On 1/30/16 12:41 PM, Andrei Alexandrescu wrote:
On 1/29/16 9:52 PM, Steven Schveighoffer wrote:
import std.experimental.allocator.gc_allocator;
void main()
{
//GCAllocator.instance.goodAllocSize(3000); // error
writeln(theAllocator.goodAllocSize(3000)); // 3008, should be 4096
}
This is known info, why is it not available? Is there a reason this
needs to be inaccurate? I can create a PR if desired.
There's no need, I just put in reasonable conservative defaults. Please
do follow up - thanks! -- Andrei
OK, I'm making a PR for this.
Incidentally, you can do aligned allocation with GC (beyond just
sizeof(real)). Just make sure your allocation requested is at least that
many bytes (GC puts data into bins, each bin having the amount of bytes
requested).
So for example, if you want a 16-byte allocation aligned to 32-bytes,
just allocate 32 bytes and slice the first 16.
Followup questions:
1. How does one detect that automatic memory cleanup will occur? In
GCAllocator, deallocate is implemented, so I can't tell that "no you
don't need to call deallocate"
2. How does one allocate with an allocator for typed info? In other
words, the GC will call the dtor, but only if it knows what type you put
in there. With std.experimental.allocator, there isn't a way to do that.
3. I'm working on a library that (hopefully) takes an allocator for
allocating a ubyte array for buffer space. If I use GCAllocator, this
will mark the array as having pointers conservatively. It will also
initialize all the data to 0 (needlessly in this case). How to do this
correctly?
Thanks
-Steve
