Unresolved external in AAIController

Development Programming & Scripting
1

I’m trying to a simple AI character to follow me around in a level. When I try to compile the project, I get the following error in the AIController class:

Error LNK2001 unresolved external symbol “public: virtual void __cdecl AFollowerAIController::Possess(class APawn *)” (?Possess@AFollowerAIController@@UEAAXPEAVAPawn@@@Z)

I have included “AIModule” in the project build file, and even tried adding “GameplayTasks”, but I keep getting the error. Possess is a virtual public function on AAIController so I don’t understand why I’m getting this error. Can anyone help?

2

This error means that you have a virtual method that has no implementation. Since virtual methods work a bit differently than regular methods, the compiler looks for them in a later phase, thats why you get “LNK” errors instead of regular compile errors. Just implement it like so

void AFollowerAIController::Possess( - your arguments -)
{

}

in the .cpp file of your class. The method body can be empty, the only thing that matters is that it’s there.

3

Thank you so much, that was exactly what was wrong. Your help is very much appreciated.