I have found the reason with "RTP over TCP". In SingleStep(), WSAGetLastError() returned 10038. So exit(0) is called. But I dont know how to deal with it. Any advices? Zhixue Zhang -------------- next part -------------- An HTML attachment was scrubbed... URL: http://lists.live555.com/pipermail/live-devel/attachments/20060704/5db2c0d9/attachment.html