On Thursday, 9 June 2016 at 20:53:38 UTC, tcak wrote:
(cast()mx).lock();
I was told casting away shared when there are still references to
it is a bad idea. Like, the Mutex object might get corrupted if
the garbage collector tries to move it while another thread is
using it.
So thread 1 casts it to unshared, locks it, then allocates
memory, triggering the GC to move things around. Meanwhile thread
2 casts it to unshared, tries to lock it, and when it checks the
locked bit, that area of memory has been replaced with another
object entirely by the GC.
That seems like a really contrived situation, and maybe not a
problem at all, if casting away shared doesn't make that memory
eligible for being moved around. But, color me cautious before
doing exactly what the FAQ says not to do.
https://dlang.org/faq.html#casting_from_shared
