Is there an object on given memory address?

[via Digitalmars-d-learn]

On Thursday, 12 February 2015 at 10:16:49 UTC, Ola Fosheim 
Grøstad wrote:
> then query the GC wether the memory is still allocated.

This is racy, though. Someone (or the GC) could have freed the 
object in the meantime, and a new object of potentially different 
type could have taken its place. You won't get around pinning it.