--- a/src/ChangeLog	Fri Jan 28 09:14:34 2000 +0000
+++ b/src/ChangeLog	Fri Jan 28 10:13:26 2000 +0000
@@ -1,5 +1,16 @@
 2000-01-28  John W. Eaton  <jwe@bevo.che.wisc.edu>
 
+	* pt-except.cc (do_catch_code): Unwind-protect buffer_error_messages.
+	Be sure to run all unwind-protects before returning.
+	(tree_try_catch_command::eval): Add do_catch_code cleanup function
+	to unwind-protect stack before resetting buffer_error_messages.
+	Use unwind-protect to save and restore buffer_error_messages.
+	If there is no catch code, discard the cleanup function and run
+	the unwind-protect for buffer_error_messages.
+
+	* error.cc (bind_global_error_variable): Avoid dereferencing
+	error_message_buffer if it is NULL.
+
 	* parse.y (evaluating_function_body): New global flag.
 	* ov-usr-fcn.cc (octave_user_function::do_index_op):
 	Protect and set it here.

--- a/src/error.cc	Fri Jan 28 09:14:34 2000 +0000
+++ b/src/error.cc	Fri Jan 28 10:13:26 2000 +0000
@@ -375,17 +375,22 @@
 void
 bind_global_error_variable (void)
 {
-  *error_message_buffer << ends;
+  if (error_message_buffer)
+    {
+      *error_message_buffer << ends;
 
-  char *error_text = error_message_buffer->str ();
+      char *error_text = error_message_buffer->str ();
 
-  bind_builtin_constant ("__error_text__", error_text, true);
+      bind_builtin_constant ("__error_text__", error_text, true);
 
-  delete [] error_text;
+      delete [] error_text;
+
+      delete error_message_buffer;
 
-  delete error_message_buffer;
-
-  error_message_buffer = 0;
+      error_message_buffer = 0;
+    }
+  else
+    bind_builtin_constant ("__error_text__", "", true);
 }
 
 void

--- a/src/pt-except.cc	Fri Jan 28 09:14:34 2000 +0000
+++ b/src/pt-except.cc	Fri Jan 28 10:13:26 2000 +0000
@@ -53,11 +53,16 @@
 {
   tree_statement_list *list = static_cast<tree_statement_list *> (ptr);
 
+  unwind_protect::begin_frame ("do_catch_code");
+
   // Set up for letting the user print any messages from errors that
   // occurred in the body of the try_catch statement.
 
+  unwind_protect_bool (buffer_error_messages);
   buffer_error_messages = false;
+
   bind_global_error_variable ();
+
   unwind_protect::add (clear_global_error_variable, 0);
 
   // Similarly, if we have seen a return or break statement, allow all
@@ -92,7 +97,7 @@
   else
     unwind_protect::run ();
 
-  unwind_protect::run ();
+  unwind_protect::run_frame ("do_catch_code");
 }
 
 void
@@ -100,16 +105,14 @@
 {
   unwind_protect::begin_frame ("tree_try_catch::eval");
 
-  unwind_protect::add (do_catch_code, catch_code);
-
-  bool old_buffer_error_messages = buffer_error_messages;
-
   if (catch_code)
     {
       unwind_protect_bool (buffer_error_messages);
       buffer_error_messages = true;
     }
 
+  unwind_protect::add (do_catch_code, catch_code);
+
   if (try_code)
     try_code->eval ();
 
@@ -121,8 +124,12 @@
   else
     {
       error_state = 0;
-      buffer_error_messages = old_buffer_error_messages;
-      unwind_protect::discard_frame ("tree_try_catch::eval");
+
+      // For clearing the do_catch_code cleanup function.
+      unwind_protect::discard ();
+
+      // For restoring buffer_error_messages.
+      unwind_protect::run ();
     }
 }