sleep in fork child causes deadlock

[Tran, Wayne]

Title: sleep in fork child causes deadlock

Hi There:

I wonder if there are any solution to this.  I have 5 clients forked and the 6 suppose to release the lock.
Don't know why if I have a sleep in the client script, all the client are struck in the semaphore-> wait () deadlock.
or process does not know how to wake up.  I am run ActiveState Perl.

I need to sleep x seconds each time.  If I don't sleep it is fine.  Any solutions ?

Thanks in advance.

Wayne.

for $j (1 .. 6)
{
   if( $parent  == $$)
   {
     if( defined (my $pid = fork() ) ){
       if( ! $pid){
         ##if $pid ==0 then this is the child process
         &handleChild($j); 
         exit;
       }
     }
     else
     {
        warn "something went wrong with fork $!";
     }
   }
}

sub handleChild {
        my $cid = shift;
        my $semaphore;

    # Each child process run this code.

    my $i = 0;
 
    if ($cid == (6))
        {
           if ($UseMaxLog == 1)
           {
             $semaphore = getSemaphore( 0, $MaxClients , "mySem");
             $semaphore->release(1);
                 print "\nClient $cid release lock\n";
           }
        }
        else
        {
                do {  # do forever or NumQueries times.

                        $i++;
                        process_query($i,$cid);

                } while (($doforever == 1) || ($i < $NumQueries)); 
        }
}

sub process_query
{
        my ($query_index,$client_index) = @_;  

        foreach $query (keys %queries) {
                $param="";
                foreach $option ( keys %{ $queries{$query}} ){
                        `sleep 5`;  # all client waiting below dead because of sleep
                        $semaphore = getSemaphore( 0, $MaxClients , "mySem");
                               
                                print "Client $client_index waiting for lock\n";
                                $semaphore->wait(); # all clients waiting here !!!!

                                print "Client $client_index releasing lock\n";
                                $semaphore->release(1);
                }              
        }      
}

Thanks,
Wayne Tran
Software Developer
McKesson Medical Imaging
Phone: (604) 279-5422 ext 442
E-mail: [EMAIL PROTECTED]