use strict;
use warnings;
use threads;

$|=1;

my $niter  = 10;
# Seems to mostly work with $nforks = 2 but usually fails with $nforks = 3.
my $nforks = 3;
my $Cmd = 'invalid_command';

warn "start niter=$niter nforks=$nforks cmd='$Cmd'\n";

sub do_one_kid {
   my $kid = shift;
   my $tid = threads->self->tid;
   warn "kid $kid (tid:$tid) pid=$$ run cmd='$Cmd'\n";
   for my $i (1..$niter) {
      my $out = `$Cmd 2>&1`;
      my $rc = $? >> 8;
      warn "$i: kid $kid pid=$$ rc=$rc\n";
   }
   warn "kid $kid pid=$$ exit\n";
   return 42;
}

my @kids = ();
for my $n (1..$nforks)
{
   warn "$n: forking\n";
   my $t = threads->new(\&do_one_kid, $n);
   warn "I am the parent\n";
   push(@kids, $t);
}

my $main = async {
    for my $t (@kids) {
        my $tid = $t->tid;
       warn "parent waiting for $tid\n";
       my $rc = $t->join();
       warn "parent $$: thread $tid exited rc=$rc\n";
    }
};


sleep 10;
warn "'main' thread still running (hung); aborting" if $main->is_running();
warn "end main\n";