On Thu, January 14, 2010 21:22, JM wrote:
> Looks like closures and threads are incompatible right now.
I came across exactly the same issue when trying to pass a parameter
to a thread. The problem is to maintain a reference to the closure
which can be released when the closure is no longer needed. This is
the best work-around I've found so far, but it involves creating a
circular reference loop:
private static class BoxedThreadFunc<T> {
public ThreadFunc<T>? run;
}
[...]
// 'param' is the value I want to pass to the thread
var param = [...];
BoxedThreadFunc<void*> btf = new BoxedThreadFunc<void*>();
btf.run = () => {
process(param);
var tmp = (owned) btf; tmp.run = null; // Cleanup
return null;
};
try {
Thread.create<void*>(btf.run, false);
} catch (ThreadError e) {
btf.run = null; // Cleanup
[...]
}
So 'btf' keeps the reference to the closure alive, as it is itself
referenced by the closure (circular ref loop). In theory 'btf.run =
null' should destroy both 'btf' and the closure, but in that case the
C code tries to reference through the now-destroyed closure and causes
a segfault, which is why this code goes via 'tmp' within the closure.
Hopefully I'm not breaking any rules.
Jim
--
Jim Peters (_)/=\~/_(_) [email protected]
(_) /=\ ~/_ (_)
Uazú (_) /=\ ~/_ (_) http://
in Peru (_) ____ /=\ ____ ~/_ ____ (_) uazu.net
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