[fpc-pascal] TThread.FreeOnTerminate

[Luca Olivetti]

El 13/12/18 a les 20:36, Martin Frb ha escrit:

> The thread may makes calls (several, one after the other) into a 
> library, and each of those calls may not return for some time (to long 
> for the main thread to wait, without the app becoming unresponsive). And 
> the structure of that library may not be possible to change.
> 

I think that TThread should have a method to kill it for such cases, 
using, e.g., pthread_cancel under unix or TerminateThread under windows 
(though the latter is not a very good option according to the 
documentation).

Another possible solution for your use case could be to use the 
OnTerminate callback and ignore the result if it's not your thread, e.g.


FMyThread:=TMyThread.Create(true);
FMyThread.OnTerminate:=@MyTerminate;
FMyThread.Start;

....


procedure TForm1.MyTerminate(Sender:TObject);
var t:tthread;
begin
   if t=FMyThread then
   begin
      //do something with the thread results

     FMyThread:=nil;
   end;
   t.free;
end;


The when you want to ignore the result of the thread, you just set 
FMyThread to nil.
There's a problem though: when the application terminates and the thread 
is still running, it will call MyTerminate possibly causing a segfault :-/
A solution to that could be to keep a list of running threads so that 
you can set their OnTerminate to nil when terminating the application 
and remove the thread of the list in MyTerminate.

Bye
-- 
Luca