PK_ERROR_code_t PK_ATTRIB_ask_nth_pointer
(
--- received arguments ---
PK_ATTRIB_t         attrib,             --- attribute
int                 field_no,           --- field number (>= 0)
int                 index,              --- index of pointer (>= 0)

--- returned arguments ---
PK_POINTER_t *const pointer             --- nth pointer.
)


This function returns a single element of the pointer array 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
    PK_ERROR_bad_index              The field has no pointer with this index