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multithreadingdelphidelphi-2007

Which is the correct way to start a suspended thread in delphi 2007?

In delphi XE I can use the start procedure, but this method does not exist in delphi 2007.

This sample code works ok in delphi xe, using Start

MyThread:=TMyThread.Create(True);
MyThread.FreeOnTerminate    :=True;
MyThread.Property1:=900;
MyThread.Property2:=2;
MyThread.Start;

but in delphi 2007 the start procedure does not exist, so I am using the resume procedure which is deprecated in the new versions of delphi.

MyThread:=TMyThread.Create(True);
MyThread.FreeOnTerminate    :=True;
MyThread.Property1:=900;
MyThread.Property2:=2;
MyThread.Resume;

Is it ok use resume in delphi 2007 or I must use another way to start a suspended thread?

Solution

  • The correct way to start a suspended thread is to never have a suspended thread in the first place.

    There's a better way to create threads. If the caller must provide a value to the object in order for the class to work correctly, then don't make it optional: Require it as a parameter to the constructor. And if there's only one valid value for that parameter, then don't even make it a parameter: Just hard-code it in the constructor. (How many times have you written a thread class that only sometimes should free itself on termination? I've never seen that.)

    constructor TMyThread.Create(Prop1, Prop2: Integer);
begin
  inherited Create(False);
  FreeOnTerminate := True;
  Property1 := Prop1;
  Property2 := Prop2;
end;

    Then you can use the Ron Popeil method of creating threads: Just set it and forget it!

    MyThread := TMyThread.Create(900, 2);

    The caller doesn't have to do anything with the thread after creating it. And since it's a free-on-terminate thread, it's possible that the caller shouldn't even keep a reference to the MyThread variable at all since the reference will become invalid as soon as the thread finishes running.

    (Worried about that inherited Create(False) line creating a thread that's going to start running before the rest of the constructor finishes running? Don't be! That was fixed in Delphi 6, over a decade ago. The thread will automatically start itself after the constructor finishes; see TThread.AfterConstruction to see how.)