On 01/21/2017 12:14 PM, bitwise wrote:
On Saturday, 21 January 2017 at 16:28:16 UTC, Andrei Alexandrescu wrote:
alignedAllocate provides access to OS/clib-provided primitives for
aligned allocation. Those don't require a special deallocation
function, see e.g.
http://en.cppreference.com/w/c/memory/aligned_alloc. -- Andrei
This makes sense, but then shouldn't alignedAllocate() be a free
function that could be used to make an aligned allocator?
You mean an aligned allocation? But then the actual method, and whether
it is supported at all or not, depends on the allocator.
Again, the point of an allocator is to provide a standard interface for
memory allocation. The user of which shouldn't have to know how that
memory was allocated, and I can't think of a case where this would be
desired either.
I don't understand this. It's possible there's a confusion at a
different level, and we're discussing the consequences.
To reboot:
* Some applications need memory aligned at special powers of two, most
are okay with more generic alignments such as word-level. See the
"alignment" enum that each allocator must define.
* Some allocators do offer allocations at unusual powers of two by means
of alignedAllocate. Don't call it naively! Only applications that need
such things (e.g. page-aligned, cache-line-aligned, etc) should need those.
* Those allocators must be able to deallocate memory allocated with
allocate() or alignedAllocate() with a single primitive deallocate().
Andrei
