--- loncom/lonmaxima	2006/03/04 02:33:54	1.7
+++ loncom/lonmaxima	2006/03/04 06:56:10	1.10
@@ -3,7 +3,7 @@
 # The LearningOnline Network with CAPA
 # Connect to MAXIMA CAS
 #
-# $Id: lonmaxima,v 1.7 2006/03/04 02:33:54 www Exp $
+# $Id: lonmaxima,v 1.10 2006/03/04 06:56:10 albertel Exp $
 #
 # Copyright Michigan State University Board of Trustees
 #
@@ -52,10 +52,8 @@ 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
-my $selector;                          # open3's selector
 use vars qw($PREFORK $MAX_CLIENTS_PER_CHILD %children $children $status
-	    $pidfile $port %perlvar $lastlog $maximapid $selector);
+	    $pidfile $port %perlvar $lastlog);
  
 sub maximareply {
     my ($cmd) = @_;
@@ -66,7 +64,7 @@ sub maximareply {
     unless ($cmd=~/\;\n$/) { $cmd.=";\n"; }
 
     my ($cmd_in, $cmd_out, $cmd_err);
-    $maximapid = open3($cmd_in, $cmd_out, $cmd_err, 'maxima');
+    my $maximapid = open3($cmd_in, $cmd_out, $cmd_err, 'maxima');
     $children{$maximapid} = 1;
     
     print $cmd_in $cmd;
@@ -76,15 +74,16 @@ sub maximareply {
 
     $SIG{ALRM} = sub { kill 9 => $maximapid; }; 
     alarm(5);
-    no strict 'refs';
 
-    $selector = IO::Select->new();
+    my $selector = IO::Select->new();
 
     $selector->add($cmd_err, $cmd_out);
     
     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>);
@@ -98,9 +97,9 @@ 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);
 }
@@ -249,15 +248,15 @@ 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');