SPUG: Pull out of a blocking subroutine?

[Charles DeRykus]

> > This sounds like exactly what I need, but it doesn't seem to

    > be working.

> >  It still freezes at the call to Does it make any difference that I am
>
    > not making a simple system call, but instead a call to a function in a

> > module?
>

  perlipc's POSIX workaround can help if the function has a
  networking call with its own timeout which interferes with the
  timeout you've set.  Here's a couple of changes to demo the
  fix although perlipc warns this will bypass safe signals:


    use POSIX qw(SIGALRM);   # <---

> while(1)
> > {
> >   eval {
> >
> >   #   local $SIG{ALRM} = sub { die "alarm\n" }; # NB: \n required
>

      POSIX::sigaction(SIGALRM,     # <---
                     POSIX::SigAction->new(sub { die "alarm"; } ) )
           or die "Error setting SIGALRM handler: $!\n";

  >   alarm 5;
  >   # $Scoop_a is my robot object

  >   $ret =
  >       $Scoop_a->nxt->get_battery_level(
  >            $LEGO::NXT::Constants:: NXT_RET);
  >    alarm 0;
  >};
  > ...


Of course,nothing helps if the function does this:

     local $SIG{ALRM} = 'IGNORE';

-- 
Charles DeRykus
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