[Lazarus] Multithreadprocs and Synchronize

[Juha Manninen (gmail)]

On Monday 23 August 2010 21:14:11 Felipe Monteiro de Carvalho wrote:
> Synchronize should work for sure.
> 
> I took a quick look and it is:  210 Object not initialized
> 
> It's hard to say without seeing your code, but I guess there is a bug
> in your code somewhere.
> 
> Another guess would be that this code is executed before the
> initialization of cthreads.


procedure TCombBlock.ShowStatus;
begin
  ;
end;

procedure TCombBlock.SolveSubBlocks(aThreadIndex: PtrInt; Data: Pointer; Item: 
TMultiThreadProcItem);
begin
  Item.Thread.Synchronize(Item.Thread, @ShowStatus); // <-- this gives error!
  ...
end;

function TCombBlock.SolveFirst: Boolean;
begin
...
    fOwner.fThreadPool.DoParallel(@SolveSubBlocks,1,fFindInd-1,nil);
...
end;

-------------

I removed the other lines from the functions for this example.
Only "Item.Thread.Synchronize(..." gives the problem.
fOwner is a normal class derived from TObject.
I debugged to see the problem. It turned out "Item.Thread" is nil!
So the problem is actually that Multithreadprocs does not pass the underlying 
thread object for a parallel function.

Juha