diff --git a/ikcp.c b/ikcp.c
index ef116900..3b3818f8 100644
--- a/ikcp.c
+++ b/ikcp.c
@@ -1155,7 +1155,7 @@ void ikcp_update(ikcpcb *kcp, IUINT32 current)
 // schedule ikcp_update (eg. implementing an epoll-like mechanism, 
 // or optimize ikcp_update when handling massive kcp connections)
 //---------------------------------------------------------------------
-IUINT32 ikcp_check(const ikcpcb *kcp, IUINT32 current)
+IUINT32 ikcp_check(ikcpcb *kcp, IUINT32 current)
 {
 	IUINT32 ts_flush = kcp->ts_flush;
 	IINT32 tm_flush = 0x7fffffff;
@@ -1182,6 +1182,7 @@ IUINT32 ikcp_check(const ikcpcb *kcp, IUINT32 current)
 		const IKCPSEG *seg = iqueue_entry(p, const IKCPSEG, node);
 		IINT32 diff = _itimediff(seg->resendts, current);
 		if (diff <= 0) {
+			kcp->ts_flush = current;
 			return current;
 		}
 		if (diff < tm_packet) tm_packet = diff;
diff --git a/ikcp.h b/ikcp.h
index c5f29a08..5024f9d9 100644
--- a/ikcp.h
+++ b/ikcp.h
@@ -358,7 +358,7 @@ void ikcp_update(ikcpcb *kcp, IUINT32 current);
 // Important to reduce unnacessary ikcp_update invoking. use it to 
 // schedule ikcp_update (eg. implementing an epoll-like mechanism, 
 // or optimize ikcp_update when handling massive kcp connections)
-IUINT32 ikcp_check(const ikcpcb *kcp, IUINT32 current);
+IUINT32 ikcp_check(ikcpcb *kcp, IUINT32 current);
 
 // when you received a low level packet (eg. UDP packet), call it
 int ikcp_input(ikcpcb *kcp, const char *data, long size);