--- loncom/lonmaxima	2006/03/09 21:38:26	1.17
+++ loncom/lonmaxima	2006/05/10 02:21:19	1.21
@@ -3,7 +3,7 @@
 # The LearningOnline Network with CAPA
 # Connect to MAXIMA CAS
 #
-# $Id: lonmaxima,v 1.17 2006/03/09 21:38:26 www Exp $
+# $Id: lonmaxima,v 1.21 2006/05/10 02:21:19 www Exp $
 #
 # Copyright Michigan State University Board of Trustees
 #
@@ -31,7 +31,6 @@
 #
 
 use Expect; 
-use IPC::Open3;
 use IO::Select;
 use IO::Socket;
 use IO::File;
@@ -52,6 +51,7 @@ my $pidfile;                           #
 my $port;                              # path to UNIX socket file
 my %perlvar;                           # configuration file info
 my $lastlog;                           # last string that was logged
+
 use vars qw($PREFORK $MAX_CLIENTS_PER_CHILD %children $children $status
 	    $pidfile $port %perlvar $lastlog);
  
@@ -254,7 +254,8 @@ sub make_new_child {
            &status('Accepting connections');
            my $client = $server->accept()     or last;
            print $command "kill(all);reset();\n";
-           &getmaximaoutput($command);
+	   &getmaximaoutput($command);
+           &sync($command);
            while (my $cmd=<$client>) {
               &status('Processing command');
               print $command &unescape($cmd);
@@ -265,7 +266,8 @@ sub make_new_child {
                  $client->close();
                  $command->hard_close();     
                  exit;
-              }
+              }	      
+	      &sync($command);
               &status('Waiting for commands');
            }
         }
@@ -281,6 +283,22 @@ sub make_new_child {
     }
 }
 
+{
+    my $counter;
+    sub sync {
+	my ($command)=@_;
+	$counter++;
+	my $expect=$counter.time;
+	print $command "$expect;\n";
+	while (1) {
+	    my $output=&getmaximaoutput($command);
+	    if (($output=~/\Q$expect\E/) || ($output=~/^Error\:/)) {
+		return;
+	    }
+	}
+    }
+}
+
 sub getmaximaoutput {
     my ($command)=@_;
     my (undef,$error,undef,$output)=$command->expect(20, -re => '\(\%i\d+\)');