sample 8.7/9.0

The sample below builds with 8.7 and 9.0 with no warnings. However it does not make full functionality of 9.0 as len is 32-bits.

int
Sandbox_Cmd(
    ClientData dummy,	/* Not used. */
    Tcl_Interp *interp,		/* Current interpreter */
    int objc,			/* Number of arguments */
    Tcl_Obj *const objv[]	/* Argument strings */
    )
{
	int len;
	Tcl_Obj *parts;
	parts = Tcl_FSSplitPath(objv[1], &len);
	Tcl_DecrRefCount(parts); /* Assume non-null */
	Tcl_SetObjResult(interp, Tcl_NewWideIntObj(len));
	return TCL_OK;
}

To make full 64-bit support on 9.0, the len variable type needs to be size_t.

int
Sandbox_Cmd(
    ClientData dummy,	/* Not used. */
    Tcl_Interp *interp,		/* Current interpreter */
    int objc,			/* Number of arguments */
    Tcl_Obj *const objv[]	/* Argument strings */
    )
{
	size_t len;
	Tcl_Obj *parts;
	parts = Tcl_FSSplitPath(objv[1], &len);
	Tcl_DecrRefCount(parts); /* Assume non-null */
	Tcl_SetObjResult(interp, Tcl_NewWideIntObj(len));
	return TCL_OK;
}

This now however results in compiler warnings with 8.7.

D:\src\sampleextension\win\..\generic\tclsample.c(343): warning C4133: 'function': incompatible types - from 'size_t *' to 'int *'

Moreover, if the warning is ignored, the function will fail miserably on bigendian machines.