基于事件的異步套接字

主要用到的是WSAEventSelect模型

下面是一個簡單的示例代碼：

//控制箱開機
		char *pCmd = "ONCP\r\n";
		SOCKET	sck=socket(PF_INET,SOCK_STREAM,0);
		if(INVALID_SOCKET ==sck)
			ATLASSERT(0);
		WSAEVENT hEvent = WSACreateEvent();
		WSAEventSelect(sck,hEvent,FD_READ|FD_CONNECT);

		struct sockaddr_in to;
		to.sin_family=AF_INET;
		to.sin_port=htons(SOCKET_POWERPORT);
		to.sin_addr.s_addr=htonl(pconfig->dwIP);

		try
		{
			WSAConnect(sck,(struct sockaddr*)&to,sizeof(to),NULL,NULL,NULL,NULL);
			int nTry=10;
			int ret=0;
			int err=-1;
			BYTE buffer[1024]={0};
			int i=0;
			for(i=0;i<30;i++)
			{
				if(WSAWaitForMultipleEvents(1,&hEvent,0,100,0)!=WSA_WAIT_EVENT_0)
				{
					err = -1;
				}
				else
				{
					WSANETWORKEVENTS events;
					WSAEnumNetworkEvents(sck,hEvent,&events);
					if( (events.lNetworkEvents | FD_CONNECT)==0 || events.iErrorCode[4]!=0)
					{
						err = -1;
					}
					else
						err=0;
				}
				
				if(err==0) break;
				Sleep(100);
			}

			if (err != 0)	
			{
				//錯誤
				*bstrMsg = SysAllocString(L"連接配接控制器失敗，請檢查控制器位址配置是否正确");
				throw(1);
			}
			else 
			{
				while(--nTry)
				{
					if(nTry<9)
						Sleep(1000);
					ret=send(sck,(const char*)pCmd, strlen(pCmd),0);
					if( ret!=strlen(pCmd) )
					{
						*bstrMsg = SysAllocString(L"錯誤：發送資料失敗");
						throw(5);
					}

					//接收傳回資料
					for(i=0;i<30;i++)
					{
						ret=0;
						ret=recv(sck, (char*)buffer, 1023, 0);
						if(ret > 0)
							break;
						Sleep(100);
					}

					//容錯M61E
					//if(ret==1)
					if(ret>0)
					{
						if( buffer[0]==0)
						{
							*lSuccess= TRUE;
							throw(0);
						}
						continue;
					}

					else
					{
						continue;
					}
				}//end while(nTry--)
			}

			if(ret>0)
			{
				if( buffer[0]==1)
				{
					*bstrMsg = SysAllocString(L"錯誤：開啟計算機失敗,請等待3分鐘後再進行操作");
					throw(2);
				}
				else if( buffer[0]==2)
				{
					*bstrMsg = SysAllocString(L"錯誤：計算機已開啟");
					throw(3);
				}
				else if( buffer[0]==3)
				{
					*bstrMsg = SysAllocString(L"錯誤：正在開機過程中");
					throw(4);
				}
				else
				{
					OutputDebugString("接收開機指令傳回不符合協定");
					*bstrMsg = SysAllocString(L"接收開機指令傳回不符合協定");
				}
			}
			else
			{
				OutputDebugString("接收開機指令失敗：指令無傳回");
				*bstrMsg = SysAllocString(L"接收開機指令失敗：指令無傳回");
				throw(5);
			}
		}
		catch(int err)
		{
			if(sck!=INVALID_SOCKET)
			{
				closesocket(sck);
			}
			sck=INVALID_SOCKET;
			
			if(err)
			{
				*lSuccess= FALSE;
				return S_FALSE;
			}
			else
			{
				*lSuccess= TRUE;
				return S_OK;
			}
		}