for the first problem, you've found a bug in the Racket CS thread scheduler (i.e., Racket BC behaves correctly in this case). Suspending a thread that is sleeping didn't prevent the thread from being woken up on its previous schedule. I've pushed a repair as commit 7a12b4ac93.
After fixing that bug and using `thread/suspend-to-kill`, the second part works as expected. But if `t1` is created with `thread`, the behavior you describe sounds right: `t2` cannot resume a thread that was created with `thread` and then terminated by a custodian. Thanks for the report! Matthew At Sat, 7 Nov 2020 15:26:17 -0800 (PST), Greg Rosenblatt wrote: > I'm experimenting with using custodians to manage threads (on Racket 7.8 > [cs]) and encountering behavior I don't understand. > > I start a looping thread `t1` under a new custodian `c1`. > > I then shutdown `c1` and expect `t1` to stop looping. If I started `t1` > with `thread` then this expectation is met. However, if I start it with > `thread/suspend-to-kill`, it continues looping even after `c1` is shut > down. Is this the correct behavior? > > Additionally, I later start a new thread `t2` under a new custodian `c2`, > which attempts to resume `t1` after the shutdown, using itself as a > benefactor. However, `t1` does not seem to resume. Is this the correct > behavior? > > Here is the code I'm working with: > > ``` > #lang racket > > (define c1 (make-custodian)) > (define c2 (make-custodian)) > (define t1 #f) > (define t2 #f) > > (parameterize ((current-custodian c1)) > ;(set! t1 (thread/suspend-to-kill ;; (custodian-shutdown-all c1) fails > to suspend this thread > (set! t1 (thread > (lambda () > (let loop () > (displayln "thread 1") > (sleep 2) > (loop)))))) > > (displayln "ENTER to continue") > (read-line) > > (custodian-shutdown-all c1) > > (displayln "ENTER to continue") > (read-line) > > (parameterize ((current-custodian c2)) > (set! t2 (thread > (lambda () > (thread-resume t1 (current-thread)) > (let loop () > (displayln "thread 2") > (sleep 2) > (loop)))))) > > (displayln "ENTER to continue") > (read-line) > > (custodian-shutdown-all c2) > > (displayln "ENTER to continue") > (read-line) > ``` > > -- > You received this message because you are subscribed to the Google Groups > "Racket Users" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to [email protected]. > To view this discussion on the web visit > https://groups.google.com/d/msgid/racket-users/f844779f-9abd-46bd-987f-b2b3ca3d > 0925n%40googlegroups.com. -- You received this message because you are subscribed to the Google Groups "Racket Users" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To view this discussion on the web visit https://groups.google.com/d/msgid/racket-users/20201107174703.320%40sirmail.smtps.cs.utah.edu.
