[Lazarus] local procedure - MultiThreadProc

[Martin]

Mattias Gärtner wrote:
> Zitat von Jan Kowalski <bor400 at gmail.com>:
>> I need to call ProcThreadPool.DoParallel with "local" procedure as a 
>> parameter.
>> Does DoParallel allow local procedures to pass a procedural parameters ?
>> I get err: Error:
>> Incompatible type for arg no. 1: Got "<address of local
>> procedure(Int64,Pointer,TMultiThreadProcItem);Register>", expected
>> "<procedure variable type of
>> procedure(Int64,Pointer,TMultiThreadProcItem);Register>"
>
> That would be really helpful.
> But I don't know how to define a local procedure type:
>
I wouldn't be sure it's possible. It makes no sense.

My guess:
A local (nested) procedure has access to the outer(parent or 
grand-parent if recursive) procedures variables (stackframe). Therefore 
a local procedure must expect to be somewhere below this parent.

If it was given as a pointer to some other procedure/object, and then 
called later, this may happen outside the parent. Then no such 
stackframe does exist, and the local procedure can not work.

Martin

> type
>   TMTLocalProcedure = procedure(Index: PtrInt; Data: Pointer;
>                                 Item: Pointer); ?
> var
>   p: TMTLocalProcedure;
>
> procedure TestWithLocalProc;
>
>   procedure LocalProc(Index: PtrInt; Data: Pointer; Item: 
> TMultiThreadProcItem);
>   begin
>
>   end;
>
> begin
>   p:=@LocalProc;
> end;
>
>
> Mattias
>
>
>
> -- 
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