use strict;
use warnings;
my $hashref = { "key" => "value" };
local *foo = $hashref;
printf("keys=%d\n", scalar(keys(%foo)));

##</code><code>##

use strict;
use warnings;
my $hashref = { "key" => "value" };
my %foo;
local *foo = $hashref;
printf("keys=%d\n", scalar(keys(%foo)));
# prints: keys=0

##</code><code>##

use strict;
use warnings;
my $hashref = { "key" => "value" };
our %foo;
local *foo = $hashref;
printf("keys=%d\n", scalar(keys(%foo)));
# prints: keys=1