On Wednesday, 12 July 2017 at 09:10:07 UTC, Jacob Carlborg wrote:
On 2017-07-11 08:18, Biotronic wrote:
If DRuntime is not made aware of the thread's existence, the
thread will not be stopped by the GC, and the GC might collect
memory that the thread is referencing on the stack or in
non-GC memory.
Are you sure? Wouldn't that make malloc or any other custom
allocators completely useless and the D GC would completely
break the C standard library because it could collect memory
allocated by the C standard library?
From "How Garbage Collection Works":
"5. Freeing all **GC** allocated memory that has no active
pointers to it and do not need destructors to run" [1]. I added
the emphasize on "GC".
From "Interfacing Garbage Collected Objects With Foreign Code"
"If the only pointer to an object is held outside of these
areas, then the collector will miss it and free the memory. To
avoid this from happening, either
* reallocate and copy the object using the foreign code's
storage allocator or using the C runtime library's
malloc/free." [2].
[1] http://dlang.org/spec/garbage.html#how_gc_works
[2] http://dlang.org/spec/garbage.html#gc_foreign_obj
That's basically what I tried to say - the GC may collect memory
*it has allocated* if the only pointers to it are in memory the
GC doesn't scan (i.e. on the stack of an unregistered thread or
in memory not allocated via the GC).
It will not collect memory allocated by other means, but that
Foo* you got from D and are using in C++ might point to a Bar
soon after the GC runs.
--
Biotronic
