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Postings from January 2001
Dan Sugalski wrote: > >In other words the C level signal handler will have to do no more than > >setting a flag, as will the implementation of die(). By cancellation > >point I mean somewhere that is defined as 'safe', i.e. not holding any > >mutexes or waiting on any CVs etc. > > I'm not sure the core should really care about that. It's arguably not the > interpreter's problem. (Though it's not a strong argument) Ah - I mean not holding locks etc inside the interpreter core, not in the application. Fixing the application is the application programmers problem ;-) Seriously, I'm not sure that we could fix the genric application-level problem even if we wanted to. However, we *could* probably get it right for the interpreter innards. > > I suspect a reasonable thing might > >be to have a special 'Now it is safe' opcode that is put out by the > >compiler at the appropriate places. It would be nice if this > >corresponded to a syntactic boundary such as an entire statement, so > >that for example > > > > my $a = $b * $c / $d; > > > >was guaranteed to either to be fully evaluated or not at all. > > The question, then, is what do we do with function calls in there (say, $a > = $b + foo()), and what about really long running statements like: > > $a = $b + 12 while 1; Hmm. Good point. Actually, I'd just settle for any point that didn't result in the interpreter being screwed up afterwards. Alan BurlisonThread Previous | Thread Next