-void MC_client_init(void);
-void MC_client_hello(void);
-void MC_client_handle_messages(void);
-void MC_client_send_message(void* message, size_t size);
+XBT_INTERNAL void MC_client_init(void);
+XBT_INTERNAL void MC_client_hello(void);
+XBT_INTERNAL void MC_client_handle_messages(void);
+XBT_INTERNAL void MC_client_send_message(void* message, size_t size);
+XBT_INTERNAL void MC_client_send_simple_message(e_mc_message_type type);