Pascal (Lazarus/Delphi)

Get the LastErrorText for an Asynchronous Method Call

See more Async Examples

Demonstrates how to get the LastErrorText information for a Chilkat method called asynchronously. Pascal (Lazarus/Delphi)

program ChilkatDemo;

// Demonstrates using the Chilkat Pascal wrapper via the C bridge DLL.
// Builds as a console application under Lazarus (FPC) or Delphi.

{$IFDEF FPC}
  {$MODE DELPHI}
{$ENDIF}
{$APPTYPE CONSOLE}

uses
  {$IFDEF UNIX}
  cthreads,
  {$ENDIF}
  SysUtils,
  CkDllLoader,
  Chilkat.Task,
  Chilkat.Socket;

// ---------------------------------------------------------------------------

procedure RunDemo;
var
  success: Boolean;
  socket: TSocket;
  maxWaitMs: Integer;
  task: TTask;

begin
  success := False;

  //  This example requires the Chilkat API to have been previously unlocked.
  //  See Global Unlock Sample for sample code.

  socket := TSocket.Create;

  //  The Async call simply creates the task.  The "Connect" method has not yet been called.
  maxWaitMs := 5000;
  //  Let's intentionally cause this connect to fail by giving it an invalid domain..
  task := socket.ConnectAsync('amazonbladflakjsdflksadjf.com',443,True,maxWaitMs);
  if (socket.LastMethodSuccess = False) then
    begin
      WriteLn(socket.LastErrorText);
      Exit;
    end;
  //  Start the background thread to run the task.
  success := task.Run();
  if (not success) then
    begin
      WriteLn(task.LastErrorText);
      task.Free;
      Exit;
    end;

  //  The application is now free to do anything else

  //  For this example, we'll simply sleep and periodically
  //  check to see if the Socket Connect if finished.
  while task.Finished <> True do
    begin
      //  Sleep 1 ms.
      task.SleepMs(1);
    end;

  //  If the task completed, it means the method (in this case the Connect method) was called and returned success or failure.
  if (task.StatusInt <> 7) then
    begin
      WriteLn('Task did not complete.');
      WriteLn('task status: ' + task.Status);
      task.Free;
      Exit;
    end;

  //  Get the success/failure of the Connect
  //  (This is the return value of the Connect method had it been called synchronously)
  success := task.GetResultBool();
  if (success = False) then
    begin
      //  Get the LastErrorText for the Connect method call.
      //  Had we called Connect synchronously, we would've simply accessed the socket object's LastErrorText property.
      //  Instead, we get the task object's ResultErrorText.
      WriteLn(task.ResultErrorText);
    end
  else
    begin
      WriteLn('Connect succeeded.');
    end;

  task.Free;


  socket.Free;

end;

// ---------------------------------------------------------------------------

begin

  try
    RunDemo;
  except
    on E: Exception do
      WriteLn('Unhandled exception: ', E.ClassName, ': ', E.Message);
  end;

  WriteLn;
  {$IFDEF MSWINDOWS}
  WriteLn('Press Enter to exit...');
  ReadLn;
  {$ENDIF}
end.