[vtkusers] vtkSocketCommunicator strange behaviour

[Joachim Pouderoux]

I did not try your example yet but I think the issue is due to your local
src.c_str() which is destroyed before the send action is really performed
(send is a asynchronous function).
So you can try something like :

else
    {
        std::string str(args[1]);
        std::size_t size = str.size();
        const char *s = str.c_str();
        comm->Send(&size, 1, /* remoteHandle */ 1, 0);
        comm->Send(s, size, /* remoteHandle */ 1, 1);
        cout << "Send" << endl;
        cout << str << endl;
        cout << size << endl;
        for (std::size_t i = 0; i < size; ++i)
        {
            cout << int(str[i]) << endl;
        }
        cout << "server comm->Barrier()" << endl;
        comm->Barrier();
    }


Regads,

*Joachim Pouderoux*

*PhD, R&D Enginee*r
*Kitware SAS <http://www.kitware.fr>*



2013/4/25 Henry Lehmann <henry.lehmann at informatik.tu-freiberg.de>

> Hello,
>
> I am playing around with vtkSocketCommunicator. I want to send integral
> data types and
> wrote a program to get myself into this topic. The source is at the end.
> If the program is started without command line arguments,
> vtkSocketCommunicator
> goes into server mode and waits for a connection at port 7777. If it is
> started
> with one command line argument, the string is send to the server who
> displays it in the terminal. However, the data is not transmitted
> correctly.
>
> Consider this example:
> At first start in server mode tp receive data:
> $ ./program
> Secondly start in client mode and send data:
> $ ./program ABCDEFGHIJKLMNOPQRSTUVWXYZ
>
> The output of the programs is as follows:
>
> Server:
> comm->WaitForConnection(7777)
> Receive
> ABCDEFGH???? MNOPQRSTUVWXYZ
> 26
> 65
> 66
> 67
> 68
> 69
> 70
> 71
> 72
> 1
> 0
> 0
> 0
> 77
> 78
> 79
> 80
> 81
> 82
> 83
> 84
> 85
> 86
> 87
> 88
> 89
> 90
> comm->Barrier()
> comm->CloseConnection()
>
> Client:
> comm->ConnectTo(localhost, 7777)
> Send
> ABCDEFGHIJKLMNOPQRSTUVWXYZ
> 26
> 65
> 66
> 67
> 68
> 69
> 70
> 71
> 72
> 73
> 74
> 75
> 76
> 77
> 78
> 79
> 80
> 81
> 82
> 83
> 84
> 85
> 86
> 87
> 88
> 89
> 90
> comm->Barrier()
> comm->CloseConnection()
>
> As you can see the data is not transmitted correctly and the numbers
> 73, 74, 75, 76 are replaced by 1, 0, 0, 0.
> What am i doing wrong? Am i using this class not as intended?
>
> Thanks in advance,
> Henry.
>
> Source Code:
>
> #include <vtkNew.h>
> #include <vtkSocketCommunicator.h>
> #include <vtkClientServerStream.h>
> #include <iostream>
> #include <string>
> int main(int argc, char *args[])
> {
>     using namespace std;
>
>     vtkNew<vtkSocketCommunicator> comm;
>     comm->SetPerformHandshake(1);
>     if (argc == 1)
>     {
>         cout << "comm->WaitForConnection(7777)**" << endl;
>         comm->WaitForConnection(7777);
>     }
>     else if (argc == 2)
>     {
>         cout << "comm->ConnectTo(localhost, 7777)" << endl;
>         comm->ConnectTo("localhost", 7777);
>     }
>     comm->Handshake();
>     comm->Barrier();
>     if (comm->GetIsServer())
>     {
>         std::size_t size = 0;
>         comm->Receive(&size, 1, /* remoteHandle */ 1, 0);
>         std::string str(size, '\n');
>         comm->Receive(&str[0], size, /* remoteHandle */ 1, 1);
>         cout << "Receive" << endl;
>         cout << str << endl;
>         cout << size << endl;
>         for (std::size_t i = 0; i < size; ++i)
>         {
>             cout << int(str[i]) << endl;
>         }
>     }
>     else
>     {
>         std::string str(args[1]);
>         std::size_t size = str.size();
>         comm->Send(&size, 1, /* remoteHandle */ 1, 0);
>         comm->Send(str.c_str(), size, /* remoteHandle */ 1, 1);
>         cout << "Send" << endl;
>         cout << str << endl;
>         cout << size << endl;
>         for (std::size_t i = 0; i < size; ++i)
>         {
>             cout << int(str[i]) << endl;
>         }
>     }
>     cout << "comm->Barrier()" << endl;
>     comm->Barrier();
>     cout << "comm->CloseConnection()" << endl;
>     comm->CloseConnection();
>     return 0;
> }
>
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