On 5-Oct-09, at 12:50 AM, Mikael More wrote:

Dear Marc,

May threads be GC:ed in case they are started, but there's no variable references to them?

I.e., might (##gc) after having evaluated

(thread-start! (make-thread (lambda () (let loop () (print ".") (thread-sleep! 0.5) (loop)))))

stop the thread?

No. The run queue managed by the thread scheduler is part of the root set. The timeout queue, which is used by thread-sleep! and other operations with a timeout, is also part of the root set. So if a thread is "runnable" or it might wake up after a timeout period has elapsed, then it will not be collected.

Unreachable blocked threads *can* be garbage collected (for example a thread blocked on a mutex that is unreachable). I tried writing a program which exhibits this behavior but couldn't, so I suspect there is a spurious reference to the thread and I need some time to track this down.

For a side question, the documentation says "The thread’s execution consists of a call to thunk with the initial continuation. This continuation causes the (then) current thread to store the result in its end-result field, abandon all mutexes it owns, and finally terminate.". By end-result, do you mean that the return value of the thread thunk is stored somehow in the thread variable?

Yes. If the result terminated normally, the result is accessible with the thread-join! procedure.

Marc