#!/usr/bin/perl -w
my $NumChilds = 4;

@sourceids=("aex", "athena", "athens","bidapa","bbic","bony","capctha","cooldo","italy","paris","xmltech");
my $sourcecount =  scalar(@sourceids)."\n";



# This section spawns the initial 4 children.

for ($counter = 1; $counter <= $NumChilds; $counter++) {

#foreach my $source (@sourceids){

        $pid = fork();

        if ($pid) # parent
        {
        $child{$pid} = $counter;
        print "forked process $counter.\n";
        }

        else # child
        {
        callScan();
        #should be callScan($source);
        exit $counter;
        }
#  }
}


#  spawns additional children .

$diecount = 0;

while ($counter <= $sourcecount)
{
        $doneproc = wait();
        $doneval = $? >> 8;
        $pid = fork();

        if ($pid) # parent
        {
        $child{$pid} = $counter;
        print "child $doneval ($doneproc) exited, forking process $counter.\n";
        $counter++;
        $diecount++;
        }

        else # child
        {
        callScan();
        #should be callScan($source);
        exit $counter;
        }
}


#  waits for all children to die.

while ($diecount <= $sourcecount)
{
        wait();
        $diecount++;
}

# subroutine.
sub callScan
{
        sleep(2);
        print "callScan with counter = $counter.\n";
}
print "Done.\n";