Hello Erik,
I don't know how to debug java processes but I have an intuition about why those threads are not interrupted: they're never waiting.
See the example below: an interruption scheduled for the interpreter thread is only executed when I put the thread to sleep (and if the garbage collector runs in the meantime it's lost).
The reason why I cared about being able to interrupt the main thread was to run finalizers from there, to avoid concurrency issues in a foreign library. In the end I implemented an alternative solution using locks so I'm not really concerned about this problem anymore.
Regards,
Carlos
CL-USER(1): (let ((main (threads:current-thread))) (threads:make-thread (lambda () (threads:interrupt-thread main (lambda () (print "Hi there!")))))) #<THREAD {3AF6EA95}>
CL-USER(2): (* 2 2) 4
CL-USER(3): (sleep 1)
"Hi there!" NIL
CL-USER(4): (let ((main (threads:current-thread))) (threads:make-thread (lambda () (threads:interrupt-thread main (lambda () (print "Hi there!")))))) #<THREAD {CE5A31A}>
CL-USER(5): (gc) 462843184
CL-USER(6): (sleep 1) NIL
On 06/09/2013, at 21:49, Erik Huelsmann ehuels@gmail.com wrote:
Hi Carlos,
is there a reason why interrupt-thread doesn't seem to run the requested function in some cases? The following code tries to run a function in each existing thread (the variable *output* logs the calls that we try to run and the ones that are actually run).
Looking at your code, there may be multiple causes for the strings not showing up in the output. Frst of all, there's a problem with concurrency in your code: pushing into the *output* variable across threads isn't thread safe. The other reason for the code not being executed could be a bug: the code "checks manually" whether the thread interrupt has been invoked and executes the function(s) handed over. Maybe these threads land in loops that do not check this condition.
(defvar *output*)
(defun test-run () (setf *output* nil) (threads:mapcar-threads (lambda (thread) (push (format nil "~A : calling" thread) *output*) (threads:interrupt-thread thread (lambda () (push (format nil "~A : running" thread) *output*))))))
(defun test-report () (format t "~{~A~%~}" (reverse *output*)))
Running in the command line:
[snip]
I can understand that the thread "TEST-RUN" that I create to run the function might disappear before it gets to run the function as requested, or maybe the reason is that a thread can't interrupt itself by design... But why doesn't the thread "interpreter" run the function?
Running in slime there are many threads present, and most of them will respond as expected. But "TEST-RUN", "interpreter" and "reader-thread" won't.
Can you interrupt the reader-thread and interpreter thread in a java debugging environment and tell me what the stack trace is when you send the signal that isn't being processed? Maybe the answer turns out to be really obvious. Thanks!
Bye,
Erik.