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Postings from April 2003
On Wed, Apr 02, 2003 at 12:39:09PM -0800, Ilya Zakharevich wrote: > On Wed, Apr 02, 2003 at 01:07:05PM +0100, Tim Bunce wrote: > > > This has nothing to do with detach()/join(). Reading the source > > > shows: what the message tries to express (but as you can see it does > > > not succeed) is that a thread requests the whole process to exit(), > > > while this thread is not the last running thread of the process. > > > > Not neccessarily "requests". It's just when an interpretter is being > > destroyed by itself for whatever reason. Hence the very general > > wording of "A thread exited". > > IIUC: Nope. The message is shown when *the process* terminates (via > Perl-visible request), not "an interpreter terminates". See below. > > Seems like it is related to detach()/join() in that when a non-detached > > thread terminates it effectively waits for another thread to join() > > it to collect the result. And, as I understand it, the thread the > > does the join() is the one that calls perl_destruct() and so the > > "A thread exited" warning isn't generated (see the code). > > Sorry, cannot parse what you wrote. The message is shown when on the > process termination there are non-joined or detached threads. Process > termination happens when a thread calls exit() or die()s (including > implicit exit() at the end of the main program). The Perl_ithread_hook() function generates the warning if active_threads != 1 and aTHX == PL_curinterp (ie a thread is destroying it's 'own' interpreter and not an interpreter created for another thread). The Perl_ithread_hook() function is only called by perl_destruct(). And perl_destruct() has no knowledge of why the interpreter is being destroyed.o There's nothing explicitly related to process termination here. But process termination is when you're most likely to trigger it. I imagine (but have no time to test) that it would also be triggered if thread A starts a non-deteched thread B then thread A terminates before thread B does. Thread B is left with no other thread to 'join' to in order to get cleaned up so must perl_destruct it's own interpreter. > Do not think this understanding of mine coincides with one of yours. > And I have some trust intoamy understanding - I spend a long time > trying to debug this message. Perhaps. I certanly can't claim to have much experience of thread. But if there is a flaw in my understanding I'd like it to be pointed out. Tim.Thread Previous | Thread Next