Handling Exceptions raised from inside a thread

[chronozphere]

Hey guys,

At this moment, I'm looking at threads more closely and it seemed to me that before you deploy threads at a large scale in your application, you have to think about how to trap and handle exceptions.

First, I'm not a fan of this:

procedure TSubsystemThread.Execute;
begin
  try
    //do your stuff here
  except  //eat all exceptions
  end;
end;

IMHO, this is one of the most awfull things you can do to yourself (programming-wise that is ), as you make it really hard to find errors later on.

So I was looking at a better solution and found this (2nd example on page):
http://edn.embarcadero.com/article/10452

What strikes me here, is that to make the mechanism work, you make a call to ExceptObject(), which seems to access global exception information. I might be nitpicking here, but is this thread-safe?

Having said that, isn't the following solution alot better?

procedure TMyThread.Execute;
begin
  FException := nil;
  try
    // raise an Exception
    raise Exception.Create('I raised an exception');
  except
    on E: Exception do 
      HandleException(E);  //Pass exception object to handler, and then to form
  end;
end;

procedure TMyThread.HandleException(ExceptionObject: Exception);
begin
  FException := ExceptionObject;
  try
    // Don't show EAbort messages
    if not (FException is EAbort) then
      Synchronize(DoHandleException);
  finally
    FException := nil;
  end;
end;

Does anyone have experience with this? Seems like an obligatory question every programmer has to answer before starting to get serieus with threads.

Thanks!

[farcodev]

for my part my help is pretty limited, sorry , the last time i used thread it wasn't w/o exception management

oops excepted i used the awful form

[chronozphere]

Can someone else shed any light on this? There must at least be some do's and don'ts on this subject, I suppose.