How to make weak object pointer to UINTERFACE-derived class?

Development Programming & Scripting UI
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1

It is my impression that an array of GC-aware references to C++ implementations of an Unreal Interface class (declared with UINTERFACE, etc) can be made like so:

UPROPERTY()
TArray<TScriptInterface<ISomeUnrealInterface>>

And that an array of GC-Aware weak references to any old UObject can be made like so (notably without any UPROPERTY macro):

TArray<TWeakObjectPtr<USomeUnrealObject>>

But I am left a bit flummoxed as to how one would make an array of GC-aware weak pointers to unreal interfaces. Is it even possible?

2

For anyone looking for an answer to this old question, check TWeakInterfacePtr<> out. It’s defined in GameplayTaskTypes.h

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3

Well, I for one am satisfied to have an answer, even if the project it was for has long ago been laid at peace. I will try to test this and accept the answer if I have the time (Though I may end up forgetting—I’m not even working on anything in Unreal at this exact moment).

4

One thing to note is TWeakInterfacePtr does not propagate cv qualifiers of the template type. Didn’t have this issue with TWeakObjectPtr. So TWeakInterfacePtr<const IMyInterface> won’t compile. I had to use TWeakInterfacePtr<IMyInterface> and cast away the constness with a const_cast<IMyInterface*> prior to invoking the TWeakInterfacePtr constructor.