Question

判断socket是否有效 libevent

Answer 1

1）创建nonblock的socket，
2）调用connect连接服务器，检查返回值，判断是否是阻塞了，如果是，就设置等待 EV_WRITE事件：
event_set(&m_evSocket, m_iSockFd, EV_WRITE, onConnect, this);
3）EV_WRITE返回后，判断event是否为EV_WRITE，
关键一点：如果EV_WRITE，还要进一步判断sockopt是否正确。

代码片段如下：

[cpp] view plain copy
bool CClientSocket::connectSocket(string szHostAddr, int nHostPort){
if (m_iSockFd == -1){
createSocket();
}

struct sockaddr_in Ser_addr;
memset(&Ser_addr, 0, sizeof(struct sockaddr_in));

Ser_addr.sin_family = AF_INET;
Ser_addr.sin_addr.s_addr = inet_addr(szHostAddr.c_str());
Ser_addr.sin_port = htons(nHostPort);