Sorry, but I do need that Deleter feature in the locked_queue to avoid memory leaks. But this way now it should not harm all non-users, I hope so. :-o

locked_queue.hh

@@ -9,7 +9,7 @@
 
 namespace utility
 {
-    template<class T>
+    template<class T, void(*Deleter)(T) = nullptr>
     class locked_queue
     {
         typedef std::recursive_mutex     Mutex;
@@ -28,6 +28,13 @@ namespace utility
         void clear()
         {
             Lock L(_mtx);
+            if(Deleter != nullptr)
+            {
+                for(auto q : _q)
+                {
+                    Deleter(q);
+                }
+            }
             _q.clear();
         }
 

test_library.cc

@@ -50,7 +50,8 @@ void consumer_thread()
 	int sum = 0;
 	while(keep_running)
 	{
-		auto q = pc.get_changed(); // might block, that is okay.
+		for(auto& q : pc)
+		{
 		    switch(q.state())
 		    {
 			case PC_State::Created:
@@ -86,6 +87,7 @@ void consumer_thread()
 			default: throw "Illegal state";
 			}
 		}
+	}
 	
 	std::cout << "Consumer sum: " << sum << ".\n";
 }