std.allocator issues

[Andrei Alexandrescu via Digitalmars-d]

On 02/19/2016 10:12 PM, Steven Schveighoffer wrote:
> On 2/19/16 9:21 PM, Steven Schveighoffer wrote:
>> I'm trying to use the std.experimental.allocator API more in my new io
>> library, and I'm having a few stumbling points:
>
> Another thought:
>
> Allocators return void[] when requesting allocations, reallocations,
> etc. For C malloc, the assumption must be that what you requested is
> what you got, because the actual block size isn't given. However, for GC
> (and I assume other allocators), we have mechanisms to know upon
> allocation the amount of data received.
>
> I would assume since we are returning both pointer and length, it would
> be possible for an allocator to return more data than requested (why
> waste it?). But it appears that the GC allocator just returns the amount
> of data requested, even though it could return the extra data that was
> received.
>
> Should the API assumptions allow returning more data than requested? It
> means code has to be wary of this, but creating a wrapper allocator that
> truncates the data would be trivial, no?
>
> I want to write some PRs to fix this, but I'm unclear what is expected.
>
> -Steve

Allocators are guaranteed to return the size requested. This is by 
design. -- Andrei