my $count = 10;
my @threads = ();
for (1..$count) {
my $tid = threads->new(\&RunChild, $_);
push (@threads, $tid);
}

foreach (@threads) {
my $num = $_->join();
#Here I want to check return code of thread, so that I can report the error.
my $error = ????;
if ($error) {
print "Thread $num returned error $error\n";
} else {
print "Thread $num completed\n";
}
}

sub RunChild {
  my $callNum = $_[0];
  `curl -o $callNum "http://192.168.1.23/abc.flv"`
  return $callNum;
}