As requested by Christian Werner/François Vogel and others: Undo many None -> 0 changes, in order to reduce the probability of merge conflicts with other branches.

Remark: Many usages of "None" in Tk are wrong, "NULL" should be used in many places where pointers are referenced in stead of XID's. Those places are corrected.

56 files changed, 734 insertions, 730 deletions

diff --git a/generic/tk3d.c b/generic/tk3d.c
index a97bed3..eebe122 100644
--- a/generic/tk3d.c
+++ b/generic/tk3d.c
@@ -236,7 +236,7 @@ Tk_Get3DBorder(
     borderPtr->bgColorPtr = bgColorPtr;
     borderPtr->darkColorPtr = NULL;
     borderPtr->lightColorPtr = NULL;
-    borderPtr->shadow = 0;
+    borderPtr->shadow = None;
     borderPtr->bgGC = 0;
     borderPtr->darkGC = 0;
     borderPtr->lightGC = 0;
@@ -375,7 +375,7 @@ Tk_3DBorderGC(
 {
     TkBorder * borderPtr = (TkBorder *) border;
 
-    if (!borderPtr->lightGC && (which != TK_3D_FLAT_GC)) {
+    if ((borderPtr->lightGC == None) && (which != TK_3D_FLAT_GC)) {
 	TkpGetShadows(borderPtr, tkwin);
     }
     if (which == TK_3D_FLAT_GC) {
@@ -392,7 +392,7 @@ Tk_3DBorderGC(
      * compilers happy.
      */
 
-    return 0;
+    return (GC) None;
 }
 
 /*
@@ -428,29 +428,29 @@ Tk_Free3DBorder(
 
     prevPtr = (TkBorder *) Tcl_GetHashValue(borderPtr->hashPtr);
     TkpFreeBorder(borderPtr);
-    if (borderPtr->bgColorPtr) {
+    if (borderPtr->bgColorPtr != NULL) {
 	Tk_FreeColor(borderPtr->bgColorPtr);
     }
-    if (borderPtr->darkColorPtr) {
+    if (borderPtr->darkColorPtr != NULL) {
 	Tk_FreeColor(borderPtr->darkColorPtr);
     }
-    if (borderPtr->lightColorPtr) {
+    if (borderPtr->lightColorPtr != NULL) {
 	Tk_FreeColor(borderPtr->lightColorPtr);
     }
-    if (borderPtr->shadow) {
+    if (borderPtr->shadow != None) {
 	Tk_FreeBitmap(display, borderPtr->shadow);
     }
-    if (borderPtr->bgGC) {
+    if (borderPtr->bgGC != None) {
 	Tk_FreeGC(display, borderPtr->bgGC);
     }
-    if (borderPtr->darkGC) {
+    if (borderPtr->darkGC != None) {
 	Tk_FreeGC(display, borderPtr->darkGC);
     }
-    if (borderPtr->lightGC) {
+    if (borderPtr->lightGC != None) {
 	Tk_FreeGC(display, borderPtr->lightGC);
     }
     if (prevPtr == borderPtr) {
-	if (!borderPtr->nextPtr) {
+	if (borderPtr->nextPtr == NULL) {
 	    Tcl_DeleteHashEntry(borderPtr->hashPtr);
 	} else {
 	    Tcl_SetHashValue(borderPtr->hashPtr, borderPtr->nextPtr);
@@ -759,7 +759,7 @@ Tk_Draw3DPolygon(
     int i, lightOnLeft, dx, dy, parallel, pointsSeen;
     Display *display = Tk_Display(tkwin);
 
-    if (!borderPtr->lightGC) {
+    if (borderPtr->lightGC == None) {
 	TkpGetShadows(borderPtr, tkwin);
     }
 
diff --git a/generic/tkBind.c b/generic/tkBind.c
index df82323..c4f8226 100644
--- a/generic/tkBind.c
+++ b/generic/tkBind.c
@@ -631,7 +631,7 @@ static const TkStateMap visNotify[] = {
 };
 
 static const TkStateMap configureRequestDetail[] = {
-    {0,			"None"},
+    {None,		"None"},
     {Above,		"Above"},
     {Below,		"Below"},
     {BottomIf,		"BottomIf"},
@@ -3870,7 +3870,7 @@ DoWarp(
 {
     TkDisplay *dispPtr = (TkDisplay *) clientData;
 
-    XWarpPointer(dispPtr->display, 0, (Window) dispPtr->warpWindow,
+    XWarpPointer(dispPtr->display, (Window) None, (Window) dispPtr->warpWindow,
 	    0, 0, 0, 0, (int) dispPtr->warpX, (int) dispPtr->warpY);
     XForceScreenSaver(dispPtr->display, ScreenSaverReset);
     dispPtr->flags &= ~TK_DISPLAY_IN_WARP;
diff --git a/generic/tkBitmap.c b/generic/tkBitmap.c
index 73ab9fd..f7df546 100644
--- a/generic/tkBitmap.c
+++ b/generic/tkBitmap.c
@@ -218,7 +218,7 @@ Tk_AllocBitmapFromObj(
     bitmapPtr = GetBitmap(interp, tkwin, Tcl_GetString(objPtr));
     objPtr->internalRep.twoPtrValue.ptr1 = (void *) bitmapPtr;
     if (bitmapPtr == NULL) {
-	return 0;
+	return None;
     }
     bitmapPtr->objRefCount++;
     return bitmapPtr->bitmap;
@@ -260,7 +260,7 @@ Tk_GetBitmap(
     TkBitmap *bitmapPtr = GetBitmap(interp, tkwin, string);
 
     if (bitmapPtr == NULL) {
-	return 0;
+	return None;
     }
     return bitmapPtr->bitmap;
 }
@@ -381,7 +381,7 @@ GetBitmap(
 	    bitmap = TkpGetNativeAppBitmap(Tk_Display(tkwin), string,
 		    &width, &height);
 
-	    if (!bitmap) {
+	    if (bitmap == None) {
 		if (interp != NULL) {
 		    Tcl_AppendResult(interp, "bitmap \"", string,
 			    "\" not defined", NULL);
@@ -395,7 +395,7 @@ GetBitmap(
 	    if (predefPtr->native) {
 		bitmap = TkpCreateNativeBitmap(Tk_Display(tkwin),
 		    predefPtr->source);
-		if (!bitmap) {
+		if (bitmap == None) {
 		    Tcl_Panic("native bitmap creation failed");
 		}
 	    } else {
diff --git a/generic/tkButton.c b/generic/tkButton.c
index 1967ab2..0d8b9a4 100644
--- a/generic/tkButton.c
+++ b/generic/tkButton.c
@@ -688,7 +688,7 @@ ButtonCreate(
     butPtr->textPtr = NULL;
     butPtr->underline = -1;
     butPtr->textVarNamePtr = NULL;
-    butPtr->bitmap = 0;
+    butPtr->bitmap = None;
     butPtr->imagePtr = NULL;
     butPtr->image = NULL;
     butPtr->selectImagePtr = NULL;
@@ -710,12 +710,12 @@ ButtonCreate(
     butPtr->normalFg = NULL;
     butPtr->activeFg = NULL;
     butPtr->disabledFg = NULL;
-    butPtr->normalTextGC = 0;
-    butPtr->activeTextGC = 0;
-    butPtr->disabledGC = 0;
-    butPtr->stippleGC = 0;
-    butPtr->gray = 0;
-    butPtr->copyGC = 0;
+    butPtr->normalTextGC = NULL;
+    butPtr->activeTextGC = NULL;
+    butPtr->disabledGC = NULL;
+    butPtr->stippleGC = NULL;
+    butPtr->gray = None;
+    butPtr->copyGC = NULL;
     butPtr->widthPtr = NULL;
     butPtr->width = 0;
     butPtr->heightPtr = NULL;
@@ -740,7 +740,7 @@ ButtonCreate(
     butPtr->onValuePtr = NULL;
     butPtr->offValuePtr = NULL;
     butPtr->tristateValuePtr = NULL;
-    butPtr->cursor = 0;
+    butPtr->cursor = NULL;
     butPtr->takeFocusPtr = NULL;
     butPtr->commandPtr = NULL;
     butPtr->flags = 0;
@@ -969,37 +969,37 @@ DestroyButton(
 		TCL_GLOBAL_ONLY|TCL_TRACE_WRITES|TCL_TRACE_UNSETS,
 		ButtonTextVarProc, (ClientData) butPtr);
     }
-    if (butPtr->image) {
+    if (butPtr->image != NULL) {
 	Tk_FreeImage(butPtr->image);
     }
-    if (butPtr->selectImage) {
+    if (butPtr->selectImage != NULL) {
 	Tk_FreeImage(butPtr->selectImage);
     }
-    if (butPtr->tristateImage) {
+    if (butPtr->tristateImage != NULL) {
 	Tk_FreeImage(butPtr->tristateImage);
     }
-    if (butPtr->normalTextGC) {
+    if (butPtr->normalTextGC != None) {
 	Tk_FreeGC(butPtr->display, butPtr->normalTextGC);
     }
-    if (butPtr->activeTextGC) {
+    if (butPtr->activeTextGC != None) {
 	Tk_FreeGC(butPtr->display, butPtr->activeTextGC);
     }
-    if (butPtr->disabledGC) {
+    if (butPtr->disabledGC != None) {
 	Tk_FreeGC(butPtr->display, butPtr->disabledGC);
     }
-    if (butPtr->stippleGC) {
+    if (butPtr->stippleGC != None) {
 	Tk_FreeGC(butPtr->display, butPtr->stippleGC);
     }
-    if (butPtr->gray) {
+    if (butPtr->gray != None) {
 	Tk_FreeBitmap(butPtr->display, butPtr->gray);
     }
-    if (butPtr->copyGC) {
+    if (butPtr->copyGC != None) {
 	Tk_FreeGC(butPtr->display, butPtr->copyGC);
     }
-    if (butPtr->textLayout) {
+    if (butPtr->textLayout != NULL) {
 	Tk_FreeTextLayout(butPtr->textLayout);
     }
-    if (butPtr->selVarNamePtr) {
+    if (butPtr->selVarNamePtr != NULL) {
 	Tcl_UntraceVar(butPtr->interp, Tcl_GetString(butPtr->selVarNamePtr),
 		TCL_GLOBAL_ONLY|TCL_TRACE_WRITES|TCL_TRACE_UNSETS,
 		ButtonVarProc, (ClientData) butPtr);
@@ -1184,7 +1184,7 @@ ConfigureButton(
 	 * don't go to zero and cause image data to be discarded.
 	 */
 
-	if (butPtr->imagePtr) {
+	if (butPtr->imagePtr != NULL) {
 	    image = Tk_GetImage(butPtr->interp, butPtr->tkwin,
 		    Tcl_GetString(butPtr->imagePtr), ButtonImageProc,
 		    (ClientData) butPtr);
@@ -1198,7 +1198,7 @@ ConfigureButton(
 	    Tk_FreeImage(butPtr->image);
 	}
 	butPtr->image = image;
-	if (butPtr->selectImagePtr) {
+	if (butPtr->selectImagePtr != NULL) {
 	    image = Tk_GetImage(butPtr->interp, butPtr->tkwin,
 		    Tcl_GetString(butPtr->selectImagePtr),
 		    ButtonSelectImageProc, (ClientData) butPtr);
@@ -1208,7 +1208,7 @@ ConfigureButton(
 	} else {
 	    image = NULL;
 	}
-	if (butPtr->selectImage) {
+	if (butPtr->selectImage != NULL) {
 	    Tk_FreeImage(butPtr->selectImage);
 	}
 	butPtr->selectImage = image;
@@ -1228,7 +1228,7 @@ ConfigureButton(
 	butPtr->tristateImage = image;
 
 	haveImage = 0;
-	if (butPtr->imagePtr || butPtr->bitmap) {
+	if (butPtr->imagePtr != NULL || butPtr->bitmap != None) {
 	    haveImage = 1;
 	}
 	if ((!haveImage || butPtr->compound != COMPOUND_NONE)
@@ -1243,14 +1243,14 @@ ConfigureButton(
 
 	    namePtr = butPtr->textVarNamePtr;
 	    valuePtr = Tcl_ObjGetVar2(interp, namePtr, NULL, TCL_GLOBAL_ONLY);
-	    if (!valuePtr) {
+	    if (valuePtr == NULL) {
 		if (Tcl_ObjSetVar2(interp, namePtr, NULL, butPtr->textPtr,
 			TCL_GLOBAL_ONLY|TCL_LEAVE_ERR_MSG)
 			== NULL) {
 		    continue;
 		}
 	    } else {
-		if (butPtr->textPtr) {
+		if (butPtr->textPtr != NULL) {
 		    Tcl_DecrRefCount(butPtr->textPtr);
 		}
 		butPtr->textPtr = valuePtr;
@@ -1258,7 +1258,7 @@ ConfigureButton(
 	    }
 	}
 
-	if (butPtr->bitmap || butPtr->imagePtr) {
+	if ((butPtr->bitmap != None) || (butPtr->imagePtr != NULL)) {
 	    /*
 	     * The button must display the contents of an image or bitmap.
 	     */
@@ -1366,17 +1366,17 @@ TkButtonWorldChanged(
     gcValues.graphics_exposures = False;
     mask = GCForeground | GCBackground | GCFont | GCGraphicsExposures;
     newGC = Tk_GetGC(butPtr->tkwin, mask, &gcValues);
-    if (butPtr->normalTextGC) {
+    if (butPtr->normalTextGC != None) {
 	Tk_FreeGC(butPtr->display, butPtr->normalTextGC);
     }
     butPtr->normalTextGC = newGC;
 
-    if (butPtr->activeFg) {
+    if (butPtr->activeFg != NULL) {
 	gcValues.foreground = butPtr->activeFg->pixel;
 	gcValues.background = Tk_3DBorderColor(butPtr->activeBorder)->pixel;
 	mask = GCForeground | GCBackground | GCFont;
 	newGC = Tk_GetGC(butPtr->tkwin, mask, &gcValues);
-	if (butPtr->activeTextGC) {
+	if (butPtr->activeTextGC != None) {
 	    Tk_FreeGC(butPtr->display, butPtr->activeTextGC);
 	}
 	butPtr->activeTextGC = newGC;
@@ -1388,13 +1388,13 @@ TkButtonWorldChanged(
      * Create the GC that can be used for stippling
      */
 
-    if (!butPtr->stippleGC) {
+    if (butPtr->stippleGC == None) {
 	gcValues.foreground = gcValues.background;
 	mask = GCForeground;
-	if (!butPtr->gray) {
+	if (butPtr->gray == None) {
 	    butPtr->gray = Tk_GetBitmap(NULL, butPtr->tkwin, "gray50");
 	}
-	if (butPtr->gray) {
+	if (butPtr->gray != None) {
 	    gcValues.fill_style = FillStippled;
 	    gcValues.stipple = butPtr->gray;
 	    mask |= GCFillStyle | GCStipple;
@@ -1408,18 +1408,18 @@ TkButtonWorldChanged(
      */
 
     mask = GCForeground | GCBackground | GCFont;
-    if (butPtr->disabledFg) {
+    if (butPtr->disabledFg != NULL) {
 	gcValues.foreground = butPtr->disabledFg->pixel;
     } else {
 	gcValues.foreground = gcValues.background;
     }
     newGC = Tk_GetGC(butPtr->tkwin, mask, &gcValues);
-    if (butPtr->disabledGC) {
+    if (butPtr->disabledGC != None) {
 	Tk_FreeGC(butPtr->display, butPtr->disabledGC);
     }
     butPtr->disabledGC = newGC;
 
-    if (!butPtr->copyGC) {
+    if (butPtr->copyGC == None) {
 	butPtr->copyGC = Tk_GetGC(butPtr->tkwin, 0, &gcValues);
     }
 
diff --git a/generic/tkCanvArc.c b/generic/tkCanvArc.c
index 101f7aa..33367de 100644
--- a/generic/tkCanvArc.c
+++ b/generic/tkCanvArc.c
@@ -296,11 +296,11 @@ CreateArc(
     arcPtr->fillColor = NULL;
     arcPtr->activeFillColor = NULL;
     arcPtr->disabledFillColor = NULL;
-    arcPtr->fillStipple = 0;
-    arcPtr->activeFillStipple = 0;
-    arcPtr->disabledFillStipple = 0;
+    arcPtr->fillStipple = None;
+    arcPtr->activeFillStipple = None;
+    arcPtr->disabledFillStipple = None;
     arcPtr->style = PIESLICE_STYLE;
-    arcPtr->fillGC = 0;
+    arcPtr->fillGC = NULL;
 
     /*
      * Process the arguments to fill in the item record.
@@ -452,11 +452,11 @@ ConfigureArc(
      */
 
     if (arcPtr->outline.activeWidth > arcPtr->outline.width ||
-	    arcPtr->outline.activeDash.number ||
-	    arcPtr->outline.activeColor ||
-	    arcPtr->outline.activeStipple ||
-	    arcPtr->activeFillColor ||
-	    arcPtr->activeFillStipple) {
+	    arcPtr->outline.activeDash.number != 0 ||
+	    arcPtr->outline.activeColor != NULL ||
+	    arcPtr->outline.activeStipple != None ||
+	    arcPtr->activeFillColor != NULL ||
+	    arcPtr->activeFillStipple != None) {
 	itemPtr->redraw_flags |= TK_ITEM_STATE_DEPENDANT;
     } else {
 	itemPtr->redraw_flags &= ~TK_ITEM_STATE_DEPENDANT;
@@ -493,9 +493,9 @@ ConfigureArc(
 	mask |= GCCapStyle;
 	newGC = Tk_GetGC(tkwin, mask, &gcValues);
     } else {
-	newGC = 0;
+	newGC = NULL;
     }
-    if (arcPtr->outline.gc) {
+    if (arcPtr->outline.gc != None) {
 	Tk_FreeGC(Tk_Display(tkwin), arcPtr->outline.gc);
     }
     arcPtr->outline.gc = newGC;
@@ -511,23 +511,23 @@ ConfigureArc(
     color = arcPtr->fillColor;
     stipple = arcPtr->fillStipple;
     if (((TkCanvas *)canvas)->currentItemPtr == itemPtr) {
-	if (arcPtr->activeFillColor) {
+	if (arcPtr->activeFillColor!=NULL) {
 	    color = arcPtr->activeFillColor;
 	}
-	if (arcPtr->activeFillStipple) {
+	if (arcPtr->activeFillStipple!=None) {
 	    stipple = arcPtr->activeFillStipple;
 	}
     } else if (state==TK_STATE_DISABLED) {
-	if (arcPtr->disabledFillColor) {
+	if (arcPtr->disabledFillColor!=NULL) {
 	    color = arcPtr->disabledFillColor;
 	}
-	if (arcPtr->disabledFillStipple) {
+	if (arcPtr->disabledFillStipple!=None) {
 	    stipple = arcPtr->disabledFillStipple;
 	}
       }
 
-    if ((arcPtr->style == ARC_STYLE) || !color) {
-	newGC = 0;
+    if ((arcPtr->style == ARC_STYLE) || (!color)) {
+	newGC = NULL;
     } else {
 	gcValues.foreground = color->pixel;
 	if (arcPtr->style == CHORD_STYLE) {
@@ -536,14 +536,14 @@ ConfigureArc(
 	    gcValues.arc_mode = ArcPieSlice;
 	}
 	mask = GCForeground|GCArcMode;
-	if (stipple) {
+	if (stipple != None) {
 	    gcValues.stipple = stipple;
 	    gcValues.fill_style = FillStippled;
 	    mask |= GCStipple|GCFillStyle;
 	}
 	newGC = Tk_GetGC(tkwin, mask, &gcValues);
     }
-    if (arcPtr->fillGC) {
+    if (arcPtr->fillGC != None) {
 	Tk_FreeGC(Tk_Display(tkwin), arcPtr->fillGC);
     }
     arcPtr->fillGC = newGC;
@@ -598,25 +598,25 @@ DeleteArc(
     if (arcPtr->numOutlinePoints != 0) {
 	ckfree((char *) arcPtr->outlinePtr);
     }
-    if (arcPtr->fillColor) {
+    if (arcPtr->fillColor != NULL) {
 	Tk_FreeColor(arcPtr->fillColor);
     }
-    if (arcPtr->activeFillColor) {
+    if (arcPtr->activeFillColor != NULL) {
 	Tk_FreeColor(arcPtr->activeFillColor);
     }
-    if (arcPtr->disabledFillColor) {
+    if (arcPtr->disabledFillColor != NULL) {
 	Tk_FreeColor(arcPtr->disabledFillColor);
     }
-    if (arcPtr->fillStipple) {
+    if (arcPtr->fillStipple != None) {
 	Tk_FreeBitmap(display, arcPtr->fillStipple);
     }
-    if (arcPtr->activeFillStipple) {
+    if (arcPtr->activeFillStipple != None) {
 	Tk_FreeBitmap(display, arcPtr->activeFillStipple);
     }
-    if (arcPtr->disabledFillStipple) {
+    if (arcPtr->disabledFillStipple != None) {
 	Tk_FreeBitmap(display, arcPtr->disabledFillStipple);
     }
-    if (arcPtr->fillGC) {
+    if (arcPtr->fillGC != None) {
 	Tk_FreeGC(display, arcPtr->fillGC);
     }
 }
@@ -747,7 +747,7 @@ ComputeArcBbox(
      * drawn) and add one extra pixel just for safety.
      */
 
-    if (!arcPtr->outline.gc) {
+    if (arcPtr->outline.gc == None) {
 	tmp = 1;
     } else {
 	tmp = (int) ((width + 1.0)/2.0 + 1);
@@ -804,20 +804,20 @@ DisplayArc(
 	if (arcPtr->outline.activeWidth>lineWidth) {
 	    lineWidth = arcPtr->outline.activeWidth;
 	}
-	if (arcPtr->outline.activeDash.number) {
+	if (arcPtr->outline.activeDash.number != 0) {
 	    dashnumber = arcPtr->outline.activeDash.number;
 	}
-	if (arcPtr->activeFillStipple) {
+	if (arcPtr->activeFillStipple != None) {
 	    stipple = arcPtr->activeFillStipple;
 	}
     } else if (state == TK_STATE_DISABLED) {
 	if (arcPtr->outline.disabledWidth > 0) {
 	    lineWidth = arcPtr->outline.disabledWidth;
 	}
-	if (arcPtr->outline.disabledDash.number) {
+	if (arcPtr->outline.disabledDash.number != 0) {
 	    dashnumber = arcPtr->outline.disabledDash.number;
 	}
-	if (arcPtr->disabledFillStipple) {
+	if (arcPtr->disabledFillStipple != None) {
 	    stipple = arcPtr->disabledFillStipple;
 	}
     }
@@ -846,8 +846,8 @@ DisplayArc(
      * window servers to crash and should be a no-op anyway.
      */
 
-    if ((arcPtr->fillGC) && (extent != 0)) {
-	if (stipple) {
+    if ((arcPtr->fillGC != None) && (extent != 0)) {
+	if (stipple != None) {
 	    int w = 0;
 	    int h = 0;
 	    Tk_TSOffset *tsoffset = &arcPtr->tsoffset;
@@ -876,14 +876,14 @@ DisplayArc(
 	}
 	XFillArc(display, drawable, arcPtr->fillGC, x1, y1, (unsigned) (x2-x1),
 		(unsigned) (y2-y1), start, extent);
-	if (stipple) {
+	if (stipple != None) {
 	    XSetTSOrigin(display, arcPtr->fillGC, 0, 0);
 	}
     }
-    if (arcPtr->outline.gc) {
+    if (arcPtr->outline.gc != None) {
 	Tk_ChangeOutlineGC(canvas, itemPtr, &(arcPtr->outline));
 
-	if (extent) {
+	if (extent != 0) {
 	    XDrawArc(display, drawable, arcPtr->outline.gc, x1, y1,
 		    (unsigned) (x2-x1), (unsigned) (y2-y1), start, extent);
 	}
@@ -895,7 +895,7 @@ DisplayArc(
 	 * outline is dashed, because then polygons don't work.
 	 */
 
-	if (lineWidth < 1.5 || dashnumber) {
+	if (lineWidth < 1.5 || dashnumber != 0) {
 	    Tk_CanvasDrawableCoords(canvas, arcPtr->center1[0],
 		    arcPtr->center1[1], &x1, &y1);
 	    Tk_CanvasDrawableCoords(canvas, arcPtr->center2[0],
@@ -918,13 +918,13 @@ DisplayArc(
 	} else {
 	    if (arcPtr->style == CHORD_STYLE) {
 		TkFillPolygon(canvas, arcPtr->outlinePtr, CHORD_OUTLINE_PTS,
-			display, drawable, arcPtr->outline.gc, 0);
+			display, drawable, arcPtr->outline.gc, NULL);
 	    } else if (arcPtr->style == PIESLICE_STYLE) {
 		TkFillPolygon(canvas, arcPtr->outlinePtr, PIE_OUTLINE1_PTS,
-			display, drawable, arcPtr->outline.gc, 0);
+			display, drawable, arcPtr->outline.gc, NULL);
 		TkFillPolygon(canvas, arcPtr->outlinePtr + 2*PIE_OUTLINE1_PTS,
 			PIE_OUTLINE2_PTS, display, drawable,
-			arcPtr->outline.gc, 0);
+			arcPtr->outline.gc, NULL);
 	    }
 	}
 
@@ -1030,12 +1030,12 @@ ArcToPoint(
 	return dist;
     }
 
-    if (arcPtr->fillGC || !arcPtr->outline.gc) {
+    if ((arcPtr->fillGC != None) || (arcPtr->outline.gc == None)) {
 	filled = 1;
     } else {
 	filled = 0;
     }
-    if (!arcPtr->outline.gc) {
+    if (arcPtr->outline.gc == None) {
 	width = 0.0;
     }
 
@@ -1157,12 +1157,12 @@ ArcToArea(
 	}
     }
 
-    if ((arcPtr->fillGC) || !arcPtr->outline.gc) {
+    if ((arcPtr->fillGC != None) || (arcPtr->outline.gc == None)) {
 	filled = 1;
     } else {
 	filled = 0;
     }
-    if (!arcPtr->outline.gc) {
+    if (arcPtr->outline.gc == None) {
 	width = 0.0;
     }
 
@@ -1857,29 +1857,29 @@ ArcToPostscript(
     fillColor = arcPtr->fillColor;
     fillStipple = arcPtr->fillStipple;
     if (((TkCanvas *)canvas)->currentItemPtr == itemPtr) {
-	if (arcPtr->outline.activeColor) {
+	if (arcPtr->outline.activeColor!=NULL) {
 	    color = arcPtr->outline.activeColor;
 	}
-	if (arcPtr->outline.activeStipple) {
+	if (arcPtr->outline.activeStipple!=None) {
 	    stipple = arcPtr->outline.activeStipple;
 	}
-	if (arcPtr->activeFillColor) {
+	if (arcPtr->activeFillColor!=NULL) {
 	    fillColor = arcPtr->activeFillColor;
 	}
-	if (arcPtr->activeFillStipple) {
+	if (arcPtr->activeFillStipple!=None) {
 	    fillStipple = arcPtr->activeFillStipple;
 	}
     } else if (state == TK_STATE_DISABLED) {
-	if (arcPtr->outline.disabledColor) {
+	if (arcPtr->outline.disabledColor!=NULL) {
 	    color = arcPtr->outline.disabledColor;
 	}
-	if (arcPtr->outline.disabledStipple) {
+	if (arcPtr->outline.disabledStipple!=None) {
 	    stipple = arcPtr->outline.disabledStipple;
 	}
-	if (arcPtr->disabledFillColor) {
+	if (arcPtr->disabledFillColor!=NULL) {
 	    fillColor = arcPtr->disabledFillColor;
 	}
-	if (arcPtr->disabledFillStipple) {
+	if (arcPtr->disabledFillStipple!=None) {
 	    fillStipple = arcPtr->disabledFillStipple;
 	}
     }
@@ -1889,7 +1889,7 @@ ArcToPostscript(
      * arc.
      */
 
-    if (arcPtr->fillGC) {
+    if (arcPtr->fillGC != None) {
 	sprintf(buffer, "matrix currentmatrix\n%.15g %.15g translate %.15g %.15g scale\n",
 		(arcPtr->bbox[0] + arcPtr->bbox[2])/2, (y1 + y2)/2,
 		(arcPtr->bbox[2] - arcPtr->bbox[0])/2, (y1 - y2)/2);
@@ -1906,12 +1906,12 @@ ArcToPostscript(
 	if (Tk_CanvasPsColor(interp, canvas, fillColor) != TCL_OK) {
 	    return TCL_ERROR;
 	}
-	if (fillStipple) {
+	if (fillStipple != None) {
 	    Tcl_AppendResult(interp, "clip ", NULL);
 	    if (Tk_CanvasPsStipple(interp, canvas, fillStipple) != TCL_OK) {
 		return TCL_ERROR;
 	    }
-	    if (arcPtr->outline.gc) {
+	    if (arcPtr->outline.gc != None) {
 		Tcl_AppendResult(interp, "grestore gsave\n", NULL);
 	    }
 	} else {
@@ -1923,7 +1923,7 @@ ArcToPostscript(
      * If there's an outline for the arc, draw it.
      */
 
-    if (arcPtr->outline.gc) {
+    if (arcPtr->outline.gc != None) {
 	sprintf(buffer, "matrix currentmatrix\n%.15g %.15g translate %.15g %.15g scale\n",
 		(arcPtr->bbox[0] + arcPtr->bbox[2])/2, (y1 + y2)/2,
 		(arcPtr->bbox[2] - arcPtr->bbox[0])/2, (y1 - y2)/2);
@@ -1946,7 +1946,7 @@ ArcToPostscript(
 			!= TCL_OK) {
 		    return TCL_ERROR;
 		}
-		if (stipple) {
+		if (stipple != None) {
 		    Tcl_AppendResult(interp, "clip ", NULL);
 		    if (Tk_CanvasPsStipple(interp, canvas, stipple) != TCL_OK){
 			return TCL_ERROR;
@@ -1963,7 +1963,7 @@ ArcToPostscript(
 		    != TCL_OK) {
 		return TCL_ERROR;
 	    }
-	    if (stipple) {
+	    if (stipple != None) {
 		Tcl_AppendResult(interp, "clip ", NULL);
 		if (Tk_CanvasPsStipple(interp, canvas, stipple) != TCL_OK) {
 		    return TCL_ERROR;
diff --git a/generic/tkCanvBmap.c b/generic/tkCanvBmap.c
index 6f38293..5f97ef2 100644
--- a/generic/tkCanvBmap.c
+++ b/generic/tkCanvBmap.c
@@ -182,16 +182,16 @@ TkcCreateBitmap(
      */
 
     bmapPtr->anchor = TK_ANCHOR_CENTER;
-    bmapPtr->bitmap = 0;
-    bmapPtr->activeBitmap = 0;
-    bmapPtr->disabledBitmap = 0;
+    bmapPtr->bitmap = None;
+    bmapPtr->activeBitmap = None;
+    bmapPtr->disabledBitmap = None;
     bmapPtr->fgColor = NULL;
     bmapPtr->activeFgColor = NULL;
     bmapPtr->disabledFgColor = NULL;
     bmapPtr->bgColor = NULL;
     bmapPtr->activeBgColor = NULL;
     bmapPtr->disabledBgColor = NULL;
-    bmapPtr->gc = 0;
+    bmapPtr->gc = NULL;
 
     /*
      * Process the arguments to fill in the item record. Only 1 (list) or 2 (x
@@ -336,9 +336,9 @@ ConfigureBitmap(
 
     state = itemPtr->state;
 
-    if (bmapPtr->activeFgColor ||
-	    bmapPtr->activeBgColor ||
-	    bmapPtr->activeBitmap) {
+    if (bmapPtr->activeFgColor!=NULL ||
+	    bmapPtr->activeBgColor!=NULL ||
+	    bmapPtr->activeBitmap!=None) {
 	itemPtr->redraw_flags |= TK_ITEM_STATE_DEPENDANT;
     } else {
 	itemPtr->redraw_flags &= ~TK_ITEM_STATE_DEPENDANT;
@@ -355,33 +355,33 @@ ConfigureBitmap(
     bgColor = bmapPtr->bgColor;
     bitmap = bmapPtr->bitmap;
     if (((TkCanvas *)canvas)->currentItemPtr == itemPtr) {
-	if (bmapPtr->activeFgColor) {
+	if (bmapPtr->activeFgColor!=NULL) {
 	    fgColor = bmapPtr->activeFgColor;
 	}
-	if (bmapPtr->activeBgColor) {
+	if (bmapPtr->activeBgColor!=NULL) {
 	    bgColor = bmapPtr->activeBgColor;
 	}
-	if (bmapPtr->activeBitmap) {
+	if (bmapPtr->activeBitmap!=None) {
 	    bitmap = bmapPtr->activeBitmap;
 	}
     } else if (state == TK_STATE_DISABLED) {
-	if (bmapPtr->disabledFgColor) {
+	if (bmapPtr->disabledFgColor!=NULL) {
 	    fgColor = bmapPtr->disabledFgColor;
 	}
-	if (bmapPtr->disabledBgColor) {
+	if (bmapPtr->disabledBgColor!=NULL) {
 	    bgColor = bmapPtr->disabledBgColor;
 	}
-	if (bmapPtr->disabledBitmap) {
+	if (bmapPtr->disabledBitmap!=None) {
 	    bitmap = bmapPtr->disabledBitmap;
 	}
     }
 
     if (!bitmap) {
-	newGC = 0;
+	newGC = NULL;
     } else {
 	gcValues.foreground = fgColor->pixel;
 	mask = GCForeground;
-	if (bgColor) {
+	if (bgColor != NULL) {
 	    gcValues.background = bgColor->pixel;
 	    mask |= GCBackground;
 	} else {
@@ -390,7 +390,7 @@ ConfigureBitmap(
 	}
 	newGC = Tk_GetGC(tkwin, mask, &gcValues);
     }
-    if (bmapPtr->gc) {
+    if (bmapPtr->gc != None) {
 	Tk_FreeGC(Tk_Display(tkwin), bmapPtr->gc);
     }
     bmapPtr->gc = newGC;
@@ -424,34 +424,34 @@ DeleteBitmap(
 {
     BitmapItem *bmapPtr = (BitmapItem *) itemPtr;
 
-    if (bmapPtr->bitmap) {
+    if (bmapPtr->bitmap != None) {
 	Tk_FreeBitmap(display, bmapPtr->bitmap);
     }
-    if (bmapPtr->activeBitmap) {
+    if (bmapPtr->activeBitmap != None) {
 	Tk_FreeBitmap(display, bmapPtr->activeBitmap);
     }
-    if (bmapPtr->disabledBitmap) {
+    if (bmapPtr->disabledBitmap != None) {
 	Tk_FreeBitmap(display, bmapPtr->disabledBitmap);
     }
-    if (bmapPtr->fgColor) {
+    if (bmapPtr->fgColor != NULL) {
 	Tk_FreeColor(bmapPtr->fgColor);
     }
-    if (bmapPtr->activeFgColor) {
+    if (bmapPtr->activeFgColor != NULL) {
 	Tk_FreeColor(bmapPtr->activeFgColor);
     }
-    if (bmapPtr->disabledFgColor) {
+    if (bmapPtr->disabledFgColor != NULL) {
 	Tk_FreeColor(bmapPtr->disabledFgColor);
     }
-    if (bmapPtr->bgColor) {
+    if (bmapPtr->bgColor != NULL) {
 	Tk_FreeColor(bmapPtr->bgColor);
     }
-    if (bmapPtr->activeBgColor) {
+    if (bmapPtr->activeBgColor != NULL) {
 	Tk_FreeColor(bmapPtr->activeBgColor);
     }
-    if (bmapPtr->disabledBgColor) {
+    if (bmapPtr->disabledBgColor != NULL) {
 	Tk_FreeColor(bmapPtr->disabledBgColor);
     }
-    if (bmapPtr->gc) {
+    if (bmapPtr->gc != NULL) {
 	Tk_FreeGC(display, bmapPtr->gc);
     }
 }
@@ -490,11 +490,11 @@ ComputeBitmapBbox(
     }
     bitmap = bmapPtr->bitmap;
     if (((TkCanvas *)canvas)->currentItemPtr == (Tk_Item *)bmapPtr) {
-	if (bmapPtr->activeBitmap) {
+	if (bmapPtr->activeBitmap!=None) {
 	    bitmap = bmapPtr->activeBitmap;
 	}
-    } else if (state == TK_STATE_DISABLED) {
-	if (bmapPtr->disabledBitmap) {
+    } else if (state==TK_STATE_DISABLED) {
+	if (bmapPtr->disabledBitmap!=None) {
 	    bitmap = bmapPtr->disabledBitmap;
 	}
     }
@@ -502,7 +502,7 @@ ComputeBitmapBbox(
     x = (int) (bmapPtr->x + ((bmapPtr->x >= 0) ? 0.5 : - 0.5));
     y = (int) (bmapPtr->y + ((bmapPtr->y >= 0) ? 0.5 : - 0.5));
 
-    if ((state == TK_STATE_HIDDEN) || !bitmap) {
+    if (state==TK_STATE_HIDDEN || bitmap == None) {
 	bmapPtr->header.x1 = bmapPtr->header.x2 = x;
 	bmapPtr->header.y1 = bmapPtr->header.y2 = y;
 	return;
@@ -600,16 +600,16 @@ DisplayBitmap(
     }
     bitmap = bmapPtr->bitmap;
     if (((TkCanvas *)canvas)->currentItemPtr == itemPtr) {
-	if (bmapPtr->activeBitmap) {
+	if (bmapPtr->activeBitmap!=None) {
 	    bitmap = bmapPtr->activeBitmap;
 	}
     } else if (state == TK_STATE_DISABLED) {
-	if (bmapPtr->disabledBitmap) {
+	if (bmapPtr->disabledBitmap!=None) {
 	    bitmap = bmapPtr->disabledBitmap;
 	}
     }
 
-    if (bitmap) {
+    if (bitmap != None) {
 	if (x > bmapPtr->header.x1) {
 	    bmapX = x - bmapPtr->header.x1;
 	    bmapWidth = bmapPtr->header.x2 - x;
@@ -868,28 +868,28 @@ BitmapToPostscript(
     bgColor = bmapPtr->bgColor;
     bitmap = bmapPtr->bitmap;
     if (((TkCanvas *)canvas)->currentItemPtr == itemPtr) {
-	if (bmapPtr->activeFgColor) {
+	if (bmapPtr->activeFgColor!=NULL) {
 	    fgColor = bmapPtr->activeFgColor;
 	}
-	if (bmapPtr->activeBgColor) {
+	if (bmapPtr->activeBgColor!=NULL) {
 	    bgColor = bmapPtr->activeBgColor;
 	}
-	if (bmapPtr->activeBitmap) {
+	if (bmapPtr->activeBitmap!=None) {
 	    bitmap = bmapPtr->activeBitmap;
 	}
     } else if (state == TK_STATE_DISABLED) {
-	if (bmapPtr->disabledFgColor) {
+	if (bmapPtr->disabledFgColor!=NULL) {
 	    fgColor = bmapPtr->disabledFgColor;
 	}
-	if (bmapPtr->disabledBgColor) {
+	if (bmapPtr->disabledBgColor!=NULL) {
 	    bgColor = bmapPtr->disabledBgColor;
 	}
-	if (bmapPtr->disabledBitmap) {
+	if (bmapPtr->disabledBitmap!=None) {
 	    bitmap = bmapPtr->disabledBitmap;
 	}
     }
 
-    if (!bitmap) {
+    if (bitmap == None) {
 	return TCL_OK;
     }
 
diff --git a/generic/tkCanvImg.c b/generic/tkCanvImg.c
index 134cc23..9e928c7 100644
--- a/generic/tkCanvImg.c
+++ b/generic/tkCanvImg.c
@@ -436,16 +436,16 @@ ComputeImageBbox(
     Tk_Image image;
     Tk_State state = imgPtr->header.state;
 
-    if (state == TK_STATE_NULL) {
+    if(state == TK_STATE_NULL) {
 	state = ((TkCanvas *)canvas)->canvas_state;
     }
     image = imgPtr->image;
     if (((TkCanvas *)canvas)->currentItemPtr == (Tk_Item *)imgPtr) {
-	if (imgPtr->activeImage) {
+	if (imgPtr->activeImage != NULL) {
 	    image = imgPtr->activeImage;
 	}
     } else if (state == TK_STATE_DISABLED) {
-	if (imgPtr->disabledImage) {
+	if (imgPtr->disabledImage != NULL) {
 	    image = imgPtr->disabledImage;
 	}
     }
@@ -453,7 +453,7 @@ ComputeImageBbox(
     x = (int) (imgPtr->x + ((imgPtr->x >= 0) ? 0.5 : - 0.5));
     y = (int) (imgPtr->y + ((imgPtr->y >= 0) ? 0.5 : - 0.5));
 
-    if ((state == TK_STATE_HIDDEN) || !image) {
+    if ((state == TK_STATE_HIDDEN) || (image == None)) {
 	imgPtr->header.x1 = imgPtr->header.x2 = x;
 	imgPtr->header.y1 = imgPtr->header.y2 = y;
 	return;
diff --git a/generic/tkCanvLine.c b/generic/tkCanvLine.c
index 78cf74c..fea2103 100644
--- a/generic/tkCanvLine.c
+++ b/generic/tkCanvLine.c
@@ -303,7 +303,7 @@ CreateLine(
     linePtr->coordPtr = NULL;
     linePtr->capStyle = CapButt;
     linePtr->joinStyle = JoinRound;
-    linePtr->arrowGC = 0;
+    linePtr->arrowGC = NULL;
     linePtr->arrow = ARROWS_NONE;
     linePtr->arrowShapeA = (float)8.0;
     linePtr->arrowShapeB = (float)10.0;
@@ -503,9 +503,9 @@ ConfigureLine(
     }
 
     if (linePtr->outline.activeWidth > linePtr->outline.width ||
-	    linePtr->outline.activeDash.number ||
-	    linePtr->outline.activeColor ||
-	    linePtr->outline.activeStipple) {
+	    linePtr->outline.activeDash.number != 0 ||
+	    linePtr->outline.activeColor != NULL ||
+	    linePtr->outline.activeStipple != None) {
 	itemPtr->redraw_flags |= TK_ITEM_STATE_DEPENDANT;
     } else {
 	itemPtr->redraw_flags &= ~TK_ITEM_STATE_DEPENDANT;
@@ -531,7 +531,7 @@ ConfigureLine(
 #endif
 	arrowGC = Tk_GetGC(tkwin, mask, &gcValues);
     } else {
-	newGC = arrowGC = 0;
+	newGC = arrowGC = NULL;
     }
     if (linePtr->outline.gc) {
 	Tk_FreeGC(Tk_Display(tkwin), linePtr->outline.gc);
@@ -552,7 +552,7 @@ ConfigureLine(
 	linePtr->splineSteps = 100;
     }
 
-    if (!linePtr->numPoints || (state==TK_STATE_HIDDEN)) {
+    if ((!linePtr->numPoints) || (state==TK_STATE_HIDDEN)) {
 	ComputeLineBbox(canvas, linePtr);
 	return TCL_OK;
     }
@@ -562,7 +562,7 @@ ConfigureLine(
      * line's endpoints (they were shortened when the arrowheads were added).
      */
 
-    if (linePtr->firstArrowPtr && (linePtr->arrow != ARROWS_FIRST)
+    if ((linePtr->firstArrowPtr != NULL) && (linePtr->arrow != ARROWS_FIRST)
 	    && (linePtr->arrow != ARROWS_BOTH)) {
 	linePtr->coordPtr[0] = linePtr->firstArrowPtr[0];
 	linePtr->coordPtr[1] = linePtr->firstArrowPtr[1];
@@ -618,16 +618,16 @@ DeleteLine(
     LineItem *linePtr = (LineItem *) itemPtr;
 
     Tk_DeleteOutline(display, &(linePtr->outline));
-    if (linePtr->coordPtr) {
+    if (linePtr->coordPtr != NULL) {
 	ckfree((char *) linePtr->coordPtr);
     }
-    if (linePtr->arrowGC) {
+    if (linePtr->arrowGC != None) {
 	Tk_FreeGC(display, linePtr->arrowGC);
     }
-    if (linePtr->firstArrowPtr) {
+    if (linePtr->firstArrowPtr != NULL) {
 	ckfree((char *) linePtr->firstArrowPtr);
     }
-    if (linePtr->lastArrowPtr) {
+    if (linePtr->lastArrowPtr != NULL) {
 	ckfree((char *) linePtr->lastArrowPtr);
     }
 }
@@ -664,7 +664,7 @@ ComputeLineBbox(
 	state = ((TkCanvas *)canvas)->canvas_state;
     }
 
-    if (!(linePtr->numPoints) || (state == TK_STATE_HIDDEN)) {
+    if (!(linePtr->numPoints) || (state==TK_STATE_HIDDEN)) {
 	linePtr->header.x1 = -1;
 	linePtr->header.x2 = -1;
 	linePtr->header.y1 = -1;
@@ -677,7 +677,7 @@ ComputeLineBbox(
 	if (linePtr->outline.activeWidth>width) {
 	    width = linePtr->outline.activeWidth;
 	}
-    } else if (state == TK_STATE_DISABLED) {
+    } else if (state==TK_STATE_DISABLED) {
 	if (linePtr->outline.disabledWidth>0) {
 	    width = linePtr->outline.disabledWidth;
 	}
@@ -846,7 +846,7 @@ DisplayLine(
     int numPoints;
     Tk_State state = itemPtr->state;
 
-    if (!linePtr->numPoints || !linePtr->outline.gc) {
+    if ((!linePtr->numPoints)||(linePtr->outline.gc==None)) {
 	return;
     }
 
@@ -2251,7 +2251,7 @@ LineToPostscript(
 				 * being created. */
 {
     LineItem *linePtr = (LineItem *) itemPtr;
-    char buffer[64 + 4*TCL_INTEGER_SPACE];
+    char buffer[64 + TCL_INTEGER_SPACE];
     char *style;
 
     double width;
@@ -2270,20 +2270,20 @@ LineToPostscript(
 	if (linePtr->outline.activeWidth>width) {
 	    width = linePtr->outline.activeWidth;
 	}
-	if (linePtr->outline.activeColor) {
+	if (linePtr->outline.activeColor!=NULL) {
 	    color = linePtr->outline.activeColor;
 	}
-	if (linePtr->outline.activeStipple) {
+	if (linePtr->outline.activeStipple!=None) {
 	    stipple = linePtr->outline.activeStipple;
 	}
     } else if (state==TK_STATE_DISABLED) {
 	if (linePtr->outline.disabledWidth>0) {
 	    width = linePtr->outline.disabledWidth;
 	}
-	if (linePtr->outline.disabledColor) {
+	if (linePtr->outline.disabledColor!=NULL) {
 	    color = linePtr->outline.disabledColor;
 	}
-	if (linePtr->outline.disabledStipple) {
+	if (linePtr->outline.disabledStipple!=None) {
 	    stipple = linePtr->outline.disabledStipple;
 	}
     }
@@ -2301,7 +2301,7 @@ LineToPostscript(
 	if (Tk_CanvasPsColor(interp, canvas, color) != TCL_OK) {
 	    return TCL_ERROR;
 	}
-	if (stipple) {
+	if (stipple != None) {
 	    Tcl_AppendResult(interp, "clip ", NULL);
 	    if (Tk_CanvasPsStipple(interp, canvas, stipple) != TCL_OK) {
 		return TCL_ERROR;
@@ -2319,7 +2319,7 @@ LineToPostscript(
     if ((!linePtr->smooth) || (linePtr->numPoints < 3)) {
 	Tk_CanvasPsPath(interp, canvas, linePtr->coordPtr, linePtr->numPoints);
     } else {
-	if (!stipple && linePtr->smooth->postscriptProc) {
+	if ((stipple == None) && linePtr->smooth->postscriptProc) {
 	    linePtr->smooth->postscriptProc(interp, canvas,
 		    linePtr->coordPtr, linePtr->numPoints, linePtr->splineSteps);
 	} else {
@@ -2379,8 +2379,8 @@ LineToPostscript(
      * Output polygons for the arrowheads, if there are any.
      */
 
-    if (linePtr->firstArrowPtr) {
-	if (stipple) {
+    if (linePtr->firstArrowPtr != NULL) {
+	if (stipple != None) {
 	    Tcl_AppendResult(interp, "grestore gsave\n", NULL);
 	}
 	if (ArrowheadPostscript(interp, canvas, linePtr,
@@ -2389,7 +2389,7 @@ LineToPostscript(
 	}
     }
     if (linePtr->lastArrowPtr != NULL) {
-	if (stipple) {
+	if (stipple != None) {
 	    Tcl_AppendResult(interp, "grestore gsave\n", NULL);
 	}
 	if (ArrowheadPostscript(interp, canvas, linePtr,
@@ -2438,17 +2438,17 @@ ArrowheadPostscript(
 
     stipple = linePtr->outline.stipple;
     if (((TkCanvas *)canvas)->currentItemPtr == (Tk_Item *)linePtr) {
-	if (linePtr->outline.activeStipple) {
+	if (linePtr->outline.activeStipple!=None) {
 	    stipple = linePtr->outline.activeStipple;
 	}
     } else if (state==TK_STATE_DISABLED) {
-	if (linePtr->outline.activeStipple) {
+	if (linePtr->outline.activeStipple!=None) {
 	    stipple = linePtr->outline.disabledStipple;
 	}
     }
 
     Tk_CanvasPsPath(interp, canvas, arrowPtr, PTS_IN_ARROW);
-    if (stipple) {
+    if (stipple != None) {
 	Tcl_AppendResult(interp, "clip ", NULL);
 	if (Tk_CanvasPsStipple(interp, canvas, stipple) != TCL_OK) {
 	    return TCL_ERROR;
diff --git a/generic/tkCanvPoly.c b/generic/tkCanvPoly.c
index 9b210fa..0810ab6 100644
--- a/generic/tkCanvPoly.c
+++ b/generic/tkCanvPoly.c
@@ -276,10 +276,10 @@ CreatePolygon(
     polyPtr->fillColor = NULL;
     polyPtr->activeFillColor = NULL;
     polyPtr->disabledFillColor = NULL;
-    polyPtr->fillStipple = 0;
-    polyPtr->activeFillStipple = 0;
-    polyPtr->disabledFillStipple = 0;
-    polyPtr->fillGC = 0;
+    polyPtr->fillStipple = None;
+    polyPtr->activeFillStipple = None;
+    polyPtr->disabledFillStipple = None;
+    polyPtr->fillGC = NULL;
     polyPtr->smooth = NULL;
     polyPtr->splineSteps = 12;
     polyPtr->autoClosed = 0;
@@ -459,11 +459,11 @@ ConfigurePolygon(
     state = itemPtr->state;
 
     if (polyPtr->outline.activeWidth > polyPtr->outline.width ||
-	    polyPtr->outline.activeDash.number ||
-	    polyPtr->outline.activeColor ||
-	    polyPtr->outline.activeStipple ||
-	    polyPtr->activeFillColor ||
-	    polyPtr->activeFillStipple) {
+	    polyPtr->outline.activeDash.number != 0 ||
+	    polyPtr->outline.activeColor != NULL ||
+	    polyPtr->outline.activeStipple != None ||
+	    polyPtr->activeFillColor != NULL ||
+	    polyPtr->activeFillStipple != None) {
 	itemPtr->redraw_flags |= TK_ITEM_STATE_DEPENDANT;
     } else {
 	itemPtr->redraw_flags &= ~TK_ITEM_STATE_DEPENDANT;
@@ -484,7 +484,7 @@ ConfigurePolygon(
 	mask |= GCCapStyle|GCJoinStyle;
 	newGC = Tk_GetGC(tkwin, mask, &gcValues);
     } else {
-	newGC = 0;
+	newGC = NULL;
     }
     if (polyPtr->outline.gc) {
 	Tk_FreeGC(Tk_Display(tkwin), polyPtr->outline.gc);
@@ -494,23 +494,23 @@ ConfigurePolygon(
     color = polyPtr->fillColor;
     stipple = polyPtr->fillStipple;
     if (((TkCanvas *)canvas)->currentItemPtr == itemPtr) {
-	if (polyPtr->activeFillColor) {
+	if (polyPtr->activeFillColor!=NULL) {
 	    color = polyPtr->activeFillColor;
 	}
-	if (polyPtr->activeFillStipple) {
+	if (polyPtr->activeFillStipple!=None) {
 	    stipple = polyPtr->activeFillStipple;
 	}
     } else if (state==TK_STATE_DISABLED) {
 	if (polyPtr->disabledFillColor!=NULL) {
 	    color = polyPtr->disabledFillColor;
 	}
-	if (polyPtr->disabledFillStipple) {
+	if (polyPtr->disabledFillStipple!=None) {
 	    stipple = polyPtr->disabledFillStipple;
 	}
     }
 
-    if (color == NULL) {
-	newGC = 0;
+    if (!color) {
+	newGC = NULL;
     } else {
 	gcValues.foreground = color->pixel;
 	mask = GCForeground;
@@ -530,7 +530,7 @@ ConfigurePolygon(
 #endif
 	newGC = Tk_GetGC(tkwin, mask, &gcValues);
     }
-    if (polyPtr->fillGC) {
+    if (polyPtr->fillGC != None) {
 	Tk_FreeGC(Tk_Display(tkwin), polyPtr->fillGC);
     }
     polyPtr->fillGC = newGC;
@@ -575,28 +575,28 @@ DeletePolygon(
     PolygonItem *polyPtr = (PolygonItem *) itemPtr;
 
     Tk_DeleteOutline(display,&(polyPtr->outline));
-    if (polyPtr->coordPtr) {
+    if (polyPtr->coordPtr != NULL) {
 	ckfree((char *) polyPtr->coordPtr);
     }
-    if (polyPtr->fillColor) {
+    if (polyPtr->fillColor != NULL) {
 	Tk_FreeColor(polyPtr->fillColor);
     }
-    if (polyPtr->activeFillColor) {
+    if (polyPtr->activeFillColor != NULL) {
 	Tk_FreeColor(polyPtr->activeFillColor);
     }
-    if (polyPtr->disabledFillColor) {
+    if (polyPtr->disabledFillColor != NULL) {
 	Tk_FreeColor(polyPtr->disabledFillColor);
     }
-    if (polyPtr->fillStipple) {
+    if (polyPtr->fillStipple != None) {
 	Tk_FreeBitmap(display, polyPtr->fillStipple);
     }
-    if (polyPtr->activeFillStipple) {
+    if (polyPtr->activeFillStipple != None) {
 	Tk_FreeBitmap(display, polyPtr->activeFillStipple);
     }
-    if (polyPtr->disabledFillStipple) {
+    if (polyPtr->disabledFillStipple != None) {
 	Tk_FreeBitmap(display, polyPtr->disabledFillStipple);
     }
-    if (polyPtr->fillGC) {
+    if (polyPtr->fillGC != None) {
 	Tk_FreeGC(display, polyPtr->fillGC);
     }
 }
@@ -698,7 +698,7 @@ ComputePolygonBbox(
 	}
     }
 
-    if (polyPtr->outline.gc) {
+    if (polyPtr->outline.gc != None) {
 	tsoffset = &polyPtr->outline.tsoffset;
 	if (tsoffset) {
 	    if (tsoffset->flags & TK_OFFSET_INDEX) {
@@ -840,11 +840,11 @@ TkFillPolygon(
      * allocated.
      */
 
-    if (gc && (numPoints > 3)) {
+    if (gc != None && numPoints>3) {
 	XFillPolygon(display, drawable, gc, pointPtr, numPoints, Complex,
 		CoordModeOrigin);
     }
-    if (outlineGC) {
+    if (outlineGC != None) {
 	XDrawLines(display, drawable, outlineGC, pointPtr,
 	    numPoints, CoordModeOrigin);
     }
@@ -885,9 +885,9 @@ DisplayPolygon(
     Pixmap stipple = polyPtr->fillStipple;
     double linewidth = polyPtr->outline.width;
 
-    if ((!polyPtr->fillGC && !polyPtr->outline.gc) ||
+    if (((polyPtr->fillGC == None) && (polyPtr->outline.gc == None)) ||
 	    (polyPtr->numPoints < 1) ||
-	    (polyPtr->numPoints < 3 && !polyPtr->outline.gc)) {
+	    (polyPtr->numPoints < 3 && polyPtr->outline.gc == None)) {
 	return;
     }
 
@@ -898,14 +898,14 @@ DisplayPolygon(
 	if (polyPtr->outline.activeWidth>linewidth) {
 	    linewidth = polyPtr->outline.activeWidth;
 	}
-	if (polyPtr->activeFillStipple) {
+	if (polyPtr->activeFillStipple != None) {
 	    stipple = polyPtr->activeFillStipple;
 	}
     } else if (state==TK_STATE_DISABLED) {
 	if (polyPtr->outline.disabledWidth>0.0) {
 	    linewidth = polyPtr->outline.disabledWidth;
 	}
-	if (polyPtr->disabledFillStipple) {
+	if (polyPtr->disabledFillStipple != None) {
 	    stipple = polyPtr->disabledFillStipple;
 	}
     }
@@ -915,7 +915,7 @@ DisplayPolygon(
      * reset the offset when done, since the GC is supposed to be read-only.
      */
 
-    if (stipple && polyPtr->fillGC) {
+    if ((stipple != None) && (polyPtr->fillGC != None)) {
 	Tk_TSOffset *tsoffset = &polyPtr->tsoffset;
 	int w=0; int h=0;
 	int flags = tsoffset->flags;
@@ -977,11 +977,11 @@ DisplayPolygon(
 	}
 	numPoints = polyPtr->smooth->coordProc(canvas, polyPtr->coordPtr,
 		polyPtr->numPoints, polyPtr->splineSteps, pointPtr, NULL);
-	if (polyPtr->fillGC) {
+	if (polyPtr->fillGC != None) {
 	    XFillPolygon(display, drawable, polyPtr->fillGC, pointPtr,
 		    numPoints, Complex, CoordModeOrigin);
 	}
-	if (polyPtr->outline.gc) {
+	if (polyPtr->outline.gc != None) {
 	    XDrawLines(display, drawable, polyPtr->outline.gc, pointPtr,
 		    numPoints, CoordModeOrigin);
 	}
@@ -990,7 +990,7 @@ DisplayPolygon(
 	}
     }
     Tk_ResetOutlineGC(canvas, itemPtr, &(polyPtr->outline));
-    if (stipple && polyPtr->fillGC) {
+    if ((stipple != None) && (polyPtr->fillGC != None)) {
 	XSetTSOrigin(display, polyPtr->fillGC, 0, 0);
     }
 }
@@ -1303,7 +1303,7 @@ PolygonToPoint(
     if (bestDist<=0.0) {
 	goto donepoint;
     }
-    if (polyPtr->outline.gc && (polyPtr->joinStyle == JoinRound)) {
+    if ((polyPtr->outline.gc != None) && (polyPtr->joinStyle == JoinRound)) {
 	dist = bestDist - radius;
 	if (dist <= 0.0) {
 	    bestDist = 0.0;
@@ -1313,7 +1313,7 @@ PolygonToPoint(
 	}
     }
 
-    if (!polyPtr->outline.gc || (width <= 1)) {
+    if ((polyPtr->outline.gc == None) || (width <= 1)) {
 	goto donepoint;
     }
 
@@ -1520,7 +1520,7 @@ PolygonToArea(
 	goto donearea;
     }
 
-    if (!polyPtr->outline.gc) {
+    if (polyPtr->outline.gc == None) {
 	goto donearea;
     }
 
@@ -1830,32 +1830,32 @@ PolygonToPostscript(
 	if (polyPtr->outline.activeWidth>width) {
 	    width = polyPtr->outline.activeWidth;
 	}
-	if (polyPtr->outline.activeColor) {
+	if (polyPtr->outline.activeColor!=NULL) {
 	    color = polyPtr->outline.activeColor;
 	}
-	if (polyPtr->outline.activeStipple) {
+	if (polyPtr->outline.activeStipple!=None) {
 	    stipple = polyPtr->outline.activeStipple;
 	}
-	if (polyPtr->activeFillColor) {
+	if (polyPtr->activeFillColor!=NULL) {
 	    fillColor = polyPtr->activeFillColor;
 	}
-	if (polyPtr->activeFillStipple) {
+	if (polyPtr->activeFillStipple!=None) {
 	    fillStipple = polyPtr->activeFillStipple;
 	}
     } else if (state==TK_STATE_DISABLED) {
 	if (polyPtr->outline.disabledWidth>0.0) {
 	    width = polyPtr->outline.disabledWidth;
 	}
-	if (polyPtr->outline.disabledColor) {
+	if (polyPtr->outline.disabledColor!=NULL) {
 	    color = polyPtr->outline.disabledColor;
 	}
-	if (polyPtr->outline.disabledStipple) {
+	if (polyPtr->outline.disabledStipple!=None) {
 	    stipple = polyPtr->outline.disabledStipple;
 	}
-	if (polyPtr->disabledFillColor) {
+	if (polyPtr->disabledFillColor!=NULL) {
 	    fillColor = polyPtr->disabledFillColor;
 	}
-	if (polyPtr->disabledFillStipple) {
+	if (polyPtr->disabledFillStipple!=None) {
 	    fillStipple = polyPtr->disabledFillStipple;
 	}
     }
@@ -1873,7 +1873,7 @@ PolygonToPostscript(
 	if (Tk_CanvasPsColor(interp, canvas, color) != TCL_OK) {
 	    return TCL_ERROR;
 	}
-	if (stipple) {
+	if (stipple != None) {
 	    Tcl_AppendResult(interp, "clip ", NULL);
 	    if (Tk_CanvasPsStipple(interp, canvas, stipple) != TCL_OK) {
 		return TCL_ERROR;
@@ -1899,7 +1899,7 @@ PolygonToPostscript(
 	if (Tk_CanvasPsColor(interp, canvas, fillColor) != TCL_OK) {
 	    return TCL_ERROR;
 	}
-	if (fillStipple) {
+	if (fillStipple != None) {
 	    Tcl_AppendResult(interp, "eoclip ", NULL);
 	    if (Tk_CanvasPsStipple(interp, canvas, fillStipple) != TCL_OK) {
 		return TCL_ERROR;
@@ -1916,7 +1916,7 @@ PolygonToPostscript(
      * Now draw the outline, if there is one.
      */
 
-    if (color) {
+    if (color != NULL) {
 	if (!polyPtr->smooth || !polyPtr->smooth->postscriptProc) {
 	    Tk_CanvasPsPath(interp, canvas, polyPtr->coordPtr,
 		    polyPtr->numPoints);
diff --git a/generic/tkCanvText.c b/generic/tkCanvText.c
index e187871..187ec40 100644
--- a/generic/tkCanvText.c
+++ b/generic/tkCanvText.c
@@ -253,9 +253,9 @@ CreateText(
     textPtr->disabledColor = NULL;
     textPtr->tkfont	= NULL;
     textPtr->justify	= TK_JUSTIFY_LEFT;
-    textPtr->stipple	= 0;
-    textPtr->activeStipple = 0;
-    textPtr->disabledStipple = 0;
+    textPtr->stipple	= None;
+    textPtr->activeStipple = None;
+    textPtr->disabledStipple = None;
     textPtr->text	= NULL;
     textPtr->width	= 0;
     textPtr->underline	= -1;
@@ -265,9 +265,9 @@ CreateText(
     textPtr->textLayout = NULL;
     textPtr->leftEdge	= 0;
     textPtr->rightEdge	= 0;
-    textPtr->gc		= 0;
-    textPtr->selTextGC	= 0;
-    textPtr->cursorOffGC = 0;
+    textPtr->gc		= NULL;
+    textPtr->selTextGC	= NULL;
+    textPtr->cursorOffGC = NULL;
 
     /*
      * Process the arguments to fill in the item record. Only 1 (list) or 2 (x
@@ -414,7 +414,7 @@ ConfigureText(
 
     state = itemPtr->state;
 
-    if (textPtr->activeColor || textPtr->activeStipple) {
+    if (textPtr->activeColor != NULL || textPtr->activeStipple != None) {
 	itemPtr->redraw_flags |= TK_ITEM_STATE_DEPENDANT;
     } else {
 	itemPtr->redraw_flags &= ~TK_ITEM_STATE_DEPENDANT;
@@ -427,29 +427,29 @@ ConfigureText(
     color = textPtr->color;
     stipple = textPtr->stipple;
     if (((TkCanvas *)canvas)->currentItemPtr == itemPtr) {
-	if (textPtr->activeColor) {
+	if (textPtr->activeColor!=NULL) {
 	    color = textPtr->activeColor;
 	}
-	if (textPtr->activeStipple) {
+	if (textPtr->activeStipple!=None) {
 	    stipple = textPtr->activeStipple;
 	}
     } else if (state==TK_STATE_DISABLED) {
-	if (textPtr->disabledColor) {
+	if (textPtr->disabledColor!=NULL) {
 	    color = textPtr->disabledColor;
 	}
-	if (textPtr->disabledStipple) {
+	if (textPtr->disabledStipple!=None) {
 	    stipple = textPtr->disabledStipple;
 	}
     }
 
-    newGC = newSelGC = 0;
-    if (textPtr->tkfont) {
+    newGC = newSelGC = NULL;
+    if (textPtr->tkfont != NULL) {
 	gcValues.font = Tk_FontId(textPtr->tkfont);
 	mask = GCFont;
 	if (color) {
 	    gcValues.foreground = color->pixel;
 	    mask |= GCForeground;
-	    if (stipple) {
+	    if (stipple != None) {
 		gcValues.stipple = stipple;
 		gcValues.fill_style = FillStippled;
 		mask |= GCStipple|GCFillStyle;
@@ -471,7 +471,7 @@ ConfigureText(
 	Tk_FreeGC(Tk_Display(tkwin), textPtr->gc);
     }
     textPtr->gc = newGC;
-    if (textPtr->selTextGC) {
+    if (textPtr->selTextGC != None) {
 	Tk_FreeGC(Tk_Display(tkwin), textPtr->selTextGC);
     }
     textPtr->selTextGC = newSelGC;
@@ -486,7 +486,7 @@ ConfigureText(
 	}
 	newGC = Tk_GetGC(tkwin, GCForeground, &gcValues);
     } else {
-	newGC = 0;
+	newGC = NULL;
     }
     if (textPtr->cursorOffGC) {
 	Tk_FreeGC(Tk_Display(tkwin), textPtr->cursorOffGC);
@@ -548,37 +548,37 @@ DeleteText(
 {
     TextItem *textPtr = (TextItem *) itemPtr;
 
-    if (textPtr->color) {
+    if (textPtr->color != NULL) {
 	Tk_FreeColor(textPtr->color);
     }
-    if (textPtr->activeColor) {
+    if (textPtr->activeColor != NULL) {
 	Tk_FreeColor(textPtr->activeColor);
     }
-    if (textPtr->disabledColor) {
+    if (textPtr->disabledColor != NULL) {
 	Tk_FreeColor(textPtr->disabledColor);
     }
     Tk_FreeFont(textPtr->tkfont);
-    if (textPtr->stipple) {
+    if (textPtr->stipple != None) {
 	Tk_FreeBitmap(display, textPtr->stipple);
     }
-    if (textPtr->activeStipple) {
+    if (textPtr->activeStipple != None) {
 	Tk_FreeBitmap(display, textPtr->activeStipple);
     }
-    if (textPtr->disabledStipple) {
+    if (textPtr->disabledStipple != None) {
 	Tk_FreeBitmap(display, textPtr->disabledStipple);
     }
-    if (textPtr->text) {
+    if (textPtr->text != NULL) {
 	ckfree(textPtr->text);
     }
 
     Tk_FreeTextLayout(textPtr->textLayout);
-    if (textPtr->gc) {
+    if (textPtr->gc != None) {
 	Tk_FreeGC(display, textPtr->gc);
     }
-    if (textPtr->selTextGC) {
+    if (textPtr->selTextGC != None) {
 	Tk_FreeGC(display, textPtr->selTextGC);
     }
-    if (textPtr->cursorOffGC) {
+    if (textPtr->cursorOffGC != None) {
 	Tk_FreeGC(display, textPtr->cursorOffGC);
     }
 }
@@ -731,16 +731,16 @@ DisplayCanvText(
     }
     stipple = textPtr->stipple;
     if (((TkCanvas *)canvas)->currentItemPtr == itemPtr) {
-	if (textPtr->activeStipple) {
+	if (textPtr->activeStipple!=None) {
 	    stipple = textPtr->activeStipple;
 	}
     } else if (state==TK_STATE_DISABLED) {
-	if (textPtr->disabledStipple) {
+	if (textPtr->disabledStipple!=None) {
 	    stipple = textPtr->disabledStipple;
 	}
     }
 
-    if (!textPtr->gc) {
+    if (textPtr->gc == None) {
 	return;
     }
 
@@ -750,7 +750,7 @@ DisplayCanvText(
      * read-only.
      */
 
-    if (stipple) {
+    if (stipple != None) {
 	Tk_CanvasSetOffset(canvas, textPtr->gc, &textPtr->tsoffset);
     }
 
@@ -830,7 +830,7 @@ DisplayCanvText(
 			drawableX, drawableY,
 			textInfoPtr->insertWidth, height,
 			textInfoPtr->insertBorderWidth, TK_RELIEF_RAISED);
-	    } else if (textPtr->cursorOffGC) {
+	    } else if (textPtr->cursorOffGC != None) {
 		/*
 		 * Redraw the background over the area of the cursor, even
 		 * though the cursor is turned off. This guarantees that the
@@ -874,7 +874,7 @@ DisplayCanvText(
     Tk_UnderlineTextLayout(display, drawable, textPtr->gc, textPtr->textLayout,
 	    drawableX, drawableY, textPtr->underline);
 
-    if (stipple) {
+    if (stipple != None) {
 	XSetTSOrigin(display, textPtr->gc, 0, 0);
     }
 }
@@ -1447,14 +1447,14 @@ TextToPostscript(
 	if (textPtr->activeColor!=NULL) {
 	    color = textPtr->activeColor;
 	}
-	if (textPtr->activeStipple) {
+	if (textPtr->activeStipple!=None) {
 	    stipple = textPtr->activeStipple;
 	}
     } else if (state==TK_STATE_DISABLED) {
-	if (textPtr->disabledColor) {
+	if (textPtr->disabledColor!=NULL) {
 	    color = textPtr->disabledColor;
 	}
-	if (textPtr->disabledStipple) {
+	if (textPtr->disabledStipple!=None) {
 	    stipple = textPtr->disabledStipple;
 	}
     }
@@ -1462,13 +1462,13 @@ TextToPostscript(
     if (Tk_CanvasPsFont(interp, canvas, textPtr->tkfont) != TCL_OK) {
 	return TCL_ERROR;
     }
-    if (prepass) {
+    if (prepass != 0) {
 	return TCL_OK;
     }
     if (Tk_CanvasPsColor(interp, canvas, color) != TCL_OK) {
 	return TCL_ERROR;
     }
-    if (stipple) {
+    if (stipple != None) {
 	Tcl_AppendResult(interp, "/StippleText {\n    ", NULL);
 	Tk_CanvasPsStipple(interp, canvas, stipple);
 	Tcl_AppendResult(interp, "} bind def\n", NULL);
@@ -1506,7 +1506,7 @@ TextToPostscript(
     Tcl_PrintDouble(NULL, y / 2.0, buffer);
     Tcl_AppendResult(interp, " ", buffer, NULL);
     sprintf(buffer, " %s %s DrawText\n",
-	    justify, (stipple ? "true" : "false"));
+	    justify, ((stipple == None) ? "false" : "true"));
     Tcl_AppendResult(interp, buffer, NULL);
 
     return TCL_OK;
diff --git a/generic/tkCanvUtil.c b/generic/tkCanvUtil.c
index cacceda..299f502 100644
--- a/generic/tkCanvUtil.c
+++ b/generic/tkCanvUtil.c
@@ -959,7 +959,7 @@ void
 Tk_CreateOutline(
     Tk_Outline *outline)	/* Outline structure to be filled in. */
 {
-    outline->gc = 0;
+    outline->gc = NULL;
     outline->width = 1.0;
     outline->activeWidth = 0.0;
     outline->disabledWidth = 0.0;
@@ -973,9 +973,9 @@ Tk_CreateOutline(
     outline->color = NULL;
     outline->activeColor = NULL;
     outline->disabledColor = NULL;
-    outline->stipple = 0;
-    outline->activeStipple = 0;
-    outline->disabledStipple = 0;
+    outline->stipple = None;
+    outline->activeStipple = None;
+    outline->disabledStipple = None;
 }
 
 /*
@@ -1000,7 +1000,7 @@ Tk_DeleteOutline(
     Display *display,		/* Display containing window. */
     Tk_Outline *outline)
 {
-    if (outline->gc) {
+    if (outline->gc != None) {
 	Tk_FreeGC(display, outline->gc);
     }
     if ((unsigned int)ABS(outline->dash.number) > sizeof(char *)) {
@@ -1012,22 +1012,22 @@ Tk_DeleteOutline(
     if ((unsigned int)ABS(outline->disabledDash.number) > sizeof(char *)) {
 	ckfree((char *) outline->disabledDash.pattern.pt);
     }
-    if (outline->color) {
+    if (outline->color != NULL) {
 	Tk_FreeColor(outline->color);
     }
-    if (outline->activeColor) {
+    if (outline->activeColor != NULL) {
 	Tk_FreeColor(outline->activeColor);
     }
-    if (outline->disabledColor) {
+    if (outline->disabledColor != NULL) {
 	Tk_FreeColor(outline->disabledColor);
     }
-    if (outline->stipple) {
+    if (outline->stipple != None) {
 	Tk_FreeBitmap(display, outline->stipple);
     }
-    if (outline->activeStipple) {
+    if (outline->activeStipple != None) {
 	Tk_FreeBitmap(display, outline->activeStipple);
     }
-    if (outline->disabledStipple) {
+    if (outline->disabledStipple != None) {
 	Tk_FreeBitmap(display, outline->disabledStipple);
     }
 }
@@ -1093,26 +1093,26 @@ Tk_ConfigOutlineGC(
 	if (outline->activeWidth>width) {
 	    width = outline->activeWidth;
 	}
-	if (outline->activeDash.number) {
+	if (outline->activeDash.number != 0) {
 	    dash = &(outline->activeDash);
 	}
-	if (outline->activeColor) {
+	if (outline->activeColor!=NULL) {
 	    color = outline->activeColor;
 	}
-	if (outline->activeStipple) {
+	if (outline->activeStipple!=None) {
 	    stipple = outline->activeStipple;
 	}
     } else if (state == TK_STATE_DISABLED) {
 	if (outline->disabledWidth>0) {
 	    width = outline->disabledWidth;
 	}
-	if (outline->disabledDash.number) {
+	if (outline->disabledDash.number != 0) {
 	    dash = &(outline->disabledDash);
 	}
-	if (outline->disabledColor) {
+	if (outline->disabledColor!=NULL) {
 	    color = outline->disabledColor;
 	}
-	if (outline->disabledStipple) {
+	if (outline->disabledStipple!=None) {
 	    stipple = outline->disabledStipple;
 	}
     }
@@ -1125,18 +1125,18 @@ Tk_ConfigOutlineGC(
     if (color != NULL) {
 	gcValues->foreground = color->pixel;
 	mask = GCForeground|GCLineWidth;
-	if (stipple) {
+	if (stipple != None) {
 	    gcValues->stipple = stipple;
 	    gcValues->fill_style = FillStippled;
 	    mask |= GCStipple|GCFillStyle;
 	}
     }
-    if (mask && dash->number) {
+    if (mask && (dash->number != 0)) {
 	gcValues->line_style = LineOnOffDash;
 	gcValues->dash_offset = outline->offset;
 	if ((unsigned int)ABS(dash->number) > sizeof(char *)) {
 	    gcValues->dashes = dash->pattern.pt[0];
-	} else if (dash->number) {
+	} else if (dash->number != 0) {
 	    gcValues->dashes = dash->pattern.array[0];
 	} else {
 	    gcValues->dashes = (char) (4 * width + 0.5);
@@ -1191,30 +1191,30 @@ Tk_ChangeOutlineGC(
 	if (outline->activeWidth > width) {
 	    width = outline->activeWidth;
 	}
-	if (outline->activeDash.number) {
+	if (outline->activeDash.number != 0) {
 	    dash = &(outline->activeDash);
 	}
-	if (outline->activeColor) {
+	if (outline->activeColor != NULL) {
 	    color = outline->activeColor;
 	}
-	if (outline->activeStipple) {
+	if (outline->activeStipple != None) {
 	    stipple = outline->activeStipple;
 	}
     } else if (state == TK_STATE_DISABLED) {
 	if (outline->disabledWidth > width) {
 	    width = outline->disabledWidth;
 	}
-	if (outline->disabledDash.number) {
+	if (outline->disabledDash.number != 0) {
 	    dash = &(outline->disabledDash);
 	}
-	if (outline->disabledColor) {
+	if (outline->disabledColor != NULL) {
 	    color = outline->disabledColor;
 	}
-	if (outline->disabledStipple) {
+	if (outline->disabledStipple != None) {
 	    stipple = outline->disabledStipple;
 	}
     }
-    if (!color) {
+    if (color==NULL) {
 	return 0;
     }
 
@@ -1236,7 +1236,7 @@ Tk_ChangeOutlineGC(
 	XSetDashes(((TkCanvas *)canvas)->display, outline->gc,
 		outline->offset, p, dash->number);
     }
-    if (stipple) {
+    if (stipple!=None) {
 	int w=0; int h=0;
 	Tk_TSOffset *tsoffset = &outline->tsoffset;
 	int flags = tsoffset->flags;
@@ -1310,26 +1310,26 @@ Tk_ResetOutlineGC(
 	if (outline->activeWidth>width) {
 	    width = outline->activeWidth;
 	}
-	if (outline->activeDash.number) {
+	if (outline->activeDash.number != 0) {
 	    dash = &(outline->activeDash);
 	}
-	if (outline->activeColor) {
+	if (outline->activeColor!=NULL) {
 	    color = outline->activeColor;
 	}
-	if (outline->activeStipple) {
+	if (outline->activeStipple!=None) {
 	    stipple = outline->activeStipple;
 	}
     } else if (state == TK_STATE_DISABLED) {
 	if (outline->disabledWidth>width) {
 	    width = outline->disabledWidth;
 	}
-	if (outline->disabledDash.number) {
+	if (outline->disabledDash.number != 0) {
 	    dash = &(outline->disabledDash);
 	}
-	if (outline->disabledColor) {
+	if (outline->disabledColor!=NULL) {
 	    color = outline->disabledColor;
 	}
-	if (outline->disabledStipple) {
+	if (outline->disabledStipple!=None) {
 	    stipple = outline->disabledStipple;
 	}
     }
@@ -1342,7 +1342,7 @@ Tk_ResetOutlineGC(
 	    ((dash->number == -1) && (dash->pattern.array[0] != ','))) {
 	if ((unsigned int)ABS(dash->number) > sizeof(char *)) {
 	    dashList = dash->pattern.pt[0];
-	} else if (dash->number) {
+	} else if (dash->number != 0) {
 	    dashList = dash->pattern.array[0];
 	} else {
 	    dashList = (char) (4 * width + 0.5);
@@ -1350,7 +1350,7 @@ Tk_ResetOutlineGC(
 	XSetDashes(((TkCanvas *)canvas)->display, outline->gc,
 		outline->offset, &dashList , 1);
     }
-    if (stipple) {
+    if (stipple != None) {
 	XSetTSOrigin(((TkCanvas *)canvas)->display, outline->gc, 0, 0);
 	return 1;
     }
@@ -1409,10 +1409,10 @@ Tk_CanvasPsOutline(
 	if (outline->activeDash.number > 0) {
 	    dash = &(outline->activeDash);
 	}
-	if (outline->activeColor) {
+	if (outline->activeColor != NULL) {
 	    color = outline->activeColor;
 	}
-	if (outline->activeStipple) {
+	if (outline->activeStipple != None) {
 	    stipple = outline->activeStipple;
 	}
     } else if (state == TK_STATE_DISABLED) {
@@ -1422,10 +1422,10 @@ Tk_CanvasPsOutline(
 	if (outline->disabledDash.number > 0) {
 	    dash = &(outline->disabledDash);
 	}
-	if (outline->disabledColor) {
+	if (outline->disabledColor != NULL) {
 	    color = outline->disabledColor;
 	}
-	if (outline->disabledStipple) {
+	if (outline->disabledStipple != None) {
 	    stipple = outline->disabledStipple;
 	}
     }
@@ -1482,7 +1482,7 @@ Tk_CanvasPsOutline(
     if (Tk_CanvasPsColor(interp, canvas, color) != TCL_OK) {
 	return TCL_ERROR;
     }
-    if (stipple) {
+    if (stipple != None) {
 	Tcl_AppendResult(interp, "StrokeClip ", NULL);
 	if (Tk_CanvasPsStipple(interp, canvas, stipple) != TCL_OK) {
 	    return TCL_ERROR;
diff --git a/generic/tkCanvWind.c b/generic/tkCanvWind.c
index c5ecf1a..b62859c 100644
--- a/generic/tkCanvWind.c
+++ b/generic/tkCanvWind.c
@@ -583,7 +583,7 @@ DisplayWinItem(
      * A drawable of None is used by the canvas UnmapNotify handler
      * to indicate that we should no longer display ourselves.
      */
-    if (state == TK_STATE_HIDDEN || !drawable) {
+    if (state == TK_STATE_HIDDEN || drawable == None) {
 	if (canvasTkwin == Tk_Parent(winItemPtr->tkwin)) {
 	    Tk_UnmapWindow(winItemPtr->tkwin);
 	} else {
diff --git a/generic/tkCanvas.c b/generic/tkCanvas.c
index 27a3a32..1024529 100644
--- a/generic/tkCanvas.c
+++ b/generic/tkCanvas.c
@@ -417,9 +417,9 @@ Tk_CanvasObjCmd(
     canvasPtr->highlightBgColorPtr = NULL;
     canvasPtr->highlightColorPtr = NULL;
     canvasPtr->inset = 0;
-    canvasPtr->pixmapGC = 0;
-    canvasPtr->width = 0;
-    canvasPtr->height = 0;
+    canvasPtr->pixmapGC = NULL;
+    canvasPtr->width = None;
+    canvasPtr->height = None;
     canvasPtr->confine = 0;
     canvasPtr->textInfo.selBorder = NULL;
     canvasPtr->textInfo.selBorderWidth = 0;
@@ -463,7 +463,7 @@ Tk_CanvasObjCmd(
     canvasPtr->scanYOrigin = 0;
     canvasPtr->hotPtr = NULL;
     canvasPtr->hotPrevPtr = NULL;
-    canvasPtr->cursor = 0;
+    canvasPtr->cursor = NULL;
     canvasPtr->takeFocus = NULL;
     canvasPtr->pixelsPerMM = WidthOfScreen(Tk_Screen(newWin));
     canvasPtr->pixelsPerMM /= WidthMMOfScreen(Tk_Screen(newWin));
@@ -1834,7 +1834,7 @@ DestroyCanvas(
      */
 
     Tcl_DeleteHashTable(&canvasPtr->idTable);
-    if (canvasPtr->pixmapGC) {
+    if (canvasPtr->pixmapGC != None) {
 	Tk_FreeGC(canvasPtr->display, canvasPtr->pixmapGC);
     }
 #ifndef USE_OLD_TAG_SEARCH
@@ -1910,7 +1910,7 @@ ConfigureCanvas(
     gcValues.foreground = Tk_3DBorderColor(canvasPtr->bgBorder)->pixel;
     newGC = Tk_GetGC(canvasPtr->tkwin,
 	    GCFunction|GCGraphicsExposures|GCForeground, &gcValues);
-    if (canvasPtr->pixmapGC) {
+    if (canvasPtr->pixmapGC != None) {
 	Tk_FreeGC(canvasPtr->display, canvasPtr->pixmapGC);
     }
     canvasPtr->pixmapGC = newGC;
@@ -2405,7 +2405,7 @@ CanvasEventProc(
 		itemPtr = itemPtr->nextPtr) {
 	    if (itemPtr->typePtr->alwaysRedraw & 1) {
 		(*itemPtr->typePtr->displayProc)((Tk_Canvas) canvasPtr,
-			itemPtr, canvasPtr->display, 0, 0, 0, 0, 0);
+			itemPtr, canvasPtr->display, None, 0, 0, 0, 0);
 	    }
 	}
     }
@@ -4545,7 +4545,7 @@ PickCurrentItem(
 	    canvasPtr->pickEvent.xcrossing.display = eventPtr->xmotion.display;
 	    canvasPtr->pickEvent.xcrossing.window = eventPtr->xmotion.window;
 	    canvasPtr->pickEvent.xcrossing.root = eventPtr->xmotion.root;
-	    canvasPtr->pickEvent.xcrossing.subwindow = 0;
+	    canvasPtr->pickEvent.xcrossing.subwindow = None;
 	    canvasPtr->pickEvent.xcrossing.time = eventPtr->xmotion.time;
 	    canvasPtr->pickEvent.xcrossing.x = eventPtr->xmotion.x;
 	    canvasPtr->pickEvent.xcrossing.y = eventPtr->xmotion.y;
diff --git a/generic/tkClipboard.c b/generic/tkClipboard.c
index 4c564e7..c6748a1 100644
--- a/generic/tkClipboard.c
+++ b/generic/tkClipboard.c
@@ -654,7 +654,7 @@ TkClipInit(
     Tk_ChangeWindowAttributes(dispPtr->clipWindow, CWOverrideRedirect, &atts);
     Tk_MakeWindowExist(dispPtr->clipWindow);
 
-    if (!dispPtr->multipleAtom) {
+    if (dispPtr->multipleAtom == None) {
 	/*
 	 * Need to invoke selection initialization to make sure that atoms we
 	 * depend on below are defined.
diff --git a/generic/tkColor.c b/generic/tkColor.c
index 1ec4ab1..bde08cf 100644
--- a/generic/tkColor.c
+++ b/generic/tkColor.c
@@ -414,7 +414,7 @@ Tk_GCForColor(
 	Tcl_Panic("Tk_GCForColor called with bogus color");
     }
 
-    if (!tkColPtr->gc) {
+    if (tkColPtr->gc == None) {
 	gcValues.foreground = tkColPtr->color.pixel;
 	tkColPtr->gc = XCreateGC(DisplayOfScreen(tkColPtr->screen), drawable,
 		GCForeground, &gcValues);
@@ -469,7 +469,7 @@ Tk_FreeColor(
      * longer any objects referencing it.
      */
 
-    if (tkColPtr->gc) {
+    if (tkColPtr->gc != None) {
 	XFreeGC(DisplayOfScreen(screen), tkColPtr->gc);
 	tkColPtr->gc = 0;
     }
diff --git a/generic/tkConfig.c b/generic/tkConfig.c
index 5fcbab8..ace7135 100644
--- a/generic/tkConfig.c
+++ b/generic/tkConfig.c
@@ -802,10 +802,10 @@ DoObjConfig(
 
 	if (nullOK && ObjectIsEmpty(valuePtr)) {
 	    valuePtr = NULL;
-	    newBitmap = 0;
+	    newBitmap = None;
 	} else {
 	    newBitmap = Tk_AllocBitmapFromObj(interp, tkwin, valuePtr);
-	    if (!newBitmap) {
+	    if (newBitmap == None) {
 		return TCL_ERROR;
 	    }
 	}
@@ -858,7 +858,7 @@ DoObjConfig(
 	    valuePtr = NULL;
 	} else {
 	    newCursor = Tk_AllocCursorFromObj(interp, tkwin, valuePtr);
-	    if (!newCursor) {
+	    if (newCursor == None) {
 		return TCL_ERROR;
 	    }
 	}
@@ -1680,9 +1680,9 @@ FreeResources(
 	break;
     case TK_OPTION_BITMAP:
 	if (internalFormExists) {
-	    if (*((Pixmap *) internalPtr)) {
+	    if (*((Pixmap *) internalPtr) != None) {
 		Tk_FreeBitmap(Tk_Display(tkwin), *((Pixmap *) internalPtr));
-		*((Pixmap *) internalPtr) = 0;
+		*((Pixmap *) internalPtr) = None;
 	    }
 	} else if (objPtr != NULL) {
 	    Tk_FreeBitmapFromObj(tkwin, objPtr);
@@ -1700,7 +1700,7 @@ FreeResources(
 	break;
     case TK_OPTION_CURSOR:
 	if (internalFormExists) {
-	    if (*((Tk_Cursor *) internalPtr)) {
+	    if (*((Tk_Cursor *) internalPtr) != None) {
 		Tk_FreeCursor(Tk_Display(tkwin), *((Tk_Cursor *) internalPtr));
 		*((Tk_Cursor *) internalPtr) = 0;
 	    }
@@ -1954,7 +1954,7 @@ GetObjectForOption(
     case TK_OPTION_BITMAP: {
 	Pixmap pixmap = *((Pixmap *) internalPtr);
 
-	if (pixmap) {
+	if (pixmap != None) {
 	    objPtr = Tcl_NewStringObj(
 		    Tk_NameOfBitmap(Tk_Display(tkwin), pixmap), -1);
 	}
@@ -1974,7 +1974,7 @@ GetObjectForOption(
     case TK_OPTION_CURSOR: {
 	Tk_Cursor cursor = *((Tk_Cursor *) internalPtr);
 
-	if (cursor) {
+	if (cursor != None) {
 	    objPtr = Tcl_NewStringObj(
 		    Tk_NameOfCursor(Tk_Display(tkwin), cursor), -1);
 	}
diff --git a/generic/tkCursor.c b/generic/tkCursor.c
index ced2534..a1c2723 100644
--- a/generic/tkCursor.c
+++ b/generic/tkCursor.c
@@ -187,7 +187,10 @@ Tk_GetCursor(
 				 * details on legal syntax. */
 {
     TkCursor *cursorPtr = TkcGetCursor(interp, tkwin, string);
-    return cursorPtr ? cursorPtr->cursor : 0;
+    if (cursorPtr == NULL) {
+	return 0;
+    }
+    return cursorPtr->cursor;
 }
 
 /*
diff --git a/generic/tkEntry.c b/generic/tkEntry.c
index 5eaca77..f5b4339 100644
--- a/generic/tkEntry.c
+++ b/generic/tkEntry.c
@@ -523,16 +523,16 @@ Tk_EntryObjCmd(
     entryPtr->selectFirst	= -1;
     entryPtr->selectLast	= -1;
 
-    entryPtr->cursor		= 0;
+    entryPtr->cursor		= NULL;
     entryPtr->exportSelection	= 1;
     entryPtr->justify		= TK_JUSTIFY_LEFT;
     entryPtr->relief		= TK_RELIEF_FLAT;
     entryPtr->state		= STATE_NORMAL;
     entryPtr->displayString	= entryPtr->string;
     entryPtr->inset		= XPAD;
-    entryPtr->textGC		= 0;
-    entryPtr->selTextGC		= 0;
-    entryPtr->highlightGC	= 0;
+    entryPtr->textGC		= NULL;
+    entryPtr->selTextGC		= NULL;
+    entryPtr->highlightGC	= NULL;
     entryPtr->avgWidth		= 1;
     entryPtr->validate		= VALIDATE_NONE;
 
@@ -1030,10 +1030,10 @@ DestroyEntry(
 		EntryTextVarProc, (ClientData) entryPtr);
 	entryPtr->flags &= ~ENTRY_VAR_TRACED;
     }
-    if (entryPtr->textGC) {
+    if (entryPtr->textGC != None) {
 	Tk_FreeGC(entryPtr->display, entryPtr->textGC);
     }
-    if (entryPtr->selTextGC) {
+    if (entryPtr->selTextGC != None) {
 	Tk_FreeGC(entryPtr->display, entryPtr->selTextGC);
     }
     Tcl_DeleteTimerHandler(entryPtr->insertBlinkHandler);
@@ -1043,7 +1043,7 @@ DestroyEntry(
     if (entryPtr->type == TK_SPINBOX) {
 	Spinbox *sbPtr = (Spinbox *) entryPtr;
 
-	if (sbPtr->listObj) {
+	if (sbPtr->listObj != NULL) {
 	    Tcl_DecrRefCount(sbPtr->listObj);
 	    sbPtr->listObj = NULL;
 	}
@@ -1423,7 +1423,7 @@ EntryWorldChanged(
     ClientData instanceData)	/* Information about widget. */
 {
     XGCValues gcValues;
-    GC gc = 0;
+    GC gc = NULL;
     unsigned long mask;
     Tk_3DBorder border;
     XColor *colorPtr;
@@ -1475,18 +1475,18 @@ EntryWorldChanged(
     gcValues.graphics_exposures = False;
     mask = GCForeground | GCFont | GCGraphicsExposures;
     gc = Tk_GetGC(entryPtr->tkwin, mask, &gcValues);
-    if (entryPtr->textGC) {
+    if (entryPtr->textGC != None) {
 	Tk_FreeGC(entryPtr->display, entryPtr->textGC);
     }
     entryPtr->textGC = gc;
 
-    if (entryPtr->selFgColorPtr) {
+    if (entryPtr->selFgColorPtr != NULL) {
 	gcValues.foreground = entryPtr->selFgColorPtr->pixel;
     }
     gcValues.font = Tk_FontId(entryPtr->tkfont);
     mask = GCForeground | GCFont;
     gc = Tk_GetGC(entryPtr->tkwin, mask, &gcValues);
-    if (entryPtr->selTextGC) {
+    if (entryPtr->selTextGC != None) {
 	Tk_FreeGC(entryPtr->display, entryPtr->selTextGC);
     }
     entryPtr->selTextGC = gc;
@@ -2451,7 +2451,7 @@ EntryEventProc(
 	    } else if ((elem == SEL_BUTTONDOWN) || (elem == SEL_BUTTONUP)) {
 		cursor = sbPtr->bCursor;
 	    } else {
-		cursor = 0;
+		cursor = NULL;
 	    }
 	    if (cursor) {
 		Tk_DefineCursor(entryPtr->tkwin, cursor);
@@ -3591,22 +3591,22 @@ Tk_SpinboxObjCmd(
     entryPtr->selectFirst	= -1;
     entryPtr->selectLast	= -1;
 
-    entryPtr->cursor		= 0;
+    entryPtr->cursor		= NULL;
     entryPtr->exportSelection	= 1;
     entryPtr->justify		= TK_JUSTIFY_LEFT;
     entryPtr->relief		= TK_RELIEF_FLAT;
     entryPtr->state		= STATE_NORMAL;
     entryPtr->displayString	= entryPtr->string;
     entryPtr->inset		= XPAD;
-    entryPtr->textGC		= 0;
-    entryPtr->selTextGC		= 0;
-    entryPtr->highlightGC	= 0;
+    entryPtr->textGC		= NULL;
+    entryPtr->selTextGC		= NULL;
+    entryPtr->highlightGC	= NULL;
     entryPtr->avgWidth		= 1;
     entryPtr->validate		= VALIDATE_NONE;
 
     sbPtr->selElement		= SEL_NONE;
     sbPtr->curElement		= SEL_NONE;
-    sbPtr->bCursor		= 0;
+    sbPtr->bCursor		= NULL;
     sbPtr->repeatDelay		= 400;
     sbPtr->repeatInterval	= 100;
     sbPtr->fromValue		= 0.0;
diff --git a/generic/tkEntry.h b/generic/tkEntry.h
index 2ea7936..7f8aa1f 100644
--- a/generic/tkEntry.h
+++ b/generic/tkEntry.h
@@ -226,7 +226,7 @@ typedef struct {
 				 * value that the users requests. Malloc'ed */
     char *valueFormat;		/* Sprintf conversion specifier used for the
 				 * value. */
-    char digitFormat[16];	/* Sprintf conversion specifier computed from
+    char digitFormat[10];	/* Sprintf conversion specifier computed from
 				 * digits and other information; used for the
 				 * value. */
 
diff --git a/generic/tkEvent.c b/generic/tkEvent.c
index ac5b68c..9b001e1 100644
--- a/generic/tkEvent.c
+++ b/generic/tkEvent.c
@@ -421,11 +421,11 @@ GetTkWindowFromXEvent(
 	}
 	TkSelPropProc(eventPtr);
 	parentXId = ParentXId(eventPtr->xany.display, handlerWindow);
-	if (!parentXId) {
+	if (parentXId == None) {
 	    return NULL;
 	}
 	winPtr = (TkWindow *) Tk_IdToWindow(eventPtr->xany.display, parentXId);
-	if (!winPtr) {
+	if (winPtr == NULL) {
 	    return NULL;
 	}
 	if (!(winPtr->flags & TK_PROP_PROPCHANGE)) {
@@ -601,7 +601,7 @@ UpdateButtonEventState(
 
     case ButtonRelease:
 	dispPtr = TkGetDisplay(eventPtr->xbutton.display);
-	dispPtr->mouseButtonWindow = 0;
+	dispPtr->mouseButtonWindow = None;
 	dispPtr->mouseButtonState &= ~GetButtonMask(eventPtr->xbutton.button);
 	eventPtr->xbutton.state |= dispPtr->mouseButtonState;
 	break;
@@ -617,7 +617,7 @@ UpdateButtonEventState(
 		 */
 
 		dispPtr->mouseButtonState &= ~allButtonsMask;
-		dispPtr->mouseButtonWindow = 0;
+		dispPtr->mouseButtonWindow = None;
 	    } else {
 		eventPtr->xmotion.state |= dispPtr->mouseButtonState;
 	    }
@@ -1192,7 +1192,7 @@ ParentXId(
 	XFree(childList);
     }
     if (status == 0) {
-	parent = 0;
+	parent = None;
     }
 
     return parent;
@@ -1365,7 +1365,7 @@ Tk_HandleEvent(
 	 * handle CreateNotify events, so we gotta pass 'em through.
 	 */
 
-	if ((ip.winPtr)
+	if ((ip.winPtr != None)
 		&& ((mask != SubstructureNotifyMask)
 		|| (eventPtr->type == CreateNotify))) {
 	    TkBindEventProc(winPtr, eventPtr);
@@ -1379,7 +1379,7 @@ Tk_HandleEvent(
      */
 
   releaseInterpreter:
-    if (interp) {
+    if (interp != NULL) {
 	Tcl_Release((ClientData) interp);
     }
 
@@ -1427,7 +1427,7 @@ TkEventDeadWindow(
      * to quit (all of the handlers are being deleted).
      */
 
-    while (winPtr->handlerList) {
+    while (winPtr->handlerList != NULL) {
 	handlerPtr = winPtr->handlerList;
 	winPtr->handlerList = handlerPtr->nextPtr;
 	for (ipPtr = tsdPtr->pendingPtr; ipPtr != NULL;
diff --git a/generic/tkFrame.c b/generic/tkFrame.c
index ef1338e..3203cfa 100644
--- a/generic/tkFrame.c
+++ b/generic/tkFrame.c
@@ -487,7 +487,7 @@ CreateFrame(
      */
 
     className = colormapName = screenName = visualName = useOption = NULL;
-    colormap = 0;
+    colormap = None;
     for (i = 2; i < objc; i += 2) {
 	arg = Tcl_GetStringFromObj(objv[i], &length);
 	if (length < 2) {
@@ -591,14 +591,14 @@ CreateFrame(
     if (visualName != NULL) {
 	visual = Tk_GetVisual(interp, newWin, visualName, &depth,
 		(colormapName == NULL) ? &colormap : NULL);
-	if (!visual) {
+	if (visual == NULL) {
 	    goto error;
 	}
 	Tk_SetWindowVisual(newWin, visual, depth, colormap);
     }
-    if (colormapName) {
+    if (colormapName != NULL) {
 	colormap = Tk_GetColormap(interp, newWin, colormapName);
-	if (!colormap) {
+	if (colormap == None) {
 	    goto error;
 	}
 	Tk_SetWindowColormap(newWin, colormap);
@@ -637,12 +637,12 @@ CreateFrame(
     framePtr->type = type;
     framePtr->colormap = colormap;
     framePtr->relief = TK_RELIEF_FLAT;
-    framePtr->cursor = 0;
+    framePtr->cursor = NULL;
 
     if (framePtr->type == TYPE_LABELFRAME) {
 	Labelframe *labelframePtr = (Labelframe *) framePtr;
 	labelframePtr->labelAnchor = LABELANCHOR_NW;
-	labelframePtr->textGC = 0;
+	labelframePtr->textGC = NULL;
     }
 
     /*
@@ -840,11 +840,11 @@ DestroyFrame(
 
     if (framePtr->type == TYPE_LABELFRAME) {
 	Tk_FreeTextLayout(labelframePtr->textLayout);
-	if (labelframePtr->textGC) {
+	if (labelframePtr->textGC != None) {
 	    Tk_FreeGC(framePtr->display, labelframePtr->textGC);
 	}
     }
-    if (framePtr->colormap) {
+    if (framePtr->colormap != None) {
 	Tk_FreeColormap(framePtr->display, framePtr->colormap);
     }
     ckfree((char *) framePtr);
@@ -967,7 +967,7 @@ ConfigureFrame(
     if (framePtr->border != NULL) {
 	Tk_SetBackgroundFromBorder(framePtr->tkwin, framePtr->border);
     } else {
-	Tk_SetWindowBackgroundPixmap(framePtr->tkwin, 0);
+	Tk_SetWindowBackgroundPixmap(framePtr->tkwin, None);
     }
 
     if (framePtr->highlightWidth < 0) {
@@ -1096,7 +1096,7 @@ FrameWorldChanged(
 	gcValues.graphics_exposures = False;
 	gc = Tk_GetGC(tkwin, GCForeground | GCFont | GCGraphicsExposures,
 		&gcValues);
-	if (labelframePtr->textGC) {
+	if (labelframePtr->textGC != None) {
 	    Tk_FreeGC(framePtr->display, labelframePtr->textGC);
 	}
 	labelframePtr->textGC = gc;
@@ -1528,8 +1528,8 @@ DisplayFrame(
 		    labelframePtr->labelTextX + LABELSPACING,
 		    labelframePtr->labelTextY + LABELSPACING, 0, -1);
 
-	    if (clipRegion) {
-		XSetClipMask(framePtr->display, labelframePtr->textGC, 0);
+	    if (clipRegion != NULL) {
+		XSetClipMask(framePtr->display, labelframePtr->textGC, None);
 		TkDestroyRegion(clipRegion);
 	    }
 	} else {
diff --git a/generic/tkGC.c b/generic/tkGC.c
index c0864d0..800e4d3 100644
--- a/generic/tkGC.c
+++ b/generic/tkGC.c
@@ -155,12 +155,12 @@ Tk_GetGC(
     if (valueMask & GCTile) {
 	valueKey.values.tile = valuePtr->tile;
     } else {
-	valueKey.values.tile = 0;
+	valueKey.values.tile = None;
     }
     if (valueMask & GCStipple) {
 	valueKey.values.stipple = valuePtr->stipple;
     } else {
-	valueKey.values.stipple = 0;
+	valueKey.values.stipple = None;
     }
     if (valueMask & GCTileStipXOrigin) {
 	valueKey.values.ts_x_origin = valuePtr->ts_x_origin;
@@ -175,7 +175,7 @@ Tk_GetGC(
     if (valueMask & GCFont) {
 	valueKey.values.font = valuePtr->font;
     } else {
-	valueKey.values.font = 0;
+	valueKey.values.font = None;
     }
     if (valueMask & GCSubwindowMode) {
 	valueKey.values.subwindow_mode = valuePtr->subwindow_mode;
@@ -200,7 +200,7 @@ Tk_GetGC(
     if (valueMask & GCClipMask) {
 	valueKey.values.clip_mask = valuePtr->clip_mask;
     } else {
-	valueKey.values.clip_mask = 0;
+	valueKey.values.clip_mask = None;
     }
     if (valueMask & GCDashOffset) {
 	valueKey.values.dash_offset = valuePtr->dash_offset;
@@ -236,8 +236,8 @@ Tk_GetGC(
      * Tk_MakeWindowExist on the window.
      */
 
-    freeDrawable = 0;
-    if (Tk_WindowId(tkwin)) {
+    freeDrawable = None;
+    if (Tk_WindowId(tkwin) != None) {
 	d = Tk_WindowId(tkwin);
     } else if (valueKey.depth ==
 	    DefaultDepth(valueKey.display, valueKey.screenNum)) {
@@ -260,7 +260,7 @@ Tk_GetGC(
     }
     Tcl_SetHashValue(valueHashPtr, gcPtr);
     Tcl_SetHashValue(idHashPtr, gcPtr);
-    if (freeDrawable) {
+    if (freeDrawable != None) {
 	Tk_FreePixmap(valueKey.display, freeDrawable);
     }
 
diff --git a/generic/tkGrab.c b/generic/tkGrab.c
index 3039ea0..44a4f8c 100644
--- a/generic/tkGrab.c
+++ b/generic/tkGrab.c
@@ -468,8 +468,8 @@ Tk_Grab(
 	for (numTries = 0; numTries < 10; numTries++) {
 	    grabResult = XGrabPointer(dispPtr->display, winPtr->window,
 		    True, ButtonPressMask|ButtonReleaseMask|ButtonMotionMask
-		    |PointerMotionMask, GrabModeAsync, GrabModeAsync, 0,
-		    0, CurrentTime);
+		    |PointerMotionMask, GrabModeAsync, GrabModeAsync, None,
+		    None, CurrentTime);
 	    if (grabResult != AlreadyGrabbed) {
 		break;
 	    }
@@ -854,7 +854,7 @@ TkPointerEvent(
 		    if (XGrabPointer(dispPtr->display,
 			    dispPtr->grabWinPtr->window, True,
 			    ButtonPressMask|ButtonReleaseMask|ButtonMotionMask,
-			    GrabModeAsync, GrabModeAsync, 0, 0,
+			    GrabModeAsync, GrabModeAsync, None, None,
 			    CurrentTime) == 0) {
 			EatGrabEvents(dispPtr, serial);
 			if (XGrabKeyboard(dispPtr->display, winPtr->window,
@@ -921,7 +921,7 @@ TkChangeEventWindow(
 	Tk_GetRootCoords((Tk_Window) winPtr, &x, &y);
 	eventPtr->xmotion.x = eventPtr->xmotion.x_root - x;
 	eventPtr->xmotion.y = eventPtr->xmotion.y_root - y;
-	eventPtr->xmotion.subwindow = 0;
+	eventPtr->xmotion.subwindow = None;
 	for (childPtr = winPtr->childList; childPtr != NULL;
 		childPtr = childPtr->nextPtr) {
 	    if (childPtr->flags & TK_TOP_HIERARCHY) {
@@ -940,7 +940,7 @@ TkChangeEventWindow(
     } else {
 	eventPtr->xmotion.x = 0;
 	eventPtr->xmotion.y = 0;
-	eventPtr->xmotion.subwindow = 0;
+	eventPtr->xmotion.subwindow = None;
 	sameScreen = 0;
     }
     if (eventPtr->type == MotionNotify) {
@@ -1029,7 +1029,7 @@ TkInOutEvents(
      */
 
 #define QUEUE(w, t, d)					\
-    if (w->window) {				\
+    if (w->window != None) {				\
 	eventPtr->type = t;				\
 	if (focus) {					\
 	    eventPtr->xfocus.window = w->window;	\
@@ -1145,9 +1145,9 @@ MovePointer2(
     TkWindow *winPtr;
 
     winPtr = sourcePtr;
-    if (!winPtr || !winPtr->window) {
+    if ((winPtr == NULL) || (winPtr->window == None)) {
 	winPtr = destPtr;
-	if (!winPtr || !winPtr->window) {
+	if ((winPtr == NULL) || (winPtr->window == None)) {
 	    return;
 	}
     }
@@ -1338,7 +1338,7 @@ QueueGrabWindowChange(
     grabEvPtr->header.proc = GrabWinEventProc;
     grabEvPtr->dispPtr = dispPtr;
     if (grabWinPtr == NULL) {
-	grabEvPtr->grabWindow = 0;
+	grabEvPtr->grabWindow = None;
     } else {
 	grabEvPtr->grabWindow = grabWinPtr->window;
     }
diff --git a/generic/tkImage.c b/generic/tkImage.c
index 99a1726..6c7c9cd 100644
--- a/generic/tkImage.c
+++ b/generic/tkImage.c
@@ -759,7 +759,7 @@ Tk_PostscriptImage(
 
     gcValues.foreground = WhitePixelOfScreen(Tk_Screen(tkwin));
     newGC = Tk_GetGC(tkwin, GCForeground, &gcValues);
-    if (newGC) {
+    if (newGC != None) {
 	XFillRectangle(Tk_Display(tkwin), pmap, newGC,
 		0, 0, (unsigned int)width, (unsigned int)height);
 	Tk_FreeGC(Tk_Display(tkwin), newGC);
@@ -772,7 +772,7 @@ Tk_PostscriptImage(
 
     Tk_FreePixmap(Tk_Display(tkwin), pmap);
 
-    if (!ximage) {
+    if (ximage == NULL) {
 	/*
 	 * The XGetImage() function is apparently not implemented on this
 	 * system. Just ignore it.
diff --git a/generic/tkImgBmap.c b/generic/tkImgBmap.c
index 4e0082a..fab6afb 100644
--- a/generic/tkImgBmap.c
+++ b/generic/tkImgBmap.c
@@ -381,9 +381,9 @@ ImgBmapConfigureInstance(
      */
 
     oldBitmap = instancePtr->bitmap;
-    instancePtr->bitmap = 0;
+    instancePtr->bitmap = None;
     oldMask = instancePtr->mask;
-    instancePtr->mask = 0;
+    instancePtr->mask = None;
 
     if (masterPtr->data != NULL) {
 	instancePtr->bitmap = XCreateBitmapFromData(
@@ -414,7 +414,7 @@ ImgBmapConfigureInstance(
 	if (instancePtr->bg) {
 	    gcValues.background = instancePtr->bg->pixel;
 	    mask |= GCBackground;
-	    if (instancePtr->mask) {
+	    if (instancePtr->mask != None) {
 		gcValues.clip_mask = instancePtr->mask;
 		mask |= GCClipMask;
 	    }
@@ -424,7 +424,7 @@ ImgBmapConfigureInstance(
 	}
 	gc = Tk_GetGC(instancePtr->tkwin, mask, &gcValues);
     } else {
-	gc = 0;
+	gc = NULL;
     }
     if (instancePtr->gc) {
 	Tk_FreeGC(Tk_Display(instancePtr->tkwin), instancePtr->gc);
@@ -441,7 +441,7 @@ ImgBmapConfigureInstance(
     if (instancePtr->gc) {
 	Tk_FreeGC(Tk_Display(instancePtr->tkwin), instancePtr->gc);
     }
-    instancePtr->gc = 0;
+    instancePtr->gc = NULL;
     Tcl_AddErrorInfo(masterPtr->interp, "\n    (while configuring image \"");
     Tcl_AddErrorInfo(masterPtr->interp, Tk_NameOfImage(masterPtr->tkMaster));
     Tcl_AddErrorInfo(masterPtr->interp, "\")");
@@ -834,9 +834,9 @@ ImgBmapGet(
     instancePtr->tkwin = tkwin;
     instancePtr->fg = NULL;
     instancePtr->bg = NULL;
-    instancePtr->bitmap = 0;
-    instancePtr->mask = 0;
-    instancePtr->gc = 0;
+    instancePtr->bitmap = None;
+    instancePtr->mask = None;
+    instancePtr->gc = NULL;
     instancePtr->nextPtr = masterPtr->instancePtr;
     masterPtr->instancePtr = instancePtr;
     ImgBmapConfigureInstance(instancePtr);
@@ -890,7 +890,7 @@ ImgBmapDisplay(
      * creating the image instance so it can't be displayed.
      */
 
-    if (!instancePtr->gc) {
+    if (instancePtr->gc == None) {
 	return;
     }
 
@@ -900,7 +900,7 @@ ImgBmapDisplay(
      * image and reset the clip origin, if there's a mask.
      */
 
-    masking = instancePtr->mask || !instancePtr->bg;
+    masking = (instancePtr->mask != None) || (instancePtr->bg == NULL);
     if (masking) {
 	XSetClipOrigin(display, instancePtr->gc, drawableX - imageX,
 		drawableY - imageY);
@@ -949,19 +949,19 @@ ImgBmapFree(
      * instance structure.
      */
 
-    if (instancePtr->fg) {
+    if (instancePtr->fg != NULL) {
 	Tk_FreeColor(instancePtr->fg);
     }
-    if (instancePtr->bg) {
+    if (instancePtr->bg != NULL) {
 	Tk_FreeColor(instancePtr->bg);
     }
-    if (instancePtr->bitmap) {
+    if (instancePtr->bitmap != None) {
 	Tk_FreePixmap(display, instancePtr->bitmap);
     }
-    if (instancePtr->mask) {
+    if (instancePtr->mask != None) {
 	Tk_FreePixmap(display, instancePtr->mask);
     }
-    if (instancePtr->gc) {
+    if (instancePtr->gc != None) {
 	Tk_FreeGC(display, instancePtr->gc);
     }
     if (instancePtr->masterPtr->instancePtr == instancePtr) {
@@ -1000,17 +1000,17 @@ ImgBmapDelete(
 {
     BitmapMaster *masterPtr = (BitmapMaster *) masterData;
 
-    if (masterPtr->instancePtr) {
+    if (masterPtr->instancePtr != NULL) {
 	Tcl_Panic("tried to delete bitmap image when instances still exist");
     }
     masterPtr->tkMaster = NULL;
-    if (masterPtr->imageCmd) {
+    if (masterPtr->imageCmd != NULL) {
 	Tcl_DeleteCommandFromToken(masterPtr->interp, masterPtr->imageCmd);
     }
-    if (masterPtr->data) {
+    if (masterPtr->data != NULL) {
 	ckfree(masterPtr->data);
     }
-    if (masterPtr->maskData) {
+    if (masterPtr->maskData != NULL) {
 	ckfree(masterPtr->maskData);
     }
     Tk_FreeOptions(configSpecs, (char *) masterPtr, NULL, 0);
@@ -1042,7 +1042,7 @@ ImgBmapCmdDeletedProc(
     BitmapMaster *masterPtr = (BitmapMaster *) clientData;
 
     masterPtr->imageCmd = NULL;
-    if (masterPtr->tkMaster) {
+    if (masterPtr->tkMaster != NULL) {
 	Tk_DeleteImage(masterPtr->interp, Tk_NameOfImage(masterPtr->tkMaster));
     }
 }
diff --git a/generic/tkImgPhoto.c b/generic/tkImgPhoto.c
index d1503f6..4e1aa01 100644
--- a/generic/tkImgPhoto.c
+++ b/generic/tkImgPhoto.c
@@ -2285,7 +2285,7 @@ ImgPhotoConfigureInstance(
      * has the side effect of allocating a pixmap for us.
      */
 
-    if (!instancePtr->pixels || !instancePtr->error
+    if ((instancePtr->pixels == None) || (instancePtr->error == NULL)
 	    || (instancePtr->width != masterPtr->width)
 	    || (instancePtr->height != masterPtr->height)) {
 	ImgPhotoInstanceSetSize(instancePtr);
@@ -2403,7 +2403,7 @@ ImgPhotoGet(
     Tk_PreserveColormap(instancePtr->display, instancePtr->colormap);
     instancePtr->refCount = 1;
     instancePtr->colorTablePtr = NULL;
-    instancePtr->pixels = 0;
+    instancePtr->pixels = None;
     instancePtr->error = NULL;
     instancePtr->width = 0;
     instancePtr->height = 0;
@@ -2776,7 +2776,7 @@ ImgPhotoDisplay(
      * the image instance so it can't be displayed.
      */
 
-    if (!instancePtr->pixels) {
+    if (instancePtr->pixels == None) {
 	return;
     }
 
@@ -2834,7 +2834,7 @@ ImgPhotoDisplay(
 	XCopyArea(display, instancePtr->pixels, drawable, instancePtr->gc,
 		imageX, imageY, (unsigned) width, (unsigned) height,
 		drawableX, drawableY);
-	XSetClipMask(display, instancePtr->gc, 0);
+	XSetClipMask(display, instancePtr->gc, None);
 	XSetClipOrigin(display, instancePtr->gc, 0, 0);
     }
     XFlush(display);
@@ -3196,7 +3196,7 @@ ImgPhotoInstanceSetSize(
 
     if ((instancePtr->width != masterPtr->width)
 	    || (instancePtr->height != masterPtr->height)
-	    || !instancePtr->pixels) {
+	    || (instancePtr->pixels == None)) {
 	newPixmap = Tk_GetPixmap(instancePtr->display,
 		RootWindow(instancePtr->display,
 			instancePtr->visualInfo.screen),
@@ -3218,7 +3218,7 @@ ImgPhotoInstanceSetSize(
 
 	TkSetPixmapColormap(newPixmap, instancePtr->colormap);
 
-	if (instancePtr->pixels) {
+	if (instancePtr->pixels != None) {
 	    /*
 	     * Copy any common pixels from the old pixmap and free it.
 	     */
@@ -3995,19 +3995,19 @@ DisposeInstance(
     PhotoInstance *instancePtr = (PhotoInstance *) clientData;
     PhotoInstance *prevPtr;
 
-    if (instancePtr->pixels) {
+    if (instancePtr->pixels != None) {
 	Tk_FreePixmap(instancePtr->display, instancePtr->pixels);
     }
-    if (instancePtr->gc) {
+    if (instancePtr->gc != None) {
 	Tk_FreeGC(instancePtr->display, instancePtr->gc);
     }
-    if (instancePtr->imagePtr) {
+    if (instancePtr->imagePtr != NULL) {
 	XDestroyImage(instancePtr->imagePtr);
     }
-    if (instancePtr->error) {
+    if (instancePtr->error != NULL) {
 	ckfree((char *) instancePtr->error);
     }
-    if (instancePtr->colorTablePtr) {
+    if (instancePtr->colorTablePtr != NULL) {
 	FreeColorTable(instancePtr->colorTablePtr, 1);
     }
 
diff --git a/generic/tkListbox.c b/generic/tkListbox.c
index 70e4e3c..1c9a8ae 100644
--- a/generic/tkListbox.c
+++ b/generic/tkListbox.c
@@ -534,15 +534,15 @@ Tk_ListboxObjCmd(
 	    ckalloc(sizeof(Tcl_HashTable));
     Tcl_InitHashTable(listPtr->itemAttrTable, TCL_ONE_WORD_KEYS);
     listPtr->relief		 = TK_RELIEF_RAISED;
-    listPtr->textGC		 = 0;
-    listPtr->selFgColorPtr	 = 0;
-    listPtr->selTextGC		 = 0;
+    listPtr->textGC		 = NULL;
+    listPtr->selFgColorPtr	 = NULL;
+    listPtr->selTextGC		 = NULL;
     listPtr->fullLines		 = 1;
     listPtr->xScrollUnit	 = 1;
     listPtr->exportSelection	 = 1;
-    listPtr->cursor		 = 0;
+    listPtr->cursor		 = NULL;
     listPtr->state		 = STATE_NORMAL;
-    listPtr->gray		 = 0;
+    listPtr->gray		 = None;
 
     /*
      * Keep a hold of the associated tkwin until we destroy the listbox,
@@ -1474,13 +1474,13 @@ DestroyListbox(
      * Tk_FreeOptions handle all the standard option-related stuff.
      */
 
-    if (listPtr->textGC) {
+    if (listPtr->textGC != None) {
 	Tk_FreeGC(listPtr->display, listPtr->textGC);
     }
-    if (listPtr->selTextGC) {
+    if (listPtr->selTextGC != None) {
 	Tk_FreeGC(listPtr->display, listPtr->selTextGC);
     }
-    if (listPtr->gray) {
+    if (listPtr->gray != None) {
 	Tk_FreeBitmap(Tk_Display(listPtr->tkwin), listPtr->gray);
     }
 
@@ -1765,10 +1765,10 @@ ListboxWorldChanged(
     } else {
 	gcValues.foreground = listPtr->fgColorPtr->pixel;
 	mask = GCForeground | GCFont;
-	if (!listPtr->gray) {
+	if (listPtr->gray == None) {
 	    listPtr->gray = Tk_GetBitmap(NULL, listPtr->tkwin, "gray50");
 	}
-	if (listPtr->gray) {
+	if (listPtr->gray != None) {
 	    gcValues.fill_style = FillStippled;
 	    gcValues.stipple = listPtr->gray;
 	    mask |= GCFillStyle | GCStipple;
@@ -1777,18 +1777,18 @@ ListboxWorldChanged(
 
     gcValues.font = Tk_FontId(listPtr->tkfont);
     gc = Tk_GetGC(listPtr->tkwin, mask, &gcValues);
-    if (listPtr->textGC) {
+    if (listPtr->textGC != None) {
 	Tk_FreeGC(listPtr->display, listPtr->textGC);
     }
     listPtr->textGC = gc;
 
-    if (listPtr->selFgColorPtr) {
+    if (listPtr->selFgColorPtr != NULL) {
 	gcValues.foreground = listPtr->selFgColorPtr->pixel;
     }
     gcValues.font = Tk_FontId(listPtr->tkfont);
     mask = GCForeground | GCFont;
     gc = Tk_GetGC(listPtr->tkwin, mask, &gcValues);
-    if (listPtr->selTextGC) {
+    if (listPtr->selTextGC != None) {
 	Tk_FreeGC(listPtr->display, listPtr->selTextGC);
     }
     listPtr->selTextGC = gc;
diff --git a/generic/tkMenu.c b/generic/tkMenu.c
index fa14b7e..171087a 100644
--- a/generic/tkMenu.c
+++ b/generic/tkMenu.c
@@ -506,7 +506,7 @@ MenuCmd(
 	    Tk_PathName(menuPtr->tkwin), MenuWidgetObjCmd,
 	    (ClientData) menuPtr, MenuCmdDeletedProc);
     menuPtr->active = -1;
-    menuPtr->cursorPtr = 0;
+    menuPtr->cursorPtr = NULL;
     menuPtr->masterMenuPtr = menuPtr;
     menuPtr->menuType = UNKNOWN_TYPE;
     menuPtr->optionTablesPtr = optionTablesPtr;
diff --git a/generic/tkMenuDraw.c b/generic/tkMenuDraw.c
index d26f83b..11faa0a 100644
--- a/generic/tkMenuDraw.c
+++ b/generic/tkMenuDraw.c
@@ -43,12 +43,12 @@ void
 TkMenuInitializeDrawingFields(
     TkMenu *menuPtr)		/* The menu we are initializing. */
 {
-    menuPtr->textGC = 0;
-    menuPtr->gray = 0;
-    menuPtr->disabledGC = 0;
-    menuPtr->activeGC = 0;
-    menuPtr->indicatorGC = 0;
-    menuPtr->disabledImageGC = 0;
+    menuPtr->textGC = NULL;
+    menuPtr->gray = None;
+    menuPtr->disabledGC = NULL;
+    menuPtr->activeGC = NULL;
+    menuPtr->indicatorGC = NULL;
+    menuPtr->disabledImageGC = NULL;
     menuPtr->totalWidth = menuPtr->totalHeight = 0;
 }
 
@@ -79,10 +79,10 @@ TkMenuInitializeEntryDrawingFields(
     mePtr->y = 0;
     mePtr->indicatorSpace = 0;
     mePtr->labelWidth = 0;
-    mePtr->textGC = 0;
-    mePtr->activeGC = 0;
-    mePtr->disabledGC = 0;
-    mePtr->indicatorGC = 0;
+    mePtr->textGC = NULL;
+    mePtr->activeGC = NULL;
+    mePtr->disabledGC = NULL;
+    mePtr->indicatorGC = NULL;
 }
 
 /*
@@ -106,22 +106,22 @@ void
 TkMenuFreeDrawOptions(
     TkMenu *menuPtr)
 {
-    if (menuPtr->textGC) {
+    if (menuPtr->textGC != None) {
 	Tk_FreeGC(menuPtr->display, menuPtr->textGC);
     }
-    if (menuPtr->disabledImageGC) {
+    if (menuPtr->disabledImageGC != None) {
 	Tk_FreeGC(menuPtr->display, menuPtr->disabledImageGC);
     }
-    if (menuPtr->gray) {
+    if (menuPtr->gray != None) {
 	Tk_FreeBitmap(menuPtr->display, menuPtr->gray);
     }
-    if (menuPtr->disabledGC) {
+    if (menuPtr->disabledGC != None) {
 	Tk_FreeGC(menuPtr->display, menuPtr->disabledGC);
     }
-    if (menuPtr->activeGC) {
+    if (menuPtr->activeGC != None) {
 	Tk_FreeGC(menuPtr->display, menuPtr->activeGC);
     }
-    if (menuPtr->indicatorGC) {
+    if (menuPtr->indicatorGC != None) {
 	Tk_FreeGC(menuPtr->display, menuPtr->indicatorGC);
     }
 }
@@ -147,16 +147,16 @@ void
 TkMenuEntryFreeDrawOptions(
     TkMenuEntry *mePtr)
 {
-    if (mePtr->textGC) {
+    if (mePtr->textGC != None) {
 	Tk_FreeGC(mePtr->menuPtr->display, mePtr->textGC);
     }
-    if (mePtr->disabledGC) {
+    if (mePtr->disabledGC != None) {
 	Tk_FreeGC(mePtr->menuPtr->display, mePtr->disabledGC);
     }
-    if (mePtr->activeGC) {
+    if (mePtr->activeGC != None) {
 	Tk_FreeGC(mePtr->menuPtr->display, mePtr->activeGC);
     }
-    if (mePtr->indicatorGC) {
+    if (mePtr->indicatorGC != None) {
 	Tk_FreeGC(mePtr->menuPtr->display, mePtr->indicatorGC);
     }
 }
@@ -205,7 +205,7 @@ TkMenuConfigureDrawOptions(
     gcValues.background = Tk_3DBorderColor(border)->pixel;
     newGC = Tk_GetGC(menuPtr->tkwin, GCForeground|GCBackground|GCFont,
 	    &gcValues);
-    if (menuPtr->textGC) {
+    if (menuPtr->textGC != None) {
 	Tk_FreeGC(menuPtr->display, menuPtr->textGC);
     }
     menuPtr->textGC = newGC;
@@ -222,34 +222,34 @@ TkMenuConfigureDrawOptions(
     } else {
 	gcValues.foreground = gcValues.background;
 	mask = GCForeground;
-	if (!menuPtr->gray) {
+	if (menuPtr->gray == None) {
 	    menuPtr->gray = Tk_GetBitmap(menuPtr->interp, menuPtr->tkwin,
 		    "gray50");
 	}
-	if (menuPtr->gray) {
+	if (menuPtr->gray != None) {
 	    gcValues.fill_style = FillStippled;
 	    gcValues.stipple = menuPtr->gray;
 	    mask = GCForeground|GCFillStyle|GCStipple;
 	}
     }
     newGC = Tk_GetGC(menuPtr->tkwin, mask, &gcValues);
-    if (menuPtr->disabledGC) {
+    if (menuPtr->disabledGC != None) {
 	Tk_FreeGC(menuPtr->display, menuPtr->disabledGC);
     }
     menuPtr->disabledGC = newGC;
 
     gcValues.foreground = Tk_3DBorderColor(border)->pixel;
-    if (!menuPtr->gray) {
+    if (menuPtr->gray == None) {
 	menuPtr->gray = Tk_GetBitmap(menuPtr->interp, menuPtr->tkwin,
 		"gray50");
     }
-    if (menuPtr->gray) {
+    if (menuPtr->gray != None) {
 	gcValues.fill_style = FillStippled;
 	gcValues.stipple = menuPtr->gray;
 	newGC = Tk_GetGC(menuPtr->tkwin,
 	    GCForeground|GCFillStyle|GCStipple, &gcValues);
     }
-    if (menuPtr->disabledImageGC) {
+    if (menuPtr->disabledImageGC != None) {
 	Tk_FreeGC(menuPtr->display, menuPtr->disabledImageGC);
     }
     menuPtr->disabledImageGC = newGC;
@@ -262,7 +262,7 @@ TkMenuConfigureDrawOptions(
     gcValues.background = Tk_3DBorderColor(activeBorder)->pixel;
     newGC = Tk_GetGC(menuPtr->tkwin, GCForeground|GCBackground|GCFont,
 	    &gcValues);
-    if (menuPtr->activeGC) {
+    if (menuPtr->activeGC != None) {
 	Tk_FreeGC(menuPtr->display, menuPtr->activeGC);
     }
     menuPtr->activeGC = newGC;
@@ -273,7 +273,7 @@ TkMenuConfigureDrawOptions(
     gcValues.background = Tk_3DBorderColor(border)->pixel;
     newGC = Tk_GetGC(menuPtr->tkwin, GCForeground|GCBackground|GCFont,
 	    &gcValues);
-    if (menuPtr->indicatorGC) {
+    if (menuPtr->indicatorGC != None) {
 	Tk_FreeGC(menuPtr->display, menuPtr->indicatorGC);
     }
     menuPtr->indicatorGC = newGC;
@@ -385,24 +385,24 @@ TkMenuConfigureEntryDrawOptions(
 		GCForeground|GCBackground|GCFont|GCGraphicsExposures,
 		&gcValues);
     } else {
-	newGC = 0;
-	newActiveGC = 0;
-	newDisabledGC = 0;
-	newIndicatorGC = 0;
+	newGC = NULL;
+	newActiveGC = NULL;
+	newDisabledGC = NULL;
+	newIndicatorGC = NULL;
     }
-    if (mePtr->textGC) {
+    if (mePtr->textGC != None) {
 	Tk_FreeGC(menuPtr->display, mePtr->textGC);
     }
     mePtr->textGC = newGC;
-    if (mePtr->activeGC) {
+    if (mePtr->activeGC != None) {
 	Tk_FreeGC(menuPtr->display, mePtr->activeGC);
     }
     mePtr->activeGC = newActiveGC;
-    if (mePtr->disabledGC) {
+    if (mePtr->disabledGC != None) {
 	Tk_FreeGC(menuPtr->display, mePtr->disabledGC);
     }
     mePtr->disabledGC = newDisabledGC;
-    if (mePtr->indicatorGC) {
+    if (mePtr->indicatorGC != None) {
 	Tk_FreeGC(menuPtr->display, mePtr->indicatorGC);
     }
     mePtr->indicatorGC = newIndicatorGC;
diff --git a/generic/tkMenubutton.c b/generic/tkMenubutton.c
index a24ab98..95fb9a4 100644
--- a/generic/tkMenubutton.c
+++ b/generic/tkMenubutton.c
@@ -251,7 +251,7 @@ Tk_MenubuttonObjCmd(
     mbPtr->text = NULL;
     mbPtr->underline = -1;
     mbPtr->textVarName = NULL;
-    mbPtr->bitmap = 0;
+    mbPtr->bitmap = None;
     mbPtr->imageString = NULL;
     mbPtr->image = NULL;
     mbPtr->state = STATE_NORMAL;
@@ -267,11 +267,11 @@ Tk_MenubuttonObjCmd(
     mbPtr->normalFg = NULL;
     mbPtr->activeFg = NULL;
     mbPtr->disabledFg = NULL;
-    mbPtr->normalTextGC = 0;
-    mbPtr->activeTextGC = 0;
-    mbPtr->gray = 0;
-    mbPtr->disabledGC = 0;
-    mbPtr->stippleGC = 0;
+    mbPtr->normalTextGC = NULL;
+    mbPtr->activeTextGC = NULL;
+    mbPtr->gray = None;
+    mbPtr->disabledGC = NULL;
+    mbPtr->stippleGC = NULL;
     mbPtr->leftBearing = 0;
     mbPtr->rightBearing = 0;
     mbPtr->widthString = NULL;
@@ -288,7 +288,7 @@ Tk_MenubuttonObjCmd(
     mbPtr->indicatorWidth = 0;
     mbPtr->indicatorHeight = 0;
     mbPtr->direction = DIRECTION_FLUSH;
-    mbPtr->cursor = 0;
+    mbPtr->cursor = NULL;
     mbPtr->takeFocus = NULL;
     mbPtr->flags = 0;
 
@@ -433,22 +433,22 @@ DestroyMenuButton(
     if (mbPtr->image != NULL) {
 	Tk_FreeImage(mbPtr->image);
     }
-    if (mbPtr->normalTextGC) {
+    if (mbPtr->normalTextGC != None) {
 	Tk_FreeGC(mbPtr->display, mbPtr->normalTextGC);
     }
-    if (mbPtr->activeTextGC) {
+    if (mbPtr->activeTextGC != None) {
 	Tk_FreeGC(mbPtr->display, mbPtr->activeTextGC);
     }
-    if (mbPtr->disabledGC) {
+    if (mbPtr->disabledGC != None) {
 	Tk_FreeGC(mbPtr->display, mbPtr->disabledGC);
     }
-    if (mbPtr->stippleGC) {
+    if (mbPtr->stippleGC != None) {
 	Tk_FreeGC(mbPtr->display, mbPtr->stippleGC);
     }
-    if (mbPtr->gray) {
+    if (mbPtr->gray != None) {
 	Tk_FreeBitmap(mbPtr->display, mbPtr->gray);
     }
-    if (mbPtr->textLayout) {
+    if (mbPtr->textLayout != NULL) {
 	Tk_FreeTextLayout(mbPtr->textLayout);
     }
     Tk_FreeConfigOptions((char *) mbPtr, mbPtr->optionTable, mbPtr->tkwin);
@@ -578,7 +578,7 @@ ConfigureMenuButton(
 	 * Recompute the geometry for the button.
 	 */
 
-	if (mbPtr->bitmap || mbPtr->image) {
+	if ((mbPtr->bitmap != None) || (mbPtr->image != NULL)) {
 	    if (Tk_GetPixels(interp, mbPtr->tkwin, mbPtr->widthString,
 		    &mbPtr->width) != TCL_OK) {
 	    widthError:
@@ -683,7 +683,7 @@ TkMenuButtonWorldChanged(
     gcValues.graphics_exposures = False;
     mask = GCForeground | GCBackground | GCFont | GCGraphicsExposures;
     gc = Tk_GetGC(mbPtr->tkwin, mask, &gcValues);
-    if (mbPtr->normalTextGC) {
+    if (mbPtr->normalTextGC != None) {
 	Tk_FreeGC(mbPtr->display, mbPtr->normalTextGC);
     }
     mbPtr->normalTextGC = gc;
@@ -692,7 +692,7 @@ TkMenuButtonWorldChanged(
     gcValues.background = Tk_3DBorderColor(mbPtr->activeBorder)->pixel;
     mask = GCForeground | GCBackground | GCFont;
     gc = Tk_GetGC(mbPtr->tkwin, mask, &gcValues);
-    if (mbPtr->activeTextGC) {
+    if (mbPtr->activeTextGC != None) {
 	Tk_FreeGC(mbPtr->display, mbPtr->activeTextGC);
     }
     mbPtr->activeTextGC = gc;
@@ -703,13 +703,13 @@ TkMenuButtonWorldChanged(
      * Create the GC that can be used for stippling
      */
 
-    if (!mbPtr->stippleGC) {
+    if (mbPtr->stippleGC == None) {
 	gcValues.foreground = gcValues.background;
 	mask = GCForeground;
-	if (!mbPtr->gray) {
+	if (mbPtr->gray == None) {
 	    mbPtr->gray = Tk_GetBitmap(NULL, mbPtr->tkwin, "gray50");
 	}
-	if (mbPtr->gray) {
+	if (mbPtr->gray != None) {
 	    gcValues.fill_style = FillStippled;
 	    gcValues.stipple = mbPtr->gray;
 	    mask |= GCFillStyle | GCStipple;
@@ -723,13 +723,13 @@ TkMenuButtonWorldChanged(
      */
 
     mask = GCForeground | GCBackground | GCFont;
-    if (mbPtr->disabledFg) {
+    if (mbPtr->disabledFg != NULL) {
 	gcValues.foreground = mbPtr->disabledFg->pixel;
     } else {
 	gcValues.foreground = gcValues.background;
     }
     gc = Tk_GetGC(mbPtr->tkwin, mask, &gcValues);
-    if (mbPtr->disabledGC) {
+    if (mbPtr->disabledGC != None) {
 	Tk_FreeGC(mbPtr->display, mbPtr->disabledGC);
     }
     mbPtr->disabledGC = gc;
diff --git a/generic/tkMessage.c b/generic/tkMessage.c
index 9cfa593..40535b3 100644
--- a/generic/tkMessage.c
+++ b/generic/tkMessage.c
@@ -254,11 +254,11 @@ Tk_MessageObjCmd(
 	    (ClientData) msgPtr, MessageCmdDeletedProc);
     msgPtr->optionTable = optionTable;
     msgPtr->relief = TK_RELIEF_FLAT;
-    msgPtr->textGC = 0;
+    msgPtr->textGC = NULL;
     msgPtr->anchor = TK_ANCHOR_CENTER;
     msgPtr->aspect = 150;
     msgPtr->justify = TK_JUSTIFY_LEFT;
-    msgPtr->cursor = 0;
+    msgPtr->cursor = NULL;
 
     Tk_SetClass(msgPtr->tkwin, "Message");
     Tk_SetClassProcs(msgPtr->tkwin, &messageClass, (ClientData) msgPtr);
@@ -396,13 +396,13 @@ DestroyMessage(
      * Tk_FreeConfigOptions handle all the standard option-related stuff.
      */
 
-    if (msgPtr->textGC) {
+    if (msgPtr->textGC != None) {
 	Tk_FreeGC(msgPtr->display, msgPtr->textGC);
     }
-    if (msgPtr->textLayout) {
+    if (msgPtr->textLayout != NULL) {
 	Tk_FreeTextLayout(msgPtr->textLayout);
     }
-    if (msgPtr->textVarName) {
+    if (msgPtr->textVarName != NULL) {
 	Tcl_UntraceVar(msgPtr->interp, msgPtr->textVarName,
 		TCL_GLOBAL_ONLY|TCL_TRACE_WRITES|TCL_TRACE_UNSETS,
 		MessageTextVarProc, (ClientData) msgPtr);
@@ -469,7 +469,7 @@ ConfigureMessage(
 	CONST char *value;
 
 	value = Tcl_GetVar(interp, msgPtr->textVarName, TCL_GLOBAL_ONLY);
-	if (!value) {
+	if (value == NULL) {
 	    Tcl_SetVar(interp, msgPtr->textVarName, msgPtr->string,
 		    TCL_GLOBAL_ONLY);
 	} else {
@@ -523,20 +523,20 @@ MessageWorldChanged(
     ClientData instanceData)	/* Information about widget. */
 {
     XGCValues gcValues;
-    GC gc = 0;
+    GC gc = NULL;
     Tk_FontMetrics fm;
     Message *msgPtr;
 
     msgPtr = (Message *) instanceData;
 
-    if (msgPtr->border) {
+    if (msgPtr->border != NULL) {
 	Tk_SetBackgroundFromBorder(msgPtr->tkwin, msgPtr->border);
     }
 
     gcValues.font = Tk_FontId(msgPtr->tkfont);
     gcValues.foreground = msgPtr->fgColorPtr->pixel;
     gc = Tk_GetGC(msgPtr->tkwin, GCForeground | GCFont, &gcValues);
-    if (msgPtr->textGC) {
+    if (msgPtr->textGC != None) {
 	Tk_FreeGC(msgPtr->display, msgPtr->textGC);
     }
     msgPtr->textGC = gc;
diff --git a/generic/tkOldConfig.c b/generic/tkOldConfig.c
index 955b3e0..cf5612b 100644
--- a/generic/tkOldConfig.c
+++ b/generic/tkOldConfig.c
@@ -431,16 +431,16 @@ DoConfig(
 	    Pixmap newBmp, oldBmp;
 
 	    if (nullValue) {
-		newBmp = 0;
+		newBmp = None;
 	    } else {
 		uid = valueIsUid ? (Tk_Uid) value : Tk_GetUid(value);
 		newBmp = Tk_GetBitmap(interp, tkwin, uid);
-		if (!newBmp) {
+		if (newBmp == None) {
 		    return TCL_ERROR;
 		}
 	    }
 	    oldBmp = *((Pixmap *) ptr);
-	    if (oldBmp) {
+	    if (oldBmp != None) {
 		Tk_FreeBitmap(Tk_Display(tkwin), oldBmp);
 	    }
 	    *((Pixmap *) ptr) = newBmp;
@@ -454,12 +454,12 @@ DoConfig(
 	    } else {
 		uid = valueIsUid ? (Tk_Uid) value : Tk_GetUid(value);
 		newBorder = Tk_Get3DBorder(interp, tkwin, uid);
-		if (!newBorder) {
+		if (newBorder == NULL) {
 		    return TCL_ERROR;
 		}
 	    }
 	    oldBorder = *((Tk_3DBorder *) ptr);
-	    if (oldBorder) {
+	    if (oldBorder != NULL) {
 		Tk_Free3DBorder(oldBorder);
 	    }
 	    *((Tk_3DBorder *) ptr) = newBorder;
@@ -480,12 +480,12 @@ DoConfig(
 	    } else {
 		uid = valueIsUid ? (Tk_Uid) value : Tk_GetUid(value);
 		newCursor = Tk_GetCursor(interp, tkwin, uid);
-		if (!newCursor) {
+		if (newCursor == None) {
 		    return TCL_ERROR;
 		}
 	    }
 	    oldCursor = *((Tk_Cursor *) ptr);
-	    if (oldCursor) {
+	    if (oldCursor != None) {
 		Tk_FreeCursor(Tk_Display(tkwin), oldCursor);
 	    }
 	    *((Tk_Cursor *) ptr) = newCursor;
@@ -794,7 +794,7 @@ FormatConfigValue(
     case TK_CONFIG_UID: {
 	Tk_Uid uid = *((Tk_Uid *) ptr);
 
-	if (uid) {
+	if (uid != NULL) {
 	    result = uid;
 	}
 	break;
@@ -802,7 +802,7 @@ FormatConfigValue(
     case TK_CONFIG_COLOR: {
 	XColor *colorPtr = *((XColor **) ptr);
 
-	if (colorPtr) {
+	if (colorPtr != NULL) {
 	    result = Tk_NameOfColor(colorPtr);
 	}
 	break;
@@ -810,7 +810,7 @@ FormatConfigValue(
     case TK_CONFIG_FONT: {
 	Tk_Font tkfont = *((Tk_Font *) ptr);
 
-	if (tkfont) {
+	if (tkfont != NULL) {
 	    result = Tk_NameOfFont(tkfont);
 	}
 	break;
@@ -818,7 +818,7 @@ FormatConfigValue(
     case TK_CONFIG_BITMAP: {
 	Pixmap pixmap = *((Pixmap *) ptr);
 
-	if (pixmap) {
+	if (pixmap != None) {
 	    result = Tk_NameOfBitmap(Tk_Display(tkwin), pixmap);
 	}
 	break;
@@ -826,7 +826,7 @@ FormatConfigValue(
     case TK_CONFIG_BORDER: {
 	Tk_3DBorder border = *((Tk_3DBorder *) ptr);
 
-	if (border) {
+	if (border != NULL) {
 	    result = Tk_NameOf3DBorder(border);
 	}
 	break;
@@ -838,7 +838,7 @@ FormatConfigValue(
     case TK_CONFIG_ACTIVE_CURSOR: {
 	Tk_Cursor cursor = *((Tk_Cursor *) ptr);
 
-	if (cursor) {
+	if (cursor != None) {
 	    result = Tk_NameOfCursor(Tk_Display(tkwin), cursor);
 	}
 	break;
@@ -995,7 +995,7 @@ Tk_FreeOptions(
 	ptr = widgRec + specPtr->offset;
 	switch (specPtr->type) {
 	case TK_CONFIG_STRING:
-	    if (*((char **) ptr)) {
+	    if (*((char **) ptr) != NULL) {
 		ckfree(*((char **) ptr));
 		*((char **) ptr) = NULL;
 	    }
@@ -1011,22 +1011,22 @@ Tk_FreeOptions(
 	    *((Tk_Font *) ptr) = NULL;
 	    break;
 	case TK_CONFIG_BITMAP:
-	    if (*((Pixmap *) ptr)) {
+	    if (*((Pixmap *) ptr) != None) {
 		Tk_FreeBitmap(display, *((Pixmap *) ptr));
-		*((Pixmap *) ptr) = 0;
+		*((Pixmap *) ptr) = None;
 	    }
 	    break;
 	case TK_CONFIG_BORDER:
-	    if (*((Tk_3DBorder *) ptr)) {
+	    if (*((Tk_3DBorder *) ptr) != NULL) {
 		Tk_Free3DBorder(*((Tk_3DBorder *) ptr));
 		*((Tk_3DBorder *) ptr) = NULL;
 	    }
 	    break;
 	case TK_CONFIG_CURSOR:
 	case TK_CONFIG_ACTIVE_CURSOR:
-	    if (*((Tk_Cursor *) ptr)) {
+	    if (*((Tk_Cursor *) ptr) != None) {
 		Tk_FreeCursor(display, *((Tk_Cursor *) ptr));
-		*((Tk_Cursor *) ptr) = 0;
+		*((Tk_Cursor *) ptr) = NULL;
 	    }
 	}
     }
diff --git a/generic/tkPanedWindow.c b/generic/tkPanedWindow.c
index f37892c..f232889 100644
--- a/generic/tkPanedWindow.c
+++ b/generic/tkPanedWindow.c
@@ -448,9 +448,9 @@ Tk_PanedWindowObjCmd(
     pwPtr->optionTable = pwOpts->pwOptions;
     pwPtr->slaveOpts = pwOpts->slaveOpts;
     pwPtr->relief = TK_RELIEF_RAISED;
-    pwPtr->gc = 0;
-    pwPtr->cursor = 0;
-    pwPtr->sashCursor = 0;
+    pwPtr->gc = NULL;
+    pwPtr->cursor = NULL;
+    pwPtr->sashCursor = NULL;
 
     /*
      * Keep a hold of the associated tkwin until we destroy the widget,
@@ -859,7 +859,7 @@ ConfigureSlaves(
 
     index = -1;
     haveLoc = 0;
-    if (options.after) {
+    if (options.after != None) {
 	tkwin = options.after;
 	haveLoc = 1;
 	for (i = 0; i < pwPtr->numSlaves; i++) {
@@ -868,7 +868,7 @@ ConfigureSlaves(
 		break;
 	    }
 	}
-    } else if (options.before) {
+    } else if (options.before != None) {
 	tkwin = options.before;
 	haveLoc = 1;
 	for (i = 0; i < pwPtr->numSlaves; i++) {
@@ -1299,7 +1299,7 @@ PanedWindowWorldChanged(
 
     gcValues.background = Tk_3DBorderColor(pwPtr->background)->pixel;
     newGC = Tk_GetGC(pwPtr->tkwin, GCBackground, &gcValues);
-    if (pwPtr->gc) {
+    if (pwPtr->gc != None) {
 	Tk_FreeGC(pwPtr->display, pwPtr->gc);
     }
     pwPtr->gc = newGC;
@@ -2018,10 +2018,10 @@ Unlink(
 
     for (i = 0; i < masterPtr->numSlaves; i++) {
 	if (masterPtr->slaves[i]->before == slavePtr->tkwin) {
-	    masterPtr->slaves[i]->before = 0;
+	    masterPtr->slaves[i]->before = NULL;
 	}
 	if (masterPtr->slaves[i]->after == slavePtr->tkwin) {
-	    masterPtr->slaves[i]->after = 0;
+	    masterPtr->slaves[i]->after = NULL;
 	}
     }
 
diff --git a/generic/tkPointer.c b/generic/tkPointer.c
index 00e1328..dd4f7e6 100644
--- a/generic/tkPointer.c
+++ b/generic/tkPointer.c
@@ -179,13 +179,14 @@ GenerateEnterLeave(
 	} else {
 	    TkWindow *targetPtr;
 
-	    if (!lastWinPtr || !lastWinPtr->window) {
+	    if ((lastWinPtr == NULL)
+		|| (lastWinPtr->window == None)) {
 		targetPtr = winPtr;
 	    } else {
 		targetPtr = lastWinPtr;
 	    }
 
-	    if (targetPtr && targetPtr->window) {
+	    if (targetPtr && (targetPtr->window != None)) {
 		XEvent event;
 
 		/*
@@ -539,7 +540,7 @@ static void
 UpdateCursor(
     TkWindow *winPtr)
 {
-    Cursor cursor = 0;
+    Cursor cursor = None;
     ThreadSpecificData *tsdPtr = (ThreadSpecificData *)
 	    Tcl_GetThreadData(&dataKey, sizeof(ThreadSpecificData));
 
@@ -549,8 +550,8 @@ UpdateCursor(
      */
 
     tsdPtr->cursorWinPtr = winPtr;
-    while (winPtr) {
-	if (winPtr->atts.cursor) {
+    while (winPtr != NULL) {
+	if (winPtr->atts.cursor != None) {
 	    cursor = winPtr->atts.cursor;
 	    break;
 	} else if (winPtr->flags & TK_TOP_HIERARCHY) {
diff --git a/generic/tkRectOval.c b/generic/tkRectOval.c
index af94c6f..53ebe61 100644
--- a/generic/tkRectOval.c
+++ b/generic/tkRectOval.c
@@ -259,10 +259,10 @@ CreateRectOval(
     rectOvalPtr->fillColor = NULL;
     rectOvalPtr->activeFillColor = NULL;
     rectOvalPtr->disabledFillColor = NULL;
-    rectOvalPtr->fillStipple = 0;
-    rectOvalPtr->activeFillStipple = 0;
-    rectOvalPtr->disabledFillStipple = 0;
-    rectOvalPtr->fillGC = 0;
+    rectOvalPtr->fillStipple = None;
+    rectOvalPtr->activeFillStipple = None;
+    rectOvalPtr->disabledFillStipple = None;
+    rectOvalPtr->fillGC = NULL;
 
     /*
      * Process the arguments to fill in the item record.
@@ -429,11 +429,11 @@ ConfigureRectOval(
      */
 
     if (rectOvalPtr->outline.activeWidth > rectOvalPtr->outline.width ||
-	    rectOvalPtr->outline.activeDash.number ||
-	    rectOvalPtr->outline.activeColor ||
-	    rectOvalPtr->outline.activeStipple ||
-	    rectOvalPtr->activeFillColor ||
-	    rectOvalPtr->activeFillStipple) {
+	    rectOvalPtr->outline.activeDash.number != 0 ||
+	    rectOvalPtr->outline.activeColor != NULL ||
+	    rectOvalPtr->outline.activeStipple != None ||
+	    rectOvalPtr->activeFillColor != NULL ||
+	    rectOvalPtr->activeFillStipple != None) {
 	itemPtr->redraw_flags |= TK_ITEM_STATE_DEPENDANT;
     } else {
 	itemPtr->redraw_flags &= ~TK_ITEM_STATE_DEPENDANT;
@@ -467,13 +467,13 @@ ConfigureRectOval(
     mask = Tk_ConfigOutlineGC(&gcValues, canvas, itemPtr,
 	    &(rectOvalPtr->outline));
     if (mask && \
-	    rectOvalPtr->outline.width && \
-	    rectOvalPtr->outline.color) {
+	    rectOvalPtr->outline.width != 0 && \
+	    rectOvalPtr->outline.color != NULL) {
 	gcValues.cap_style = CapProjecting;
 	mask |= GCCapStyle;
 	newGC = Tk_GetGC(tkwin, mask, &gcValues);
     } else {
-	newGC = 0;
+	newGC = NULL;
     }
     if (rectOvalPtr->outline.gc) {
 	Tk_FreeGC(Tk_Display(tkwin), rectOvalPtr->outline.gc);
@@ -494,23 +494,23 @@ ConfigureRectOval(
 	if (rectOvalPtr->activeFillColor!=NULL) {
 	    color = rectOvalPtr->activeFillColor;
 	}
-	if (rectOvalPtr->activeFillStipple) {
+	if (rectOvalPtr->activeFillStipple!=None) {
 	    stipple = rectOvalPtr->activeFillStipple;
 	}
     } else if (state == TK_STATE_DISABLED) {
-	if (rectOvalPtr->disabledFillColor) {
+	if (rectOvalPtr->disabledFillColor!=NULL) {
 	    color = rectOvalPtr->disabledFillColor;
 	}
-	if (rectOvalPtr->disabledFillStipple) {
+	if (rectOvalPtr->disabledFillStipple!=None) {
 	    stipple = rectOvalPtr->disabledFillStipple;
 	}
     }
 
     if (!color) {
-	newGC = 0;
+	newGC = NULL;
     } else {
 	gcValues.foreground = color->pixel;
-	if (stipple) {
+	if (stipple != None) {
 	    gcValues.stipple = stipple;
 	    gcValues.fill_style = FillStippled;
 	    mask = GCForeground|GCStipple|GCFillStyle;
@@ -583,25 +583,25 @@ DeleteRectOval(
     RectOvalItem *rectOvalPtr = (RectOvalItem *) itemPtr;
 
     Tk_DeleteOutline(display, &(rectOvalPtr->outline));
-    if (rectOvalPtr->fillColor) {
+    if (rectOvalPtr->fillColor != NULL) {
 	Tk_FreeColor(rectOvalPtr->fillColor);
     }
-    if (rectOvalPtr->activeFillColor) {
+    if (rectOvalPtr->activeFillColor != NULL) {
 	Tk_FreeColor(rectOvalPtr->activeFillColor);
     }
-    if (rectOvalPtr->disabledFillColor) {
+    if (rectOvalPtr->disabledFillColor != NULL) {
 	Tk_FreeColor(rectOvalPtr->disabledFillColor);
     }
-    if (rectOvalPtr->fillStipple) {
+    if (rectOvalPtr->fillStipple != None) {
 	Tk_FreeBitmap(display, rectOvalPtr->fillStipple);
     }
-    if (rectOvalPtr->activeFillStipple) {
+    if (rectOvalPtr->activeFillStipple != None) {
 	Tk_FreeBitmap(display, rectOvalPtr->activeFillStipple);
     }
-    if (rectOvalPtr->disabledFillStipple) {
+    if (rectOvalPtr->disabledFillStipple != None) {
 	Tk_FreeBitmap(display, rectOvalPtr->disabledFillStipple);
     }
-    if (rectOvalPtr->fillGC) {
+    if (rectOvalPtr->fillGC != None) {
 	Tk_FreeGC(display, rectOvalPtr->fillGC);
     }
 }
@@ -670,7 +670,7 @@ ComputeRectOvalBbox(
 	rectOvalPtr->bbox[0] = tmpX;
     }
 
-    if (!rectOvalPtr->outline.gc) {
+    if (rectOvalPtr->outline.gc == None) {
 	/*
 	 * The Win32 switch was added for 8.3 to solve a problem with ovals
 	 * leaving traces on bottom and right of 1 pixel. This may not be the
@@ -783,17 +783,17 @@ DisplayRectOval(
     }
     fillStipple = rectOvalPtr->fillStipple;
     if (((TkCanvas *)canvas)->currentItemPtr == (Tk_Item *)rectOvalPtr) {
-	if (rectOvalPtr->activeFillStipple) {
+	if (rectOvalPtr->activeFillStipple != None) {
 	    fillStipple = rectOvalPtr->activeFillStipple;
 	}
     } else if (state == TK_STATE_DISABLED) {
-	if (rectOvalPtr->disabledFillStipple) {
+	if (rectOvalPtr->disabledFillStipple != None) {
 	    fillStipple = rectOvalPtr->disabledFillStipple;
 	}
     }
 
-    if (rectOvalPtr->fillGC) {
-	if (fillStipple) {
+    if (rectOvalPtr->fillGC != None) {
+	if (fillStipple != None) {
 	    Tk_TSOffset *tsoffset;
 	    int w = 0, h = 0;
 
@@ -831,12 +831,12 @@ DisplayRectOval(
 		    x1, y1, (unsigned) (x2-x1), (unsigned) (y2-y1),
 		    0, 360*64);
 	}
-	if (fillStipple) {
+	if (fillStipple != None) {
 	    XSetTSOrigin(display, rectOvalPtr->fillGC, 0, 0);
 	}
     }
 
-    if (rectOvalPtr->outline.gc) {
+    if (rectOvalPtr->outline.gc != None) {
 	Tk_ChangeOutlineGC(canvas, itemPtr, &(rectOvalPtr->outline));
 	if (rectOvalPtr->header.typePtr == &tkRectangleType) {
 	    XDrawRectangle(display, drawable, rectOvalPtr->outline.gc,
@@ -907,7 +907,7 @@ RectToPoint(
     y1 = rectPtr->bbox[1];
     x2 = rectPtr->bbox[2];
     y2 = rectPtr->bbox[3];
-    if (rectPtr->outline.gc) {
+    if (rectPtr->outline.gc != None) {
 	inc = width/2.0;
 	x1 -= inc;
 	y1 -= inc;
@@ -923,7 +923,7 @@ RectToPoint(
 
     if ((pointPtr[0] >= x1) && (pointPtr[0] < x2)
 	    && (pointPtr[1] >= y1) && (pointPtr[1] < y2)) {
-	if (rectPtr->fillGC || !rectPtr->outline.gc) {
+	if ((rectPtr->fillGC != None) || (rectPtr->outline.gc == None)) {
 	    return 0.0;
 	}
 	xDiff = pointPtr[0] - x1;
@@ -1019,8 +1019,8 @@ OvalToPoint(
     }
 
 
-    filled = ovalPtr->fillGC != 0;
-    if (!ovalPtr->outline.gc) {
+    filled = ovalPtr->fillGC != None;
+    if (ovalPtr->outline.gc == None) {
 	width = 0.0;
 	filled = 1;
     }
@@ -1075,7 +1075,7 @@ RectToArea(
     }
 
     halfWidth = width/2.0;
-    if (!rectPtr->outline.gc) {
+    if (rectPtr->outline.gc == None) {
 	halfWidth = 0.0;
     }
 
@@ -1085,7 +1085,7 @@ RectToArea(
 	    || (areaPtr[1] >= (rectPtr->bbox[3] + halfWidth))) {
 	return -1;
     }
-    if (!rectPtr->fillGC && rectPtr->outline.gc
+    if ((rectPtr->fillGC == None) && (rectPtr->outline.gc != None)
 	    && (areaPtr[0] >= (rectPtr->bbox[0] + halfWidth))
 	    && (areaPtr[1] >= (rectPtr->bbox[1] + halfWidth))
 	    && (areaPtr[2] <= (rectPtr->bbox[2] - halfWidth))
@@ -1154,7 +1154,7 @@ OvalToArea(
      */
 
     halfWidth = width/2.0;
-    if (!ovalPtr->outline.gc) {
+    if (ovalPtr->outline.gc == None) {
 	halfWidth = 0.0;
     }
     oval[0] = ovalPtr->bbox[0] - halfWidth;
@@ -1171,8 +1171,8 @@ OvalToArea(
      * return "outside".
      */
 
-    if ((result == 0) && ovalPtr->outline.gc
-	    && !ovalPtr->fillGC) {
+    if ((result == 0) && (ovalPtr->outline.gc != None)
+	    && (ovalPtr->fillGC == None)) {
 	double centerX, centerY, height;
 	double xDelta1, yDelta1, xDelta2, yDelta2;
 
@@ -1335,20 +1335,20 @@ RectOvalToPostscript(
 	if (rectOvalPtr->outline.activeColor!=NULL) {
 	    color = rectOvalPtr->outline.activeColor;
 	}
-	if (rectOvalPtr->activeFillColor) {
+	if (rectOvalPtr->activeFillColor!=NULL) {
 	    fillColor = rectOvalPtr->activeFillColor;
 	}
-	if (rectOvalPtr->activeFillStipple) {
+	if (rectOvalPtr->activeFillStipple!=None) {
 	    fillStipple = rectOvalPtr->activeFillStipple;
 	}
     } else if (state == TK_STATE_DISABLED) {
 	if (rectOvalPtr->outline.disabledColor!=NULL) {
 	    color = rectOvalPtr->outline.disabledColor;
 	}
-	if (rectOvalPtr->disabledFillColor) {
+	if (rectOvalPtr->disabledFillColor!=NULL) {
 	    fillColor = rectOvalPtr->disabledFillColor;
 	}
-	if (rectOvalPtr->disabledFillStipple) {
+	if (rectOvalPtr->disabledFillStipple!=None) {
 	    fillStipple = rectOvalPtr->disabledFillStipple;
 	}
     }
@@ -1357,12 +1357,12 @@ RectOvalToPostscript(
      * First draw the filled area of the rectangle.
      */
 
-    if (fillColor) {
+    if (fillColor != NULL) {
 	Tcl_AppendResult(interp, pathCmd, NULL);
 	if (Tk_CanvasPsColor(interp, canvas, fillColor) != TCL_OK) {
 	    return TCL_ERROR;
 	}
-	if (fillStipple) {
+	if (fillStipple != None) {
 	    Tcl_AppendResult(interp, "clip ", NULL);
 	    if (Tk_CanvasPsStipple(interp, canvas, fillStipple) != TCL_OK) {
 		return TCL_ERROR;
@@ -1379,7 +1379,7 @@ RectOvalToPostscript(
      * Now draw the outline, if there is one.
      */
 
-    if (color) {
+    if (color != NULL) {
 	Tcl_AppendResult(interp, pathCmd, "0 setlinejoin 2 setlinecap\n",
 		NULL);
 	if (Tk_CanvasPsOutline(canvas, itemPtr,
diff --git a/generic/tkScale.c b/generic/tkScale.c
index 32cb1b2..a804c36 100644
--- a/generic/tkScale.c
+++ b/generic/tkScale.c
@@ -264,11 +264,11 @@ Tk_ScaleObjCmd(
     scalePtr->activeBorder	= NULL;
     scalePtr->sliderRelief	= TK_RELIEF_RAISED;
     scalePtr->troughColorPtr	= NULL;
-    scalePtr->troughGC		= 0;
-    scalePtr->copyGC		= 0;
+    scalePtr->troughGC		= NULL;
+    scalePtr->copyGC		= NULL;
     scalePtr->tkfont		= NULL;
     scalePtr->textColorPtr	= NULL;
-    scalePtr->textGC		= 0;
+    scalePtr->textGC		= NULL;
     scalePtr->relief		= TK_RELIEF_FLAT;
     scalePtr->highlightWidth	= 0;
     scalePtr->highlightBorder	= NULL;
@@ -285,7 +285,7 @@ Tk_ScaleObjCmd(
     scalePtr->vertTroughX	= 0;
     scalePtr->vertLabelX	= 0;
     scalePtr->fontHeight	= 0;
-    scalePtr->cursor		= 0;
+    scalePtr->cursor		= NULL;
     scalePtr->takeFocusPtr	= NULL;
     scalePtr->flags		= NEVER_SET;
 
@@ -514,13 +514,13 @@ DestroyScale(
 		TCL_GLOBAL_ONLY|TCL_TRACE_WRITES|TCL_TRACE_UNSETS,
 		ScaleVarProc, (ClientData) scalePtr);
     }
-    if (scalePtr->troughGC) {
+    if (scalePtr->troughGC != None) {
 	Tk_FreeGC(scalePtr->display, scalePtr->troughGC);
     }
-    if (scalePtr->copyGC) {
+    if (scalePtr->copyGC != None) {
 	Tk_FreeGC(scalePtr->display, scalePtr->copyGC);
     }
-    if (scalePtr->textGC) {
+    if (scalePtr->textGC != None) {
 	Tk_FreeGC(scalePtr->display, scalePtr->textGC);
     }
     Tk_FreeConfigOptions((char *) scalePtr, scalePtr->optionTable,
@@ -727,7 +727,7 @@ ScaleWorldChanged(
 
     gcValues.foreground = scalePtr->troughColorPtr->pixel;
     gc = Tk_GetGC(scalePtr->tkwin, GCForeground, &gcValues);
-    if (scalePtr->troughGC) {
+    if (scalePtr->troughGC != None) {
 	Tk_FreeGC(scalePtr->display, scalePtr->troughGC);
     }
     scalePtr->troughGC = gc;
@@ -735,12 +735,12 @@ ScaleWorldChanged(
     gcValues.font = Tk_FontId(scalePtr->tkfont);
     gcValues.foreground = scalePtr->textColorPtr->pixel;
     gc = Tk_GetGC(scalePtr->tkwin, GCForeground | GCFont, &gcValues);
-    if (scalePtr->textGC) {
+    if (scalePtr->textGC != None) {
 	Tk_FreeGC(scalePtr->display, scalePtr->textGC);
     }
     scalePtr->textGC = gc;
 
-    if (!scalePtr->copyGC) {
+    if (scalePtr->copyGC == None) {
 	gcValues.graphics_exposures = False;
 	scalePtr->copyGC = Tk_GetGC(scalePtr->tkwin, GCGraphicsExposures,
 		&gcValues);
diff --git a/generic/tkScale.h b/generic/tkScale.h
index a19695f..a2c5f2b 100644
--- a/generic/tkScale.h
+++ b/generic/tkScale.h
@@ -78,7 +78,7 @@ typedef struct TkScale {
 				 * values. 0 means we get to choose the number
 				 * based on resolution and/or the range of the
 				 * scale. */
-    char format[16];		/* Sprintf conversion specifier computed from
+    char format[10];		/* Sprintf conversion specifier computed from
 				 * digits and other information. */
     double bigIncrement;	/* Amount to use for large increments to scale
 				 * value. (0 means we pick a value). */
diff --git a/generic/tkScrollbar.c b/generic/tkScrollbar.c
index 67fdd2b..7e39056 100644
--- a/generic/tkScrollbar.c
+++ b/generic/tkScrollbar.c
@@ -188,7 +188,7 @@ Tk_ScrollbarCmd(
     scrollPtr->lastUnit = 0;
     scrollPtr->firstFraction = 0.0;
     scrollPtr->lastFraction = 0.0;
-    scrollPtr->cursor = 0;
+    scrollPtr->cursor = NULL;
     scrollPtr->takeFocus = NULL;
     scrollPtr->flags = 0;
 
diff --git a/generic/tkSelect.c b/generic/tkSelect.c
index 2f74172..7c96b94 100644
--- a/generic/tkSelect.c
+++ b/generic/tkSelect.c
@@ -130,7 +130,7 @@ Tk_CreateSelHandler(
     register TkSelHandler *selPtr;
     TkWindow *winPtr = (TkWindow *) tkwin;
 
-    if (!winPtr->dispPtr->multipleAtom) {
+    if (winPtr->dispPtr->multipleAtom == None) {
 	TkSelInit(tkwin);
     }
 
@@ -362,7 +362,7 @@ Tk_OwnSelection(
     ClientData clearData = NULL;/* Initialization needed only to prevent
 				 * compiler warning. */
 
-    if (!dispPtr->multipleAtom) {
+    if (dispPtr->multipleAtom == None) {
 	TkSelInit(tkwin);
     }
     Tk_MakeWindowExist(tkwin);
@@ -471,7 +471,7 @@ Tk_ClearSelection(
     ClientData clearData = NULL;/* Initialization needed only to prevent
 				 * compiler warning. */
 
-    if (!dispPtr->multipleAtom) {
+    if (dispPtr->multipleAtom == None) {
 	TkSelInit(tkwin);
     }
 
@@ -494,7 +494,7 @@ Tk_ClearSelection(
 	clearData = infoPtr->clearData;
 	ckfree((char *) infoPtr);
     }
-    XSetSelectionOwner(winPtr->display, selection, 0, CurrentTime);
+    XSetSelectionOwner(winPtr->display, selection, None, CurrentTime);
 
     if (clearProc != NULL) {
 	(*clearProc)(clearData);
@@ -561,7 +561,7 @@ Tk_GetSelection(
     ThreadSpecificData *tsdPtr = (ThreadSpecificData *)
 	    Tcl_GetThreadData(&dataKey, sizeof(ThreadSpecificData));
 
-    if (!dispPtr->multipleAtom) {
+    if (dispPtr->multipleAtom == None) {
 	TkSelInit(tkwin);
     }
 
diff --git a/generic/tkSquare.c b/generic/tkSquare.c
index 305d756..355a447 100644
--- a/generic/tkSquare.c
+++ b/generic/tkSquare.c
@@ -166,7 +166,7 @@ SquareObjCmd(
     squarePtr->widgetCmd = Tcl_CreateObjCommand(interp,
 	    Tk_PathName(squarePtr->tkwin), SquareWidgetObjCmd,
 	    (ClientData) squarePtr, SquareDeletedProc);
-    squarePtr->gc = 0;
+    squarePtr->gc = NULL;
     squarePtr->optionTable = optionTable;
 
     if (Tk_InitOptions(interp, (char *) squarePtr, optionTable, tkwin)
@@ -332,7 +332,7 @@ SquareConfigure(
     Tk_SetWindowBackground(squarePtr->tkwin,
 	    Tk_3DBorderColor(bgBorder)->pixel);
     Tcl_GetBooleanFromObj(NULL, squarePtr->doubleBufferPtr, &doubleBuffer);
-    if (!squarePtr->gc && doubleBuffer) {
+    if ((squarePtr->gc == None) && (doubleBuffer)) {
 	XGCValues gcValues;
 	gcValues.function = GXcopy;
 	gcValues.graphics_exposures = False;
@@ -394,10 +394,10 @@ SquareObjEventProc(
 	    squarePtr->updatePending = 1;
 	}
     } else if (eventPtr->type == DestroyNotify) {
-	if (squarePtr->tkwin) {
+	if (squarePtr->tkwin != NULL) {
 	    Tk_FreeConfigOptions((char *) squarePtr, squarePtr->optionTable,
 		    squarePtr->tkwin);
-	    if (squarePtr->gc) {
+	    if (squarePtr->gc != None) {
 		Tk_FreeGC(squarePtr->display, squarePtr->gc);
 	    }
 	    squarePtr->tkwin = NULL;
@@ -472,7 +472,7 @@ SquareDisplay(
 {
     Square *squarePtr = (Square *) clientData;
     Tk_Window tkwin = squarePtr->tkwin;
-    Pixmap pm = 0;
+    Pixmap pm = None;
     Drawable d;
     int borderWidth, size, relief;
     Tk_3DBorder bgBorder, fgBorder;
diff --git a/generic/tkTest.c b/generic/tkTest.c
index 8f54781..d06769d 100644
--- a/generic/tkTest.c
+++ b/generic/tkTest.c
@@ -1047,7 +1047,7 @@ TestobjconfigObjCmd(
 	recordPtr->index = 0;
 	recordPtr->colorPtr = NULL;
 	recordPtr->tkfont = NULL;
-	recordPtr->bitmap = 0;
+	recordPtr->bitmap = None;
 	recordPtr->border = NULL;
 	recordPtr->relief = TK_RELIEF_FLAT;
 	recordPtr->cursor = NULL;
@@ -1985,7 +1985,7 @@ TestpropCmd(
 	    w, propName, 0, 100000, False, AnyPropertyType,
 	    &actualType, &actualFormat, &length,
 	    &bytesAfter, &property);
-    if ((result == Success) && actualType) {
+    if ((result == Success) && (actualType != None)) {
 	if ((actualFormat == 8) && (actualType == XA_STRING)) {
 	    for (p = property; ((unsigned long)(p-property)) < length; p++) {
 		if (*p == 0) {
diff --git a/generic/tkText.c b/generic/tkText.c
index 425687f..004bcaf 100644
--- a/generic/tkText.c
+++ b/generic/tkText.c
@@ -568,7 +568,7 @@ CreateWidget(
 
     textPtr->state = TK_TEXT_STATE_NORMAL;
     textPtr->relief = TK_RELIEF_FLAT;
-    textPtr->cursor = 0;
+    textPtr->cursor = NULL;
     textPtr->charWidth = 1;
     textPtr->charHeight = 10;
     textPtr->wrapMode = TEXT_WRAPMODE_CHAR;
@@ -2186,28 +2186,28 @@ ConfigureText(
     textPtr->selTagPtr->fgColor = textPtr->selFgColorPtr;
     textPtr->selTagPtr->affectsDisplay = 0;
     textPtr->selTagPtr->affectsDisplayGeometry = 0;
-    if (textPtr->selTagPtr->elideString
-	    || textPtr->selTagPtr->tkfont
-	    || textPtr->selTagPtr->justifyString
-	    || textPtr->selTagPtr->lMargin1String
-	    || textPtr->selTagPtr->lMargin2String
-	    || textPtr->selTagPtr->offsetString
-	    || textPtr->selTagPtr->rMarginString
-	    || textPtr->selTagPtr->spacing1String
-	    || textPtr->selTagPtr->spacing2String
-	    || textPtr->selTagPtr->spacing3String
-	    || textPtr->selTagPtr->tabStringPtr
+    if ((textPtr->selTagPtr->elideString != NULL)
+	    || (textPtr->selTagPtr->tkfont != None)
+	    || (textPtr->selTagPtr->justifyString != NULL)
+	    || (textPtr->selTagPtr->lMargin1String != NULL)
+	    || (textPtr->selTagPtr->lMargin2String != NULL)
+	    || (textPtr->selTagPtr->offsetString != NULL)
+	    || (textPtr->selTagPtr->rMarginString != NULL)
+	    || (textPtr->selTagPtr->spacing1String != NULL)
+	    || (textPtr->selTagPtr->spacing2String != NULL)
+	    || (textPtr->selTagPtr->spacing3String != NULL)
+	    || (textPtr->selTagPtr->tabStringPtr != NULL)
 	    || (textPtr->selTagPtr->wrapMode != TEXT_WRAPMODE_NULL)) {
 	textPtr->selTagPtr->affectsDisplay = 1;
 	textPtr->selTagPtr->affectsDisplayGeometry = 1;
     }
-    if (textPtr->selTagPtr->border
-	    || textPtr->selTagPtr->reliefString
-	    || textPtr->selTagPtr->bgStipple
-	    || textPtr->selTagPtr->fgColor
-	    || textPtr->selTagPtr->fgStipple
-	    || textPtr->selTagPtr->overstrikeString
-	    || textPtr->selTagPtr->underlineString) {
+    if ((textPtr->selTagPtr->border != NULL)
+	    || (textPtr->selTagPtr->reliefString != NULL)
+	    || (textPtr->selTagPtr->bgStipple != None)
+	    || (textPtr->selTagPtr->fgColor != NULL)
+	    || (textPtr->selTagPtr->fgStipple != None)
+	    || (textPtr->selTagPtr->overstrikeString != NULL)
+	    || (textPtr->selTagPtr->underlineString != NULL)) {
 	textPtr->selTagPtr->affectsDisplay = 1;
     }
     TkTextRedrawTag(NULL, textPtr, NULL, NULL, textPtr->selTagPtr, 1);
diff --git a/generic/tkTextDisp.c b/generic/tkTextDisp.c
index cc304de..904fa1a 100644
--- a/generic/tkTextDisp.c
+++ b/generic/tkTextDisp.c
@@ -632,7 +632,7 @@ TkTextCreateDInfo(
     dInfoPtr = (TextDInfo *) ckalloc(sizeof(TextDInfo));
     Tcl_InitHashTable(&dInfoPtr->styleTable, sizeof(StyleValues)/sizeof(int));
     dInfoPtr->dLinePtr = NULL;
-    dInfoPtr->copyGC = 0;
+    dInfoPtr->copyGC = NULL;
     gcValues.graphics_exposures = True;
     dInfoPtr->scrollGC = Tk_GetGC(textPtr->tkwin, GCGraphicsExposures,
 	    &gcValues);
@@ -696,19 +696,19 @@ TkTextFreeDInfo(
 
     FreeDLines(textPtr, dInfoPtr->dLinePtr, NULL, DLINE_UNLINK);
     Tcl_DeleteHashTable(&dInfoPtr->styleTable);
-    if (dInfoPtr->copyGC) {
+    if (dInfoPtr->copyGC != None) {
 	Tk_FreeGC(textPtr->display, dInfoPtr->copyGC);
     }
     Tk_FreeGC(textPtr->display, dInfoPtr->scrollGC);
     if (dInfoPtr->flags & REDRAW_PENDING) {
 	Tcl_CancelIdleCall(DisplayText, (ClientData) textPtr);
     }
-    if (dInfoPtr->lineUpdateTimer) {
+    if (dInfoPtr->lineUpdateTimer != NULL) {
 	Tcl_DeleteTimerHandler(dInfoPtr->lineUpdateTimer);
 	textPtr->refCount--;
 	dInfoPtr->lineUpdateTimer = NULL;
     }
-    if (dInfoPtr->scrollbarTimer) {
+    if (dInfoPtr->scrollbarTimer != NULL) {
 	Tcl_DeleteTimerHandler(dInfoPtr->scrollbarTimer);
 	textPtr->refCount--;
 	dInfoPtr->scrollbarTimer = NULL;
@@ -827,70 +827,70 @@ GetStyle(
 	    styleValues.relief = tagPtr->relief;
 	    reliefPrio = tagPtr->priority;
 	}
-	if ((tagPtr->bgStipple)
+	if ((tagPtr->bgStipple != None)
 		&& (tagPtr->priority > bgStipplePrio)) {
 	    styleValues.bgStipple = tagPtr->bgStipple;
 	    bgStipplePrio = tagPtr->priority;
 	}
-	if ((tagPtr->fgColor) && (tagPtr->priority > fgPrio)) {
+	if ((tagPtr->fgColor != None) && (tagPtr->priority > fgPrio)) {
 	    styleValues.fgColor = tagPtr->fgColor;
 	    fgPrio = tagPtr->priority;
 	}
-	if ((tagPtr->tkfont) && (tagPtr->priority > fontPrio)) {
+	if ((tagPtr->tkfont != None) && (tagPtr->priority > fontPrio)) {
 	    styleValues.tkfont = tagPtr->tkfont;
 	    fontPrio = tagPtr->priority;
 	}
-	if ((tagPtr->fgStipple)
+	if ((tagPtr->fgStipple != None)
 		&& (tagPtr->priority > fgStipplePrio)) {
 	    styleValues.fgStipple = tagPtr->fgStipple;
 	    fgStipplePrio = tagPtr->priority;
 	}
-	if ((tagPtr->justifyString)
+	if ((tagPtr->justifyString != NULL)
 		&& (tagPtr->priority > justifyPrio)) {
 	    styleValues.justify = tagPtr->justify;
 	    justifyPrio = tagPtr->priority;
 	}
-	if ((tagPtr->lMargin1String)
+	if ((tagPtr->lMargin1String != NULL)
 		&& (tagPtr->priority > lMargin1Prio)) {
 	    styleValues.lMargin1 = tagPtr->lMargin1;
 	    lMargin1Prio = tagPtr->priority;
 	}
-	if ((tagPtr->lMargin2String)
+	if ((tagPtr->lMargin2String != NULL)
 		&& (tagPtr->priority > lMargin2Prio)) {
 	    styleValues.lMargin2 = tagPtr->lMargin2;
 	    lMargin2Prio = tagPtr->priority;
 	}
-	if ((tagPtr->offsetString)
+	if ((tagPtr->offsetString != NULL)
 		&& (tagPtr->priority > offsetPrio)) {
 	    styleValues.offset = tagPtr->offset;
 	    offsetPrio = tagPtr->priority;
 	}
-	if ((tagPtr->overstrikeString)
+	if ((tagPtr->overstrikeString != NULL)
 		&& (tagPtr->priority > overstrikePrio)) {
 	    styleValues.overstrike = tagPtr->overstrike;
 	    overstrikePrio = tagPtr->priority;
 	}
-	if ((tagPtr->rMarginString)
+	if ((tagPtr->rMarginString != NULL)
 		&& (tagPtr->priority > rMarginPrio)) {
 	    styleValues.rMargin = tagPtr->rMargin;
 	    rMarginPrio = tagPtr->priority;
 	}
-	if ((tagPtr->spacing1String)
+	if ((tagPtr->spacing1String != NULL)
 		&& (tagPtr->priority > spacing1Prio)) {
 	    styleValues.spacing1 = tagPtr->spacing1;
 	    spacing1Prio = tagPtr->priority;
 	}
-	if ((tagPtr->spacing2String)
+	if ((tagPtr->spacing2String != NULL)
 		&& (tagPtr->priority > spacing2Prio)) {
 	    styleValues.spacing2 = tagPtr->spacing2;
 	    spacing2Prio = tagPtr->priority;
 	}
-	if ((tagPtr->spacing3String)
+	if ((tagPtr->spacing3String != NULL)
 		&& (tagPtr->priority > spacing3Prio)) {
 	    styleValues.spacing3 = tagPtr->spacing3;
 	    spacing3Prio = tagPtr->priority;
 	}
-	if ((tagPtr->tabStringPtr)
+	if ((tagPtr->tabStringPtr != NULL)
 		&& (tagPtr->priority > tabPrio)) {
 	    styleValues.tabArrayPtr = tagPtr->tabArrayPtr;
 	    tabPrio = tagPtr->priority;
@@ -900,12 +900,12 @@ GetStyle(
 	    styleValues.tabStyle = tagPtr->tabStyle;
 	    tabStylePrio = tagPtr->priority;
 	}
-	if ((tagPtr->underlineString)
+	if ((tagPtr->underlineString != NULL)
 		&& (tagPtr->priority > underlinePrio)) {
 	    styleValues.underline = tagPtr->underline;
 	    underlinePrio = tagPtr->priority;
 	}
-	if ((tagPtr->elideString)
+	if ((tagPtr->elideString != NULL)
 		&& (tagPtr->priority > elidePrio)) {
 	    styleValues.elide = tagPtr->elide;
 	    elidePrio = tagPtr->priority;
@@ -916,7 +916,7 @@ GetStyle(
 	    wrapPrio = tagPtr->priority;
 	}
     }
-    if (tagPtrs) {
+    if (tagPtrs != NULL) {
 	ckfree((char *) tagPtrs);
     }
 
@@ -941,20 +941,20 @@ GetStyle(
     if (styleValues.border != NULL) {
 	gcValues.foreground = Tk_3DBorderColor(styleValues.border)->pixel;
 	mask = GCForeground;
-	if (styleValues.bgStipple) {
+	if (styleValues.bgStipple != None) {
 	    gcValues.stipple = styleValues.bgStipple;
 	    gcValues.fill_style = FillStippled;
 	    mask |= GCStipple|GCFillStyle;
 	}
 	stylePtr->bgGC = Tk_GetGC(textPtr->tkwin, mask, &gcValues);
     } else {
-	stylePtr->bgGC = 0;
+	stylePtr->bgGC = NULL;
     }
     mask = GCFont;
     gcValues.font = Tk_FontId(styleValues.tkfont);
     mask |= GCForeground;
     gcValues.foreground = styleValues.fgColor->pixel;
-    if (styleValues.fgStipple) {
+    if (styleValues.fgStipple != None) {
 	gcValues.stipple = styleValues.fgStipple;
 	gcValues.fill_style = FillStippled;
 	mask |= GCStipple|GCFillStyle;
@@ -994,10 +994,10 @@ FreeStyle(
 {
     stylePtr->refCount--;
     if (stylePtr->refCount == 0) {
-	if (stylePtr->bgGC) {
+	if (stylePtr->bgGC != None) {
 	    Tk_FreeGC(textPtr->display, stylePtr->bgGC);
 	}
-	if (stylePtr->fgGC) {
+	if (stylePtr->fgGC != None) {
 	    Tk_FreeGC(textPtr->display, stylePtr->fgGC);
 	}
 	Tcl_DeleteHashEntry(stylePtr->hPtr);
@@ -2578,7 +2578,7 @@ DisplayLineBackground(
 	if ((chunkPtr->nextPtr == NULL) && (rightX < maxX)) {
 	    rightX = maxX;
 	}
-	if (chunkPtr->stylePtr->bgGC) {
+	if (chunkPtr->stylePtr->bgGC != None) {
 	    /*
 	     * Not visible - bail out now.
 	     */
@@ -4335,7 +4335,7 @@ DisplayText(
 			    dlPtr->spaceAbove,
 			    dlPtr->height-dlPtr->spaceAbove-dlPtr->spaceBelow,
 			    dlPtr->baseline - dlPtr->spaceAbove, NULL,
-			    0, dlPtr->y + dlPtr->spaceAbove);
+			    (Drawable) None, dlPtr->y + dlPtr->spaceAbove);
 		}
 
 	    }
@@ -4970,7 +4970,7 @@ TkTextRelayoutWindow(
 
     gcValues.graphics_exposures = False;
     newGC = Tk_GetGC(textPtr->tkwin, GCGraphicsExposures, &gcValues);
-    if (dInfoPtr->copyGC) {
+    if (dInfoPtr->copyGC != None) {
 	Tk_FreeGC(textPtr->display, dInfoPtr->copyGC);
     }
     dInfoPtr->copyGC = newGC;
@@ -7708,7 +7708,7 @@ CharDisplayProc(
      */
 
     if (!sValuePtr->elide && (numBytes > offsetBytes)
-	    && stylePtr->fgGC) {
+	    && (stylePtr->fgGC != None)) {
 #if TK_DRAW_IN_CONTEXT
 	int start = ciPtr->baseOffset + offsetBytes;
 	int len = ciPtr->numBytes - offsetBytes;
diff --git a/generic/tkTextTag.c b/generic/tkTextTag.c
index 5bf1899..a310dd7 100644
--- a/generic/tkTextTag.c
+++ b/generic/tkTextTag.c
@@ -489,29 +489,29 @@ TkTextTagCmd(
 
 	    tagPtr->affectsDisplay = 0;
 	    tagPtr->affectsDisplayGeometry = 0;
-	    if (tagPtr->elideString
-		    || tagPtr->tkfont
-		    || tagPtr->justifyString
-		    || tagPtr->lMargin1String
-		    || tagPtr->lMargin2String
-		    || tagPtr->offsetString
-		    || tagPtr->rMarginString
-		    || tagPtr->spacing1String
-		    || tagPtr->spacing2String
-		    || tagPtr->spacing3String
-		    || tagPtr->tabStringPtr
+	    if ((tagPtr->elideString != NULL)
+		    || (tagPtr->tkfont != None)
+		    || (tagPtr->justifyString != NULL)
+		    || (tagPtr->lMargin1String != NULL)
+		    || (tagPtr->lMargin2String != NULL)
+		    || (tagPtr->offsetString != NULL)
+		    || (tagPtr->rMarginString != NULL)
+		    || (tagPtr->spacing1String != NULL)
+		    || (tagPtr->spacing2String != NULL)
+		    || (tagPtr->spacing3String != NULL)
+		    || (tagPtr->tabStringPtr != NULL)
 		    || (tagPtr->tabStyle != TK_TEXT_TABSTYLE_NONE)
 		    || (tagPtr->wrapMode != TEXT_WRAPMODE_NULL)) {
 		tagPtr->affectsDisplay = 1;
 		tagPtr->affectsDisplayGeometry = 1;
 	    }
-	    if (tagPtr->border
-		    || tagPtr->reliefString
-		    || tagPtr->bgStipple
-		    || tagPtr->fgColor
-		    || tagPtr->fgStipple
-		    || tagPtr->overstrikeString
-		    || tagPtr->underlineString) {
+	    if ((tagPtr->border != NULL)
+		    || (tagPtr->reliefString != NULL)
+		    || (tagPtr->bgStipple != None)
+		    || (tagPtr->fgColor != NULL)
+		    || (tagPtr->fgStipple != None)
+		    || (tagPtr->overstrikeString != NULL)
+		    || (tagPtr->underlineString != NULL)) {
 		tagPtr->affectsDisplay = 1;
 	    }
 	    if (!newTag) {
@@ -987,10 +987,10 @@ TkTextCreateTag(
     tagPtr->borderWidthPtr = NULL;
     tagPtr->reliefString = NULL;
     tagPtr->relief = TK_RELIEF_FLAT;
-    tagPtr->bgStipple = 0;
+    tagPtr->bgStipple = None;
     tagPtr->fgColor = NULL;
     tagPtr->tkfont = NULL;
-    tagPtr->fgStipple = 0;
+    tagPtr->fgStipple = None;
     tagPtr->justifyString = NULL;
     tagPtr->justify = TK_JUSTIFY_LEFT;
     tagPtr->lMargin1String = NULL;
@@ -1556,7 +1556,7 @@ TkTextPickCurrent(
 	    textPtr->pickEvent.xcrossing.display = eventPtr->xmotion.display;
 	    textPtr->pickEvent.xcrossing.window = eventPtr->xmotion.window;
 	    textPtr->pickEvent.xcrossing.root = eventPtr->xmotion.root;
-	    textPtr->pickEvent.xcrossing.subwindow = 0;
+	    textPtr->pickEvent.xcrossing.subwindow = None;
 	    textPtr->pickEvent.xcrossing.time = eventPtr->xmotion.time;
 	    textPtr->pickEvent.xcrossing.x = eventPtr->xmotion.x;
 	    textPtr->pickEvent.xcrossing.y = eventPtr->xmotion.y;
diff --git a/generic/tkVisual.c b/generic/tkVisual.c
index fe3e447..ec8be11 100644
--- a/generic/tkVisual.c
+++ b/generic/tkVisual.c
@@ -398,18 +398,18 @@ Tk_GetColormap(
      */
 
     other = Tk_NameToWindow(interp, string, tkwin);
-    if (!other) {
-	return 0;
+    if (other == NULL) {
+	return None;
     }
     if (Tk_Screen(other) != Tk_Screen(tkwin)) {
 	Tcl_AppendResult(interp, "can't use colormap for ", string,
 		": not on same screen", NULL);
-	return 0;
+	return None;
     }
     if (Tk_Visual(other) != Tk_Visual(tkwin)) {
 	Tcl_AppendResult(interp, "can't use colormap for ", string,
 		": incompatible visuals", NULL);
-	return 0;
+	return None;
     }
     colormap = Tk_Colormap(other);
 
diff --git a/generic/tkWindow.c b/generic/tkWindow.c
index c122128..1257e22 100644
--- a/generic/tkWindow.c
+++ b/generic/tkWindow.c
@@ -73,7 +73,7 @@ static const XWindowChanges defChanges = {
     EnterWindowMask|LeaveWindowMask|PointerMotionMask|ExposureMask| \
     VisibilityChangeMask|PropertyChangeMask|ColormapChangeMask
 static const XSetWindowAttributes defAtts= {
-    0,			/* background_pixmap */
+    None,			/* background_pixmap */
     0,				/* background_pixel */
     CopyFromParent,		/* border_pixmap */
     0,				/* border_pixel */
@@ -87,7 +87,7 @@ static const XSetWindowAttributes defAtts= {
     0,				/* do_not_propagate_mask */
     False,			/* override_redirect */
     CopyFromParent,		/* colormap */
-    0			/* cursor */
+    None			/* cursor */
 };
 
 /*
@@ -504,9 +504,9 @@ GetScreen(
 
 	    dispPtr->lastEventTime = CurrentTime;
 	    dispPtr->bindInfoStale = 1;
-	    dispPtr->cursorFont = 0;
-	    dispPtr->warpWindow = 0;
-	    dispPtr->multipleAtom = 0;
+	    dispPtr->cursorFont = None;
+	    dispPtr->warpWindow = None;
+	    dispPtr->multipleAtom = None;
 
 	    /*
 	     * By default we do want to collapse motion events in
@@ -667,7 +667,7 @@ TkAllocWindow(
 	winPtr->visual = DefaultVisual(dispPtr->display, screenNum);
 	winPtr->depth = DefaultDepth(dispPtr->display, screenNum);
     }
-    winPtr->window = 0;
+    winPtr->window = None;
     winPtr->childList = NULL;
     winPtr->lastChildPtr = NULL;
     winPtr->parentPtr = NULL;
@@ -1403,7 +1403,7 @@ Tk_DestroyWindow(
 	    winPtr->pathName != NULL &&
 	    !(winPtr->flags & TK_ANONYMOUS_WINDOW)) {
 	halfdeadPtr->flags |= HD_DESTROY_EVENT;
-	if (!winPtr->window) {
+	if (winPtr->window == None) {
 	    Tk_MakeWindowExist(tkwin);
 	}
 	event.type = DestroyNotify;
@@ -1449,7 +1449,7 @@ Tk_DestroyWindow(
     } else if (winPtr->flags & TK_WM_COLORMAP_WINDOW) {
 	TkWmRemoveFromColormapWindows(winPtr);
     }
-    if (winPtr->window) {
+    if (winPtr->window != None) {
 #if defined(MAC_OSX_TK) || defined(__WIN32__)
 	XDestroyWindow(winPtr->display, winPtr->window);
 #else
@@ -1469,7 +1469,7 @@ Tk_DestroyWindow(
 	TkFreeWindowId(dispPtr, winPtr->window);
 	Tcl_DeleteHashEntry(Tcl_FindHashEntry(&dispPtr->winTable,
 		(char *) winPtr->window));
-	winPtr->window = 0;
+	winPtr->window = None;
     }
     dispPtr->destroyCount--;
     UnlinkWindow(winPtr);
@@ -1642,7 +1642,7 @@ Tk_MapWindow(
     if (winPtr->flags & TK_MAPPED) {
 	return;
     }
-    if (!winPtr->window) {
+    if (winPtr->window == None) {
 	Tk_MakeWindowExist(tkwin);
     }
     /*
@@ -1704,21 +1704,21 @@ Tk_MakeWindowExist(
     Tk_ClassCreateProc *createProc;
     int isNew;
 
-    if (winPtr->window) {
+    if (winPtr->window != None) {
 	return;
     }
 
     if ((winPtr->parentPtr == NULL) || (winPtr->flags & TK_TOP_HIERARCHY)) {
 	parent = XRootWindow(winPtr->display, winPtr->screenNum);
     } else {
-	if (!winPtr->parentPtr->window) {
+	if (winPtr->parentPtr->window == None) {
 	    Tk_MakeWindowExist((Tk_Window) winPtr->parentPtr);
 	}
 	parent = winPtr->parentPtr->window;
     }
 
     createProc = Tk_GetClassProc(winPtr->classProcsPtr, createProc);
-    if (createProc != NULL && parent) {
+    if (createProc != NULL && parent != None) {
 	winPtr->window = (*createProc)(tkwin, parent, winPtr->instanceData);
     } else {
 	winPtr->window = TkpMakeWindow(winPtr, parent);
@@ -1744,7 +1744,7 @@ Tk_MakeWindowExist(
 
 	for (winPtr2 = winPtr->nextPtr; winPtr2 != NULL;
 		winPtr2 = winPtr2->nextPtr) {
-	    if (winPtr2->window
+	    if ((winPtr2->window != None)
 		    && !(winPtr2->flags & (TK_TOP_HIERARCHY|TK_REPARENTED))) {
 		XWindowChanges changes;
 		changes.sibling = winPtr2->window;
@@ -1863,7 +1863,7 @@ Tk_ConfigureWindow(
 	Tcl_Panic("Can't set sibling or stack mode from Tk_ConfigureWindow.");
     }
 
-    if (winPtr->window) {
+    if (winPtr->window != None) {
 	XConfigureWindow(winPtr->display, winPtr->window,
 		valueMask, valuePtr);
 	TkDoConfigureNotify(winPtr);
@@ -1882,7 +1882,7 @@ Tk_MoveWindow(
 
     winPtr->changes.x = x;
     winPtr->changes.y = y;
-    if (winPtr->window) {
+    if (winPtr->window != None) {
 	XMoveWindow(winPtr->display, winPtr->window, x, y);
 	TkDoConfigureNotify(winPtr);
     } else {
@@ -1900,7 +1900,7 @@ Tk_ResizeWindow(
 
     winPtr->changes.width = (unsigned) width;
     winPtr->changes.height = (unsigned) height;
-    if (winPtr->window) {
+    if (winPtr->window != None) {
 	XResizeWindow(winPtr->display, winPtr->window, (unsigned) width,
 		(unsigned) height);
 	TkDoConfigureNotify(winPtr);
@@ -1922,7 +1922,7 @@ Tk_MoveResizeWindow(
     winPtr->changes.y = y;
     winPtr->changes.width = (unsigned) width;
     winPtr->changes.height = (unsigned) height;
-    if (winPtr->window) {
+    if (winPtr->window != None) {
 	XMoveResizeWindow(winPtr->display, winPtr->window, x, y,
 		(unsigned) width, (unsigned) height);
 	TkDoConfigureNotify(winPtr);
@@ -1940,7 +1940,7 @@ Tk_SetWindowBorderWidth(
     register TkWindow *winPtr = (TkWindow *) tkwin;
 
     winPtr->changes.border_width = width;
-    if (winPtr->window) {
+    if (winPtr->window != None) {
 	XSetWindowBorderWidth(winPtr->display, winPtr->window,
 		(unsigned) width);
 	TkDoConfigureNotify(winPtr);
@@ -2007,7 +2007,7 @@ Tk_ChangeWindowAttributes(
 	winPtr->atts.cursor = attsPtr->cursor;
     }
 
-    if (winPtr->window) {
+    if (winPtr->window != None) {
 	XChangeWindowAttributes(winPtr->display, winPtr->window,
 		valueMask, attsPtr);
     } else {
@@ -2025,7 +2025,7 @@ Tk_SetWindowBackground(
 
     winPtr->atts.background_pixel = pixel;
 
-    if (winPtr->window) {
+    if (winPtr->window != None) {
 	XSetWindowBackground(winPtr->display, winPtr->window, pixel);
     } else {
 	winPtr->dirtyAtts = (winPtr->dirtyAtts & (unsigned) ~CWBackPixmap)
@@ -2042,7 +2042,7 @@ Tk_SetWindowBackgroundPixmap(
 
     winPtr->atts.background_pixmap = pixmap;
 
-    if (winPtr->window) {
+    if (winPtr->window != None) {
 	XSetWindowBackgroundPixmap(winPtr->display,
 		winPtr->window, pixmap);
     } else {
@@ -2060,7 +2060,7 @@ Tk_SetWindowBorder(
 
     winPtr->atts.border_pixel = pixel;
 
-    if (winPtr->window) {
+    if (winPtr->window != None) {
 	XSetWindowBorder(winPtr->display, winPtr->window, pixel);
     } else {
 	winPtr->dirtyAtts = (winPtr->dirtyAtts & (unsigned) ~CWBorderPixmap)
@@ -2077,7 +2077,7 @@ Tk_SetWindowBorderPixmap(
 
     winPtr->atts.border_pixmap = pixmap;
 
-    if (winPtr->window) {
+    if (winPtr->window != None) {
 	XSetWindowBorderPixmap(winPtr->display,
 		winPtr->window, pixmap);
     } else {
@@ -2099,7 +2099,7 @@ Tk_DefineCursor(
     winPtr->atts.cursor = (Cursor) cursor;
 #endif
 
-    if (winPtr->window) {
+    if (winPtr->window != None) {
 	XDefineCursor(winPtr->display, winPtr->window, winPtr->atts.cursor);
     } else {
 	winPtr->dirtyAtts = winPtr->dirtyAtts | CWCursor;
@@ -2110,7 +2110,7 @@ void
 Tk_UndefineCursor(
     Tk_Window tkwin)		/* Window to manipulate. */
 {
-    Tk_DefineCursor(tkwin, 0);
+    Tk_DefineCursor(tkwin, NULL);
 }
 
 void
@@ -2122,7 +2122,7 @@ Tk_SetWindowColormap(
 
     winPtr->atts.colormap = colormap;
 
-    if (winPtr->window) {
+    if (winPtr->window != None) {
 	XSetWindowColormap(winPtr->display, winPtr->window, colormap);
 	if (!(winPtr->flags & TK_WIN_MANAGED)) {
 	    TkWmAddToColormapWindows(winPtr);
@@ -2162,7 +2162,7 @@ Tk_SetWindowVisual(
 {
     register TkWindow *winPtr = (TkWindow *) tkwin;
 
-    if (winPtr->window) {
+    if (winPtr->window != None) {
 	/* Too late! */
 	return 0;
     }
@@ -2222,7 +2222,7 @@ TkDoConfigureNotify(
     if (winPtr->changes.stack_mode == Above) {
 	event.xconfigure.above = winPtr->changes.sibling;
     } else {
-	event.xconfigure.above = 0;
+	event.xconfigure.above = None;
     }
     event.xconfigure.override_redirect = winPtr->atts.override_redirect;
     Tk_HandleEvent(&event);
@@ -2585,7 +2585,7 @@ Tk_RestackWindow(
      * will be handled properly when the window is finally created.
      */
 
-    if (winPtr->window) {
+    if (winPtr->window != None) {
 	XWindowChanges changes;
 	unsigned int mask;
 
@@ -2593,7 +2593,7 @@ Tk_RestackWindow(
 	changes.stack_mode = Above;
 	for (otherPtr = winPtr->nextPtr; otherPtr != NULL;
 		otherPtr = otherPtr->nextPtr) {
-	    if (otherPtr->window
+	    if ((otherPtr->window != None)
 		    && !(otherPtr->flags & (TK_TOP_HIERARCHY|TK_REPARENTED))){
 		changes.sibling = otherPtr->window;
 		changes.stack_mode = Below;
diff --git a/generic/ttk/ttkEntry.c b/generic/ttk/ttkEntry.c
index 48aeb5c..ae43ae6 100644
--- a/generic/ttk/ttkEntry.c
+++ b/generic/ttk/ttkEntry.c
@@ -1151,7 +1151,7 @@ static GC EntryGetGC(Entry *entryPtr, Tcl_Obj *colorObj, TkRegion clip)
 	mask |= GCForeground;
     }
     gc = Tk_GetGC(entryPtr->core.tkwin, mask, &gcValues);
-    if (clip) {
+    if (clip != None) {
 	TkSetRegion(Tk_Display(entryPtr->core.tkwin), gc, clip);
     }
     return gc;
@@ -1256,7 +1256,7 @@ static void EntryDisplay(void *clientData, Drawable d)
 	gc = EntryGetGC(entryPtr, es.insertColorObj, clipRegion);
 	XFillRectangle(Tk_Display(tkwin), d, gc,
 	    cursorX-cursorWidth/2, cursorY, cursorWidth, cursorHeight);
-	XSetClipMask(Tk_Display(tkwin), gc, 0);
+	XSetClipMask(Tk_Display(tkwin), gc, None);
 	Tk_FreeGC(Tk_Display(tkwin), gc);
     }
 
@@ -1267,7 +1267,7 @@ static void EntryDisplay(void *clientData, Drawable d)
 	Tk_Display(tkwin), d, gc, entryPtr->entry.textLayout,
 	entryPtr->entry.layoutX, entryPtr->entry.layoutY,
 	leftIndex, rightIndex);
-    XSetClipMask(Tk_Display(tkwin), gc, 0);
+    XSetClipMask(Tk_Display(tkwin), gc, None);
     Tk_FreeGC(Tk_Display(tkwin), gc);
 
     /* Overwrite the selected portion (if any) in the -selectforeground color:
@@ -1278,7 +1278,7 @@ static void EntryDisplay(void *clientData, Drawable d)
 	    Tk_Display(tkwin), d, gc, entryPtr->entry.textLayout,
 	    entryPtr->entry.layoutX, entryPtr->entry.layoutY,
 	    selFirst, selLast);
-	XSetClipMask(Tk_Display(tkwin), gc, 0);
+	XSetClipMask(Tk_Display(tkwin), gc, None);
 	Tk_FreeGC(Tk_Display(tkwin), gc);
     }
 
@@ -1286,7 +1286,7 @@ static void EntryDisplay(void *clientData, Drawable d)
      * it from the Xft guts (if they're being used).
      */
 #ifdef HAVE_XFT
-    TkUnixSetXftClipRegion(0);
+    TkUnixSetXftClipRegion(None);
 #endif
     TkDestroyRegion(clipRegion);
 }
diff --git a/generic/ttk/ttkLabel.c b/generic/ttk/ttkLabel.c
index 9b80c59..1037840 100644
--- a/generic/ttk/ttkLabel.c
+++ b/generic/ttk/ttkLabel.c
@@ -183,10 +183,10 @@ static void TextDraw(TextElement *text, Tk_Window tkwin, Drawable d, Ttk_Box b)
 
     if (clipRegion != NULL) {
 #ifdef HAVE_XFT
-	TkUnixSetXftClipRegion(0);
+	TkUnixSetXftClipRegion(None);
 #endif
-	XSetClipMask(Tk_Display(tkwin), gc1, 0);
-	XSetClipMask(Tk_Display(tkwin), gc2, 0);
+	XSetClipMask(Tk_Display(tkwin), gc1, None);
+	XSetClipMask(Tk_Display(tkwin), gc2, None);
 	TkDestroyRegion(clipRegion);
     }
     Tk_FreeGC(Tk_Display(tkwin), gc1);
@@ -305,7 +305,7 @@ static void StippleOver(
     Pixmap stipple = Tk_AllocBitmapFromObj(NULL, tkwin, image->stippleObj);
     XColor *color = Tk_GetColorFromObj(tkwin, image->backgroundObj);
 
-    if (stipple) {
+    if (stipple != None) {
 	unsigned long mask = GCFillStyle | GCStipple | GCForeground;
 	XGCValues gcvalues;
 	GC gc;
diff --git a/macosx/tkMacOSXDefault.h b/macosx/tkMacOSXDefault.h
index 60d6cda..b80a3cf 100644
--- a/macosx/tkMacOSXDefault.h
+++ b/macosx/tkMacOSXDefault.h
@@ -37,7 +37,7 @@
 #define ACTIVE_BG		"systemButtonFacePressed"
 #define ACTIVE_FG		"systemPushButtonPressedText"
 #define SELECT_BG		"systemHighlight"
-#define SELECT_FG		None
+#define SELECT_FG		NULL
 #define INACTIVE_SELECT_BG	"systemHighlightSecondary"
 #define TROUGH			"#c3c3c3"
 #define INDICATOR		"#b03060"
@@ -281,7 +281,7 @@
 #define DEF_MENU_ENTRY_ACTIVE_FG	((char *) NULL)
 #define DEF_MENU_ENTRY_ACCELERATOR	((char *) NULL)
 #define DEF_MENU_ENTRY_BG		((char *) NULL)
-#define DEF_MENU_ENTRY_BITMAP		None
+#define DEF_MENU_ENTRY_BITMAP		NULL
 #define DEF_MENU_ENTRY_COLUMN_BREAK	"0"
 #define DEF_MENU_ENTRY_COMMAND		((char *) NULL)
 #define DEF_MENU_ENTRY_COMPOUND		"none"
diff --git a/macosx/tkMacOSXEmbed.c b/macosx/tkMacOSXEmbed.c
index bd7e0a8..03a724d 100644
--- a/macosx/tkMacOSXEmbed.c
+++ b/macosx/tkMacOSXEmbed.c
@@ -491,7 +491,7 @@ TkMacOSXContainerId(
 	}
     }
     Tcl_Panic("TkMacOSXContainerId couldn't find window");
-    return None;
+    return NULL;
 }
 
 /*
@@ -527,8 +527,8 @@ TkMacOSXGetHostToplevel(
      * TODO: Here we should handle out of process embedding.
      */
 
-    if (contWinPtr == NULL) {
-	return None;
+    if (!contWinPtr) {
+	return NULL;
     }
     return TkMacOSXGetHostToplevel(contWinPtr);
 }
diff --git a/macosx/tkMacOSXMenu.c b/macosx/tkMacOSXMenu.c
index 8f20447..6b957dc 100644
--- a/macosx/tkMacOSXMenu.c
+++ b/macosx/tkMacOSXMenu.c
@@ -1460,10 +1460,10 @@ TkpMenuInit(void)
 #undef observe
 
     [NSMenuItem setUsesUserKeyEquivalents:NO];
-    tkColPtr = TkpGetColor(None, DEF_MENU_BG_COLOR);
+    tkColPtr = TkpGetColor(NULL, DEF_MENU_BG_COLOR);
     defaultBg = tkColPtr->color.pixel;
     ckfree((char *) tkColPtr);
-    tkColPtr = TkpGetColor(None, DEF_MENU_FG);
+    tkColPtr = TkpGetColor(NULL, DEF_MENU_FG);
     defaultFg = tkColPtr->color.pixel;
     ckfree((char *) tkColPtr);
 
diff --git a/macosx/tkMacOSXScrlbr.c b/macosx/tkMacOSXScrlbr.c
index 7dde501..ea0fdd0 100644
--- a/macosx/tkMacOSXScrlbr.c
+++ b/macosx/tkMacOSXScrlbr.c
@@ -104,8 +104,8 @@ TkpCreateScrollbar(
 
     MacScrollbar *scrollPtr = (MacScrollbar *)ckalloc(sizeof(MacScrollbar));
 
-    scrollPtr->troughGC = None;
-    scrollPtr->copyGC = None;
+    scrollPtr->troughGC = NULL;
+    scrollPtr->copyGC = NULL;
 
     Tk_CreateEventHandler(tkwin,ExposureMask|StructureNotifyMask|FocusChangeMask|ButtonPressMask|VisibilityChangeMask, ScrollbarEventProc, scrollPtr);
     
diff --git a/macosx/tkMacOSXXStubs.c b/macosx/tkMacOSXXStubs.c
index e928298..a541945 100644
--- a/macosx/tkMacOSXXStubs.c
+++ b/macosx/tkMacOSXXStubs.c
@@ -1371,7 +1371,7 @@ void
 Tk_ResetUserInactiveTime(
     Display *dpy)
 {
-    IOGPoint loc;
+    IOGPoint loc = {0};
     kern_return_t kr;
     NXEvent nullEvent = {NX_NULLEVENT, {0, 0}, 0, -1, 0};
     enum { kNULLEventPostThrottle = 10 };
diff --git a/unix/tkUnix3d.c b/unix/tkUnix3d.c
index 417866b..14f5827 100644
--- a/unix/tkUnix3d.c
+++ b/unix/tkUnix3d.c
@@ -47,7 +47,7 @@ TkBorder *
 TkpGetBorder(void)
 {
     UnixBorder *borderPtr = (UnixBorder *) ckalloc(sizeof(UnixBorder));
-    borderPtr->solidGC = None;
+    borderPtr->solidGC = NULL;
     return (TkBorder *) borderPtr;
 }
 
@@ -215,7 +215,7 @@ Tk_3DHorizontalBevel(
     Display *display = Tk_Display(tkwin);
     int bottom, halfway, x1, x2, x1Delta, x2Delta;
     UnixBorder *unixBorderPtr = (UnixBorder *) borderPtr;
-    GC topGC = None, bottomGC = None;
+    GC topGC = NULL, bottomGC = NULL;
 				/* Initializations needed only to prevent
 				 * compiler warnings. */
 
diff --git a/unix/tkUnixDefault.h b/unix/tkUnixDefault.h
index a8ecdc1..7663903 100644
--- a/unix/tkUnixDefault.h
+++ b/unix/tkUnixDefault.h
@@ -243,7 +243,7 @@
 #define DEF_MENU_ENTRY_ACTIVE_FG	(char *) NULL
 #define DEF_MENU_ENTRY_ACCELERATOR	(char *) NULL
 #define DEF_MENU_ENTRY_BG		(char *) NULL
-#define DEF_MENU_ENTRY_BITMAP		None
+#define DEF_MENU_ENTRY_BITMAP		NULL
 #define DEF_MENU_ENTRY_COLUMN_BREAK	"0"
 #define DEF_MENU_ENTRY_COMMAND		(char *) NULL
 #define DEF_MENU_ENTRY_COMPOUND 	"none"
diff --git a/win/tkWinDefault.h b/win/tkWinDefault.h
index 7f48703..cc561ec 100644
--- a/win/tkWinDefault.h
+++ b/win/tkWinDefault.h
@@ -246,7 +246,7 @@
 #define DEF_MENU_ENTRY_ACTIVE_FG	(char *) NULL
 #define DEF_MENU_ENTRY_ACCELERATOR	(char *) NULL
 #define DEF_MENU_ENTRY_BG		(char *) NULL
-#define DEF_MENU_ENTRY_BITMAP		0
+#define DEF_MENU_ENTRY_BITMAP		NULL
 #define DEF_MENU_ENTRY_COLUMN_BREAK	"0"
 #define DEF_MENU_ENTRY_COMMAND		(char *) NULL
 #define DEF_MENU_ENTRY_COMPOUND 	"none"