On 01/21/2017 01:06 AM, Eugene Wissner wrote:
On Saturday, 21 January 2017 at 05:52:49 UTC, bitwise wrote:
I hadn't noticed this, but I immediately see two problems:
1) there is no alignedDeallocate() which is needed because aligned
allocators usually prepend metadata containing a pointer to the actual
start of the memory to be passed to free(). So deallocate() can't know
if the memory came from allocate() or alignedAllocate(), and hence
does not now how to properly free the memory.
2) The whole point of using an allocator is that is allocates memory
in a different way, but provides a standard interface. It shouldn't be
up to a container to know whether to call allocate() or
alignedAllocate(). A container should simply call allocate() of
whatever allocator it was given.
yes, agreed. alignedAllocate() seems then to make the interface
complexer without reason.
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
