Allocator

In the project (Novodex v2.3.3) I use Allocator
gMyAllocator = new UserAllocator;
...
// Initialize PhysicsSDK
gPhysicsSDK = NxCreatePhysicsSDK (NX_PHYSICS_SDK_VERSION, gMyAllocator, NULL);
necessary whether me to use these functions:

gMyAllocator->checkDEBUG
gMyAllocator->free
gMyAllocator->malloc
gMyAllocator->mallocDEBUG
????

Question why 2.3.3?

As for the allocator, I don't have the SDK handy but I believe it's optional. So just leave it NULL.