RE: Setting up signal handlers for an object with access to $self

I like this quite a lot... only problem being that signals are unique to processes, not objects, so if you try to instantiate more than 1 of your objects and attach it to a signal handler, only the last object attached will actually have the signal handler installed.

For example, if I have this code:

package Obj;

sub new {
    my $class = shift;
    my $self = { @_ };
    bless $self, $class;
    $self->set_signal_handlers;
    $self;
}

sub name {
    shift->{'name'};
}

sub set_signal_handlers {
    my $self = shift;
    $SIG{USR1} = sub { $self->handle_USR1() }
}

sub handle_USR1 {
    my $self = shift;
    print "handling USR1 for ", $self->name, "\n";
}


package main;

my $obj1 = new Obj(name => 'obj1');
my $obj2 = new Obj(name => 'obj2');

while (1) { }
[download]

and I run this little script, then give it a USR1 signal, the only object that's ever going to catch that signal will be obj2. See what I'm saying?

All the same, it's a nice little method. :)

Comment on RE: Setting up signal handlers for an object with access to $self Download Code

Replies are listed 'Best First'.
RE: RE: Setting up signal handlers for an object with access to $self by ZZamboni (Curate) on Apr 20, 2000 at 01:39 UTC
Good point (about the signal being per-process). But with a little more work, you could make your signal handler "intelligent" to call the handlers for all the objects that have registered. Using your sample code as a base: package Obj; # Class variable %handlers=(); sub new { my $class = shift; my $self = { @_ }; bless $self, $class; $self->set_signal_handlers; $self; } sub name { shift->{'name'}; } sub set_signal_handlers { my $self = shift; if (!%handlers) { # Class signal handler, only set the first time $SIG{USR1} = \&class_handle_USR1; } # You could index by $self->name, or by any other identifier $handlers{$self} = sub { $self->handle_USR1() }; } sub handle_USR1 { my $self = shift; print "handling USR1 for ", $self->name, "\n"; } sub class_handle_USR1 { foreach (keys %handlers) { &{$handlers{$_}}(); } } package main; my $obj1 = new Obj(name => 'obj1'); my $obj2 = new Obj(name => 'obj2'); while (1) { } [download]	[reply] [d/l]
RE: RE: RE: Setting up signal handlers for an object with access to $self by chromatic (Archbishop) on Apr 20, 2000 at 02:41 UTC
Because I like CODE refs way too much: `sub set_signal_handlers { my $self = shift; if (!%handlers) { # Class signal handler, only set the first time $SIG{USR1} = \&class_handle_USR1; } # You could index by $self->name, or by any other identifier $handlers{$self} = $self->handle_USR1(); } # skip a few sub handle_USR1 { my $self = shift; return sub { print "handling USR1 for ", $self->name, "\n"; } }` [download] That fits all of my definitions of beautiful.	[reply] [d/l]