-SR_PRIV void sr_source_remove(int fd);
-SR_PRIV void sr_source_add(int fd, int events, int timeout,
- sr_receive_data_callback rcv_cb, void *user_data);
+SR_PRIV int sr_source_remove(int fd);
+SR_PRIV int sr_source_add(int fd, int events, int timeout,
+ sr_receive_data_callback_t cb, void *cb_data);