Do I have to use FObjectInitializer in constructor?

Development Programming & Scripting C++
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1

I see some classes don’t have FObjectInitializer in their constructor, while others do. I wonder what the difference is here?

Thanks,

wcl1993

2

They are both valid unreal engine class constructor, FObjectInitializer has some very useful function to initialize the object properties but some simple classes don’t really need that functionalities, and that is why, I think, Epic made an alternative constructor that has no parameter, just to make things simple and tidy.

I don’t know when Epic added the capability of creating this simple constructor, but I remembered that before 4.5 you can’t create such a thing and it’s kinda waste having to write object initializer (it was called PCIP back then), call the super constructor and then never use it in the constructor because what I wanted to do is to just set the default value of some simple properties.

3

Exactly! Sometimes I only need to set some default values and using it would be very redundant.

4

They are the same. The difference is that the 1 constructor takes an initializer, the other constructor, creates the initializer, and routes all the CreateCalls through the Initializer behind the scenes. The change is because people are too lazy to type out the Initializer…

5

Nope, take a look at the two constructors in Actor.cpp, note the comment in the second constructor.

AActor::AActor()
{
	InitializeDefaults();
}

AActor::AActor(const FObjectInitializer& ObjectInitializer)
{
	// Forward to default constructor (we don't use ObjectInitializer for anything, this is for compatibility with inherited classes that call Super( ObjectInitializer )
	InitializeDefaults();
}
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