--- loncom/homework/default_homework.lcpm	2004/03/12 16:55:35	1.70
+++ loncom/homework/default_homework.lcpm	2004/03/13 00:36:11	1.72
@@ -1,7 +1,7 @@
 # The LearningOnline Network with CAPA 
 # used by lonxml::xmlparse() as input variable $safeinit to Apache::run::run()
 #
-# $Id: default_homework.lcpm,v 1.70 2004/03/12 16:55:35 albertel Exp $
+# $Id: default_homework.lcpm,v 1.72 2004/03/13 00:36:11 albertel Exp $
 #
 # Copyright Michigan State University Board of Trustees
 #
@@ -55,6 +55,9 @@ sub caparesponse_check {
   #type's definitons come from capaParser.h
   my $message='';
   #remove leading and trailing whitespace
+  if (!defined($response)) {
+      $response='';
+  }
   if ($response=~ /^\s|\s$/) {
     $response=~ s:^\s+|\s+$::g;
     $message .="Removed ws now :$response:\n";
@@ -109,11 +112,13 @@ sub caparesponse_check {
     }
     if (!defined($sig_ubound)) { $sig_ubound=$sig_lbound; }
   }
+  my $reterror="";
   my $result = &caparesponse_capa_check_answer($response,$answer,$type,
 					       $tol_type,$tol,
 					       $sig_lbound,$sig_ubound,
 					       $ans_fmt,$unit,$calc,$id_list,
-					       $points,$external::randomseed);
+					       $points,$external::randomseed,
+					       \$reterror);
 
   if    ($result == '1') { $result='EXACT_ANS'; } 
   elsif ($result == '2') { $result='APPROX_ANS'; }
@@ -129,7 +134,7 @@ sub caparesponse_check {
   elsif ($result =='12') { $result='WANTED_NUMERIC'; }
   else  {$result = "ERROR: Unknown Result:$result:$@:";}
 
-  return "$result:\nError $error:\nAnswer $answer:\nResponse $response:\n type-$type|$tol|$tol_type|$sig:$sig_lbound:$sig_ubound|$unit|\n$message$expr";
+  return ("$result:\nRetError $reterror:\nError $error:\nAnswer $answer:\nResponse $response:\n type-$type|$tol|$tol_type|$sig:$sig_lbound:$sig_ubound|$unit|\n$message$expr",$reterror);
 }
 
 sub get_array_args {
@@ -186,25 +191,29 @@ sub caparesponse_check_list {
   $unit=~s/\s//;
   my $i=0;
   my $awards='';
+  my @msgs;
   for ($i=0; $i<@list;$i++) {
+      my $msg;
     $result.="trying answer :$list[$i]:\n";
     my $thisanswer=$list[$i];
 #    $thisanswer=~ s/\\/\\\\/g;
 #    $thisanswer =~ s/\'/\\\'/g;
     $result.="trying answer :$thisanswer:\n";
     if ($unit eq '') {
-      $aresult=&caparesponse_check($thisanswer,$responselist[$i],
-			     $expr);
+	($aresult,$msg)=&caparesponse_check($thisanswer,$responselist[$i],
+					    $expr);
     } else {
-      $aresult=&caparesponse_check($thisanswer,$responselist[$i]." $unit",
-				   $expr);
+	($aresult,$msg)=&caparesponse_check($thisanswer,
+					    $responselist[$i]." $unit",
+					    $expr);
     }
     my ($temp)=split /:/, $aresult;
     $awards.="$temp,";
     $result.=$aresult;
+    push(@msgs,$msg);
   }
   chop $awards;
-  return "$awards:\n$result";
+  return ("$awards:\n$result",@msgs);
 }
 
 sub tex {