Memory allocation in D

[Sean Kelly]

Sean Kelly wrote:
> Jason House wrote:
>>
>> If object sizes are a power of 2, is that because of special padding of a
>> struct/object to make it align well?  Maybe some clever trick could be 
>> done
>> to use wasted space, if it exists, for special tracking data... 
>> Otherwise,
>> allocating a bit more seems the most sensible.
> 
> Only arrays get the +1 byte added to their size during allocations.  If 
> an object occupies 16 bytes then it will end up in a 16 byte bucket. The 
> +1 issue for arrays exists to make the program a bit more forgiving for 
> "past the end" errors.  Interestingly, the ANSI C standard actually 
> requires this behavior in its allocators.

So I went and looked up the clause and I'm not clear whether it requires 
the location to be physically available or merely fore the address to be 
valid for pointer mathematics.  I also realized that I don't need to 
worry about malloc and vmalloc because they're already ANSI C complaint, 
so it's just potentially a matter of sorting out VirtualAlloc and mmap. 
  I'm going to do a bit more research and see what comes out of it.


Sean