get a pointer to the index map's internal ID vector (the id_map field).
The outputs of this function become invalid after any operation that can
modify the index.
@param index opaque pointer to index object
@param p_id_map output, the pointer to the beginning of id_map.
@param p_size output, the current length of id_map.
get a pointer to the index map's internal ID vector (the id_map field). The outputs of this function become invalid after any operation that can modify the index.
@param index opaque pointer to index object @param p_id_map output, the pointer to the beginning of id_map. @param p_size output, the current length of id_map.