use strict;
use warnings;
use Config;
use threads;
use threads::shared;

print("Config{useithreads} : " . $Config{"useithreads"} . "\n");
print("main starting\n");


my $t1 = threads->create(&__logger);
my $t2 = threads->create(&__logger);

$t1->join();
$t2->join();

print("main done\n");


sub __logger{
    
    #threads->detach(); # raise the error "already detached"
    print("logger init\n");
    sleep(10);
    print("logger closed\n");
}

##</code><code>##

Config{useithreads} : define
main starting
logger init
logger closed
logger init
Thread 1 terminated abnormally: Undefined subroutine &main::1 called at ./test_threads.pl line 19.
logger closed
Thread 2 terminated abnormally: Undefined subroutine &main::1 called at ./test_threads.pl line 20.
main done

##</code><code>##

This is perl 5, version 16, subversion 3 (v5.16.3) built for x86_64-linux-thread-multi