I am using CoDeSys version V3.3 SP1 patch 2 and using the socket libary SysSocket23 to make a TCP listening socket. Then I use SysSockSelect() to see if there is any connection on the socket. I expect a return of either 0 (timeout), or 1 because I have only 1 socket in my SOCKET_FD_SET structure. But it returns straight away with 2, why? I don't have any connection and the call to SysSockAccept() then blocks. Here is the code.

// Process TCP sockets in steps using state

CASE TCPState OF

0:   // Create a Socket

    SocketCreateHandle := SysSockCreate(SOCKET_AF_INET, SOCKET_STREAM, 0);

    IF SocketCreateHandle <> SOCKET_INVALID THEN

        dwValue := 1;

        // Set the option that we can reuse 'old' port addresses

        SysSockSetOption(SocketCreateHandle, SOCKET_SOL, SOCKET_SO_REUSEADDR, ADR(dwValue), SIZEOF (dwValue));

        TCPState := 10;

    END_IF

10:  // Bind the socket to our IP address and port

    SocketAddress.sin_family := SOCKET_AF_INET ;

    InetAddr := '127.0.0.1'; // This just for loopback

    SocketAddress.sin_addr := SysSockInetAddr(InetAddr);

    SocketAddress.sin_port := SysSockHtons(TCP_LEUTWIL);

    bResult := SysSockBind(SocketCreateHandle, ADR(SocketAddress), SIZEOF(SocketAddress));

    IF bResult THEN

        TCPState := 20;

    END_IF

20:  // Listen for a connection

    bResult := SysSockListen(SocketCreateHandle, diMaxConnections);

    IF bResult THEN

        MasterSocketList.fd_count := 1; // only socket is the listening

        MasterSocketList.fd_array[0] := SocketCreateHandle;

        TCPState := 30;

    END_IF

30:  // Build a list of open sockets and use select to detect activity (read)

    FDCopy(source := ADR(MasterSocketList), dest := ADR(SlaveSocketList));

    SelectTimeOut.tv_sec := 30;

    SelectTimeOut.tv_usec := 0; // very short time out

    diSize := SysSockSelect(SOCKET_FD_SETSIZE, ADR(SlaveSocketList), 0, 0, ADR(SelectTimeOut));

    IF diSize > 0 THEN

        TCPState := 40;

        TCPindex := 0;

    END_IF

40:  // Process next active socket in slave list

    SocketHandle := SlaveSocketList.fd_array[TCPindex];

    IF SocketHandle = SocketCreateHandle THEN

        // We have a new connection to handle

        diSize := SIZEOF(SocketAddress);

        SocketHandle := SysSockAccept(SocketCreateHandle, ADR(SocketAddress), ADR(diSize));

        IF SocketHandle <> SOCKET_INVALID THEN

            // Good Socket add it to master list

            TCPMax := SocketHandle; // new socket is bigger

            MasterSocketList.fd_array[MasterSocketList.fd_count] := SocketHandle;

            MasterSocketList.fd_count := MasterSocketList.fd_count + 1;

        END_IF

        TCPState := 100;

    ELSE

        // Try to read a data block

        diSize := SysSockRecv(SocketHandle, ADR(TCPData), TCP_BUFF_SIZE, 0);

For target I am using the CoDeSys SP Win V3

I based my code on the example for TCP on CoDeSys site so I think my code is correct but SysSockSelect() has bug.

Help please anybody.

Regards

Dave Warren

Posting here is almost useless as I end up taking to myself

I overcame my problems with SysSockSelect(), basically it is useless so rather than use it I set the socket to be non-blocking and check the return value from the SysSockAccept().

But can someone fix the SysSockSelect() ?

Hello Mr. Warren,

Now I am developing a tcp server for the controller based on CodeSys.
Could you send me last version of your server code please?
Of course, if it is not a secret or non-secret part of it.

Email: e listouque@gmail.com e

Best regards.

wisher hat geschrieben:
Hello Mr. Warren,
Now I am developing a tcp server for the controller based on CodeSys.
Could you send me last version of your server code please?
Of course, if it is not a secret or non-secret part of it.
Email: e listouque@gmail.com e
Best regards.

Hi, I'm working on a similar project. I have a raspberry in which I need to run a TCP server where I will receive messages from clients by sockets. I can not get it to work properly, have you managed to get it to work properly? Do you have more information about the server or an example project?

Thank you very much.

Originally created by: KevinR

danyamian hat geschrieben:
Hi, I'm working on a similar project. I have a raspberry in which I need to run a TCP server where I will receive messages from clients by sockets. I can not get it to work properly, have you managed to get it to work properly? Do you have more information about the server or an example project?
Thank you very much.

Hello danyamian,

the topic is from 2010.

In the meantime, there are ready-to-use libraries that contain complete function blocks for your application. Check out the CAA Net Base Services Library from the CAA Technical Workgroup (Namespace: NBS).

Of course, you can also use the SysSocket Library. However, you should be familiar with SysSocket.

Thank you very much KevinR, I am testing this library and it really seems easier and safer than SysSocket. A greeting!

KevinR hat geschrieben:
Hello danyamian,
the topic is from 2010.
In the meantime, there are ready-to-use libraries that contain complete function blocks for your application. Check out the CAA Net Base Services Library from the CAA Technical Workgroup (Namespace: NBS).
Of course, you can also use the SysSocket Library. However, you should be familiar with SysSocket.

Originally created by: KevinR

You are welcome

Cheers,
Kevin

danyamian hat geschrieben:
Thank you very much KevinR, I am testing this library and it really seems easier and safer than SysSocket. A greeting!