added compile time check to cnm for the validity of the supplied policy

chat_networking.hpp

@@ -6,6 +6,7 @@
 #include <boost/asio.hpp>
 #include <algorithm>
 #include "chat_messages.hpp"
+#include "check_policy.hpp"
 
 
 
@@ -19,21 +20,23 @@ namespace chat
     struct receive_policy_stdout
     {
         static void message_do_what(chat_message msg)
-        {
+        { std::cout << msg << '\n'; }
-            std::cout << msg << '\n';
-        }
 
         // TODO: handshake_policy
     };
 
 
     /* most ezt így üres template paraméterekkel kell példányosítani,
+     * már amennyiben nem akarunk valami custom receive policyt megadni,
      * pl.: client_network_manager<> cnm;
      * meg lehet oldani úgy, hogy ne kelljen? usingot/typedefet nem enged saját magára */
     template <class receive_policy = receive_policy_stdout>
     class client_network_manager
     {
-    // TODO: add static assert to check receive_policy
+        /* compile-time check for whether receive_policy is valid or not */
+        static_assert(is_valid_policy<receive_policy>::value,
+                      "Receive policy does not supply neccessary methods!");
+
     /* members */
     private:
         asio::io_service& _ios;