Re: Accessing smob data

[Neil Jerram <neil at ossau dot uklinux dot net>]

Dirk Herrman writes:

   > (2) Is SCM_SMOB_DATA the recommended way to extract a struct pointer
   >     from a smob SCM value?

   Actually, SCM_SMOB_DATA is the recommended way to extract arbitrary data
   from a smob SCM value, not only to extract struct pointers.  Thus, it was
   decided that SCM_SMOB_DATA should return a value of type scm_bits_t, which
   is guile's type for any kind of raw data that can be stored in scheme
   cells.  Two weeks ago (about), SCM_SMOB_DATA returned a value of type SCM,
   which at that time was of type void*.

   A first attempt at explaining the relationship between scm_bits_t and SCM
   can be found in the file api.txt in the doc directory of the current cvs.

Cool.  So, just to confirm my understanding, SCM_SMOB_DATA returns
(notionally) a scm_bits_t, and it's correct to cast a scm_bits_t to a
pointer.

Many thanks!

     Neil