Pinning C# Arrays (GCHandle vs. PinGCObjectAndGetAddress)

Was fiddling with this over the weekend, but couldn't figure it out... so here goes:

So I need to pin some C# arrays and get the address of the first element (Byte[] arrays to be specific). I'm used to doing this with GCHandle.Alloc(array, GCHandleType.Pinned) but I saw that there's a method called PinGCObjectAndGetAddress in the Unity.Collections.LowLevel.Unsafe.UnsafeUtility class.

1) What is the difference between doing it the regular .NET way with GCHandle and PinGCObjectAndGetAddress?

2) Can I use PinGCObjectAndGetAddress to pin arrays, and if thats the case where does the address that is returned point to? The first element?

I thought I saw a method specifically designed to pin GC arrays somewhere in the low level APIs exposed ... but couldn't find it again.

 

Okey so I installed the latest 2018.3 beta10, and with this version it seems a method called PinGCArrayAndGetDataAddress is available in the UnityEngine.CoreModule.dll on the Unity.Collections.LowLevel.Unsafe.UnsafeUtility class.

Can someone from Unity (as I assume nobody else knows how these functions really work) confirm something:

1) Is the void pointer returned from the method the pointer to the first element?
2) The handle returned as a ulong on the second parameter, that can be passed into ReleaseGCObject ? There is no ReleaseGCArray so I assume this is where you're supposed to release a pinned array also?

 

Anyone that knows this?

 

AFAIK:

1) Yes
2) Yes

 

From my tests I've seen this to be the correct answers to both questions, but it'd still be nice to have an official word from a Unity employee.

 

https://docs.unity3d.com/2018.3/Doc...nsafeUtility.PinGCArrayAndGetDataAddress.html

 

Oh... there is some documentation! Thanks!