Link error : unresolved GetPositionalTrackingCameraParameters


I’m trying to use the function UHeadMountedDisplayFunctionLibrary::GetPositionalTrackingCameraParameters(). I’m following its prototype, my code compiles. However, it doesn’t link.

Here’s the error :

error LNK2019: unresolved external symbol "public: static void __cdecl UHeadMountedDisplayFunctionLibrary::GetPositionalTrackingCameraParameters(struct FVector &,struct FRotator &,float &,float &,float &,float &,float &)" (?GetPositionalTrackingCameraParameters@UHeadMountedDisplayFunctionLibrary@@SAXAEAUFVector@@AEAUFRotator@@AEAM2222@Z) referenced in function "private: static struct FHMDCamParams __cdecl UHMDHelpers::GetPositionalTrackingCameraFuckingParameters(void)" (?GetPositionalTrackingCameraFuckingParameters@UHMDHelpers@@CA?AUFHMDCamParams@@XZ)	D:\Documents\Unreal Projects\Automatisation\Intermediate\ProjectFiles\HMDHelpers.cpp.obj	Automatisation

By the way, the equivalent blueprint function works fine on the same project.
What am I missing?

So it appears that the engine blueprint function libraries aren’t meant to be used from the c++ outside the engine (similar issue?).
I should have used the actual c++ pendant. I didn’t find it in the first place because the name of the function isn’t exactly the same. So : IHeadMountedDisplay::GetPositionalTrackingCameraProperties().
To make this work, I called it as GEngine->HMDDevice->GetPositionalTrackingCameraProperties, included "Runtime/HeadMountedDisplay/Public/HeadMountedDisplay.h" and added the HeadMountedDisplay module in my Build.cs.