Unreal's garbage collection system and UPROPERTY( )

When you have an object (such as TArray< >) as a UPROPERTY() member of UCLASS(), you need to declare that member as UPROPERTY() (even if you won't edit it in Blueprints); otherwise, TArray will not stay allocated properly.

How to do it...

Say we have a UCLASS() macro as follows:

UCLASS() 
class MYPROJECT_API AWarrior : public AActor 
{ 
  //TArray< FSoundEffect > Greets; // Incorrect 
  UPROPERTY() TArray< FSoundEffect > Greets; // Correct 
}; 

You'd have to list the TArray member as UPROPERTY() for it to be properly reference-counted. If you don't do so, you'll get an unexpected memory error-type bug sitting about in the code.

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