TSimpleIPCServer, TSimpleIPCClient, and TThread questions.

[mfurlend]

I am trying to bridge two applications (MT4 strategy testers) together through a GUI application I made with Lazarus. I am using TSimpleIPCServer and TSimpleIPCClient.

Tester_1 -------> Central_Application <------- Tester_2

Tester_1 and Tester_2 are using a .dll file that I made which allows communication between them and Central_Application.


cliff's notes of question: What is the best way to freeze Tester_1 until it receives a message from Central_Application?

extended version of question:
When a certain condition occurs Tester_1 must freeze all actions and wait for Central_Application to send it a message before proceeding. Central_Application will get this message from Tester_2 an undefined amount of time after receiving the request from Tester_1.

While waiting for this specific message to arrive from Tester_2, Central_Application must be able to receive/send/process other communications with Tester_2.

From what I understand, I need to use threads to do this...
From the Central_Application I use application.processmessage .

But how about from the .dll files attached to Tester_1 and Tester_2? Do I have to use TThread?

Am I on the right track with this code?:

Code: [Select]

 constructor TYourThread.Create(CreateSuspended: boolean);
  begin
    FreeOnTerminate := True;
    inherited Create(CreateSuspended);
  end;

  destructor TYourThread.Destroy;
  begin
    CloseHandle(FEvent);
  end;

  procedure TYourThread.Execute;
  begin
    while (not server1.PeekMessage(INFINITE, False)) and (not Terminated) do
    begin
    Sleep(500);
    end;

    SetEvent(FEvent);
  end;

Code: [Select]

function GetVar2(): ansistring; stdcall;
  var
    srvmsg: ansistring;
  begin

    srvmsg := 'VAR2_TRANSFER_FAIL';

    server1 := TSimpleIPCServer.Create(nil);
    server1.Global := True;
    server1.ServerID := '98765';
    server1.Startserver;
    YourThread := TYourThread.Create(True);

    SendMsg('get2','0');
    YourThread.Resume;
    if (WaitForSingleObject(YourThread.FEvent, INFINITE) = WAIT_OBJECT_0) then
    begin
      srvmsg := server1.StringMessage;
    end;
    YourThread.Terminate;
    server1.StopServer;

    Result := srvmsg;
  end;                                                  

I know that various completed systems are already out there for communication between separate MT4 apps, but I want to do it myself(ish) with lazarus.

I'd appreciate any tips or lazarus code that may help me out!