I have a question similar to this, but in delphi.
type
TThreadPopulator = class(TThread)
private
_owner:TASyncPopulator; //Undeclared identifier
end;
type
TAsyncPopulator = class
private
_updater: TThreadPopulator;
end;
Solution of mentioned question is not applicable to delphi
See Forward Declarations and Mutually Dependent Classes documentation.
type (* start type section - one unified section "to rule them all" *)
TAsyncPopulator = class; (* forward declaration, it basically serves just to
fix SizeOf(TAsyncPopulator) so compiler would be able to draft dependent types'
in-memory layout. Down the CPU level `class` and `pointer` is the same, so now
Delphi knows SizeOf(TAsyncPopulator) = SizeOf(pointer) to compose further types *)
TThreadPopulator = class(TThread)
private
_owner:TASyncPopulator;
end;
TAsyncPopulator = class (* the final declaration now, it should go WITHIN
that very TYPE-section where the forward declaration was made! *)
private
_updater: TThreadPopulator;
end;
....
type
(* now, that you had BOTH forward and final declarations for TAsyncPopulator
spelled out above, you finally may start another TYPE-section, if you choose so.
But only after them both, and never should a new `type` section be inserted
in between those declarations. *)
....
Use the source, Luke! Your Delphi installation has full VCL and RTL sources for you to read and watch and learn. And it uses this template a lot. Every time when you ask yourself "how I could do it", just think along "how did Borland do it" and pretty chance that you can already get a ready-made example in Delphi-provided sources.