clean up memory allocated for singletons before exit * singleton-cleanup.h, singleton-cleanup.cc: New files. * liboctave/Makefile.am (INCS, LIBOCTAVE_CXX_SOURCES): Add them to the lists. * toplev.cc (clean_up_and_exit): Call singleton_cleanup_list::cleanup. * debug.h, debug.cc (bp_table::instance_ok): Move definition to debug.cc. * coment-list.h (octave_comment_buffer::~octave_comment_buffer): Define destructor for class. * ov-typeinfo.h (octave_value_typeinfo::~octave_value_typeinfo): Likewise. * cmd-edit.h (command_editor::cleanup_instance): New function. * cmd-hist.h (command_history::cleanup_instance): New function. * file-ops.h (file_ops::cleanup_instance): New function. * mach-info.h (oct_mach_info::cleanup_instance): New function. * oct-env.h (octave_env::cleanup_instance): New function. * oct-fftw.h (octave_fftw_planner::cleanup_instance): New function. * oct-rand.h (octave_rand::cleanup_instance): New function. * oct-spparms.h (octave_sparse_params::cleanup_instance): New function. * pathsearch.h (static_members::cleanup_instance): New function. * comment-list.h (octave_comment_buffer::cleanup_instance): New function. * debug.h (bp_table::cleanup_instance): New function. * display.h (display_info::cleanup_instance): New function. * dynamic-ld.cc (octave_shlib_list::cleanup_instance, octave_mex_file_list::cleanup_instance): New functions. * dynamic-ld.h (octave_dynamic_loader::cleanup_instance): New function. * load-path.h (load_path::cleanup_instance): New function. * oct-stream.h (octave_stream_list::cleanup_instance): New function. * ov-typeinfo.h (octave_value_typeinfo::cleanup_instance): New function. * pager.h, pager.cc (octave_pager_stream::instance_ok, octave_pager_stream::cleanup_instance): New functions. (octave_diary_stream::instance_ok, octave_diary_stream::cleanup_instance): New functions. * sighandlers.h (octave_child_list::cleanup_instance): New function. * toplev.h (octave_call_stack * pager.cc (octave_pager_stream::stream, octave_diary_stream::stream): Use instance_ok to create instance. * toplev.h (octave_call_stack::cleanup_instance): New function. * cmd-edit.cc (command_editor::instance_ok): Register cleanup function. * cmd-hist.cc (command_history::instance_ok): Likewise. * file-ops.cc (file_ops::instance_ok): Likewise. * mach-info.cc (oct_mach_info::instance_ok): Likewise. * oct-env.cc (octave_env::instance_ok): Likewise. * oct-fftw.cc (octave_fftw_planner::instance_ok): Likewise. * oct-rand.cc (octave_rand::instance_ok): Likewise. * oct-spparms.cc (octave_sparse_params::instance_ok): Likewise. * pathsearch.cc (dir_path::static_members::instance_ok): Likewise. * comment-list.cc (comment_list::instance_ok): Likewise. * debug.cc (bp_table::instance_ok): Likewise. * display.cc (display_info::instance_ok): Likewise. * dynamic-ld.cc (octave_shlib_list::instance_ok, octave_mex_file_list::instance_ok, octave_dynamic_loader): Likewise. * load-path.cc (load_path::instance_ok): Likewise. * oct-stream.cc (octave_stream_list::instance_ok): Likewise. * ov-typeinfo.cc (octave_value_typeinfo::instance_ok): Likewise. * sighandlers.cc (octave_child_list::instance_ok): Likewise. * symtab.h, symtab.cc (symbol_table::scope_id::create_instance): New function. * symtab.h (symbol_table::scope_id::instance_ok): Call create_instance. * toplev.h, toplev.cc (octave_call_stack::create_instance): New function. * toplev.cc (octave_call_stack::instance_ok): Call create_instance. * pager.h, pager.cc (octave_pager_stream::set_diary_skip, octave_pager_stream::flush_current_contents_to_diary): Now static. octave_pager_stream::do_set_diary_skip, octave_pager_stream::do_flush_current_contents_to_diary): New functions. (octave_pager_stream::stream): Return std::ostream&, not octave_pager_stream&. If instance creation fails, return std::cout. (octave_diary_stream::stream): Return std::ostream&, not octave_diary_stream&. If instance creation fails, return std::cout. (octave_pager_stream::do_reset, octave_diary_stream::do_reset): Use instance_ok to create instance.

--- a/src/pager.cc
+++ b/src/pager.cc
@@ -30,16 +30,16 @@
 
 #include "cmd-edit.h"
 #include "oct-env.h"
+#include "singleton-cleanup.h"
 
-#include "procstream.h"
-
-#include <defaults.h>
+#include "defaults.h"
 #include "defun.h"
 #include "error.h"
 #include "gripes.h"
 #include "input.h"
 #include "oct-obj.h"
 #include "pager.h"
+#include "procstream.h"
 #include "sighandlers.h"
 #include "unwind-prot.h"
 #include "utils.h"
@@ -311,27 +311,24 @@
   delete pb;
 }
 
-octave_pager_stream&
+std::ostream&
 octave_pager_stream::stream (void)
 {
-  if (! instance)
-    instance = new octave_pager_stream ();
-
-  return *instance;
+  return instance_ok () ? *instance : std::cout;
 }
 
 void
 octave_pager_stream::flush_current_contents_to_diary (void)
 {
-  if (pb)
-    pb->flush_current_contents_to_diary ();
+  if (instance_ok ())
+    instance->flush_current_contents_to_diary ();
 }
 
 void
 octave_pager_stream::set_diary_skip (void)
 {
-  if (pb)
-    pb->set_diary_skip ();
+  if (instance_ok ())
+    instance->do_set_diary_skip ();
 }
 
 // Reinitialize the pager buffer to avoid hanging on to large internal
@@ -342,10 +339,22 @@
 void
 octave_pager_stream::reset (void)
 {
-  if (! instance)
-    instance = new octave_pager_stream ();
+  if (instance_ok ())
+    instance->do_reset ();
+}
 
-  instance->do_reset ();
+void
+octave_pager_stream::do_flush_current_contents_to_diary (void)
+{
+  if (pb)
+    pb->flush_current_contents_to_diary ();
+}
+
+void
+octave_pager_stream::do_set_diary_skip (void)
+{
+  if (pb)
+    pb->set_diary_skip ();
 }
 
 void
@@ -357,6 +366,29 @@
   setf (unitbuf);
 }
 
+bool
+octave_pager_stream::instance_ok (void)
+{
+  bool retval = true;
+
+  if (! instance)
+    {
+      instance = new octave_pager_stream ();
+
+      if (instance)
+        singleton_cleanup_list::add (cleanup_instance);
+    }
+
+  if (! instance)
+    {
+      ::error ("unable to create pager_stream object!");
+
+      retval = false;
+    }
+
+  return retval;
+}
+
 octave_diary_stream *octave_diary_stream::instance = 0;
 
 octave_diary_stream::octave_diary_stream (void) : std::ostream (0), db (0)
@@ -372,13 +404,10 @@
   delete db;
 }
 
-octave_diary_stream&
+std::ostream&
 octave_diary_stream::stream (void)
 {
-  if (! instance)
-    instance = new octave_diary_stream ();
-
-  return *instance;
+  return instance_ok () ? *instance : std::cout;
 }
 
 // Reinitialize the diary buffer to avoid hanging on to large internal
@@ -389,10 +418,8 @@
 void
 octave_diary_stream::reset (void)
 {
-  if (! instance)
-    instance = new octave_diary_stream ();
-
-  instance->do_reset ();
+  if (instance_ok ())
+    instance->do_reset ();
 }
 
 void
@@ -404,6 +431,29 @@
   setf (unitbuf);
 }
 
+bool
+octave_diary_stream::instance_ok (void)
+{
+  bool retval = true;
+
+  if (! instance)
+    {
+      instance = new octave_diary_stream ();
+
+      if (instance)
+        singleton_cleanup_list::add (cleanup_instance);
+    }
+
+  if (! instance)
+    {
+      ::error ("unable to create diary_stream object!");
+
+      retval = false;
+    }
+
+  return retval;
+}
+
 void
 flush_octave_stdout (void)
 {
@@ -437,7 +487,7 @@
   //
   // will do the right thing.
 
-  octave_stdout.flush_current_contents_to_diary ();
+  octave_pager_stream::flush_current_contents_to_diary ();
 
   if (external_diary_file.is_open ())
     {
@@ -454,7 +504,7 @@
   // If there is pending output in the pager buf, it should not go
   // into the diary file.
 
-  octave_stdout.set_diary_skip ();
+  octave_pager_stream::set_diary_skip ();
 
   external_diary_file.open (diary_file.c_str (), std::ios::app);