+/* prototypes from mr_call.h */
+int mr_do_call(struct mr_params *params, struct mr_params *reply);
+int mr_send(int fd, struct mr_params *params);
+int mr_receive(int fd, struct mr_params *params);
+int mr_cont_receive(int fd, struct mr_params *params);
+void mr_destroy_reply(mr_params reply);