Re: [Swig-user] how to return error (TCL_ERROR) from Swig'd C function?

[William S F. <ws...@fu...>]

On 12/01/11 05:03, ran...@gm... wrote:
> Hi all,
>
> I'd like my C function to return an error code to calling Tcl
> interpreter. If I were not using Swig, I would do this by 'return
> TCL_ERROR' instead of 'return TCL_OK'.
>
> But with Swig, I see that 'return TCL_OK' is the only possibility
> after my function call.
>
> Is there any way to do what I want?
>
> I see something like in the generated wrapper function:
>
> result = (int)myfoo();
> Tcl_SetObjResult(interp,SWIG_From_int(static_cast<  int>(result)));
> return TCL_OK;  //<-- this is the line which I want to have control over

Do this with typemaps. If you run SWIG -E, you'll get the preprocessed 
output, from which you can hunt down the appropriate out typemap, eg you 
need the 'out' typemap for int for

int myfoo();

Here it is:

   %typemap(out,noblock=1,fragment="SWIG_" "From" "_" {int}) int, const 
int {
     Tcl_SetObjResult(interp,SWIG_From_int(static_cast< int >($1)));
   }

Copy this and modify to your hearts contents, eg adding in SWIG_fail, 
which is a macro to 'goto fail;' which does a return TCL_ERROR.

William