Problem with new datatype

[Ralf Schmelter <ralfs@heineken.chemie.uni-dortmund.de>]

Hello!

I have encountered a strange problem while implementing a
new data structure in Guile. I have a C++ class named Coordinate,
which is more or less only a structure with 3 doubles. I have
installed the new datatype with the scm_newsmob function and
added procedures to cope with it, which were installed with
the gh_new_procedure functions. Now I have a problem with a
function which should add 2 or more Coordinates. The function was
installed with the command:

gh_new_procedure("coordinate-add", (SCM (*) (...)) GuileCoordinateAdd, 1, 0, 1);


And the function itself is looking like this:

SCM GuileCoordinateAdd(SCM scm_coordinate, SCM rest_coordinates)
{
    Coordinate * coordinate = (Coordinate *) SCM_CDR(scm_coordinate);
    Coordinate result = *coordinate;
    SCM scm_result;

    while(rest_coordinates != SCM_EOL)
    {
	Coordinate * arg = (Coordinate *) SCM_CDR(SCM_CAR(rest_coordinates));
	result = result + *arg;
	rest_coordinates = SCM_CDR(rest_coordinates);
    }
       
    SCM_NEWCELL(SCM scm_result);
    SCM_SETCDR(scm_result, new Coordinate(result)); 
    SCM_SETCAR(scm_result, type_tag);
    
    return scm_result;
}

Now this works well, but if I move the definition "SCM scm_result;" after the
while loop the program crashed with a segmentation fault.
Can anoyone explain this behavior?

With best regards,

	Ralf Schmelter



--  
Ralf Schmelter
Physikalische Chemie 2a
Uni Dortmund
44221 Dortmund

Tel.: +49 231 / 755 3942
Fax: +49 231 / 755 3937
e-mail: ralfs@heineken.chemie.uni-dortmund.de