Tk Source Code

As described in https://core.tcl-lang.org/tcl/info/8ab8a138c915

Aside from the attached patch, which mostly undoes [9279332cf22a] and [4854aa119bd0], there is one more instance to address in tkImage.c, but I would first like to understand why DeleteImage() is not consistently used as a Tcl_FreeProc (via Tcl_EventuallyFree()).

Sorry, those warnings/errors were because I tried building with outdated Tcl 8.7 (from before https://core.tcl-lang.org/tcl/info/56cb488cc3d4).

Don, I assume you are building with Tcl 8.7. There are warnings for Tk 8.7 + Tcl 8.7 which by default are errors in LLVM.org Clang 16. Examples:

tk87ontcl87/generic/tkBusy.c:140:33: error: incompatible function pointer types passing 'void (void *)' to parameter of type 'Tcl_FreeProc *' (aka 'void (*)(char *)') [-Wincompatible-function-pointer-types]
  140 |     Tcl_EventuallyFree(busyPtr, DestroyBusy);
      |                                 ^~~~~~~~~~~
tk87ontcl87/generic/tkBusy.c:265:30: error: incompatible function pointer types passing 'void (void *)' to parameter of type 'Tcl_FreeProc *' (aka 'void (*)(char *)') [-Wincompatible-function-pointer-types]
  265 |         Tcl_EventuallyFree(busyPtr, DestroyBusy);
      |                                     ^~~~~~~~~~~
tk87ontcl87/generic/tkBusy.c:386:30: error: incompatible function pointer types passing 'void (void *)' to parameter of type 'Tcl_FreeProc *' (aka 'void (*)(char *)') [-Wincompatible-function-pointer-types]
  386 |         Tcl_EventuallyFree(busyPtr, DestroyBusy);
      |                                     ^~~~~~~~~~~
tk87ontcl87/generic/tkBusy.c:921:30: error: incompatible function pointer types passing 'void (void *)' to parameter of type 'Tcl_FreeProc *' (aka 'void (*)(char *)') [-Wincompatible-function-pointer-types]
  921 |         Tcl_EventuallyFree(busyPtr, DestroyBusy);
      |                                     ^~~~~~~~~~~

Testing the Tk trunk today I see many compiler warnings that
appear to be about this issue.

For reference: in the Tcl ticket, the issue of compatibility with both Tcl 8 and 9 had been brought up; and there has since been discussion of shortcomings of the originally proposed fixes like [12043dec2720]—revising ticket name accordingly.

Note that in tkSquare.c and ttkWidget.c, the relevant function only calls ckfree(). In my patch, I assumed it was preferable to remove those functions and use TCL_DYNAMIC instead.

Hi Christofer.

Your patch will work for Tcl 8.6, but the same approach would not work in Tk 8.7 when compiled with Tcl 9.0. Therefore, what I would like to do now is [12043dec272011fd|this].

This approach means that all functions use a (void *) parameter. When used with Tcl 9.0, the type-cast won't be necessary any more, but - hopelully - this way the -fsanitize=function message will be surpressed as well.

Thanks!