> 
>    Notice that in the following piece of code shmget() returns
>    a value incremented by (64 *1024) on each invocation. Is this expected?
> 
> Is there some reason to think it's wrong?

Because the return value from shmget() seems to be very different
from other OS'.

> The code works as intended.

I agree that it works, but this return value seems unusual.