我常用的 socket connect 代码，主要是为了记录非阻塞问题

SOCKET connectToS()
{
	int e=0;
	struct timeval timeout ;  
	fd_set r;
	SOCKET s=socket(AF_INET,SOCK_STREAM,0);
	//设置非阻塞方式连接  
	unsigned long ul1 = 1;  
	e = ioctlsocket(s,FIONBIO,(unsigned long*)&ul1);  
	if(e==SOCKET_ERROR)
	{ 
		fprintf(stderr,"设置[非阻塞]方式错误，请重新启动！/n");
		::closesocket (s); 
		return -1;   
	}
	struct sockaddr_in addr;	
	memset(&addr,0,sizeof(struct sockaddr_in));
	addr.sin_family = AF_INET;	
	addr.sin_port = htons(SERVERPORT);
	addr.sin_addr.s_addr = inet_addr(SERVERIP);

	connect(s,(SOCKADDR*)&addr,sizeof(SOCKADDR));
	//select   模型，即设置超时  
	FD_ZERO(&r);  
	FD_SET(s,&r);  
	timeout.tv_sec = 5;   //连接超时10秒  
	timeout.tv_usec =0;  
	e=select(NULL,NULL,&r,NULL,&timeout);  
	if(e<=0)  
	{
		fprintf(stderr,"连接超时,请检查网络是否可用！/n");
		::closesocket(s);  
		return -1; 
	}

	unsigned long ul2= 0;  
	e   =   ioctlsocket(s,FIONBIO,(unsigned long*)&ul2);  
	if(e==SOCKET_ERROR)
	{
		fprintf(stderr,"设置[阻塞]方式错误，请重新启动！/n");
		::closesocket (s);  
		return -1; 
	}
	return s;
}