APPROVE COMMIT 21.5 I already patched scrollbar-x.c to fix code where a pointer was dereferenced twice, then checked to see if it is NULL. This patch fixes the same problem in the same place in scrollbar-gtk.c and scrollbar-msw.c. src/ChangeLog addition: 2006-06-29 Jerry James <james(a)xemacs.org&gt; * scrollbar-gtk.c (gtk_free_scrollbar_instance): Compare instance->scrollbar_data against NULL before using it. * scrollbar-msw.c (mswindows_free_scrollbar_instance): Compare sb->scrollbar_data against NULL before using it. xemacs-21.5 source patch: Diff command: cvs -q diff -uN Files affected: src/scrollbar-msw.c src/scrollbar-gtk.c Index: src/scrollbar-gtk.c =================================================================== RCS file: /pack/xemacscvs/XEmacs/xemacs/src/scrollbar-gtk.c,v retrieving revision 1.19 diff -d -u -r1.19 scrollbar-gtk.c --- src/scrollbar-gtk.c 2005/10/25 08:32:48 1.19 +++ src/scrollbar-gtk.c 2006/06/29 16:48:59 ＠＠ -56,14 +56,16 ＠＠ static void gtk_free_scrollbar_instance (struct scrollbar_instance *instance) { - if (SCROLLBAR_GTK_WIDGET (instance)) + if (instance->scrollbar_data) { - gtk_widget_hide_all (SCROLLBAR_GTK_WIDGET (instance)); - gtk_widget_destroy (SCROLLBAR_GTK_WIDGET (instance)); - } + if (SCROLLBAR_GTK_WIDGET (instance)) + { + gtk_widget_hide_all (SCROLLBAR_GTK_WIDGET (instance)); + gtk_widget_destroy (SCROLLBAR_GTK_WIDGET (instance)); + } - if (instance->scrollbar_data) - xfree (instance->scrollbar_data, void *); + xfree (instance->scrollbar_data, void *); + } } /* A device method. */ Index: src/scrollbar-msw.c =================================================================== RCS file: /pack/xemacscvs/XEmacs/xemacs/src/scrollbar-msw.c,v retrieving revision 1.31 diff -d -u -r1.31 scrollbar-msw.c --- src/scrollbar-msw.c 2005/10/25 08:32:49 1.31 +++ src/scrollbar-msw.c 2006/06/29 16:48:59 ＠＠ -90,17 +90,19 ＠＠ static void mswindows_free_scrollbar_instance (struct scrollbar_instance *sb) { - void *opaque = - (void *) qxeGetWindowLong (SCROLLBAR_MSW_HANDLE (sb), GWL_USERDATA); - Lisp_Object ptr; - - ptr = VOID_TO_LISP (opaque); - assert (OPAQUE_PTRP (ptr)); - ptr = Fremhash (ptr, Vmswindows_scrollbar_instance_table); - assert (!NILP (ptr)); - DestroyWindow (SCROLLBAR_MSW_HANDLE (sb)); if (sb->scrollbar_data) - xfree (sb->scrollbar_data, void *); + { + void *opaque = + (void *) qxeGetWindowLong (SCROLLBAR_MSW_HANDLE (sb), GWL_USERDATA); + Lisp_Object ptr; + + ptr = VOID_TO_LISP (opaque); + assert (OPAQUE_PTRP (ptr)); + ptr = Fremhash (ptr, Vmswindows_scrollbar_instance_table); + assert (!NILP (ptr)); + DestroyWindow (SCROLLBAR_MSW_HANDLE (sb)); + xfree (sb->scrollbar_data, void *); + } } static void -- Jerry James, Assistant Professor james(a)xemacs.org Computer Science Department http://www.cs.usu.edu/~jerry/ Utah State University