--- loncom/lonmaxima	2006/03/04 06:44:11	1.8
+++ loncom/lonmaxima	2006/03/04 06:51:02	1.9
@@ -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 1.9 2006/03/04 06:51:02 albertel Exp $
 #
 # Copyright Michigan State University Board of Trustees
 #
@@ -74,7 +74,6 @@ sub maximareply {
 
     $SIG{ALRM} = sub { kill 9 => $maximapid; }; 
     alarm(5);
-    no strict 'refs';
 
     my $selector = IO::Select->new();
 
@@ -82,7 +81,9 @@ 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 +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);
 }