--- a/src/core/attribute-test.cc	Fri Mar 07 12:18:34 2008 -0800
+++ b/src/core/attribute-test.cc	Sun Mar 09 21:07:14 2008 +0100
@@ -240,7 +240,7 @@
 
   AttributeList params;
   Ptr<AttributeObjectTest> p;
-  NS_TEST_ASSERT (params.Set ("AttributeObjectTest::TestBoolName", String ("false")));
+  NS_TEST_ASSERT (params.SetFailSafe ("AttributeObjectTest::TestBoolName", String ("false")));
   p = CreateObject<AttributeObjectTest> (params);
   CHECK_GET_STR (p, "TestBoolName", "false");
   CHECK_GET_PARAM (p, "TestBoolName", Boolean, false);
@@ -408,12 +408,12 @@
     NS_TEST_ASSERT_EQUAL (vector.GetN (), 2);
   }
 
-  NS_TEST_ASSERT (AttributeList::GetGlobal ()->Set ("AttributeObjectTest::TestBoolName", String ("true")));
+  NS_TEST_ASSERT (AttributeList::GetGlobal ()->SetFailSafe ("AttributeObjectTest::TestBoolName", String ("true")));
   p = CreateObjectWith<AttributeObjectTest> ();
   Boolean boolV = p->GetAttribute ("TestBoolName");
   NS_TEST_ASSERT_EQUAL (boolV, Boolean (true));
 
-  NS_TEST_ASSERT (AttributeList::GetGlobal ()->Set ("AttributeObjectTest::TestBoolName", String ("false")));
+  NS_TEST_ASSERT (AttributeList::GetGlobal ()->SetFailSafe ("AttributeObjectTest::TestBoolName", String ("false")));
   p = CreateObjectWith<AttributeObjectTest> ();
   boolV = p->GetAttribute ("TestBoolName");
   NS_TEST_ASSERT_EQUAL (boolV, Boolean (false));

--- a/src/core/config.cc	Fri Mar 07 12:18:34 2008 -0800
+++ b/src/core/config.cc	Sun Mar 09 21:07:14 2008 +0100
@@ -409,10 +409,18 @@
 {
   AttributeList::GetGlobal ()->Set (name, value);
 }
+bool SetDefaultFailSafe (std::string name, Attribute value)
+{
+  return AttributeList::GetGlobal ()->SetFailSafe (name, value);
+}
 void SetGlobal (std::string name, Attribute value)
 {
   GlobalValue::Bind (name, value);
 }
+bool SetGlobalFailSafe (std::string name, Attribute value)
+{
+  return GlobalValue::BindFailSafe (name, value);
+}
 void Connect (std::string path, const CallbackBase &cb)
 {
   Singleton<ConfigImpl>::Get ()->Connect (path, cb);

--- a/src/core/config.h	Fri Mar 07 12:18:34 2008 -0800
+++ b/src/core/config.h	Sun Mar 09 21:07:14 2008 +0100
@@ -12,7 +12,9 @@
 
 void Set (std::string path, Attribute value);
 void SetDefault (std::string name, Attribute value);
+bool SetDefaultFailSafe (std::string name, Attribute value);
 void SetGlobal (std::string name, Attribute value);
+bool SetGlobalFailSafe (std::string name, Attribute value);
 void Connect (std::string path, const CallbackBase &cb);
 void Disconnect (std::string path, const CallbackBase &cb);
 void ConnectWithContext (std::string path, const CallbackBase &cb);

--- a/src/core/global-value.cc	Fri Mar 07 12:18:34 2008 -0800
+++ b/src/core/global-value.cc	Sun Mar 09 21:07:14 2008 +0100
@@ -40,14 +40,15 @@
   return m_checker;
 }
   
-void 
+bool
 GlobalValue::SetValue (Attribute value)
 {
   if (!m_checker->Check (value))
     {
-      NS_FATAL_ERROR ("Invalid new value.");
+      return false;
     }
   m_initialValue = value;
+  return true;
 }
 
 void 
@@ -57,10 +58,26 @@
     {
       if ((*i)->GetName () == name)
 	{
-	  (*i)->SetValue (value);
+	  if (!(*i)->SetValue (value))
+	    {
+	      NS_FATAL_ERROR ("Invalid new value for global value: "<<name);
+	    }
 	  return;
 	}
     }
+  NS_FATAL_ERROR ("Non-existant global value: "<<name);
+}
+bool 
+GlobalValue::BindFailSafe (std::string name, Attribute value)
+{
+  for (Iterator i = Begin (); i != End (); i++)
+    {
+      if ((*i)->GetName () == name)
+	{
+	  return (*i)->SetValue (value);
+	}
+    }
+  return false;
 }
 GlobalValue::Iterator 
 GlobalValue::Begin (void)

--- a/src/core/global-value.h	Fri Mar 07 12:18:34 2008 -0800
+++ b/src/core/global-value.h	Sun Mar 09 21:07:14 2008 +0100
@@ -24,9 +24,10 @@
   Attribute GetValue (void) const;
   Ptr<const AttributeChecker> GetChecker (void) const;
   
-  void SetValue (Attribute value);
+  bool SetValue (Attribute value);
 
   static void Bind (std::string name, Attribute value);
+  static bool BindFailSafe (std::string name, Attribute value);
 
   static Iterator Begin (void);
   static Iterator End (void);

--- a/src/core/object.cc	Fri Mar 07 12:18:34 2008 -0800
+++ b/src/core/object.cc	Sun Mar 09 21:07:14 2008 +0100
@@ -403,6 +403,18 @@
   return TypeId (uid);
 }
 bool
+TypeId::LookupByNameFailSafe (std::string name, TypeId *tid)
+{
+  uint16_t uid = Singleton<IidManager>::Get ()->GetUid (name);
+  if (uid == 0)
+    {
+      return false;
+    }
+  *tid = TypeId (uid);
+  return true;
+}
+
+bool
 TypeId::LookupAttributeByFullName (std::string fullName, struct TypeId::AttributeInfo *info)
 {
   std::string::size_type pos = fullName.find ("::");
@@ -412,7 +424,12 @@
     }
   std::string tidName = fullName.substr (0, pos);
   std::string paramName = fullName.substr (pos+2, fullName.size () - (pos+2));
-  TypeId tid = LookupByName (tidName);
+  TypeId tid;
+  bool ok = LookupByNameFailSafe (tidName, &tid);
+  if (!ok)
+    {
+      return false;
+    }
   return tid.LookupAttributeByName (paramName, info);
 }
 uint32_t 
@@ -683,7 +700,11 @@
 {
   std::string tidString;
   is >> tidString;
-  tid = TypeId::LookupByName (tidString);
+  bool ok = TypeId::LookupByNameFailSafe (tidString, &tid);
+  if (!ok)
+    {
+      is.setstate (std::ios_base::badbit);
+    }
   return is;
 }
 
@@ -735,8 +756,23 @@
   Reset ();
 }
 
+void
+AttributeList::Set (std::string name, Attribute value)
+{
+  struct TypeId::AttributeInfo info;
+  bool ok = TypeId::LookupAttributeByFullName (name, &info);
+  if (!ok)
+    {
+      NS_FATAL_ERROR ("Could not find attribute "<<name);
+    }
+  ok = DoSet (&info, value);
+  if (!ok)
+    {
+      NS_FATAL_ERROR ("Could not set value for attribute "<<name);
+    }
+}
 bool 
-AttributeList::Set (std::string name, Attribute value)
+AttributeList::SetFailSafe (std::string name, Attribute value)
 {
   struct TypeId::AttributeInfo info;
   TypeId::LookupAttributeByFullName (name, &info);

--- a/src/core/object.h	Fri Mar 07 12:18:34 2008 -0800
+++ b/src/core/object.h	Sun Mar 09 21:07:14 2008 +0100
@@ -69,7 +69,7 @@
   };
 
   /**
-   * \param name the name of the requested interface
+   * \param name the name of the requested TypeId
    * \returns the unique id associated with the requested
    *          name. 
    *
@@ -77,6 +77,13 @@
    * name is not a valid interface name.
    */
   static TypeId LookupByName (std::string name);
+  /**
+   * \param name the name of the requested TypeId
+   * \param tid a pointer to the TypeId instance where the 
+   *        result of this function should be stored.
+   * \returns true if the requested name was found, false otherwise.
+   */
+  static bool LookupByNameFailSafe (std::string name, TypeId *tid);
 
   /**
    * \returns the number of TypeId instances constructed
@@ -316,7 +323,8 @@
    * value of that attribute. If any of these checks fails,
    * the program terminates with a message.
    */
-  bool Set (std::string name, Attribute value);
+  void Set (std::string name, Attribute value);
+  bool SetFailSafe (std::string name, Attribute value);
 
   bool SetWithTid (TypeId tid, std::string name, Attribute value);
   bool SetWithTid (TypeId tid, uint32_t position, Attribute value);