The entries passed to the search entry callback function do not need to be freed. If you need to access an entry after returning from the callback function, call slapi_entry_dup() to make a copy.
The referral URLs passed to the referral entry callback function do not need to be freed. If you need to access a referral string after returning from the callback function, call slapi_ch_strdup() to make a copy.
You do not need to call slapi_free_search_results_internal() after calling slapi_search_internal_callback_pb().