Download

Automatically updated Pointers

I am currently learning more about pointers and read, that UPROPERTY pointers to UObjects are automatically updated to NULL, if the UObject is destroyed and and TWeakObjectPtrs can be checked for validity. I assume normal, raw pointers could potentially become invalid, i.e. point to something other than NULL or a valid object. Are raw pointers therefore dangerous to use, if I store them for some time, so that some other class could delete the UObject the pointer points to? And if so, should I always use UPROPERTY pointers or TWeakObjectPtrs, when I am storing pointers for a short or long duration?

Secondly is it good practice or even possible to use TSharedPtr for UObjects? And what should I do if I need a weak UPROPERTY pointer, that does not prevent garbage collection? Or what if I need a non-UPROPERTY pointer, that prevents garbage collection?

Yes, anytime you hold a pointer across multiple frames, you need to use one of the above two methods.

Nope, they’re for non-UObjects only.


UPROPERTY()
TWeakObjectPtr< UMyObject > Ptr;

Rarely needed - you can declare a UPROPERTY as above without exposing it to blueprint, editor, etc, so there is rarely an advantage to it not being a UPROPERTY. If you need to store it within something that is not a UCLASS/USTRUCT and therefore can’t use UPROPERTY, you can derive your class from FGCObject. There are lots of examples in the engine codebase.

Thank you so much for your answer. That clarifies a lot for me. You are my hero of the day!