Can't add C++ class of type "DestructibleActor" in 4.9

Development World Creation
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1

I’m running on a fresh win7 install, a fresh 4.9 release branch pulled off git today. I load up a blank project and try to add a c++ class of the type DestructibleActor and hot reload breaks… looking at the output log

1>TestDA.cpp.obj : error LNK2001: unresolved external symbol "public: virtual void __cdecl ADestructibleActor::PostEditChangeProperty(struct FPropertyChangedEvent &)" (?PostEditChangeProperty@ADestructibleActor@@UEAAXAEAUFPropertyChangedEvent@@@Z)
1>FirstProjectTest.generated.cpp.obj : error LNK2001: unresolved external symbol "public: virtual void __cdecl ADestructibleActor::PostEditChangeProperty(struct FPropertyChangedEvent &)" (?PostEditChangeProperty@ADestructibleActor@@UEAAXAEAUFPropertyChangedEvent@@@Z)
1>TestDA.cpp.obj : error LNK2001: unresolved external symbol "public: virtual void __cdecl ADestructibleActor::PostLoad(void)" (?PostLoad@ADestructibleActor@@UEAAXXZ)
1>FirstProjectTest.generated.cpp.obj : error LNK2001: unresolved external symbol "public: virtual void __cdecl ADestructibleActor::PostLoad(void)" (?PostLoad@ADestructibleActor@@UEAAXXZ)
1>C:\Users\dcyoung\Documents\Unreal Projects\FirstProjectTest\Binaries\Win64\UE4Editor-FirstProjectTest.dll : fatal error LNK1120: 2 unresolved externals

I tried regenerating visual studio project files and manually creating the source files as well. Neither worked

EDIT:
The closest post I’ve found dealing with this issue is the following (regarding APointLight, instead of ADestructibleActor):

The provided solution was:

tag the function in APointLight with ENGINE_API

Could someone elaborate on what this means?

EDIT #2:
I also found this…

which seems to elaborate the change. I’m trying it now. I’m confused why destructible actors would be set by default to not be inheritable.

2

This might be because you’ve got some function declarations, but not the definitions.

You’ll need to write some definitions for the virtual functions: PostEditChangeProperty and PostLoad

3

the methods are already part of the base class (DestructibleActor)… i tried overriding them again and simply calling Super::PostEditChangeProperty inside the method but I received the exact same error log. This issue seems to be only with destructible actors, as other c++ classes can be created without error. This also was never an issue in previous versions of the engine.

4

Messing with the engine code (DestructibleActor.h) fixed the issue… very strange that this change was necessary though. If someone knows of a solution not involving changing engine code I’d like to hear it.

5

hello dcyoung…

So all you are supposed to do is override both of these methods and NOT call the Super::PostEditChangeProperty / Super::PostLoad …

The Class ADestructibleActor wants you to override these functions and also write the implementation (and not call the Super class implementation) as there is a keyword ‘override’ written there in base class

6

Hello
It’s a bit hacky, but, it works for me.
The trick is to define the functions by ourselves, letting them empty.
Put this into your .cpp file :

void ADestructibleActor::PostEditChangeProperty(struct FPropertyChangedEvent& Prop)
{
	Super::PostEditChangeProperty(Prop);
}

void ADestructibleActor::PostLoad()
{
	Super::PostLoad();
}