Fixed double free in Finalize subprograms

90 files changed, 91 insertions, 0 deletions

diff --git a/src/fltk-devices-surfaces-copy.adb b/src/fltk-devices-surfaces-copy.adb
index a904c42..8c90ffb 100644
--- a/src/fltk-devices-surfaces-copy.adb
+++ b/src/fltk-devices-surfaces-copy.adb
@@ -70,6 +70,7 @@ package body FLTK.Devices.Surfaces.Copy is
     begin
         if This.Void_Ptr /= Null_Pointer and This.Needs_Dealloc then
             free_fl_copy_surface (This.Void_Ptr);
+            This.Void_Ptr := Null_Pointer;
         end if;
     end Finalize;
 
diff --git a/src/fltk-devices-surfaces-image.adb b/src/fltk-devices-surfaces-image.adb
index 4eadc9a..56566ea 100644
--- a/src/fltk-devices-surfaces-image.adb
+++ b/src/fltk-devices-surfaces-image.adb
@@ -70,6 +70,7 @@ package body FLTK.Devices.Surfaces.Image is
     begin
         if This.Void_Ptr /= Null_Pointer and This.Needs_Dealloc then
             free_fl_image_surface (This.Void_Ptr);
+            This.Void_Ptr := Null_Pointer;
         end if;
     end Finalize;
 
diff --git a/src/fltk-devices-surfaces-paged-printers.adb b/src/fltk-devices-surfaces-paged-printers.adb
index 944efa6..601f425 100644
--- a/src/fltk-devices-surfaces-paged-printers.adb
+++ b/src/fltk-devices-surfaces-paged-printers.adb
@@ -142,6 +142,7 @@ package body FLTK.Devices.Surfaces.Paged.Printers is
     begin
         if This.Void_Ptr /= Null_Pointer and This.Needs_Dealloc then
             free_fl_printer (This.Void_Ptr);
+            This.Void_Ptr := Null_Pointer;
         end if;
     end Finalize;
 
diff --git a/src/fltk-devices-surfaces-paged.adb b/src/fltk-devices-surfaces-paged.adb
index 990d1ea..5de3fec 100644
--- a/src/fltk-devices-surfaces-paged.adb
+++ b/src/fltk-devices-surfaces-paged.adb
@@ -140,6 +140,7 @@ package body FLTK.Devices.Surfaces.Paged is
     begin
         if This.Void_Ptr /= Null_Pointer and This.Needs_Dealloc then
             free_fl_paged_device (This.Void_Ptr);
+            This.Void_Ptr := Null_Pointer;
         end if;
     end Finalize;
 
diff --git a/src/fltk-devices-surfaces.adb b/src/fltk-devices-surfaces.adb
index cee6910..58a5fa0 100644
--- a/src/fltk-devices-surfaces.adb
+++ b/src/fltk-devices-surfaces.adb
@@ -39,6 +39,7 @@ package body FLTK.Devices.Surfaces is
     begin
         if This.Void_Ptr /= Null_Pointer and This.Needs_Dealloc then
             free_fl_surface (This.Void_Ptr);
+            This.Void_Ptr := Null_Pointer;
         end if;
     end Finalize;
 
diff --git a/src/fltk-environment.adb b/src/fltk-environment.adb
index 4cafb19..1632717 100644
--- a/src/fltk-environment.adb
+++ b/src/fltk-environment.adb
@@ -400,6 +400,7 @@ package body FLTK.Environment is
     begin
         if This.Void_Ptr /= Null_Pointer and This.Needs_Dealloc then
             free_fl_pref_database (This.Void_Ptr);
+            This.Void_Ptr := Null_Pointer;
         end if;
     end Finalize;
 
@@ -409,6 +410,7 @@ package body FLTK.Environment is
     begin
         if This.Void_Ptr /= Null_Pointer and This.Needs_Dealloc then
             free_fl_pref_group (This.Void_Ptr);
+            This.Void_Ptr := Null_Pointer;
             if This.Root_Ptr /= Null_Pointer then
                 free_fl_pref_database (This.Root_Ptr);
             end if;
diff --git a/src/fltk-help_dialogs.adb b/src/fltk-help_dialogs.adb
index fa84f01..323fcab 100644
--- a/src/fltk-help_dialogs.adb
+++ b/src/fltk-help_dialogs.adb
@@ -151,6 +151,7 @@ package body FLTK.Help_Dialogs is
     begin
         if This.Void_Ptr /= Null_Pointer and This.Needs_Dealloc then
             free_fl_help_dialog (This.Void_Ptr);
+            This.Void_Ptr := Null_Pointer;
         end if;
     end Finalize;
 
diff --git a/src/fltk-images-bitmaps-xbm.adb b/src/fltk-images-bitmaps-xbm.adb
index 1d063c4..eb8c093 100644
--- a/src/fltk-images-bitmaps-xbm.adb
+++ b/src/fltk-images-bitmaps-xbm.adb
@@ -31,6 +31,7 @@ package body FLTK.Images.Bitmaps.XBM is
     begin
         if This.Void_Ptr /= Null_Pointer and This.Needs_Dealloc then
             free_fl_xbm_image (This.Void_Ptr);
+            This.Void_Ptr := Null_Pointer;
         end if;
     end Finalize;
 
diff --git a/src/fltk-images-bitmaps.adb b/src/fltk-images-bitmaps.adb
index 68c7253..90150c9 100644
--- a/src/fltk-images-bitmaps.adb
+++ b/src/fltk-images-bitmaps.adb
@@ -68,6 +68,7 @@ package body FLTK.Images.Bitmaps is
     begin
         if This.Void_Ptr /= Null_Pointer and This.Needs_Dealloc then
             free_fl_bitmap (This.Void_Ptr);
+            This.Void_Ptr := Null_Pointer;
         end if;
     end Finalize;
 
diff --git a/src/fltk-images-pixmaps-gif.adb b/src/fltk-images-pixmaps-gif.adb
index f882749..535debf 100644
--- a/src/fltk-images-pixmaps-gif.adb
+++ b/src/fltk-images-pixmaps-gif.adb
@@ -31,6 +31,7 @@ package body FLTK.Images.Pixmaps.GIF is
     begin
         if This.Void_Ptr /= Null_Pointer and This.Needs_Dealloc then
             free_fl_gif_image (This.Void_Ptr);
+            This.Void_Ptr := Null_Pointer;
         end if;
     end Finalize;
 
diff --git a/src/fltk-images-pixmaps-xpm.adb b/src/fltk-images-pixmaps-xpm.adb
index 3b170ec..006c8b4 100644
--- a/src/fltk-images-pixmaps-xpm.adb
+++ b/src/fltk-images-pixmaps-xpm.adb
@@ -31,6 +31,7 @@ package body FLTK.Images.Pixmaps.XPM is
     begin
         if This.Void_Ptr /= Null_Pointer and This.Needs_Dealloc then
             free_fl_xpm_image (This.Void_Ptr);
+            This.Void_Ptr := Null_Pointer;
         end if;
     end Finalize;
 
diff --git a/src/fltk-images-pixmaps.adb b/src/fltk-images-pixmaps.adb
index d76132f..2e66d2f 100644
--- a/src/fltk-images-pixmaps.adb
+++ b/src/fltk-images-pixmaps.adb
@@ -76,6 +76,7 @@ package body FLTK.Images.Pixmaps is
     begin
         if This.Void_Ptr /= Null_Pointer and This.Needs_Dealloc then
             free_fl_pixmap (This.Void_Ptr);
+            This.Void_Ptr := Null_Pointer;
         end if;
     end Finalize;
 
diff --git a/src/fltk-images-rgb-bmp.adb b/src/fltk-images-rgb-bmp.adb
index 73d3293..01669eb 100644
--- a/src/fltk-images-rgb-bmp.adb
+++ b/src/fltk-images-rgb-bmp.adb
@@ -31,6 +31,7 @@ package body FLTK.Images.RGB.BMP is
     begin
         if This.Void_Ptr /= Null_Pointer and This.Needs_Dealloc then
             free_fl_bmp_image (This.Void_Ptr);
+            This.Void_Ptr := Null_Pointer;
         end if;
     end Finalize;
 
diff --git a/src/fltk-images-rgb-jpeg.adb b/src/fltk-images-rgb-jpeg.adb
index f5f5419..17debb5 100644
--- a/src/fltk-images-rgb-jpeg.adb
+++ b/src/fltk-images-rgb-jpeg.adb
@@ -38,6 +38,7 @@ package body FLTK.Images.RGB.JPEG is
     begin
         if This.Void_Ptr /= Null_Pointer and This.Needs_Dealloc then
             free_fl_jpeg_image (This.Void_Ptr);
+            This.Void_Ptr := Null_Pointer;
         end if;
     end Finalize;
 
diff --git a/src/fltk-images-rgb-png.adb b/src/fltk-images-rgb-png.adb
index a60a3e0..67befe3 100644
--- a/src/fltk-images-rgb-png.adb
+++ b/src/fltk-images-rgb-png.adb
@@ -39,6 +39,7 @@ package body FLTK.Images.RGB.PNG is
     begin
         if This.Void_Ptr /= Null_Pointer and This.Needs_Dealloc then
             free_fl_png_image (This.Void_Ptr);
+            This.Void_Ptr := Null_Pointer;
         end if;
     end Finalize;
 
diff --git a/src/fltk-images-rgb-pnm.adb b/src/fltk-images-rgb-pnm.adb
index 8227cd9..362b8d6 100644
--- a/src/fltk-images-rgb-pnm.adb
+++ b/src/fltk-images-rgb-pnm.adb
@@ -31,6 +31,7 @@ package body FLTK.Images.RGB.PNM is
     begin
         if This.Void_Ptr /= Null_Pointer and This.Needs_Dealloc then
             free_fl_pnm_image (This.Void_Ptr);
+            This.Void_Ptr := Null_Pointer;
         end if;
     end Finalize;
 
diff --git a/src/fltk-images-rgb.adb b/src/fltk-images-rgb.adb
index 8ea3646..19a7952 100644
--- a/src/fltk-images-rgb.adb
+++ b/src/fltk-images-rgb.adb
@@ -100,6 +100,7 @@ package body FLTK.Images.RGB is
     begin
         if This.Void_Ptr /= Null_Pointer and This.Needs_Dealloc then
             free_fl_rgb_image (This.Void_Ptr);
+            This.Void_Ptr := Null_Pointer;
         end if;
     end Finalize;
 
diff --git a/src/fltk-images-shared.adb b/src/fltk-images-shared.adb
index fd2663b..d475cc3 100644
--- a/src/fltk-images-shared.adb
+++ b/src/fltk-images-shared.adb
@@ -140,6 +140,7 @@ package body FLTK.Images.Shared is
     begin
         if This.Void_Ptr /= Null_Pointer and This.Needs_Dealloc then
             fl_shared_image_release (This.Void_Ptr);
+            This.Void_Ptr := Null_Pointer;
         end if;
     end Finalize;
 
diff --git a/src/fltk-images-tiled.adb b/src/fltk-images-tiled.adb
index a489f82..6bed730 100644
--- a/src/fltk-images-tiled.adb
+++ b/src/fltk-images-tiled.adb
@@ -85,6 +85,7 @@ package body FLTK.Images.Tiled is
     begin
         if This.Void_Ptr /= Null_Pointer and This.Needs_Dealloc then
             free_fl_tiled_image (This.Void_Ptr);
+            This.Void_Ptr := Null_Pointer;
         end if;
     end Finalize;
 
diff --git a/src/fltk-images.adb b/src/fltk-images.adb
index e435976..19a1f86 100644
--- a/src/fltk-images.adb
+++ b/src/fltk-images.adb
@@ -166,6 +166,7 @@ package body FLTK.Images is
     begin
         if This.Void_Ptr /= Null_Pointer and This.Needs_Dealloc then
             free_fl_image (This.Void_Ptr);
+            This.Void_Ptr := Null_Pointer;
         end if;
     end Finalize;
 
diff --git a/src/fltk-labels.adb b/src/fltk-labels.adb
index 4f5ff28..006db6b 100644
--- a/src/fltk-labels.adb
+++ b/src/fltk-labels.adb
@@ -139,6 +139,7 @@ package body FLTK.Labels is
     begin
         if This.Void_Ptr /= Null_Pointer and This.Needs_Dealloc then
             free_fl_label (This.Void_Ptr);
+            This.Void_Ptr := Null_Pointer;
             Interfaces.C.Strings.Free (This.My_Text);
         end if;
     end Finalize;
diff --git a/src/fltk-menu_items.adb b/src/fltk-menu_items.adb
index 73e4c3c..b93f1f5 100644
--- a/src/fltk-menu_items.adb
+++ b/src/fltk-menu_items.adb
@@ -230,6 +230,7 @@ package body FLTK.Menu_Items is
     begin
         if This.Void_Ptr /= Null_Pointer and This.Needs_Dealloc then
             free_fl_menu_item (This.Void_Ptr);
+            This.Void_Ptr := Null_Pointer;
         end if;
     end Finalize;
 
diff --git a/src/fltk-text_buffers.adb b/src/fltk-text_buffers.adb
index e3755a1..5d88b10 100644
--- a/src/fltk-text_buffers.adb
+++ b/src/fltk-text_buffers.adb
@@ -517,6 +517,7 @@ package body FLTK.Text_Buffers is
     begin
         if This.Void_Ptr /= Null_Pointer and This.Needs_Dealloc then
             free_fl_text_buffer (This.Void_Ptr);
+            This.Void_Ptr := Null_Pointer;
         end if;
     end Finalize;
 
diff --git a/src/fltk-widgets-boxes.adb b/src/fltk-widgets-boxes.adb
index 3194237..a506fd3 100644
--- a/src/fltk-widgets-boxes.adb
+++ b/src/fltk-widgets-boxes.adb
@@ -68,6 +68,7 @@ package body FLTK.Widgets.Boxes is
         Extra_Final (This);
         if This.Void_Ptr /= Null_Pointer and This.Needs_Dealloc then
             free_fl_box (This.Void_Ptr);
+            This.Void_Ptr := Null_Pointer;
         end if;
     end Finalize;
 
diff --git a/src/fltk-widgets-buttons-enter.adb b/src/fltk-widgets-buttons-enter.adb
index cefe2b1..20ce598 100644
--- a/src/fltk-widgets-buttons-enter.adb
+++ b/src/fltk-widgets-buttons-enter.adb
@@ -68,6 +68,7 @@ package body FLTK.Widgets.Buttons.Enter is
         Extra_Final (This);
         if This.Void_Ptr /= Null_Pointer and This.Needs_Dealloc then
             free_fl_return_button (This.Void_Ptr);
+            This.Void_Ptr := Null_Pointer;
         end if;
     end Finalize;
 
diff --git a/src/fltk-widgets-buttons-light-check.adb b/src/fltk-widgets-buttons-light-check.adb
index 7594782..d6a7ef7 100644
--- a/src/fltk-widgets-buttons-light-check.adb
+++ b/src/fltk-widgets-buttons-light-check.adb
@@ -68,6 +68,7 @@ package body FLTK.Widgets.Buttons.Light.Check is
         Extra_Final (This);
         if This.Void_Ptr /= Null_Pointer and This.Needs_Dealloc then
             free_fl_check_button (This.Void_Ptr);
+            This.Void_Ptr := Null_Pointer;
         end if;
     end Finalize;
 
diff --git a/src/fltk-widgets-buttons-light-radio.adb b/src/fltk-widgets-buttons-light-radio.adb
index a1f0e95..c7ba63f 100644
--- a/src/fltk-widgets-buttons-light-radio.adb
+++ b/src/fltk-widgets-buttons-light-radio.adb
@@ -68,6 +68,7 @@ package body FLTK.Widgets.Buttons.Light.Radio is
         Extra_Final (This);
         if This.Void_Ptr /= Null_Pointer and This.Needs_Dealloc then
             free_fl_radio_light_button (This.Void_Ptr);
+            This.Void_Ptr := Null_Pointer;
         end if;
     end Finalize;
 
diff --git a/src/fltk-widgets-buttons-light-round-radio.adb b/src/fltk-widgets-buttons-light-round-radio.adb
index cabcb0d..1f1e3f8 100644
--- a/src/fltk-widgets-buttons-light-round-radio.adb
+++ b/src/fltk-widgets-buttons-light-round-radio.adb
@@ -68,6 +68,7 @@ package body FLTK.Widgets.Buttons.Light.Round.Radio is
         Extra_Final (This);
         if This.Void_Ptr /= Null_Pointer and This.Needs_Dealloc then
             free_fl_radio_round_button (This.Void_Ptr);
+            This.Void_Ptr := Null_Pointer;
         end if;
     end Finalize;
 
diff --git a/src/fltk-widgets-buttons-light-round.adb b/src/fltk-widgets-buttons-light-round.adb
index b0ed29a..9730413 100644
--- a/src/fltk-widgets-buttons-light-round.adb
+++ b/src/fltk-widgets-buttons-light-round.adb
@@ -67,6 +67,7 @@ package body FLTK.Widgets.Buttons.Light.Round is
     begin
         if This.Void_Ptr /= Null_Pointer and This.Needs_Dealloc then
             free_fl_round_button (This.Void_Ptr);
+            This.Void_Ptr := Null_Pointer;
         end if;
     end Finalize;
 
diff --git a/src/fltk-widgets-buttons-light.adb b/src/fltk-widgets-buttons-light.adb
index 13afeb6..6ab55bb 100644
--- a/src/fltk-widgets-buttons-light.adb
+++ b/src/fltk-widgets-buttons-light.adb
@@ -68,6 +68,7 @@ package body FLTK.Widgets.Buttons.Light is
         Extra_Final (This);
         if This.Void_Ptr /= Null_Pointer and This.Needs_Dealloc then
             free_fl_light_button (This.Void_Ptr);
+            This.Void_Ptr := Null_Pointer;
         end if;
     end Finalize;
 
diff --git a/src/fltk-widgets-buttons-radio.adb b/src/fltk-widgets-buttons-radio.adb
index 7fb764e..143beeb 100644
--- a/src/fltk-widgets-buttons-radio.adb
+++ b/src/fltk-widgets-buttons-radio.adb
@@ -68,6 +68,7 @@ package body FLTK.Widgets.Buttons.Radio is
         Extra_Final (This);
         if This.Void_Ptr /= Null_Pointer and This.Needs_Dealloc then
             free_fl_radio_button (This.Void_Ptr);
+            This.Void_Ptr := Null_Pointer;
         end if;
     end Finalize;
 
diff --git a/src/fltk-widgets-buttons-repeat.adb b/src/fltk-widgets-buttons-repeat.adb
index de4cf29..9446a22 100644
--- a/src/fltk-widgets-buttons-repeat.adb
+++ b/src/fltk-widgets-buttons-repeat.adb
@@ -68,6 +68,7 @@ package body FLTK.Widgets.Buttons.Repeat is
         Extra_Final (This);
         if This.Void_Ptr /= Null_Pointer and This.Needs_Dealloc then
             free_fl_repeat_button (This.Void_Ptr);
+            This.Void_Ptr := Null_Pointer;
         end if;
     end Finalize;
 
diff --git a/src/fltk-widgets-buttons-toggle.adb b/src/fltk-widgets-buttons-toggle.adb
index 0fe7962..a1dcc60 100644
--- a/src/fltk-widgets-buttons-toggle.adb
+++ b/src/fltk-widgets-buttons-toggle.adb
@@ -68,6 +68,7 @@ package body FLTK.Widgets.Buttons.Toggle is
         Extra_Final (This);
         if This.Void_Ptr /= Null_Pointer and This.Needs_Dealloc then
             free_fl_toggle_button (This.Void_Ptr);
+            This.Void_Ptr := Null_Pointer;
         end if;
     end Finalize;
 
diff --git a/src/fltk-widgets-buttons.adb b/src/fltk-widgets-buttons.adb
index a6c98d0..64f351a 100644
--- a/src/fltk-widgets-buttons.adb
+++ b/src/fltk-widgets-buttons.adb
@@ -115,6 +115,7 @@ package body FLTK.Widgets.Buttons is
         Extra_Final (This);
         if This.Void_Ptr /= Null_Pointer and This.Needs_Dealloc then
             free_fl_button (This.Void_Ptr);
+            This.Void_Ptr := Null_Pointer;
         end if;
     end Finalize;
 
diff --git a/src/fltk-widgets-charts.adb b/src/fltk-widgets-charts.adb
index fd477cc..e9a0f03 100644
--- a/src/fltk-widgets-charts.adb
+++ b/src/fltk-widgets-charts.adb
@@ -199,6 +199,7 @@ package body FLTK.Widgets.Charts is
         Extra_Final (This);
         if This.Void_Ptr /= Null_Pointer and This.Needs_Dealloc then
             free_fl_chart (This.Void_Ptr);
+            This.Void_Ptr := Null_Pointer;
         end if;
     end Finalize;
 
diff --git a/src/fltk-widgets-clocks-updated-round.adb b/src/fltk-widgets-clocks-updated-round.adb
index aa08655..f22b785 100644
--- a/src/fltk-widgets-clocks-updated-round.adb
+++ b/src/fltk-widgets-clocks-updated-round.adb
@@ -74,6 +74,7 @@ package body FLTK.Widgets.Clocks.Updated.Round is
         Extra_Final (This);
         if This.Void_Ptr /= Null_Pointer and This.Needs_Dealloc then
             free_fl_round_clock (This.Void_Ptr);
+            This.Void_Ptr := Null_Pointer;
         end if;
     end Finalize;
 
diff --git a/src/fltk-widgets-clocks-updated.adb b/src/fltk-widgets-clocks-updated.adb
index 9ca47ce..b0843b6 100644
--- a/src/fltk-widgets-clocks-updated.adb
+++ b/src/fltk-widgets-clocks-updated.adb
@@ -82,6 +82,7 @@ package body FLTK.Widgets.Clocks.Updated is
         Extra_Final (This);
         if This.Void_Ptr /= Null_Pointer and This.Needs_Dealloc then
             free_fl_clock (This.Void_Ptr);
+            This.Void_Ptr := Null_Pointer;
         end if;
     end Finalize;
 
diff --git a/src/fltk-widgets-clocks.adb b/src/fltk-widgets-clocks.adb
index 535dd36..a3cb315 100644
--- a/src/fltk-widgets-clocks.adb
+++ b/src/fltk-widgets-clocks.adb
@@ -116,6 +116,7 @@ package body FLTK.Widgets.Clocks is
         Extra_Final (This);
         if This.Void_Ptr /= Null_Pointer and This.Needs_Dealloc then
             free_fl_clock_output (This.Void_Ptr);
+            This.Void_Ptr := Null_Pointer;
         end if;
     end Finalize;
 
diff --git a/src/fltk-widgets-groups-browsers.adb b/src/fltk-widgets-groups-browsers.adb
index cd9b3f3..9798c89 100644
--- a/src/fltk-widgets-groups-browsers.adb
+++ b/src/fltk-widgets-groups-browsers.adb
@@ -644,6 +644,7 @@ package body FLTK.Widgets.Groups.Browsers is
         Extra_Final (This);
         if This.Void_Ptr /= Null_Pointer and This.Needs_Dealloc then
             free_fl_abstract_browser (This.Void_Ptr);
+            This.Void_Ptr := Null_Pointer;
         end if;
     end Finalize;
 
diff --git a/src/fltk-widgets-groups-color_choosers.adb b/src/fltk-widgets-groups-color_choosers.adb
index cd97fb3..9c02667 100644
--- a/src/fltk-widgets-groups-color_choosers.adb
+++ b/src/fltk-widgets-groups-color_choosers.adb
@@ -158,6 +158,7 @@ package body FLTK.Widgets.Groups.Color_Choosers is
         Extra_Final (This);
         if This.Void_Ptr /= Null_Pointer and This.Needs_Dealloc then
             free_fl_color_chooser (This.Void_Ptr);
+            This.Void_Ptr := Null_Pointer;
         end if;
     end Finalize;
 
diff --git a/src/fltk-widgets-groups-help_views.adb b/src/fltk-widgets-groups-help_views.adb
index 24a592f..b5ed154 100644
--- a/src/fltk-widgets-groups-help_views.adb
+++ b/src/fltk-widgets-groups-help_views.adb
@@ -281,6 +281,7 @@ package body FLTK.Widgets.Groups.Help_Views is
         Extra_Final (This);
         if This.Void_Ptr /= Null_Pointer and This.Needs_Dealloc then
             free_fl_help_view (This.Void_Ptr);
+            This.Void_Ptr := Null_Pointer;
         end if;
     end Finalize;
 
diff --git a/src/fltk-widgets-groups-input_choices.adb b/src/fltk-widgets-groups-input_choices.adb
index 7fc6870..6f36a31 100644
--- a/src/fltk-widgets-groups-input_choices.adb
+++ b/src/fltk-widgets-groups-input_choices.adb
@@ -182,6 +182,7 @@ package body FLTK.Widgets.Groups.Input_Choices is
         Extra_Final (This);
         if This.Void_Ptr /= Null_Pointer and This.Needs_Dealloc then
             free_fl_input_choice (This.Void_Ptr);
+            This.Void_Ptr := Null_Pointer;
         end if;
     end Finalize;
 
diff --git a/src/fltk-widgets-groups-packed.adb b/src/fltk-widgets-groups-packed.adb
index 5bc4d37..ef9ab88 100644
--- a/src/fltk-widgets-groups-packed.adb
+++ b/src/fltk-widgets-groups-packed.adb
@@ -83,6 +83,7 @@ package body FLTK.Widgets.Groups.Packed is
         Extra_Final (This);
         if This.Void_Ptr /= Null_Pointer and This.Needs_Dealloc then
             free_fl_pack (This.Void_Ptr);
+            This.Void_Ptr := Null_Pointer;
         end if;
     end Finalize;
 
diff --git a/src/fltk-widgets-groups-scrolls.adb b/src/fltk-widgets-groups-scrolls.adb
index a31dea3..9bc6a05 100644
--- a/src/fltk-widgets-groups-scrolls.adb
+++ b/src/fltk-widgets-groups-scrolls.adb
@@ -118,6 +118,7 @@ package body FLTK.Widgets.Groups.Scrolls is
         Extra_Final (This);
         if This.Void_Ptr /= Null_Pointer and This.Needs_Dealloc then
             free_fl_scroll (This.Void_Ptr);
+            This.Void_Ptr := Null_Pointer;
         end if;
     end Finalize;
 
diff --git a/src/fltk-widgets-groups-spinners.adb b/src/fltk-widgets-groups-spinners.adb
index b87e27e..91ed74a 100644
--- a/src/fltk-widgets-groups-spinners.adb
+++ b/src/fltk-widgets-groups-spinners.adb
@@ -204,6 +204,7 @@ package body FLTK.Widgets.Groups.Spinners is
         Extra_Final (This);
         if This.Void_Ptr /= Null_Pointer and This.Needs_Dealloc then
             free_fl_spinner (This.Void_Ptr);
+            This.Void_Ptr := Null_Pointer;
         end if;
     end Finalize;
 
diff --git a/src/fltk-widgets-groups-tabbed.adb b/src/fltk-widgets-groups-tabbed.adb
index b0b0c2f..cd7684a 100644
--- a/src/fltk-widgets-groups-tabbed.adb
+++ b/src/fltk-widgets-groups-tabbed.adb
@@ -110,6 +110,7 @@ package body FLTK.Widgets.Groups.Tabbed is
         Extra_Final (This);
         if This.Void_Ptr /= Null_Pointer and This.Needs_Dealloc then
             free_fl_tabs (This.Void_Ptr);
+            This.Void_Ptr := Null_Pointer;
         end if;
     end Finalize;
 
diff --git a/src/fltk-widgets-groups-text_displays-text_editors.adb b/src/fltk-widgets-groups-text_displays-text_editors.adb
index 55399e7..2ff5afc 100644
--- a/src/fltk-widgets-groups-text_displays-text_editors.adb
+++ b/src/fltk-widgets-groups-text_displays-text_editors.adb
@@ -398,6 +398,7 @@ package body FLTK.Widgets.Groups.Text_Displays.Text_Editors is
         if This.Void_Ptr /= Null_Pointer and This.Needs_Dealloc then
             free_fl_text_editor (This.Void_Ptr);
             free_fl_text_buffer (This.Raw_Buffer);
+            This.Void_Ptr := Null_Pointer;
         end if;
     end Finalize;
 
diff --git a/src/fltk-widgets-groups-text_displays.adb b/src/fltk-widgets-groups-text_displays.adb
index d8e296f..563fbbf 100644
--- a/src/fltk-widgets-groups-text_displays.adb
+++ b/src/fltk-widgets-groups-text_displays.adb
@@ -480,6 +480,7 @@ package body FLTK.Widgets.Groups.Text_Displays is
         if This.Void_Ptr /= Null_Pointer and This.Needs_Dealloc then
             free_fl_text_display (This.Void_Ptr);
             free_fl_text_buffer (This.Raw_Buffer);
+            This.Void_Ptr := Null_Pointer;
         end if;
     end Finalize;
 
diff --git a/src/fltk-widgets-groups-tiled.adb b/src/fltk-widgets-groups-tiled.adb
index 9619a06..05dcd61 100644
--- a/src/fltk-widgets-groups-tiled.adb
+++ b/src/fltk-widgets-groups-tiled.adb
@@ -77,6 +77,7 @@ package body FLTK.Widgets.Groups.Tiled is
         Extra_Final (This);
         if This.Void_Ptr /= Null_Pointer and This.Needs_Dealloc then
             free_fl_tile (This.Void_Ptr);
+            This.Void_Ptr := Null_Pointer;
         end if;
     end Finalize;
 
diff --git a/src/fltk-widgets-groups-windows-double-overlay.adb b/src/fltk-widgets-groups-windows-double-overlay.adb
index ca0936c..90f4754 100644
--- a/src/fltk-widgets-groups-windows-double-overlay.adb
+++ b/src/fltk-widgets-groups-windows-double-overlay.adb
@@ -133,6 +133,7 @@ package body FLTK.Widgets.Groups.Windows.Double.Overlay is
         Extra_Final (This);
         if This.Void_Ptr /= Null_Pointer and This.Needs_Dealloc then
             free_fl_overlay_window (This.Void_Ptr);
+            This.Void_Ptr := Null_Pointer;
         end if;
     end Finalize;
 
diff --git a/src/fltk-widgets-groups-windows-double.adb b/src/fltk-widgets-groups-windows-double.adb
index 190b743..24ee93d 100644
--- a/src/fltk-widgets-groups-windows-double.adb
+++ b/src/fltk-widgets-groups-windows-double.adb
@@ -93,6 +93,7 @@ package body FLTK.Widgets.Groups.Windows.Double is
         Extra_Final (This);
         if This.Void_Ptr /= Null_Pointer and This.Needs_Dealloc then
             free_fl_double_window (This.Void_Ptr);
+            This.Void_Ptr := Null_Pointer;
         end if;
     end Finalize;
 
diff --git a/src/fltk-widgets-groups-windows-opengl.adb b/src/fltk-widgets-groups-windows-opengl.adb
index e315cc4..fd43bc0 100644
--- a/src/fltk-widgets-groups-windows-opengl.adb
+++ b/src/fltk-widgets-groups-windows-opengl.adb
@@ -223,6 +223,7 @@ package body FLTK.Widgets.Groups.Windows.OpenGL is
         Extra_Final (This);
         if This.Void_Ptr /= Null_Pointer and This.Needs_Dealloc then
             free_fl_gl_window (This.Void_Ptr);
+            This.Void_Ptr := Null_Pointer;
         end if;
     end Finalize;
 
diff --git a/src/fltk-widgets-groups-windows-single-menu.adb b/src/fltk-widgets-groups-windows-single-menu.adb
index 9aa0ded..fa2c9b3 100644
--- a/src/fltk-widgets-groups-windows-single-menu.adb
+++ b/src/fltk-widgets-groups-windows-single-menu.adb
@@ -116,6 +116,7 @@ package body FLTK.Widgets.Groups.Windows.Single.Menu is
         Extra_Final (This);
         if This.Void_Ptr /= Null_Pointer and This.Needs_Dealloc then
             free_fl_menu_window (This.Void_Ptr);
+            This.Void_Ptr := Null_Pointer;
         end if;
     end Finalize;
 
diff --git a/src/fltk-widgets-groups-windows-single.adb b/src/fltk-widgets-groups-windows-single.adb
index a012920..1c90ba3 100644
--- a/src/fltk-widgets-groups-windows-single.adb
+++ b/src/fltk-widgets-groups-windows-single.adb
@@ -88,6 +88,7 @@ package body FLTK.Widgets.Groups.Windows.Single is
         Extra_Final (This);
         if This.Void_Ptr /= Null_Pointer and This.Needs_Dealloc then
             free_fl_single_window (This.Void_Ptr);
+            This.Void_Ptr := Null_Pointer;
         end if;
     end Finalize;
 
diff --git a/src/fltk-widgets-groups-windows.adb b/src/fltk-widgets-groups-windows.adb
index af5cef7..0c02f6c 100644
--- a/src/fltk-widgets-groups-windows.adb
+++ b/src/fltk-widgets-groups-windows.adb
@@ -313,6 +313,7 @@ package body FLTK.Widgets.Groups.Windows is
         Extra_Final (This);
         if This.Void_Ptr /= Null_Pointer and This.Needs_Dealloc then
             free_fl_window (This.Void_Ptr);
+            This.Void_Ptr := Null_Pointer;
         end if;
     end Finalize;
 
diff --git a/src/fltk-widgets-groups-wizards.adb b/src/fltk-widgets-groups-wizards.adb
index b3d6d6d..df0d653 100644
--- a/src/fltk-widgets-groups-wizards.adb
+++ b/src/fltk-widgets-groups-wizards.adb
@@ -95,6 +95,7 @@ package body FLTK.Widgets.Groups.Wizards is
         Extra_Final (This);
         if This.Void_Ptr /= Null_Pointer and This.Needs_Dealloc then
             free_fl_wizard (This.Void_Ptr);
+            This.Void_Ptr := Null_Pointer;
         end if;
     end Finalize;
 
diff --git a/src/fltk-widgets-groups.adb b/src/fltk-widgets-groups.adb
index f61104a..17cb4fa 100644
--- a/src/fltk-widgets-groups.adb
+++ b/src/fltk-widgets-groups.adb
@@ -180,6 +180,7 @@ package body FLTK.Widgets.Groups is
         Extra_Final (This);
         if This.Void_Ptr /= Null_Pointer and This.Needs_Dealloc then
             free_fl_group (This.Void_Ptr);
+            This.Void_Ptr := Null_Pointer;
         end if;
     end Finalize;
 
diff --git a/src/fltk-widgets-inputs-file.adb b/src/fltk-widgets-inputs-file.adb
index f928187..b8aa4f3 100644
--- a/src/fltk-widgets-inputs-file.adb
+++ b/src/fltk-widgets-inputs-file.adb
@@ -115,6 +115,7 @@ package body FLTK.Widgets.Inputs.File is
         Extra_Final (This);
         if This.Void_Ptr /= Null_Pointer and This.Needs_Dealloc then
             free_fl_file_input (This.Void_Ptr);
+            This.Void_Ptr := Null_Pointer;
         end if;
     end Finalize;
 
diff --git a/src/fltk-widgets-inputs-float.adb b/src/fltk-widgets-inputs-float.adb
index be8e05a..248b9ad 100644
--- a/src/fltk-widgets-inputs-float.adb
+++ b/src/fltk-widgets-inputs-float.adb
@@ -72,6 +72,7 @@ package body FLTK.Widgets.Inputs.Float is
         Extra_Final (This);
         if This.Void_Ptr /= Null_Pointer and This.Needs_Dealloc then
             free_fl_float_input (This.Void_Ptr);
+            This.Void_Ptr := Null_Pointer;
         end if;
     end Finalize;
 
diff --git a/src/fltk-widgets-inputs-integer.adb b/src/fltk-widgets-inputs-integer.adb
index 6633354..401ca7c 100644
--- a/src/fltk-widgets-inputs-integer.adb
+++ b/src/fltk-widgets-inputs-integer.adb
@@ -72,6 +72,7 @@ package body FLTK.Widgets.Inputs.Integer is
         Extra_Final (This);
         if This.Void_Ptr /= Null_Pointer and This.Needs_Dealloc then
             free_fl_int_input (This.Void_Ptr);
+            This.Void_Ptr := Null_Pointer;
         end if;
     end Finalize;
 
diff --git a/src/fltk-widgets-inputs-multiline.adb b/src/fltk-widgets-inputs-multiline.adb
index b240631..3c33ef9 100644
--- a/src/fltk-widgets-inputs-multiline.adb
+++ b/src/fltk-widgets-inputs-multiline.adb
@@ -68,6 +68,7 @@ package body FLTK.Widgets.Inputs.Multiline is
         Extra_Final (This);
         if This.Void_Ptr /= Null_Pointer and This.Needs_Dealloc then
             free_fl_multiline_input (This.Void_Ptr);
+            This.Void_Ptr := Null_Pointer;
         end if;
     end Finalize;
 
diff --git a/src/fltk-widgets-inputs-outputs-multiline.adb b/src/fltk-widgets-inputs-outputs-multiline.adb
index d0fb8f7..626a4ee 100644
--- a/src/fltk-widgets-inputs-outputs-multiline.adb
+++ b/src/fltk-widgets-inputs-outputs-multiline.adb
@@ -68,6 +68,7 @@ package body FLTK.Widgets.Inputs.Outputs.Multiline is
         Extra_Final (This);
         if This.Void_Ptr /= Null_Pointer and This.Needs_Dealloc then
             free_fl_multiline_output (This.Void_Ptr);
+            This.Void_Ptr := Null_Pointer;
         end if;
     end Finalize;
 
diff --git a/src/fltk-widgets-inputs-outputs.adb b/src/fltk-widgets-inputs-outputs.adb
index e7d5f44..924e60b 100644
--- a/src/fltk-widgets-inputs-outputs.adb
+++ b/src/fltk-widgets-inputs-outputs.adb
@@ -68,6 +68,7 @@ package body FLTK.Widgets.Inputs.Outputs is
         Extra_Final (This);
         if This.Void_Ptr /= Null_Pointer and This.Needs_Dealloc then
             free_fl_output (This.Void_Ptr);
+            This.Void_Ptr := Null_Pointer;
         end if;
     end Finalize;
 
diff --git a/src/fltk-widgets-inputs-secret.adb b/src/fltk-widgets-inputs-secret.adb
index 0f56085..2cd59eb 100644
--- a/src/fltk-widgets-inputs-secret.adb
+++ b/src/fltk-widgets-inputs-secret.adb
@@ -68,6 +68,7 @@ package body FLTK.Widgets.Inputs.Secret is
         Extra_Final (This);
         if This.Void_Ptr /= Null_Pointer and This.Needs_Dealloc then
             free_fl_secret_input (This.Void_Ptr);
+            This.Void_Ptr := Null_Pointer;
         end if;
     end Finalize;
 
diff --git a/src/fltk-widgets-inputs.adb b/src/fltk-widgets-inputs.adb
index 3281a00..254712a 100644
--- a/src/fltk-widgets-inputs.adb
+++ b/src/fltk-widgets-inputs.adb
@@ -321,6 +321,7 @@ package body FLTK.Widgets.Inputs is
         Extra_Final (This);
         if This.Void_Ptr /= Null_Pointer and This.Needs_Dealloc then
             free_fl_input (This.Void_Ptr);
+            This.Void_Ptr := Null_Pointer;
         end if;
     end Finalize;
 
diff --git a/src/fltk-widgets-menus-choices.adb b/src/fltk-widgets-menus-choices.adb
index 211114f..fc60efc 100644
--- a/src/fltk-widgets-menus-choices.adb
+++ b/src/fltk-widgets-menus-choices.adb
@@ -94,6 +94,7 @@ package body FLTK.Widgets.Menus.Choices is
         Extra_Final (This);
         if This.Void_Ptr /= Null_Pointer and This.Needs_Dealloc then
             free_fl_choice (This.Void_Ptr);
+            This.Void_Ptr := Null_Pointer;
         end if;
     end Finalize;
 
diff --git a/src/fltk-widgets-menus-menu_bars.adb b/src/fltk-widgets-menus-menu_bars.adb
index 3840f2e..f0c9569 100644
--- a/src/fltk-widgets-menus-menu_bars.adb
+++ b/src/fltk-widgets-menus-menu_bars.adb
@@ -68,6 +68,7 @@ package body FLTK.Widgets.Menus.Menu_Bars is
         Extra_Final (This);
         if This.Void_Ptr /= Null_Pointer and This.Needs_Dealloc then
             free_fl_menu_bar (This.Void_Ptr);
+            This.Void_Ptr := Null_Pointer;
         end if;
     end Finalize;
 
diff --git a/src/fltk-widgets-menus-menu_buttons.adb b/src/fltk-widgets-menus-menu_buttons.adb
index 51c35f8..9a15d8b 100644
--- a/src/fltk-widgets-menus-menu_buttons.adb
+++ b/src/fltk-widgets-menus-menu_buttons.adb
@@ -89,6 +89,7 @@ package body FLTK.Widgets.Menus.Menu_Buttons is
         Extra_Final (This);
         if This.Void_Ptr /= Null_Pointer and This.Needs_Dealloc then
             free_fl_menu_button (This.Void_Ptr);
+            This.Void_Ptr := Null_Pointer;
         end if;
     end Finalize;
 
diff --git a/src/fltk-widgets-menus.adb b/src/fltk-widgets-menus.adb
index 5bd67df..4476332 100644
--- a/src/fltk-widgets-menus.adb
+++ b/src/fltk-widgets-menus.adb
@@ -295,6 +295,7 @@ package body FLTK.Widgets.Menus is
         Extra_Final (This);
         if This.Void_Ptr /= Null_Pointer and This.Needs_Dealloc then
             free_fl_menu (This.Void_Ptr);
+            This.Void_Ptr := Null_Pointer;
         end if;
     end Finalize;
 
diff --git a/src/fltk-widgets-progress_bars.adb b/src/fltk-widgets-progress_bars.adb
index 9b1301f..39b2b2d 100644
--- a/src/fltk-widgets-progress_bars.adb
+++ b/src/fltk-widgets-progress_bars.adb
@@ -107,6 +107,7 @@ package body FLTK.Widgets.Progress_Bars is
         Extra_Final (This);
         if This.Void_Ptr /= Null_Pointer and This.Needs_Dealloc then
             free_fl_progress (This.Void_Ptr);
+            This.Void_Ptr := Null_Pointer;
         end if;
     end Finalize;
 
diff --git a/src/fltk-widgets-valuators-adjusters.adb b/src/fltk-widgets-valuators-adjusters.adb
index 9d12b12..0c96332 100644
--- a/src/fltk-widgets-valuators-adjusters.adb
+++ b/src/fltk-widgets-valuators-adjusters.adb
@@ -87,6 +87,7 @@ package body FLTK.Widgets.Valuators.Adjusters is
         Extra_Final (This);
         if This.Void_Ptr /= Null_Pointer and This.Needs_Dealloc then
             free_fl_adjuster (This.Void_Ptr);
+            This.Void_Ptr := Null_Pointer;
         end if;
     end Finalize;
 
diff --git a/src/fltk-widgets-valuators-counters-simple.adb b/src/fltk-widgets-valuators-counters-simple.adb
index b7a35a2..d811722 100644
--- a/src/fltk-widgets-valuators-counters-simple.adb
+++ b/src/fltk-widgets-valuators-counters-simple.adb
@@ -68,6 +68,7 @@ package body FLTK.Widgets.Valuators.Counters.Simple is
         Extra_Final (This);
         if This.Void_Ptr /= Null_Pointer and This.Needs_Dealloc then
             free_fl_simple_counter (This.Void_Ptr);
+            This.Void_Ptr := Null_Pointer;
         end if;
     end Finalize;
 
diff --git a/src/fltk-widgets-valuators-counters.adb b/src/fltk-widgets-valuators-counters.adb
index a8cb10a..fd0619e 100644
--- a/src/fltk-widgets-valuators-counters.adb
+++ b/src/fltk-widgets-valuators-counters.adb
@@ -128,6 +128,7 @@ package body FLTK.Widgets.Valuators.Counters is
         Extra_Final (This);
         if This.Void_Ptr /= Null_Pointer and This.Needs_Dealloc then
             free_fl_counter (This.Void_Ptr);
+            This.Void_Ptr := Null_Pointer;
         end if;
     end Finalize;
 
diff --git a/src/fltk-widgets-valuators-dials-fill.adb b/src/fltk-widgets-valuators-dials-fill.adb
index b83d329..cb7d025 100644
--- a/src/fltk-widgets-valuators-dials-fill.adb
+++ b/src/fltk-widgets-valuators-dials-fill.adb
@@ -68,6 +68,7 @@ package body FLTK.Widgets.Valuators.Dials.Fill is
         Extra_Final (This);
         if This.Void_Ptr /= Null_Pointer and This.Needs_Dealloc then
             free_fl_fill_dial (This.Void_Ptr);
+            This.Void_Ptr := Null_Pointer;
         end if;
     end Finalize;
 
diff --git a/src/fltk-widgets-valuators-dials-line.adb b/src/fltk-widgets-valuators-dials-line.adb
index a02d1b8..7ee67ce 100644
--- a/src/fltk-widgets-valuators-dials-line.adb
+++ b/src/fltk-widgets-valuators-dials-line.adb
@@ -68,6 +68,7 @@ package body FLTK.Widgets.Valuators.Dials.Line is
         Extra_Final (This);
         if This.Void_Ptr /= Null_Pointer and This.Needs_Dealloc then
             free_fl_line_dial (This.Void_Ptr);
+            This.Void_Ptr := Null_Pointer;
         end if;
     end Finalize;
 
diff --git a/src/fltk-widgets-valuators-dials.adb b/src/fltk-widgets-valuators-dials.adb
index a796a8c..588b8ec 100644
--- a/src/fltk-widgets-valuators-dials.adb
+++ b/src/fltk-widgets-valuators-dials.adb
@@ -116,6 +116,7 @@ package body FLTK.Widgets.Valuators.Dials is
         Extra_Final (This);
         if This.Void_Ptr /= Null_Pointer and This.Needs_Dealloc then
             free_fl_dial (This.Void_Ptr);
+            This.Void_Ptr := Null_Pointer;
         end if;
     end Finalize;
 
diff --git a/src/fltk-widgets-valuators-rollers.adb b/src/fltk-widgets-valuators-rollers.adb
index 69e0f39..520a816 100644
--- a/src/fltk-widgets-valuators-rollers.adb
+++ b/src/fltk-widgets-valuators-rollers.adb
@@ -68,6 +68,7 @@ package body FLTK.Widgets.Valuators.Rollers is
         Extra_Final (This);
         if This.Void_Ptr /= Null_Pointer and This.Needs_Dealloc then
             free_fl_roller (This.Void_Ptr);
+            This.Void_Ptr := Null_Pointer;
         end if;
     end Finalize;
 
diff --git a/src/fltk-widgets-valuators-sliders-fill.adb b/src/fltk-widgets-valuators-sliders-fill.adb
index 6d88d56..3568838 100644
--- a/src/fltk-widgets-valuators-sliders-fill.adb
+++ b/src/fltk-widgets-valuators-sliders-fill.adb
@@ -68,6 +68,7 @@ package body FLTK.Widgets.Valuators.Sliders.Fill is
         Extra_Final (This);
         if This.Void_Ptr /= Null_Pointer and This.Needs_Dealloc then
             free_fl_fill_slider (This.Void_Ptr);
+            This.Void_Ptr := Null_Pointer;
         end if;
     end Finalize;
 
diff --git a/src/fltk-widgets-valuators-sliders-hor_fill.adb b/src/fltk-widgets-valuators-sliders-hor_fill.adb
index c35d10a..1b0e7ea 100644
--- a/src/fltk-widgets-valuators-sliders-hor_fill.adb
+++ b/src/fltk-widgets-valuators-sliders-hor_fill.adb
@@ -68,6 +68,7 @@ package body FLTK.Widgets.Valuators.Sliders.Hor_Fill is
         Extra_Final (This);
         if This.Void_Ptr /= Null_Pointer and This.Needs_Dealloc then
             free_fl_hor_fill_slider (This.Void_Ptr);
+            This.Void_Ptr := Null_Pointer;
         end if;
     end Finalize;
 
diff --git a/src/fltk-widgets-valuators-sliders-hor_nice.adb b/src/fltk-widgets-valuators-sliders-hor_nice.adb
index d280df4..f6a0751 100644
--- a/src/fltk-widgets-valuators-sliders-hor_nice.adb
+++ b/src/fltk-widgets-valuators-sliders-hor_nice.adb
@@ -68,6 +68,7 @@ package body FLTK.Widgets.Valuators.Sliders.Hor_Nice is
         Extra_Final (This);
         if This.Void_Ptr /= Null_Pointer and This.Needs_Dealloc then
             free_fl_hor_nice_slider (This.Void_Ptr);
+            This.Void_Ptr := Null_Pointer;
         end if;
     end Finalize;
 
diff --git a/src/fltk-widgets-valuators-sliders-horizontal.adb b/src/fltk-widgets-valuators-sliders-horizontal.adb
index 302b620..b4d7035 100644
--- a/src/fltk-widgets-valuators-sliders-horizontal.adb
+++ b/src/fltk-widgets-valuators-sliders-horizontal.adb
@@ -68,6 +68,7 @@ package body FLTK.Widgets.Valuators.Sliders.Horizontal is
         Extra_Final (This);
         if This.Void_Ptr /= Null_Pointer and This.Needs_Dealloc then
             free_fl_horizontal_slider (This.Void_Ptr);
+            This.Void_Ptr := Null_Pointer;
         end if;
     end Finalize;
 
diff --git a/src/fltk-widgets-valuators-sliders-nice.adb b/src/fltk-widgets-valuators-sliders-nice.adb
index 7fef1e8..73fc2c3 100644
--- a/src/fltk-widgets-valuators-sliders-nice.adb
+++ b/src/fltk-widgets-valuators-sliders-nice.adb
@@ -68,6 +68,7 @@ package body FLTK.Widgets.Valuators.Sliders.Nice is
         Extra_Final (This);
         if This.Void_Ptr /= Null_Pointer and This.Needs_Dealloc then
             free_fl_nice_slider (This.Void_Ptr);
+            This.Void_Ptr := Null_Pointer;
         end if;
     end Finalize;
 
diff --git a/src/fltk-widgets-valuators-sliders-scrollbars.adb b/src/fltk-widgets-valuators-sliders-scrollbars.adb
index e950e93..2afca08 100644
--- a/src/fltk-widgets-valuators-sliders-scrollbars.adb
+++ b/src/fltk-widgets-valuators-sliders-scrollbars.adb
@@ -101,6 +101,7 @@ package body FLTK.Widgets.Valuators.Sliders.Scrollbars is
         Extra_Final (This);
         if This.Void_Ptr /= Null_Pointer and This.Needs_Dealloc then
             free_fl_scrollbar (This.Void_Ptr);
+            This.Void_Ptr := Null_Pointer;
         end if;
     end Finalize;
 
diff --git a/src/fltk-widgets-valuators-sliders-value-horizontal.adb b/src/fltk-widgets-valuators-sliders-value-horizontal.adb
index 0b4d1e9..bac9b5d 100644
--- a/src/fltk-widgets-valuators-sliders-value-horizontal.adb
+++ b/src/fltk-widgets-valuators-sliders-value-horizontal.adb
@@ -68,6 +68,7 @@ package body FLTK.Widgets.Valuators.Sliders.Value.Horizontal is
         Extra_Final (This);
         if This.Void_Ptr /= Null_Pointer and This.Needs_Dealloc then
             free_fl_hor_value_slider (This.Void_Ptr);
+            This.Void_Ptr := Null_Pointer;
         end if;
     end Finalize;
 
diff --git a/src/fltk-widgets-valuators-sliders-value.adb b/src/fltk-widgets-valuators-sliders-value.adb
index 878f498..40f935b 100644
--- a/src/fltk-widgets-valuators-sliders-value.adb
+++ b/src/fltk-widgets-valuators-sliders-value.adb
@@ -107,6 +107,7 @@ package body FLTK.Widgets.Valuators.Sliders.Value is
         Extra_Final (This);
         if This.Void_Ptr /= Null_Pointer and This.Needs_Dealloc then
             free_fl_value_slider (This.Void_Ptr);
+            This.Void_Ptr := Null_Pointer;
         end if;
     end Finalize;
 
diff --git a/src/fltk-widgets-valuators-sliders.adb b/src/fltk-widgets-valuators-sliders.adb
index 793fffb..4c99cca 100644
--- a/src/fltk-widgets-valuators-sliders.adb
+++ b/src/fltk-widgets-valuators-sliders.adb
@@ -123,6 +123,7 @@ package body FLTK.Widgets.Valuators.Sliders is
         Extra_Final (This);
         if This.Void_Ptr /= Null_Pointer and This.Needs_Dealloc then
             free_fl_slider (This.Void_Ptr);
+            This.Void_Ptr := Null_Pointer;
         end if;
     end Finalize;
 
diff --git a/src/fltk-widgets-valuators-value_inputs.adb b/src/fltk-widgets-valuators-value_inputs.adb
index 8513680..62cd320 100644
--- a/src/fltk-widgets-valuators-value_inputs.adb
+++ b/src/fltk-widgets-valuators-value_inputs.adb
@@ -165,6 +165,7 @@ package body FLTK.Widgets.Valuators.Value_Inputs is
         Extra_Final (This);
         if This.Void_Ptr /= Null_Pointer and This.Needs_Dealloc then
             free_fl_value_input (This.Void_Ptr);
+            This.Void_Ptr := Null_Pointer;
         end if;
     end Finalize;
 
diff --git a/src/fltk-widgets-valuators-value_outputs.adb b/src/fltk-widgets-valuators-value_outputs.adb
index e677850..dcd763d 100644
--- a/src/fltk-widgets-valuators-value_outputs.adb
+++ b/src/fltk-widgets-valuators-value_outputs.adb
@@ -126,6 +126,7 @@ package body FLTK.Widgets.Valuators.Value_Outputs is
         Extra_Final (This);
         if This.Void_Ptr /= Null_Pointer and This.Needs_Dealloc then
             free_fl_value_output (This.Void_Ptr);
+            This.Void_Ptr := Null_Pointer;
         end if;
     end Finalize;
 
diff --git a/src/fltk-widgets-valuators.adb b/src/fltk-widgets-valuators.adb
index e2f87ee..79b576c 100644
--- a/src/fltk-widgets-valuators.adb
+++ b/src/fltk-widgets-valuators.adb
@@ -157,6 +157,7 @@ package body FLTK.Widgets.Valuators is
         Extra_Final (This);
         if This.Void_Ptr /= Null_Pointer and This.Needs_Dealloc then
             free_fl_valuator (This.Void_Ptr);
+            This.Void_Ptr := Null_Pointer;
         end if;
     end Finalize;
 
diff --git a/src/fltk-widgets.adb b/src/fltk-widgets.adb
index e9bf587..b4b8a67 100644
--- a/src/fltk-widgets.adb
+++ b/src/fltk-widgets.adb
@@ -514,6 +514,7 @@ package body FLTK.Widgets is
         Extra_Final (This);
         if This.Void_Ptr /= Null_Pointer and This.Needs_Dealloc then
             free_fl_widget (This.Void_Ptr);
+            This.Void_Ptr := Null_Pointer;
         end if;
     end Finalize;