BlueprintImplementableEvents should not be virtual

Development Programming & Scripting AI
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1

LogCompile:Error: BlueprintImplementableEvents should not be virtual. Use BlueprintNativeEvent instead.

But, it compiles even with this error.

Here is the function"
UFUNCTION(BlueprintImplementableEvent, Category = “AI”)
virtual void SetupAI(const TArray &pillers, UBehaviorTree* Tree);

On switching the tag to BlueprintNativeEvent the project then doesn’t compile.

The class extends from ACharacter.

Any insight into this would help. Thank you.

2

BlueprintImplementableEvent are for functions that will be only implemented blueprint. They must not be virtual and should not have any implementation in C++. You just call the function.

BlueprintNativeEvent are for functions that will have a C++ implementation. Theses C++ functions are auto-generated and will have the name of the function + “_Implementation”.
It allows the system to call just the SetupAI function, that will call SetupAI_Implementation (function that is virtual and overridable), then the blueprint function.

You have to setup things like this :

// header
UFUNCTION(BlueprintNativeEvent, Category = "AI")
void SetupAI(const TArray &pillers, UBehaviorTree* Tree);

// cpp
void MyClass::SetupAI_Implementation(const TArray &pillers, UBehaviorTree* Tree);

Edit : @staticvoidlol, thanks to point this detail out. I should have been more accurate with the words I used.

3

Minor correction though:

The “BlueprintImplementableEvent” decorator specifies that the function body will be implemented in Blueprints - it’s not about calling the event from Blueprints. There’s a separate decorator for that called “BlueprintCallable”. As far as I recall I actually have functions with the following decorators:

UFUNCTION(BlueprintImplementableEvent, BlueprintCallable, Category = "PWNGame-General")
// Can implement behaviour in Blueprints as well as call it from a Blueprint

UFUNCTION(BlueprintCallable, Category = "PWNGame-General")
// Can NOT implement behaviour in Blueprints, but can call it from a Blueprint - requires C++ implementation

UFUNCTION(BlueprintImplementableEvent, Category = "PWNGame-General")
// Can implement behaviour in Blueprints, but can NOT call it from a Blueprint - no C++ implementation

As for “BlueprintNativeEvent”, I agree.