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Why const UFUNCTIONS?

When interacting with blueprints though C++, you can modify the C++ members through UPROPERTYs to your heart's content, but when it comes to UFUNCTIONs, the inputs need to remain const. Why is that?

I have a situation where I want UMG to launch a rocket to another planet when I hit a button, and have the rocket class internally track the destination until it arrives:

 UFUNCTION(BlueprintCallable, Category = "Mechanics")
             virtual void launch(AActor* &destination);

AActor* &destination would need to be non-const, because the member I'm assigning that destination to will repeatedly change as the rocket goes from planet to planet. Unfortunately, even though the return is void, it still sets up &destination as an output in the blueprint.

I also have a function that should allow UMG to set the rocket's location based on actor and offset from the actor:

 UFUNCTION(BlueprintCallable, Category = "Mechanics")
     virtual void setLandedLocation(AActor* &body, const FVector offset = FVector(0, 0, 0));

The parameter AActor* &body also needs to be non-const, because the body will eventually change when the rocket goes from planet to planet.

Abstracting away members and variables is nice way to keep classes bug-free, so I'm slightly confused as to why OOP getters and setters are not allowed in UFUNCTIONS.

Am I missing something here?

Thank you, BeariksonStudios

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asked Dec 13 '14 at 07:50 PM in C++ Programming

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BeariksonStudios
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