calling exit() (I know, it is not recommended)

Then don't do that.

If you want to trap an abnormal exit from a thread, use eval & die just like you normally would:

use strict;
use threads;
use threads::shared;

my $inthread : shared;


# the exit handler (END block) is never called when a thread performs 
+an exit()
# using a lower main sleep time will result in a normal exit of the ma
+in thread.
my $threadsleeptime : shared = 2;
my $mainsleeptime = 5;

my $thread = async {

    eval {
        $inthread = 1;

        sleep($threadsleeptime);
        print "Sleep in thread finished\n";

        die('abnormal exit');
    };
    if( $@ =~ /^abnormal exit/ ) {
        ## do cleanup
        print "doing cleanup in thread\n";
    }
}

sleep($mainsleeptime);
print "Sleep in main finished\n";
$thread->join if ($thread);

print "End of main program\n";

__END__
C:\test>junk29
Sleep in main finished
Sleep in thread finished
doing cleanup in thread
End of main program
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