On Friday, 13 August 2021 at 16:18:06 UTC, Ruby The Roobster
wrote:
Context for this: I am creating a module of my own, and this
is a class contained in the module. You will notice that after
calling this class' constructor anywhere in a Win32 API
program, that the program doesn't close after the window is
closed.
You're hanging in `Runtime.terminate`. That's because of your
`Entity` destructor, specifically this line:
entitytable.length -= 1;
Comment it out and the program exits successfully.
You aren't supposed to be manipulating GC-managed memory via
class destructors. You can not rely on that memory being valid at
the time that it's accessed in the destructor---the object may
already have been destroyed. Nondeterministic destruction is the
price you pay for letting the GC manager your object memory.
Of course, in this case, the problem will only crop up at
termination since the array is declared at module scope so will
be live up until the GC shuts down. But still, not something you
should be doing.
The runtime will help you by throwing an error if you do anything
that directly triggers an allocation, like calling `new` or
performing an array append. But it won't help you with anything
else.
Someone more versed than I with the GC innards may be able to
answer whether an error should be thrown here as well, or if this
goes under the undefined behavior category.
