#!/usr/bin/perl
#
#   To the best of my knowledge, regular expressions aren't thread
#   safe in Perl. That's why the variable $Net::Daemon::RegExpLock
#   exists. If you want to check your Perl, try this script.
#
#   On my Perl, 5.005_03 (i386-linux-thread) this produces a
#   Segfault almost reproducible.
#
#   Please let me know if you are having better luck.
#
#   Jochen Wiedmann, joe@ispsoft.de, 24-Jul-1999
#
#

use Thread ();

my $numChilds;
my $regExpLock = @ARGV ? 1 : 0;

# Repeat generating a random number and check if it contains the
# substring '35'.
sub Loop {
    my $myNum = shift;
    my $num1 = 0;
    my $num2 = 0;
    for (my $i = 1;  $i <= 100000;  $i++) {
  	if (($myNum == 1) and ($i % 10000) == 0) {
  	    my $lck = lock $numChilds;
  	    print $i, "\n";
  	}
	my $r = int(rand(100000));
	++$num1 if index($r, '35') >= 0;
	{
	    my $lck = lock $regExpLock if $regExpLock;
	++$num2 if $r =~ /(.*)35(.*)/;
    }
    }
    return ($num1, $num2);
}

sub Run {
    my $myNum = shift;
    {
	my $lck = lock $numChilds;
	++$numChilds;
	print "Thread $myNum starting\n";
    }
    my($num1, $num2) = eval { Loop($myNum) };
    my $err = $@;
    $num1 ||= 0;
    $num2 ||= 0;
    {
	my $lck = lock $numChilds;
	--$numChilds;
	print "Thread $myNum: Fatal error ($@)\n" if $err;
	print "Thread $myNum, error: index = $num1, regexp = $num2\n"
	    if $num1 != $num2;
	print "Thread $myNum leaving\n";
    }
    return 1;
}


my @childs;
for (my $i = 0;  $i < 10;  ++$i) {
    print "Creating thread $i, TID = ", Thread->self->tid(), "\n";
    my $tid = Thread->new(\&Run, $i);
    die "Failed to create thread: $!" unless $tid;
    push(@childs, $tid);
}

foreach my $tid (@childs) {
    $tid->join();
}