--- loncom/lonmaxima	2006/03/04 06:44:11	1.8
+++ loncom/lonmaxima	2006/03/04 15:47:26	1.11
@@ -3,7 +3,7 @@
 # The LearningOnline Network with CAPA
 # Connect to MAXIMA CAS
 #
-# $Id: lonmaxima,v 1.8 2006/03/04 06:44:11 albertel Exp $
+# $Id: lonmaxima,v 1.11 2006/03/04 15:47:26 www Exp $
 #
 # Copyright Michigan State University Board of Trustees
 #
@@ -52,8 +52,9 @@ my $pidfile;                           #
 my $port;                              # path to UNIX socket file
 my %perlvar;                           # configuration file info
 my $lastlog;                           # last string that was logged
+my $maximapid;                         # PID of Maxima process
 use vars qw($PREFORK $MAX_CLIENTS_PER_CHILD %children $children $status
-	    $pidfile $port %perlvar $lastlog);
+	    $pidfile $port %perlvar $lastlog $maximapid);
  
 sub maximareply {
     my ($cmd) = @_;
@@ -64,7 +65,7 @@ sub maximareply {
     unless ($cmd=~/\;\n$/) { $cmd.=";\n"; }
 
     my ($cmd_in, $cmd_out, $cmd_err);
-    my $maximapid = open3($cmd_in, $cmd_out, $cmd_err, 'maxima');
+    $maximapid = open3($cmd_in, $cmd_out, $cmd_err, 'maxima');
     $children{$maximapid} = 1;
     
     print $cmd_in $cmd;
@@ -72,9 +73,8 @@ sub maximareply {
 
     &status("Command sent");
 
-    $SIG{ALRM} = sub { kill 9 => $maximapid; }; 
+    $SIG{ALRM} = sub { kill(9 => $maximapid); }; 
     alarm(5);
-    no strict 'refs';
 
     my $selector = IO::Select->new();
 
@@ -82,7 +82,9 @@ sub maximareply {
     
     while (my @ready = $selector->can_read()) {
 	foreach my $fh (@ready) {
-	    if (fileno($fh) == fileno($cmd_err)) {
+	    if (ref($fh) 
+		&& ref($cmd_err)
+		&& fileno($fh) == fileno($cmd_err)) {
 		$error.=<$cmd_err>;
 	    } else {
 		my $line = scalar(<$cmd_out>);
@@ -96,9 +98,9 @@ sub maximareply {
     }
     alarm(0);
     $SIG{ALRM} = 'DEFAULT';
-    close($cmd_out);
-    close($cmd_err);
-    use strict 'refs';
+    if (ref($cmd_out)) { close($cmd_out); }
+    if (ref($cmd_err)) { close($cmd_err); }
+
     &status("Command processed");
     return ($reply,$error,$exitstatus);
 }
@@ -247,15 +249,15 @@ close(PIDSAVE);
 &status('Starting');
      
 
+# Install signal handlers.
+$SIG{CHLD} = \&REAPER;
+$SIG{INT}  = $SIG{TERM} = \&HUNTSMAN;
+ 
 # Fork off our children.
 for (1 .. $PREFORK) {
     &make_new_child($server);
 }
  
-# Install signal handlers.
-$SIG{CHLD} = \&REAPER;
-$SIG{INT}  = $SIG{TERM} = \&HUNTSMAN;
- 
 # And maintain the population.
 while (1) {
     &status('Parent process, sleeping');