PK_ERROR_code_t PK_ATTRIB_ask_pointers
(
--- received arguments ---
PK_ATTRIB_t          attrib,              --- attribute
int                  field_no,            --- field number (>= 0)

--- returned arguments ---
int           *const n_pointers,          --- number of pointers (>=0)
PK_POINTER_t **const pointers             --- pointers (optional)
)


This function returns the array of pointers from field field_no
of the given attribute.


Specific Errors:
    PK_ERROR_bad_field_number       The attribute does not have a field with
                                    this number
    PK_ERROR_field_of_wrong_type    The field is not a pointer field


The output array pointers is optional.  If it is set to NULL, the function
will only return the number of pointers in the field.