-extern int utcp_send(struct utcp_connection *connection, void *data, size_t len);
-extern int utcp_recv(struct utcp *utcp, void *data, size_t len);
-extern void utcp_close(struct utcp_connection *connection);
-extern void utcp_abort(struct utcp_connection *connection);
-extern void utcp_shutdown(struct utcp_connection *connection, int how);
-extern void utcp_timeout(struct utcp *utcp);
+extern ssize_t utcp_send(struct utcp_connection *connection, const void *data, size_t len);
+extern int utcp_recv(struct utcp *utcp, const void *data, size_t len);
+extern int utcp_close(struct utcp_connection *connection);
+extern int utcp_abort(struct utcp_connection *connection);
+extern int utcp_shutdown(struct utcp_connection *connection, int how);
+extern int utcp_timeout(struct utcp *utcp);
+extern int utcp_set_connection_timeout(struct utcp *utcp, int seconds);