C callbacks getting a value of 0! Bug in D?

[Moritz Maxeiner via Digitalmars-d-learn]

On Tuesday, 29 August 2017 at 01:34:40 UTC, Johnson Jones wrote:
> [...]
>
>
> produces 4 on both x86 and x64. So, I'm not sure how you are 
> getting 8.

There are different 64bit data models [1] and it seems your 
platform uses LLP64, which uses 32bit longs. Am I correct in 
assuming you're on Windows (as they are the only major modern 
platform that I'm aware of that made this choice)?

[1] 
https://en.wikipedia.org/wiki/64-bit_computing#64-bit_data_models