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Implementing a UInterface in a UStruct c++


I have just started learning Unreal and am trying to create a USTRUCT that implements a UINTERFACE

I have an Item struct:

 struct FAMINE_API FItem : public IInteractableInterface
     virtual void Interact(class AActor* InteractingActor) override;
     UPROPERTY(EditAnywhere, meta = (AllowPrivateAccess = "true"))
     class UItemDataAsset* ItemData;

and an Interactable UINTERFACE

 class UInteractableInterface : public UInterface
 class FAMINE_API IInteractableInterface
     // Add interface functions to this class. This is the class that will be inherited to implement this interface.
     virtual void Interact(class AActor* InteractingActor) = 0;

The problem is that the header tool expects the struct to inherit from another UStruct and then throws the following error at compile time:

Parent Struct 'IInteractableInterface' is missing a valid Unreal prefix, expecting 'UInteractableInterface'

Is there any way to implement an interface in a UStruct? If not, is my only option then to switch to a UClass?


Product Version: UE 4.18
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asked Feb 23 '18 at 09:14 AM in C++ Programming

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avatar image BrUnO XaVIeR Feb 23 '18 at 12:13 PM

Even if you'd do this the right way, you cannot have UFunctions inside UStruct because, for Unreal Engine, UStructs are value types. Implementing an interface on a UStruct woudn't work.

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No, reflection system does not support interfaces in structs, as well as functions which is what you trying to do. But it should work in C++ as long as you not use U-macros on them and potentially you can make static Blueprints nodes to manageable them in Blueprint (for example make function in blueprint that calls struct function).

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answered Feb 23 '18 at 03:09 PM

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