(PHP 7 >= 7.2.0, PHP 8)
ldap_exop — Performs an extended operation
$ldap,$request_oid,$request_data = null,$controls = null,&$response_data = ?,&$response_oid = ?
   Performs an extended operation on the specified ldap with
   request_oid the OID of the operation and
   request_data the data.
  
ldapAn LDAP\Connection instance, returned by ldap_connect().
request_oid
       The extended operation request OID. You may use one of LDAP_EXOP_START_TLS, LDAP_EXOP_MODIFY_PASSWD, LDAP_EXOP_REFRESH, LDAP_EXOP_WHO_AM_I, LDAP_EXOP_TURN, or a string with the OID of the operation you want to send.
     
request_data
       The extended operation request data. May be NULL for some operations like LDAP_EXOP_WHO_AM_I, may also need to be BER encoded.
     
controlsArray of LDAP Controls to send with the request.
response_dataWill be filled with the extended operation response data if provided. If not provided you may use ldap_parse_exop on the result object later to get this data.
response_oidWill be filled with the response OID if provided, usually equal to the request OID.
   When used with response_data, returns true on success or false on error.
   When used without response_data, returns a result identifier or false on error.
  
| Version | Description | 
|---|---|
| 8.1.0 | The ldapparameter expects an LDAP\Connection
  instance now; previously, a validldap linkresource was expected. | 
| 7.3.0 | Support for serverctrlsadded | 
Example #1 Whoami extended operation
<?php
$ds = ldap_connect("localhost");  // assuming the LDAP server is on this host
if ($ds) {
    // bind with appropriate dn to give update access
    $bind = ldap_bind($ds, "cn=root, o=My Company, c=US", "secret");
    if (!$bind) {
      echo "Unable to bind to LDAP server";
      exit;
    }
    // Call WHOAMI EXOP
    $r = ldap_exop($ds, LDAP_EXOP_WHO_AM_I);
    // Parse the result object
    ldap_parse_exop($ds, $r, $retdata);
    // Output: string(31) "dn:cn=root, o=My Company, c=US"
    var_dump($retdata);
    // Same thing using $response_data parameter
    $success = ldap_exop($ds, LDAP_EXOP_WHO_AM_I, NULL, NULL, $retdata, $retoid);
    if ($success) {
      var_dump($retdata);
    }
    ldap_close($ds);
} else {
    echo "Unable to connect to LDAP server";
}
?>