These are described in draft-ietf-ldapext-ldap-c-api-xx.txt
The parameter option can be one of: LDAP_OPT_DEREF, LDAP_OPT_SIZELIMIT, LDAP_OPT_TIMELIMIT, LDAP_OPT_PROTOCOL_VERSION, LDAP_OPT_ERROR_NUMBER, LDAP_OPT_REFERRALS, LDAP_OPT_RESTART, LDAP_OPT_HOST_NAME, LDAP_OPT_ERROR_STRING, LDAP_OPT_MATCHED_DN. These are described in draft-ietf-ldapext-ldap-c-api-xx.txt