我常用的 socket connect 代碼，主要是為了記錄非阻塞問題

SOCKET connectToS()<br />{<br />int e=0;<br />struct timeval timeout ;<br />fd_set r;<br />SOCKET s=socket(AF_INET,SOCK_STREAM,0);<br />//設定非阻塞方式串連<br />unsigned long ul1 = 1;<br />e = ioctlsocket(s,FIONBIO,(unsigned long*)&ul1);<br />if(e==SOCKET_ERROR)<br />{<br />fprintf(stderr,"設定[非阻塞]方式錯誤，請重新啟動！/n");<br />::closesocket (s);<br />return -1;<br />}<br />struct sockaddr_in addr;<br />memset(&addr,0,sizeof(struct sockaddr_in));<br />addr.sin_family = AF_INET;<br />addr.sin_port = htons(SERVERPORT);<br />addr.sin_addr.s_addr = inet_addr(SERVERIP);</p><p>connect(s,(SOCKADDR*)&addr,sizeof(SOCKADDR));<br />//select 模型，即設定逾時<br />FD_ZERO(&r);<br />FD_SET(s,&r);<br />timeout.tv_sec = 5; //連線逾時10秒<br />timeout.tv_usec =0;<br />e=select(NULL,NULL,&r,NULL,&timeout);<br />if(e<=0)<br />{<br />fprintf(stderr,"連線逾時,請檢查網路是否可用！/n");<br />::closesocket(s);<br />return -1;<br />}</p><p>unsigned long ul2= 0;<br />e = ioctlsocket(s,FIONBIO,(unsigned long*)&ul2);<br />if(e==SOCKET_ERROR)<br />{<br />fprintf(stderr,"設定[阻塞]方式錯誤，請重新啟動！/n");<br />::closesocket (s);<br />return -1;<br />}<br />return s;<br />}