well..I use a typical model of epoll+multithread to handle massive sockets, that is, I have a thread called epollWorkThread that use epoll_wait to handle i/o sockets. While there's an event of EPOLLIN, recv() will do the work and I do use the noblocking mode to allow immediate return. And recv() is indeed in a while(true) loop. Everything is fine in the intial time(maybe a couple of hours or maybe minutes or if I'm lucky days), I can receive the information. But some time later, recv() insists to return -1 with the errno = 107(ENOTCONN). The other peer of the transport is written in AS3 which makes sure that the socket is connected. So I'm confused by the recv() behaviour. Thank you in advance and any comment is appreciated!