Link errors in UBTTaskNode classes

Unreal Engine Programming & Scripting C++
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#1

After converting my project to 4.12 I have link errors in 2 of my UBTTaskNode classes:

2>AllowNextMarker.cpp.obj : error LNK2001: unresolved external symbol "public: virtual void __cdecl IGameplayTaskOwnerInterface::OnGameplayTaskActivated(class UGameplayTask &)" (?OnGameplayTaskActivated@IGameplayTaskOwnerInterface@@UEAAXAEAVUGameplayTask@@@Z)

.h

#pragma once

#include "BehaviorTree/BTTaskNode.h"
#include "AllowNextMarker.generated.h"

/**
 * 
 */
UCLASS()
class GAME_API UAllowNextMarker : public UBTTaskNode
{
	GENERATED_BODY()
		EBTNodeResult::Type ExecuteTask(UBehaviorTreeComponent & OwnerComp, uint8 * NodeMemory) override;
	
	
	
};
#2

I am having similar issues and would equally appreciate some assistance with why 4.12 is causing this.

#3

This is a known issue with changing to 4.12 and using tasks. It can be resolved by simply adding “GameplayTasks” to the PublicDependencyModuleNames section inside your ‘ProjectName’.Build.cs For example:

PublicDependencyModuleNames.AddRange(new string[] { “Core”, “CoreUObject”, “Engine”, “InputCore”, “AIModule”, “GameplayTasks” });

1 Like
#4

Life saver. Thanks!

#5

THANKS!!!

#6

THANKS!!!

#7

Thanks so much.

#8

Thank you so much!

#9

Thanks you!

#10

Thank you, and when will this be fixed?

#11

life saver thx.

#12

4.19 still has this issue. but I’m a bit curious. I have another .cpp and .h that use the
virtual EBTNodeResult::Type ExecuteTask(UBehaviorTreeComponent& OwnerComp, uint8* NodeMemory) override;

but cause no issues. Why is that?

#13

THANKS!!! Life saver!

#14

OMG Thanks I’ve been struggling with this for an hour trying to dig through my project and linker settings. You’re a real hero.

#15

A true hero :wink: Thanks man!

#16

Thank you kindly for saving me a bunch of frustration

#17

It will throw this error in 5.0.2 as well when you add any class of type BTTask_BlackBoardBase. This one I would consider moderately evil considering that there is not a good way to really understand why this is happening or even where to begin to look to resolve it.