基于IOCP的服务器中使用TCP连接时如何知道客户端已经异常断开？
基于IOCP的服务器，经常会发生客户端断开连接。由于网络经常出现一些异常情况，比如一方的机器突然断电，这时要过很久后才能得知该TCP链接已经断掉。如何才能很快知道该TCP链接已经断了？
pluto
12 years, 9 months ago
Answers
BOOL r = ::GetQueuedCompletionStatus(hCompletionPort, &dwBytesTransferred, (LPDWORD)&hCompletionSocket, (LPWSAOVERLAPPED *) &lpOvlpEx, INFINITE);
if (hCompletionSocket== INVALID_SOCKET || lpOvlpEx == NULL)
{
Sleep(10);
continue;
}
if (!r)
{
proxy->SafeClose(lpOvlpEx);
TRACE("GetQueuedCompletionStatus error! %d\n",hSocket);
continue;
}
else if (dwBytesTransferred ==0)
{
proxy->SafeClose(lpOvlpEx);
TRACE(".....................%d..........closed & freed........\n",hSocket);
continue;
}
}
上面的GetQueuedCompletionStatus是接收IOCP通知的主要函数，通过dwBytesTransferred、hCompletionSocket、lpOvlpEx以及返回值r即可判断出客户端是否关闭。
stoomy
answered 12 years, 9 months ago