You're right. Here it is the quintessence of the problem: 
#!/usr/bin/perl 
use strict;
use warnings;

use threads;


sub create_thread {
    warn "in create_thread() before async()\n";
    my $thr = async { warn "in thread\n"; };
    warn "in create_thread() before join()\n";
    sleep 2;
    $thr->join;
    warn "in create_thread() before return\n";
    return;
}


use Event;
my $timer = Event->timer( cb => \&create_thread, after => 2);

warn "starting event loop\n";
Event::loop;

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When create_thread() returns, the interpreter segfaults.
The problem seems to be caused when join() is called, if you comment the call, the event loop ends and you get the warning: 
Perl exited with active threads:
        0 running and unjoined
        1 finished and unjoined
        0 running and detached

[download]

In reply to Re^2: Event module and threads/fork segfault on Win32 by gurbo
in thread Event module and threads/fork segfault on Win32 by gurbo

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