0

我正在使用 TF6310 TCP/IP 启动 TCP 服务器，等待连接（保证只有一个客户端连接），当连接到来时我接受它。一旦被接受，我就会接收/发送数据。

我遇到的问题是我无法识别客户端是否断开连接，并且我无法弄清楚如何检测到它以关闭套接字。

特别是，只要客户端连接，我只想留在第 3 步，如果他断开连接，我想转到第 100 步。

        1:  // Open Listener-Socket

        fbSocketListen(
            sSrvNetId:='', 
            sLocalHost:=sLocalHost, 
            nLocalPort:=nLocalPort, 
            bExecute:=TRUE, 
            tTimeout:=T#5S, 
            bBusy=> , 
            bError=>bError, 
            nErrId=>nErrorID,
            hListener=>hListener);

        IF hListener.handle <> 0
        THEN
            iState:=2;
        ELSIF bError
        THEN
            iState:=99;
        END_IF

    2:  // Accept Client connection

        fbSocketAccept(
            sSrvNetId:='', 
            hListener:=fbSocketListen.hListener, 
            bExecute:= bAcceptExecute:= NOT bAcceptExecute, 
            tTimeout:=T#5S, 
            bAccepted=> , 
            bBusy=> , 
            bError=>bError, 
            nErrId=>nErrorID,
            hSocket=>hSocket);
        //  bExecute:= bAcceptExecute:= NOT bAcceptExecute, 

        IF bError
        THEN
            iState:=99;
        ELSIF hSocket.handle <> 0
        THEN
            iState:=3;
            bConnected:=TRUE;
        END_IF

    3:  // client connected, send and receive data
        
        fbSocketListen();
        fbSocketAccept();
        fbSocketReceive(
            sSrvNetId:='', 
            hSocket:=fbSocketAccept.hSocket, 
            cbLen:=SIZEOF(stDataRx), 
            pDest:=ADR(stDataRx), 
            bExecute:= bReceiveExecute:= NOT bReceiveExecute,       // Check for new client telegrams every second cycle
            tTimeout:=T#14S, 
            bBusy=> , 
            bError=>bError, 
            nErrId=>nErrorID,
            nRecBytes=> );
            

        IF fbSocketReceive.nRecBytes <> 0       // Switch to send-state when data are received
        THEN
            bNewDataReceived:=TRUE;
        END_IF
                            
        IF fbSocketReceive.bError OR(NOT bEnable)       // Close connection when error is occuring or trigger is set
        THEN
            iState:=100;
        END_IF
        
        IF bNewDataReceived THEN
            (* got data, write it to the outputs..  *)
            stScannerRx := stDataRx;
            bNewDataReceived := FALSE;
        END_IF
        
        
        impNewPal(clk:=bNewPal);
        
        IF impNewPal.Q THEN
            MEMSET(ADR(stScannerRx),16#00,SIZEOF(stScannerRx));
        END_IF
        
        
        (* if a new crate is ready, send the packet *)
    
        IF bNewPal THEN
            
            stDataTx.iPalId := iPalId;
            stDataTx.iStackId := iStackId;
            stDataTx.bReady := 1;
            stDataTx.iCrateCnt := iCrateCnt;
                        
            
            fbSocketSend(           // Send Data to client
                sSrvNetId:='', 
                hSocket:=hSocket, 
                cbLen:=SIZEOF(stDataTx),
                pSrc:=ADR(stDataTx),
                bExecute:=TRUE, 
                tTimeout:=T#3S, 
                bBusy=> , 
                bError=>bError, 
                nErrId=>nErrorID);
                
        ELSE                
            fbSocketSend(bExecute:=FALSE);
        END_IF
        
        
        IF fbSocketSend.bError
        THEN
            iState:=100;            // Close connection in case of error 
        END_IF
4

0 回答 0