TCP_KEEPALIVE inKeepAlive = {0};
unsigned long ulInLen = sizeof(TCP_KEEPALIVE);
TCP_KEEPALIVE outKeepAlive = {0};
unsigned long ulOutLen = sizeof(TCP_KEEPALIVE);
unsigned long ulBytesReturn = 0;
//设置socket的keep alive为10秒，并且发送次数为3次
inKeepAlive.onoff = 1;
inKeepAlive.keepaliveinterval = 1;
inKeepAlive.keepalivetime = 3000;
//为选定的SOCKET设置Keep Alive，成功后SOCKET可通过Keep Alive自动检测连接是否断开
WSAIoctl(m_hSocket, SIO_KEEPALIVE_VALS,
(LPVOID)&inKeepAlive, ulInLen,
(LPVOID)&outKeepAlive, ulOutLen,
&ulBytesReturn, NULL, NULL);
