Src question

[Robert John Andersen <anderman@anderware.com>]

I was poking around the vector code and noticed a reference to
zero_length_vector which gets created in scheme_init_vector.  I was
wondering what the following allocation line was supposed to accomplish
since the size seems to say allocate 0 bytes:

zero_length_vector =  (Scheme_Object
*)scheme_malloc_tagged(sizeof(Scheme_Vector) - sizeof(Scheme_Object *));

I wrote a test program and the size of Scheme_Vector and Scheme_Object are
both 12.

RJA