On 3/1/18 10:35 AM, John Burton wrote:
On Thursday, 1 March 2018 at 12:20:08 UTC, Steven Schveighoffer wrote:
On 3/1/18 7:05 AM, Gary Willoughby wrote:
On Thursday, 1 March 2018 at 10:10:27 UTC, John Burton wrote:
My question is how do I tell if a pointer is "garbage collected" or
not?
You could try `GC.addrOf()` or `GC.query()` in core.memory.
I was going to say this, but then I realized, it's not that the
pointer points at GC-allocated memory, but that the pointer itself is
stored in a location that is scanned by the GC. That's not as easy to
figure out, as you have to look at stacks, added ranges, etc.
Ah.... it's where the pointer is stored. That makes some sense.
Thanks
Yes, the text isn't exactly clear. For instance, C rules apply for a
pointer stored in a block allocated by C malloc, even if it points at a
GC piece of memory -- as long as the block hasn't been added as a root
or range to the GC.
Also note that realistically, even though the document talks about a
"copying GC", this probably will never happen. Many things that are
identified as "undefined behavior" in that doc, are probably going to be
fine. I really wish it didn't say UB for a lot of those things. It
should really say that it's up to the GC implementation whether it's UB
or not.
-Steve
