A quick note: Detaching the thread doesn't cause it to exit cleanly, just silently.

#!/usr/bin/perl

use threads;

DESTROY { print "Destroyed\n" }

sub test {
   my $x = bless({});
   sleep() while 1;
}

$SIG{INT} = sub { exit };
my $thread = threads->create('test')->detach();
print("Press Ctrl-C to exit\n");
sleep();
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If the thread exited cleanly, the above prints Destroyed. It doesn't.