On 9/26/14 3:24 PM, monarch_dodra wrote:
On Friday, 26 September 2014 at 18:03:40 UTC, Steven Schveighoffer wrote:
On 9/25/14 6:03 PM, Sean Kelly wrote:
On Thursday, 25 September 2014 at 21:43:53 UTC, monarch_dodra wrote:
On Thursday, 25 September 2014 at 20:58:29 UTC, Gary Willoughby wrote:
What does BlkAttr.FINALIZE do when used in the GC.malloc call?
I have no idea. I think its for classes though, since we (currently)
don't finalize structs anyways.
Yes it's for memory blocks containing class instances. It basically
tells the GC to call Object.~this() when collecting the block.
Just to add to Sean's statement, don't use this flag. It will crash
the runtime, unless you have properly set up the classinfo pointer :)
It does NOT work on structs, though I think there is a PR in the works
to have structs destroyed from the GC.
Kind of like APPENDABLE I guess, since it only works if you correctly
setup the appendable data, and correctly slice at the correct offset,
both of which are implementation defined.
Well, kind of yes.
But the difference here is that if APPENDABLE is set, and you never
actually append to an array in that block, then you are going to be
fine. Even if you didn't set it up, it's most likely that you will not
encounter a problem, because whatever is there is likely not the right
size (and that simply results in a reallocation without touching
anything). Even if you do manage to use appending on that block, and the
data that happens to be where the allocated size is matches the current
slice end, it will corrupt some data (or not, the smaller block sizes
keep the append data at the end of the block). This could potentially
crash, or it could do nothing.
If FINALIZE is set, when the GC collects the memory it WILL crash if you
didn't set up some sort of mock classinfo.
I don't recommend using either, but FINALIZE is a much worse outcome IMO :)
-Steve
