Re: [TCLCORE] TIP #340: Const Qualification of Tcl_SetResult's Argument and -Wwrite-strings

[Andreas L. <av...@lo...>]

"Jan Nijtmans" <jan...@gm...> wrote:
> 2008/11/17 Joe English <jen...@fl...>:
> > Specifically: with the proposed change,
> >    Tcl_SetResult(interp, "Hi!", TCL_DYNAMIC);
> > would not raise a compiler error even with -Wwrite-strings.
> > That's a step backwards.

I don't know, if Tcl_SetResult  has still any value apart from
compatibility.  If it has, then it might be worth a consideration
adding a variant like "Tcl_SetResultRO"(bikeshed-warning) that will
take a const char*, and a pointer to a function that in turn will
also take a const-pointer. That means, there'd also be a 
typedef void (Tcl_FreeProcRO) _ANSI_ARGS_((const char *blockPtr));
and TCL_STATIC would be eventually be typed as Tcl_FreeProcRO, so
it could be passed to the const char* taking Tcl_SetResultRO().

This appears to me to avoid the "lying to the compiler", by splitting
up the Tcl_SetResult into one for the const-cases and one for general
cases.   Anyone who cares about the compiler warnings (hopefully
including the core) could then use the appropriate one, if creating
a TclObject and using the "Obj" variant is not desired..

It may of course be, that if one changes a source at all, he should
really change it to the "Obj" variant and also make sure that he doesn't
use interp->result, and also clean up all further legacy-stuff here and
there in the course... That would of course void my suggestion, but
possibly be too much work for old code to be reasonable.