void av_thread_message_queue_set_free_func(AVThreadMessageQueue *mq,
void (*free_func)(void *msg));
+/**
+ * Return the current number of messages in the queue.
+ *
+ * @return the current number of messages or AVERROR(ENOSYS) if lavu was built
+ * without thread support
+ */
+int av_thread_message_queue_nb_elems(AVThreadMessageQueue *mq);
+
/**
* Flush the message queue
*