Clarification about GC and NewObject<>

Development Programming & Scripting C++
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1

I have a plugin module where the implementation class is derived from custom derivation of IModuleInterface. The module loads fine and is accessible. Inside the module implementation I have a private regular C++ pointer (not decorated with UPROPERTY because after all this class is a module class and not an UObject) to a custom UObject. Inside StartupModule I allocate an instance of that object using NewObject<>.

Is this sufficient for keeping said private UObject alive? NewObject<> assigns a default Outer object, no? And so isn’t that good enough to keep it alive from the GC? I test the persistence by calling GetWorld()->ForceGarbageCollection(true) inside my custom PlayerController in the main game module repeatedly through a triggered UFUNCTION, and the UObject in question seems to stay accessible. I am just getting lucky or is what I am doing legit?

2

As I understand things that shouldn’t be safe, I didn’t think that the outer contributed to reference counting by default. So I’m surprised it’s working. Anyway, to be safe, just call AddToRoot() on your object immediately after creating it. This will make sure it remains referenced for the duration your program runs.

3

Got it. Will do, although I hope one day UE4 memory rules and structure will be clarified further.