[program deleted]
So, this basically means that my finalizer did not get run :( [...] It should run, in separate thread or not, it doesn't matter here.
Any ideas why doesn't it work?
Hopefully the GHC folk will correct me if I'm wrong but I think what happens is: - you allocate object with finalizer - the object becomes inaccessible - performGC causes the object to be freed by the garbage collector - the garbage collector schedules a thread to run your finalizer BUT - before the finalizer thread has a chance to be scheduled, your program exits. You could give the finalizer thread a chance to run by calling Control.Concurrent.yield before exiting: http://etudiants.insia.org/~jbobbio/pafp/docs/base/Control.Concurrent.html#v... 3Ayield That is, call yield just after calling performGC. -- Alastair Reid