Using Unreal's CreateLambda function in C++

GitHub Repo

Recently when working with timers I wanted a quick way to toggle an actor's boolean value without having to write an additional function. I just wanted something quick and simple and using CreateLambda was the solution.

Typically when creating a timer I would create something similar to the below snippet where we have an established FTimerHandle (MyTimerHandle) that binds to call a member function (MyFunction).

GetWorldTimerManager().SetTimer(MyTimerHandle, this, &AMyActor::MyFunction, 1.f, false);

In my situation MyFunction was only setting Tick to false and I was wondering if there was another way to do this without having to create new function. The SetTimer accepts an FTimerDelegate as it's third parameter so we use the CreateLambda method inherited from the delegate type. So, we can do FTimerDelegate::CreateLambda([]() { // code here }). Below is how updated the above snippet to use CreateLambda, in my scenario I'm setting Tick to true.

GetWorldTimerManager().SetTimer(MyTimerHandle, 
    FTimerDelegate::CreateLambda([this]() 
    { 
        SetActorTickEnabled(true);
    }), 1.f, false);

Using lambdas can be great and I found that using CreateLambda in a timer function was fun to use when doing very basic logic.

Harrison McGuire

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