 {
    is.imbue(l);
 #ifndef BOOST_NO_STD_MESSAGES
-   const std::messages<char>* pm = &BOOST_USE_FACET(std::messages<char>, l);
-   std::messages<char>::catalog cat = regex_message_catalogue.size() ? pm->open(regex_message_catalogue, l) : -1;
+
+   const std::messages<char>* pm = 0;
+   std::messages<char>::catalog cat = -1;
+   if(regex_message_catalogue.size())
+   {
+      pm = &BOOST_USE_FACET(std::messages<char>, l);
+      cat = pm->open(regex_message_catalogue, l);
+      if(cat < 0)
+      {
+         std::string m("Unable to open message catalog: ");
+         throw std::runtime_error(m + regex_message_catalogue);
+      }
+   } 
 #endif
    std::memset(syntax_map, cpp_regex_traits<char>::syntax_char, 256);
    unsigned int i;
@@ -222,39 +233,26 @@ message_data<char>::message_data(const std::locale& l, const std::string& regex_
    std::string c1, c2;
    i = 400;
    if((int)cat >= 0)
-      c2 = pm->get(cat, 0, i, c1);
-   while(c2.size())
    {
-      const char* p1, *p2, *p3, *p4;;
-      p1 = c2.c_str();
-      while(*p1 && std::isspace((char)*p1, l))++p1;
-      p2 = p1;
-      while(*p2 && !std::isspace((char)*p2, l))++p2;
-      p3 = p2;
-      while(*p3 && std::isspace((char)*p3, l))++p3;
-      p4 = p3;
-      while(*p4 && !std::isspace((char)*p4, l))++p4;
-      collating_elements[std::string(p1, p2)] = std::string(p3, p4);
-      
-      ++i;
       c2 = pm->get(cat, 0, i, c1);
+      while(c2.size())
+      {
+         const char* p1, *p2, *p3, *p4;;
+         p1 = c2.c_str();
+         while(*p1 && std::isspace((char)*p1, l))++p1;
+         p2 = p1;
+         while(*p2 && !std::isspace((char)*p2, l))++p2;
+         p3 = p2;
+         while(*p3 && std::isspace((char)*p3, l))++p3;
+         p4 = p3;
+         while(*p4 && !std::isspace((char)*p4, l))++p4;
+         collating_elements[std::string(p1, p2)] = std::string(p3, p4);
+
+         ++i;
+         c2 = pm->get(cat, 0, i, c1);
+      }
    }
 #endif
-/*
-   std::string n("zero");
-   std::map<std::string, std::string, std::less<std::string > >::const_iterator pos = collating_elements.find(n);
-   if(pos != collating_elements.end())
-      _zero = *(*pos).second.c_str();
-   else
-      _zero = '0';
-
-   n = "ten";
-   pos = collating_elements.find(n);
-   if(pos != collating_elements.end())
-      _ten = *(*pos).second.c_str();
-   else
-      _ten = 'a';
-*/
    std::string m;
    std::string s;
 #ifndef BOOST_NO_STD_MESSAGES
@@ -562,7 +560,16 @@ message_data<wchar_t>::message_data(const std::locale& l, const std::string& reg
    const cvt_type& cvt = BOOST_USE_FACET(cvt_type, l);
 #ifndef BOOST_NO_STD_MESSAGES
    const std::messages<wchar_t>& msgs = BOOST_USE_FACET(std::messages<wchar_t>, l);
-   std::messages<wchar_t>::catalog cat = regex_message_catalogue.size() ? msgs.open(regex_message_catalogue, l) : -1;
+   std::messages<wchar_t>::catalog cat = -1;
+   if(regex_message_catalogue.size())
+   {
+      cat = msgs.open(regex_message_catalogue, l);
+      if(cat < 0)
+      {
+         std::string m("Unable to open message catalog: ");
+         throw std::runtime_error(m + regex_message_catalogue);
+      }
+   }
 #endif
    scoped_array<char> a;
    unsigned array_size = 0;
@@ -602,22 +609,24 @@ message_data<wchar_t>::message_data(const std::locale& l, const std::string& reg
    string_type c1, c2;
    i = 400;
    if((int)cat >= 0)
-      c2 = msgs.get(cat, 0, i, c1);
-   while(c2.size())
    {
-      const wchar_t* p1, *p2, *p3, *p4;;
-      p1 = c2.c_str();
-      while(*p1 && std::isspace((wchar_t)*p1, l))++p1;
-      p2 = p1;
-      while(*p2 && !std::isspace((wchar_t)*p2, l))++p2;
-      p3 = p2;
-      while(*p3 && std::isspace((wchar_t)*p3, l))++p3;
-      p4 = p3;
-      while(*p4 && !std::isspace((wchar_t)*p4, l))++p4;
-      collating_elements[std::basic_string<wchar_t>(p1, p2)] = std::basic_string<wchar_t>(p3, p4);
-      
-      ++i;
       c2 = msgs.get(cat, 0, i, c1);
+      while(c2.size())
+      {
+         const wchar_t* p1, *p2, *p3, *p4;;
+         p1 = c2.c_str();
+         while(*p1 && std::isspace((wchar_t)*p1, l))++p1;
+         p2 = p1;
+         while(*p2 && !std::isspace((wchar_t)*p2, l))++p2;
+         p3 = p2;
+         while(*p3 && std::isspace((wchar_t)*p3, l))++p3;
+         p4 = p3;
+         while(*p4 && !std::isspace((wchar_t)*p4, l))++p4;
+         collating_elements[std::basic_string<wchar_t>(p1, p2)] = std::basic_string<wchar_t>(p3, p4);
+
+         ++i;
+         c2 = msgs.get(cat, 0, i, c1);
+      }
    }
 
    if((int)cat >= 0)
diff --git a/src/cregex.cpp b/src/cregex.cpp
index 8de9ddeb..c39b8dc9 100644
--- a/src/cregex.cpp
+++ b/src/cregex.cpp
@@ -465,18 +465,18 @@ unsigned int RegEx::Position(int i)const
    switch(pdata->t)
    {
    case re_detail::RegExData::type_pc:
-      return pdata->m[i].matched ? pdata->m[i].first - pdata->pbase : (unsigned int)-1;
+      return pdata->m[i].matched ? pdata->m[i].first - pdata->pbase : RegEx::npos;
    case re_detail::RegExData::type_pf:
-      return pdata->fm[i].matched ? pdata->fm[i].first - pdata->fbase : (unsigned int)-1;
+      return pdata->fm[i].matched ? pdata->fm[i].first - pdata->fbase : RegEx::npos;
    case re_detail::RegExData::type_copy:
       {
       std::map<int, int, std::less<int> >::iterator pos = pdata->positions.find(i);
       if(pos == pdata->positions.end())
-         return (unsigned int)-1;
+         return RegEx::npos;
       return (*pos).second;
       }
    }
-   return (unsigned int)-1;
+   return RegEx::npos;
 }
 
 unsigned int RegEx::Line()const
@@ -485,15 +485,15 @@ unsigned int RegEx::Line()const
    switch(pdata->t)
    {
    case re_detail::RegExData::type_pc:
-      return pdata->m[0].matched ? pdata->m.line() : (unsigned int)-1;
+      return pdata->m[0].matched ? pdata->m.line() : RegEx::npos;
    case re_detail::RegExData::type_pf:
-      return pdata->fm[0].matched ? pdata->fm.line() : (unsigned int)-1;
+      return pdata->fm[0].matched ? pdata->fm.line() : RegEx::npos;
    case re_detail::RegExData::type_copy:
       {
          return pdata->line;
       }
    }
-   return (unsigned int)-1;
+   return RegEx::npos;
 }
 
 unsigned int RegEx::Marks()const
@@ -509,20 +509,41 @@ unsigned int RegEx::Length(int i)const
    switch(pdata->t)
    {
    case re_detail::RegExData::type_pc:
-      return pdata->m[i].matched ? pdata->m[i].second - pdata->m[i].first : (unsigned)-1;
+      return pdata->m[i].matched ? pdata->m[i].second - pdata->m[i].first : RegEx::npos;
    case re_detail::RegExData::type_pf:
-      return pdata->fm[i].matched ? pdata->fm[i].second - pdata->fm[i].first : (unsigned)-1;
+      return pdata->fm[i].matched ? pdata->fm[i].second - pdata->fm[i].first : RegEx::npos;
    case re_detail::RegExData::type_copy:
       {
       std::map<int, std::string, std::less<int> >::iterator pos = pdata->strings.find(i);
       if(pos == pdata->strings.end())
-         return (unsigned)-1;
+         return RegEx::npos;
       return (*pos).second.size();
       }
    }
-   return (unsigned)-1;
+   return RegEx::npos;
 }
 
+bool RegEx::Matched(int i)const
+{
+   BOOST_RE_GUARD_STACK
+   switch(pdata->t)
+   {
+   case re_detail::RegExData::type_pc:
+      return pdata->m[i].matched;
+   case re_detail::RegExData::type_pf:
+      return pdata->fm[i].matched;
+   case re_detail::RegExData::type_copy:
+      {
+      std::map<int, std::string, std::less<int> >::iterator pos = pdata->strings.find(i);
+      if(pos == pdata->strings.end())
+         return false;
+      return true;
+      }
+   }
+   return false;
+}
+
+
 std::string RegEx::What(int i)const
 {
    BOOST_RE_GUARD_STACK
@@ -548,6 +569,8 @@ std::string RegEx::What(int i)const
    return result;
 }
 
+const unsigned int RegEx::npos = ~0u;
+
 
 } // namespace boost
 
diff --git a/src/w32_regex_traits.cpp b/src/w32_regex_traits.cpp
index dab7e7fa..0549c3bb 100644
--- a/src/w32_regex_traits.cpp
+++ b/src/w32_regex_traits.cpp
@@ -230,10 +230,17 @@ void BOOST_REGEX_CALL w32_traits_base::do_init()
    if(is_init == 0)
    {
       //
-      // upadte the messages first:
+      // update the messages first:
       is_init = true;
       if(*regex_message_catalogue)
+      {
          hresmod = LoadLibraryA(regex_message_catalogue);
+         if(hresmod == NULL)
+         {
+            std::string s("Unable to open dll: ");
+            throw std::runtime_error(s + regex_message_catalogue);
+         }
+      }
       unsigned int i;
       for(i = 0; i < REG_E_UNKNOWN; ++i)
       {