write_queue: Add callback for exceptions as well.
diff --git a/include/osmocore/write_queue.h b/include/osmocore/write_queue.h
index 64d4159..ef244c3 100644
--- a/include/osmocore/write_queue.h
+++ b/include/osmocore/write_queue.h
@@ -35,6 +35,7 @@
 
 	int (*read_cb)(struct bsc_fd *fd);
 	int (*write_cb)(struct bsc_fd *fd, struct msgb *msg);
+	int (*except_cb)(struct bsc_fd *fd);
 };
 
 void write_queue_init(struct write_queue *queue, int max_length);