Luiz Americo Pereira Camara wrote:
Cesar Romero wrote:
Luiz Americo,
Anyway, calling manually _Release avoid the leak and i will stay with
it for now (I hope did not break anything).
It can work for that case, but I think that is not a good ideia.
If you are using a TInterfacedObject descendant, it will call the
_Release when out of context, so in that especific case seems to never
go out of context, and then you _realease call works, but in other
place it can go out of context before, and the you will have others AV.
- As Joao suggest, the best way is create a weak reference, where when
2 objects need to reference each other one should use Pointer to hold
one reference
- Avoid circular reference
The problem here is that i'm using a third party design. And the code
complexity allied with my inexperience with interfaces/COM makes the
chance of breaking things big.
Anyway i did not find, with my limitations, any circular references
between interfaces. Exists a circular reference but is between an
Interface (IVTDragManager) and a TVirtualTreeView(TCustomControl)
already used as a weak reference (TObject).
The design is more or less the following:
TBaseVirtualTree holds a reference to a IVTDragManager.
TVTDragManager (IVTDragManager) holds a reference to TBaseVirtualTree
stored in a TObject field
TVTDragManager also holds reference for IDataObject (TVTDataObject) and
IDropTargetHelper (returned by a win32 call)
TVTDataObject holds a reference to TBaseVirtualTree as a TObject
There are two circular references:
TVTDragManager <-> TBaseVirtualTree
TBaseVirtualTree <-> TVTDragManager > TVTDataObject > TBaseVirtualTree
Circular references of object is not the problem, you should look at
circular references of interfaces.
However, I don't expect that this is the case for the virtualtree. THat
you need a _release for fpc and not for delphi sounds like a bug in fpc.
(only where)
Normally you never ever have to call _release yourself (unless you
called _addref yourself)
Marc
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