How to find out event-function parameter signatures?

Hi all,
After I made my first gameplay experiments with Blueprint Projects I am currently on learning the UE4 API from the C++ side too.
So far everything went well but now I have a question in my mind…

Where do I find event-signatures? (Except in the forums and awenser hub^^ )

For example:

UFUNCTION()
void OnBeginOverlap(class AActor* OtherActor,
               class UPrimitiveComponent* OtherComp,
               int32 OtherBodyIndex,
               bool bFromSweep,
               const FHitResult& SweepResult);

So that I can use this function via:

trigger->OnBeginOverlap.AddDynamic(this, &ASomeActor::OnBeginOverlap);

So where to find the signature of the UFUNCTION above?
Hope someone can help me out with this research problem^^

For example:

You know that OnActorBeginOverlap belongs to AActor.

So:

  1. First go to the declaration of OnActorBeginOverlap in AActor.h
  2. You’ll see that the declaration type is FActorBeginOverlapSignature
  3. Go to the declaration of FActorBeginOverlapSignature (in Visual Studio use the F12 key)
  4. And now you should find something like this: DECLARE_DYNAMIC_MULTICAST_DELEGATE_TwoParams( FActorBeginOverlapSignature, AActor, OverlappedActor, AActor, OtherActor );**

And there you have your signature :wink:

Warning about this – it takes forever (or at least it did for me). Don’t cancel it; just let it work for a little while.

Could you explain what the macro means? I’m assuming it’s DECLARE...(OwningType, Param1Type, Param1Name, Param2Type, Param2Name); is that correct?

I usually use Visual Assist its the quickest way (Visual Studio Plugin with a loot of awesome Features)

But if you want a Quick way to find out just Add any Function and Compile. Look at the Output log it will tell you that it failed because blahblablah… expected Parameters → hard to read list of the Parameters here

But hey they are there =)

And yes you are Correct about the Macro. There is one variation with _RetVal at the end and this will be the first Parameter followed by DelegateName followed by Parameters. More info here: