modify Tk_Create(Old)ImageType signature, relaxing

the constraint that every Tk_ImageType can only
be passed to this function once. This allows
tkImg to be loaded in multiple interpreters
in a thread-enabled build of Tk.
This CONSTification complies with TIP #27. It is
binary compatible with the old interface, but not
fully source compatible (although tkImg does not suffer).

9 files changed, 118 insertions, 55 deletions

diff --git a/ChangeLog b/ChangeLog
index 17e5811..0365864 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -8,6 +8,17 @@
 	* win/tcl.m4:       reverted change from 2008-11-06 (was under the impression
 	                    that "-Wno-implicit-int" added an extra warning)
 	* win/configure     (regenerated)
+	* generic/tk.decls     modify Tk_Create(Old)ImageType signature, relaxing
+	* generic/tk.h         the constraint that every Tk_ImageType can only
+	* generic/tkImage.c    be passed to this function once. This allows
+	* generic/tkImgBmap.c  tkImg to be loaded in multiple interpreters
+	* generic/tkImgPhoto.c in a thread-enabled build of Tk.
+	* generic/tkTest.c     This CONSTification complies with TIP #27. It is
+	* doc/CrtImgType.3     binary compatible with the old interface, but not
+	                       fully source compatible (although tkImg does not suffer).
+	* generic/tkDecls.h (regenerated)
+
+	*** POTENTIAL INCOMPATIBILITY ***
 
 2008-11-09  Joe English  <jenglish@users.sourceforge.net>
 
diff --git a/doc/CrtImgType.3 b/doc/CrtImgType.3
index 5b074d2..2505272 100644
--- a/doc/CrtImgType.3
+++ b/doc/CrtImgType.3
@@ -5,7 +5,7 @@
 '\" See the file "license.terms" for information on usage and redistribution
 '\" of this file, and for a DISCLAIMER OF ALL WARRANTIES.
 '\" 
-'\" RCS: @(#) $Id: CrtImgType.3,v 1.15 2008/11/09 23:16:56 nijtmans Exp $
+'\" RCS: @(#) $Id: CrtImgType.3,v 1.16 2008/11/12 00:15:26 nijtmans Exp $
 '\" 
 .so man.macros
 .TH Tk_CreateImageType 3 8.5 Tk "Tk Library Procedures"
@@ -23,11 +23,12 @@ ClientData
 .sp
 \fBTk_InitImageArgs\fR(\fIinterp, argc, argvPtr\fR)
 .SH ARGUMENTS
-.AS Tk_ImageType *typePtrPtr
-.AP Tk_ImageType *typePtr in
+.AS "const Tk_ImageType" *typePtrPtr
+.AP "const Tk_ImageType" *typePtr in
 Structure that defines the new type of image.
-Must be static: a
+For Tk 8.4 and earlier this must be static: a
 pointer to this structure is retained by the image code.
+In Tk 8.5, this limitation was relaxed.
 .AP Tcl_Interp *interp in
 Interpreter in which image was created.
 .AP "const char" *name in
@@ -113,7 +114,7 @@ typedef int \fBTk_ImageCreateProc\fR(
         const char *\fIname\fR,
         int \fIobjc\fR,
         Tcl_Obj *const \fIobjv\fR[],
-        Tk_ImageType *\fItypePtr\fR,
+        const Tk_ImageType *\fItypePtr\fR,
         Tk_ImageMaster \fImaster\fR,
         ClientData *\fImasterDataPtr\fR);
 .CE
diff --git a/generic/tk.decls b/generic/tk.decls
index 632c85f..8d3740e 100644
--- a/generic/tk.decls
+++ b/generic/tk.decls
@@ -11,7 +11,7 @@
 # See the file "license.terms" for information on usage and redistribution
 # of this file, and for a DISCLAIMER OF ALL WARRANTIES.
 #
-# RCS: @(#) $Id: tk.decls,v 1.44 2008/11/09 23:16:56 nijtmans Exp $
+# RCS: @(#) $Id: tk.decls,v 1.45 2008/11/12 00:15:24 nijtmans Exp $
 
 library tk
 
@@ -185,7 +185,7 @@ declare 37 generic {
     void Tk_CreateGenericHandler(Tk_GenericProc *proc, ClientData clientData)
 }
 declare 38 generic {
-    void Tk_CreateImageType(Tk_ImageType *typePtr)
+    void Tk_CreateImageType(const Tk_ImageType *typePtr)
 }
 declare 39 generic {
     void Tk_CreateItemType(Tk_ItemType *typePtr)
@@ -405,7 +405,7 @@ declare 97 generic {
 }
 declare 98 generic {
     ClientData Tk_GetImageMasterData(Tcl_Interp *interp,
-	    const char *name, Tk_ImageType **typePtrPtr)
+	    const char *name, CONST86 Tk_ImageType **typePtrPtr)
 }
 declare 99 generic {
     Tk_ItemType * Tk_GetItemTypes(void)
@@ -1068,7 +1068,7 @@ declare 271 generic {
 # Developers who need to produce a file [load]able into legacy interps must
 # build against legacy sources.
 declare 272 generic {
-    void Tk_CreateOldImageType(Tk_ImageType *typePtr)
+    void Tk_CreateOldImageType(const Tk_ImageType *typePtr)
 }
 declare 273 generic {
     void Tk_CreateOldPhotoImageFormat(const Tk_PhotoImageFormat *formatPtr)
diff --git a/generic/tk.h b/generic/tk.h
index 003143c..516205b 100644
--- a/generic/tk.h
+++ b/generic/tk.h
@@ -12,7 +12,7 @@
  * See the file "license.terms" for information on usage and redistribution of
  * this file, and for a DISCLAIMER OF ALL WARRANTIES.
  *
- * RCS: @(#) $Id: tk.h,v 1.123 2008/11/02 11:20:03 dkf Exp $
+ * RCS: @(#) $Id: tk.h,v 1.124 2008/11/12 00:15:26 nijtmans Exp $
  */
 
 #ifndef _TK
@@ -1187,8 +1187,8 @@ typedef int (Tk_ImageCreateProc) (Tcl_Interp *interp, char *name, int argc,
 	char **argv, Tk_ImageType *typePtr, Tk_ImageMaster master,
 	ClientData *masterDataPtr);
 #else
-typedef int (Tk_ImageCreateProc) (Tcl_Interp *interp, char *name, int objc,
-	Tcl_Obj *const objv[], Tk_ImageType *typePtr, Tk_ImageMaster master,
+typedef int (Tk_ImageCreateProc) (Tcl_Interp *interp, CONST86 char *name, int objc,
+	Tcl_Obj *const objv[], CONST86 Tk_ImageType *typePtr, Tk_ImageMaster master,
 	ClientData *masterDataPtr);
 #endif
 typedef ClientData (Tk_ImageGetProc) (Tk_Window tkwin, ClientData masterData);
diff --git a/generic/tkDecls.h b/generic/tkDecls.h
index a105ab0..16af814 100644
--- a/generic/tkDecls.h
+++ b/generic/tkDecls.h
@@ -8,7 +8,7 @@
  * See the file "license.terms" for information on usage and redistribution
  * of this file, and for a DISCLAIMER OF ALL WARRANTIES.
  *
- * RCS: @(#) $Id: tkDecls.h,v 1.39 2008/11/09 23:16:56 nijtmans Exp $
+ * RCS: @(#) $Id: tkDecls.h,v 1.40 2008/11/12 00:15:26 nijtmans Exp $
  */
 
 #ifndef _TKDECLS
@@ -284,7 +284,7 @@ EXTERN void		Tk_CreateGenericHandler (Tk_GenericProc * proc,
 #ifndef Tk_CreateImageType_TCL_DECLARED
 #define Tk_CreateImageType_TCL_DECLARED
 /* 38 */
-EXTERN void		Tk_CreateImageType (Tk_ImageType * typePtr);
+EXTERN void		Tk_CreateImageType (const Tk_ImageType * typePtr);
 #endif
 #ifndef Tk_CreateItemType_TCL_DECLARED
 #define Tk_CreateItemType_TCL_DECLARED
@@ -650,7 +650,7 @@ EXTERN Tk_Image		Tk_GetImage (Tcl_Interp * interp, Tk_Window tkwin,
 /* 98 */
 EXTERN ClientData	Tk_GetImageMasterData (Tcl_Interp * interp,
 				const char * name,
-				Tk_ImageType ** typePtrPtr);
+				CONST86 Tk_ImageType ** typePtrPtr);
 #endif
 #ifndef Tk_GetItemTypes_TCL_DECLARED
 #define Tk_GetItemTypes_TCL_DECLARED
@@ -1686,7 +1686,7 @@ EXTERN Tcl_Interp *	Tk_Interp (Tk_Window tkwin);
 #ifndef Tk_CreateOldImageType_TCL_DECLARED
 #define Tk_CreateOldImageType_TCL_DECLARED
 /* 272 */
-EXTERN void		Tk_CreateOldImageType (Tk_ImageType * typePtr);
+EXTERN void		Tk_CreateOldImageType (const Tk_ImageType * typePtr);
 #endif
 #ifndef Tk_CreateOldPhotoImageFormat_TCL_DECLARED
 #define Tk_CreateOldPhotoImageFormat_TCL_DECLARED
@@ -1744,7 +1744,7 @@ typedef struct TkStubs {
     Tk_ErrorHandler (*tk_CreateErrorHandler) (Display * display, int errNum, int request, int minorCode, Tk_ErrorProc * errorProc, ClientData clientData); /* 35 */
     void (*tk_CreateEventHandler) (Tk_Window token, unsigned long mask, Tk_EventProc * proc, ClientData clientData); /* 36 */
     void (*tk_CreateGenericHandler) (Tk_GenericProc * proc, ClientData clientData); /* 37 */
-    void (*tk_CreateImageType) (Tk_ImageType * typePtr); /* 38 */
+    void (*tk_CreateImageType) (const Tk_ImageType * typePtr); /* 38 */
     void (*tk_CreateItemType) (Tk_ItemType * typePtr); /* 39 */
     void (*tk_CreatePhotoImageFormat) (const Tk_PhotoImageFormat * formatPtr); /* 40 */
     void (*tk_CreateSelHandler) (Tk_Window tkwin, Atom selection, Atom target, Tk_SelectionProc * proc, ClientData clientData, Atom format); /* 41 */
@@ -1804,7 +1804,7 @@ typedef struct TkStubs {
     void (*tk_GetFontMetrics) (Tk_Font font, Tk_FontMetrics * fmPtr); /* 95 */
     GC (*tk_GetGC) (Tk_Window tkwin, unsigned long valueMask, XGCValues * valuePtr); /* 96 */
     Tk_Image (*tk_GetImage) (Tcl_Interp * interp, Tk_Window tkwin, const char * name, Tk_ImageChangedProc * changeProc, ClientData clientData); /* 97 */
-    ClientData (*tk_GetImageMasterData) (Tcl_Interp * interp, const char * name, Tk_ImageType ** typePtrPtr); /* 98 */
+    ClientData (*tk_GetImageMasterData) (Tcl_Interp * interp, const char * name, CONST86 Tk_ImageType ** typePtrPtr); /* 98 */
     Tk_ItemType * (*tk_GetItemTypes) (void); /* 99 */
     int (*tk_GetJoinStyle) (Tcl_Interp * interp, const char * str, int * joinPtr); /* 100 */
     int (*tk_GetJustify) (Tcl_Interp * interp, const char * str, Tk_Justify * justifyPtr); /* 101 */
@@ -1978,7 +1978,7 @@ typedef struct TkStubs {
     long (*tk_GetUserInactiveTime) (Display * dpy); /* 269 */
     void (*tk_ResetUserInactiveTime) (Display * dpy); /* 270 */
     Tcl_Interp * (*tk_Interp) (Tk_Window tkwin); /* 271 */
-    void (*tk_CreateOldImageType) (Tk_ImageType * typePtr); /* 272 */
+    void (*tk_CreateOldImageType) (const Tk_ImageType * typePtr); /* 272 */
     void (*tk_CreateOldPhotoImageFormat) (const Tk_PhotoImageFormat * formatPtr); /* 273 */
 } TkStubs;
 
diff --git a/generic/tkImage.c b/generic/tkImage.c
index 0f25906..3ce3a8d 100644
--- a/generic/tkImage.c
+++ b/generic/tkImage.c
@@ -10,7 +10,7 @@
  * See the file "license.terms" for information on usage and redistribution of
  * this file, and for a DISCLAIMER OF ALL WARRANTIES.
  *
- * RCS: @(#) $Id: tkImage.c,v 1.40 2008/11/08 18:44:40 dkf Exp $
+ * RCS: @(#) $Id: tkImage.c,v 1.41 2008/11/12 00:15:26 nijtmans Exp $
  */
 
 #include "tkInt.h"
@@ -74,6 +74,8 @@ typedef struct ThreadSpecificData {
     Tk_ImageType *oldImageTypeList;
 				/* First in a list of all known old-style
 				 * image types. */
+    int initialized;		/* Set to 1 if we've initialized the
+				 * structure. */
 } ThreadSpecificData;
 static Tcl_ThreadDataKey dataKey;
 
@@ -81,6 +83,7 @@ static Tcl_ThreadDataKey dataKey;
  * Prototypes for local functions:
  */
 
+static void		ImageTypeThreadExitProc(ClientData clientData);
 static void		DeleteImage(ImageMaster *masterPtr);
 static void		EventuallyDeleteImage(ImageMaster *masterPtr,
 			    int forgetImageHashNow);
@@ -88,6 +91,42 @@ static void		EventuallyDeleteImage(ImageMaster *masterPtr,
 /*
  *----------------------------------------------------------------------
  *
+ * ImageTypeThreadExitProc --
+ *
+ *	Clean up the registered list of image types.
+ *
+ * Results:
+ *	None.
+ *
+ * Side effects:
+ *	The thread's linked lists of photo image formats is deleted.
+ *
+ *----------------------------------------------------------------------
+ */
+
+static void
+ImageTypeThreadExitProc(
+    ClientData clientData)	/* not used */
+{
+	Tk_ImageType *freePtr;
+    ThreadSpecificData *tsdPtr =
+	    Tcl_GetThreadData(&dataKey, sizeof(ThreadSpecificData));
+
+    while (tsdPtr->oldImageTypeList != NULL) {
+	freePtr = tsdPtr->oldImageTypeList;
+	tsdPtr->oldImageTypeList = tsdPtr->oldImageTypeList->nextPtr;
+	ckfree((char *) freePtr);
+    }
+    while (tsdPtr->imageTypeList != NULL) {
+	freePtr = tsdPtr->imageTypeList;
+	tsdPtr->imageTypeList = tsdPtr->imageTypeList->nextPtr;
+	ckfree((char *) freePtr);
+    }
+}
+
+/*
+ *----------------------------------------------------------------------
+ *
  * Tk_CreateOldImageType, Tk_CreateImageType --
  *
  *	This function is invoked by an image manager to tell Tk about a new
@@ -106,30 +145,42 @@ static void		EventuallyDeleteImage(ImageMaster *masterPtr,
 
 void
 Tk_CreateOldImageType(
-    Tk_ImageType *typePtr)	/* Structure describing the type. All of the
+    const Tk_ImageType *typePtr)	/* Structure describing the type. All of the
 				 * fields except "nextPtr" must be filled in
-				 * by caller. Must not have been passed to
-				 * Tk_CreateImageType previously. */
+				 * by caller. */
 {
-    ThreadSpecificData *tsdPtr = (ThreadSpecificData *)
-            Tcl_GetThreadData(&dataKey, sizeof(ThreadSpecificData));
+	Tk_ImageType *copyPtr;
+    ThreadSpecificData *tsdPtr =
+	    Tcl_GetThreadData(&dataKey, sizeof(ThreadSpecificData));
 
-    typePtr->nextPtr = tsdPtr->oldImageTypeList;
-    tsdPtr->oldImageTypeList = typePtr;
+    if (!tsdPtr->initialized) {
+	tsdPtr->initialized = 1;
+	Tcl_CreateThreadExitHandler(ImageTypeThreadExitProc, NULL);
+    }
+    copyPtr = (Tk_ImageType *) ckalloc(sizeof(Tk_ImageType));
+    *copyPtr = *typePtr;
+    copyPtr->nextPtr = tsdPtr->oldImageTypeList;
+    tsdPtr->oldImageTypeList = copyPtr;
 }
 
 void
 Tk_CreateImageType(
-    Tk_ImageType *typePtr)	/* Structure describing the type. All of the
+    const Tk_ImageType *typePtr)	/* Structure describing the type. All of the
 				 * fields except "nextPtr" must be filled in
-				 * by caller. Must not have been passed to
-				 * Tk_CreateImageType previously. */
+				 * by caller. */
 {
-    ThreadSpecificData *tsdPtr = (ThreadSpecificData *)
-            Tcl_GetThreadData(&dataKey, sizeof(ThreadSpecificData));
+	Tk_ImageType *copyPtr;
+    ThreadSpecificData *tsdPtr =
+	    Tcl_GetThreadData(&dataKey, sizeof(ThreadSpecificData));
 
-    typePtr->nextPtr = tsdPtr->imageTypeList;
-    tsdPtr->imageTypeList = typePtr;
+    if (!tsdPtr->initialized) {
+	tsdPtr->initialized = 1;
+	Tcl_CreateThreadExitHandler(ImageTypeThreadExitProc, NULL);
+    }
+    copyPtr = (Tk_ImageType *) ckalloc(sizeof(Tk_ImageType));
+    *copyPtr = *typePtr;
+    copyPtr->nextPtr = tsdPtr->imageTypeList;
+    tsdPtr->imageTypeList = copyPtr;
 }
 
 /*
@@ -1011,7 +1062,7 @@ Tk_GetImageMasterData(
     Tcl_Interp *interp,		/* Interpreter in which the image was
 				 * created. */
     const char *name,		/* Name of image. */
-    Tk_ImageType **typePtrPtr)	/* Points to location to fill in with pointer
+    const Tk_ImageType **typePtrPtr)	/* Points to location to fill in with pointer
 				 * to type information for image. */
 {
     Tcl_HashEntry *hPtr;
diff --git a/generic/tkImgBmap.c b/generic/tkImgBmap.c
index 3fc7561..b7de72a 100644
--- a/generic/tkImgBmap.c
+++ b/generic/tkImgBmap.c
@@ -10,7 +10,7 @@
  * See the file "license.terms" for information on usage and redistribution
  * of this file, and for a DISCLAIMER OF ALL WARRANTIES.
  *
- * RCS: @(#) $Id: tkImgBmap.c,v 1.26 2008/11/05 22:48:58 nijtmans Exp $
+ * RCS: @(#) $Id: tkImgBmap.c,v 1.27 2008/11/12 00:15:26 nijtmans Exp $
  */
 
 #include "tkInt.h"
@@ -77,8 +77,8 @@ typedef struct BitmapInstance {
 
 static int		GetByte(Tcl_Channel chan);
 static int		ImgBmapCreate(Tcl_Interp *interp,
-			    char *name, int argc, Tcl_Obj *const objv[],
-			    Tk_ImageType *typePtr, Tk_ImageMaster master,
+			    const char *name, int argc, Tcl_Obj *const objv[],
+			    const Tk_ImageType *typePtr, Tk_ImageMaster master,
 			    ClientData *clientDataPtr);
 static ClientData	ImgBmapGet(Tk_Window tkwin, ClientData clientData);
 static void		ImgBmapDisplay(ClientData clientData,
@@ -175,11 +175,11 @@ static int
 ImgBmapCreate(
     Tcl_Interp *interp,		/* Interpreter for application containing
 				 * image. */
-    char *name,			/* Name to use for image. */
+    const char *name,			/* Name to use for image. */
     int argc,			/* Number of arguments. */
     Tcl_Obj *const argv[],	/* Argument objects for options (doesn't
 				 * include image name or type). */
-    Tk_ImageType *typePtr,	/* Pointer to our type record (not used). */
+    const Tk_ImageType *typePtr,	/* Pointer to our type record (not used). */
     Tk_ImageMaster master,	/* Token for image, to be used by us in later
 				 * callbacks. */
     ClientData *clientDataPtr)	/* Store manager's token for image here; it
diff --git a/generic/tkImgPhoto.c b/generic/tkImgPhoto.c
index 0c19640..6213472 100644
--- a/generic/tkImgPhoto.c
+++ b/generic/tkImgPhoto.c
@@ -17,7 +17,7 @@
  *	   Department of Computer Science,
  *	   Australian National University.
  *
- * RCS: @(#) $Id: tkImgPhoto.c,v 1.85 2008/11/09 23:16:56 nijtmans Exp $
+ * RCS: @(#) $Id: tkImgPhoto.c,v 1.86 2008/11/12 00:15:26 nijtmans Exp $
  */
 
 #include "tkImgPhoto.h"
@@ -77,7 +77,7 @@ struct SubcommandOptions {
  * of the OPT_* constants above.
  */
 
-static const char *optionNames[] = {
+static const char *const optionNames[] = {
     "-background",
     "-compositingrule",
     "-format",
@@ -102,9 +102,9 @@ static const char *optionNames[] = {
  * Functions used in the type record for photo images.
  */
 
-static int		ImgPhotoCreate(Tcl_Interp *interp, char *name,
+static int		ImgPhotoCreate(Tcl_Interp *interp, const char *name,
 			    int objc, Tcl_Obj *const objv[],
-			    Tk_ImageType *typePtr, Tk_ImageMaster master,
+			    const Tk_ImageType *typePtr, Tk_ImageMaster master,
 			    ClientData *clientDataPtr);
 static void		ImgPhotoDelete(ClientData clientData);
 static int		ImgPhotoPostscript(ClientData clientData,
@@ -135,7 +135,7 @@ typedef struct ThreadSpecificData {
 				/* Pointer to the first in the list of known
 				 * photo image formats.*/
     int initialized;		/* Set to 1 if we've initialized the
-				 * strucuture. */
+				 * structure. */
 } ThreadSpecificData;
 static Tcl_ThreadDataKey dataKey;
 
@@ -333,11 +333,11 @@ static int
 ImgPhotoCreate(
     Tcl_Interp *interp,		/* Interpreter for application containing
 				 * image. */
-    char *name,			/* Name to use for image. */
+    const char *name,			/* Name to use for image. */
     int objc,			/* Number of arguments. */
     Tcl_Obj *const objv[],	/* Argument objects for options (doesn't
 				 * include image name or type). */
-    Tk_ImageType *typePtr,	/* Pointer to our type record (not used). */
+    const Tk_ImageType *typePtr,	/* Pointer to our type record (not used). */
     Tk_ImageMaster master,	/* Token for image, to be used by us in later
 				 * callbacks. */
     ClientData *clientDataPtr)	/* Store manager's token for image here; it
@@ -1401,8 +1401,8 @@ ParseSubcommandOptions(
 {
     int index, c, bit, currentBit, length;
     int values[4], numValues, maxValues, argIndex;
-    char *option;
-    const char **listPtr;
+    const char *option;
+    const char *const *listPtr;
 
     for (index = *optIndexPtr; index < objc; *optIndexPtr = ++index) {
 	/*
@@ -2518,7 +2518,7 @@ Tk_FindPhoto(
 				 * exists. */
     const char *imageName)	/* Name of the desired photo image. */
 {
-    Tk_ImageType *typePtr;
+    const Tk_ImageType *typePtr;
     ClientData clientData =
 	    Tk_GetImageMasterData(interp, imageName, &typePtr);
 
diff --git a/generic/tkTest.c b/generic/tkTest.c
index cba8546..b7a27a6 100644
--- a/generic/tkTest.c
+++ b/generic/tkTest.c
@@ -13,7 +13,7 @@
  * See the file "license.terms" for information on usage and redistribution of
  * this file, and for a DISCLAIMER OF ALL WARRANTIES.
  *
- * RCS: @(#) $Id: tkTest.c,v 1.40 2008/10/30 23:18:59 nijtmans Exp $
+ * RCS: @(#) $Id: tkTest.c,v 1.41 2008/11/12 00:15:26 nijtmans Exp $
  */
 
 #include "tkInt.h"
@@ -61,8 +61,8 @@ typedef struct TImageInstance {
  */
 
 static int		ImageCreate(Tcl_Interp *interp,
-			    char *name, int argc, Tcl_Obj *const objv[],
-			    Tk_ImageType *typePtr, Tk_ImageMaster master,
+			    const char *name, int argc, Tcl_Obj *const objv[],
+			    const Tk_ImageType *typePtr, Tk_ImageMaster master,
 			    ClientData *clientDataPtr);
 static ClientData	ImageGet(Tk_Window tkwin, ClientData clientData);
 static void		ImageDisplay(ClientData clientData,
@@ -1491,11 +1491,11 @@ static int
 ImageCreate(
     Tcl_Interp *interp,		/* Interpreter for application containing
 				 * image. */
-    char *name,			/* Name to use for image. */
+    const char *name,			/* Name to use for image. */
     int objc,			/* Number of arguments. */
     Tcl_Obj *const objv[],	/* Argument strings for options (doesn't
 				 * include image name or type). */
-    Tk_ImageType *typePtr,	/* Pointer to our type record (not used). */
+    const Tk_ImageType *typePtr,	/* Pointer to our type record (not used). */
     Tk_ImageMaster master,	/* Token for image, to be used by us in later
 				 * callbacks. */
     ClientData *clientDataPtr)	/* Store manager's token for image here; it