On Wednesday, 13 December 2023 at 12:49:14 UTC, fred wrote:
a bug ?
It helps if you explain what you're talking about so we don't
have to guess.
I tried the code on my computer and it worked fine. But then
figuring, you must be saying something doesn't work right, I
tried it on another compiler and saw it endlessly loop.
So it ended using my dmd 2.098, looped on my dmd 2.105.... but
this is actually just coincidence. Consider this:
---
void s2()
{
shared(bool) isDone = false;
spawn(&w2, &isDone);
Thread.sleep(400.msecs);
w("done");
isDone = true;
}
---
The variable `isDone` is temporary; as a local variable, it
ceases to exist when s2 returns. So when w2 tries to check if it
is done or not, it takes a bit of luck for the memory to still be
the same value as it was; it has likely been recycled or
otherwise cleared by then.
You need to keep the variable alive until *both* threads are done
with it, either by doing some fancy synchronization between the
threads or just letting the garbage collector manage the shared
variable:
```
void s2()
{
// let the GC do it
shared(bool)* isDone = new shared bool;
spawn(&w2, isDone);
Thread.sleep(400.msecs);
w("done");
*isDone = true;
}
```
