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in reply to Signal Handling throws Core Dump

Not sure if this is of any help (because on the Solaris 10 box I have within reach, there's only an older Perl installed), but just in case: the following works fine here 

#!/usr/bin/perl

our $sig;  # same for my $sig

$SIG{INT} = \&handler;

sub handler {
    print "got SIGINT\n";
    $sig++;
}

until ($sig) {
    print "running...\n";
    sleep 1;
}
print "terminated.\n";

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outputs as expected (until/when I send it SIGINT) 

running...
running...
running...
got SIGINT
terminated.

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Can you produce a backtrace, loading your core file in a debugger (gdb perl core, then, at the prompt, typing "bt" — in case you have gdb available, that is...)? This might give a first hint at where things are going wrong. (A perl binary built with debugging info would be better, of course...)

___

$ uname -a
SunOS solaris10 5.10 Generic sun4u sparc SUNW,Sun-Blade-2500

$ perl -v

This is perl, v5.8.4 built for sun4-solaris-64int
(with 27 registered patches, see perl -V for more detail)
(...)

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Replies are listed 'Best First'.
Re^2: Signal Handling throws Core Dump
by dsb (Chaplain) on Apr 25, 2007 at 16:43 UTC
    When I give $SIG{INT} an anonymous subroutine, I can at least get it it to increment $sig and exit cleanly.

    But when I try to run an object method designed to remove a stored PID from a DB, it cores. 

    # doesn't work
$SIG{INT}  = sub {
     $sig++;
     $control->removeMonitorPID($monitor->{PID});
};

    [download]

    dsb
    This @ISA my( $cool ) %SIG
[reply]
[d/l]
      Well, that shouldn't be too surprising. You're not really supposed to do stuff like that from a signal handler. That's not even a perl specific issue.

      -Paul

[reply]
      I first want to clarify that there are WAY better ways to do this, but if you want to increment a global variable to detect a signal being caught this will do the trick. As Paul noted earlier you shouldn't be trying to do anything complicated in the signal handler itself. 
      our $sig;
$sig = 1;

$SIG{INT}  = sub {
     $sig++;
};

my $oldsig;
while (1) {
  if ($sig != $oldsig) {
   $control->removeMonitorPID($monitor->{PID});  #Execute the code ori
+ginally in the signal handler.
   $oldsig = $sig;
  }
  .... Run main loop, but make sure to poll the status of the global v
+ariable ....
}

      [download]
[reply]
[d/l]
        Can you mention some of the WAY better ways or point at some references for them?
[reply]
        I actually did take the "complicated" code out of the sig handler and put it into a couple of conditional blocks as you demonstrated. I did still get the core dumps. However, I can't remember if I left the handler as simple as incrementing the global $sig. I'll give that a go...

        dsb
        This @ISA my( $cool ) %SIG
[reply]

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