Winsock例子代码：初始化、阻塞/非阻塞、超时设置、select等

WSADATA wsd;

SOCKET cClient;

int ret;

struct sockaddr_in server;

hostent *host=NULL;



if(WSAStartup(MAKEWORD(2,0),&wsd)){return 0;}

cClient=socket(AF_INET,SOCK_STREAM,IPPROTO_TCP);

if(cClient==INVALID_SOCKET){return 0;}

//set Recv and Send time out

int TimeOut=6000; //设置发送超时6秒

if(::setsockopt(cClient,SOL_SOCKET,SO_SNDTIMEO,(char *)&TimeOut,sizeof(TimeOut))==SOCKET_ERROR){

return 0;

}

TimeOut=6000;//设置接收超时6秒

if(::setsockopt(cClient,SOL_SOCKET,SO_RCVTIMEO,(char *)&TimeOut,sizeof(TimeOut))==SOCKET_ERROR){

return 0;

}

//设置非阻塞方式连接

unsigned long ul = 1;

ret = ioctlsocket(cClient, FIONBIO, (unsigned long*)&ul);

if(ret==SOCKET_ERROR)return 0;



//连接

server.sin_family = AF_INET;

server.sin_port = htons(25);

server.sin_addr .s_addr = inet_addr((LPCSTR)pSmtp);

if(server.sin_addr.s_addr == INADDR_NONE){return 0;}



connect(cClient,(const struct sockaddr *)&server,sizeof(server));



//select 模型，即设置超时

struct timeval timeout ;

fd_set r;



FD_ZERO(&r);

FD_SET(cClient, &r);

timeout.tv_sec = 15; //连接超时15秒

timeout.tv_usec =0;

ret = select(0, 0, &r, 0, &timeout);

if ( ret <= 0 )

{

::closesocket(cClient);

return 0;

}

//一般非锁定模式套接比较难控制，可以根据实际情况考虑 再设回阻塞模式

unsigned long ul1= 0 ;

ret = ioctlsocket(cClient, FIONBIO, (unsigned long*)&ul1);

if(ret==SOCKET_ERROR){

::closesocket (cClient);

return 0;

}