use strict;
use warnings;

sub foo {
    my @list if 0;
    print "list: (@list)\n";
    push @list, @_;
    \@list;
}

my $ref1 = foo(1..3);
push @$ref1, 'a', 'b';
my $ref2 = foo(4..6);
print "first ref: (@$ref1)\n";
print "last list: (@$ref2)\n";
__END__
list: ()
list: ()
first ref: (1 2 3 a b)
final list: (4 5 6)

##</code><code>##

use strict;
use warnings;

sub foo {
    my @list if 0;
    print "list: (@list)\n";
    push @list, @_;
    \@list;
}

my $ref1 = foo(1..3);
push @$ref1, 'a', 'b';
my $ref2 = foo(4..6);
print "first ref: (@$ref1)\n";
print "final list: (@$ref2)\n";
__END__
list: ()
list: (1 2 3 a b)
first ref: (1 2 3 a b 4 5 6)
last list: (1 2 3 a b 4 5 6)

##</code><code>##

use strict;
use warnings;

{
    my @list;
    sub foo {
        print "list: (@list)\n";
        push @list, @_;
        \@list;
    }
}

my $ref1 = foo(1..3);
push @$ref1, 'a', 'b';
my $ref2 = foo(4..6);
print "first ref: (@$ref1)\n";
print "final list: (@$ref2)\n";