Directory Services


The ldap_search_ext function searches the LDAP directory and returns a requested set of attributes for each entry matched.

ULONG ldap_search_ext(
  LDAP* ld,
  PCHAR base,
  ULONG scope,
  PCHAR filter,
  PCHAR attrs[],
  ULONG attrsonly,
  PLDAPControl* ServerControls,
  PLDAPControl* ClientControls,
  ULONG TimeLimit,
  ULONG SizeLimit,
  ULONG* MessageNumber


[in] The session handle.
[in] A pointer to a null-terminated string that contains the distinguished name of the entry at which to start the search.
[in] Specifies one of the following values to indicate the search scope.
Value Meaning
LDAP_SCOPE_BASE Search the base entry only.
LDAP_SCOPE_ONELEVEL Search all entries in the first level below the base entry, excluding the base entry.
LDAP_SCOPE_SUBTREE Search the base entry and all entries in the tree below the base.
[in] A pointer to a null-terminated string that specifies the search filter. For more information, see Search Filter Syntax.
[in] A null-terminated array of null-terminated strings indicating which attributes to return for each matching entry. To retrieve all available attributes, pass NULL.
[in] A Boolean value that should be zero if both attribute types and values are to be returned, nonzero if only types are to be returned.
[in] A list of LDAP server controls.
[in] A list of client controls.
[in] Specifies both the local search time-out value in seconds and the operation time limit sent to the server within the search request.
[in] A limit on the number of entries to return from the search. A value of zero means there is no limit.
[out] The message ID of the request.

Return Values

If the function succeeds, the return value is LDAP_SUCCESS.

If the function fails, it returns an error code. For more information, see Return Values.


The ldap_search_ext function initiates an asynchronous search operation. The parameters and effects of ldap_search_ext subsume those of ldap_search. The extended routine includes additional parameters to support client and server controls and thread safety, and to specify size and time limits for each search operation.

Use the ldap_set_option function with the ld session handle to set the LDAP_OPT_DEREF option that determine how the search is performed. For more information, see Session Options. Two other session options, LDAP_OPT_SIZELIMIT and LDAP_OPT_TIMELIMIT, are ignored in favor of the SizeLimit and TimeLimit parameters in this function.

If the operation succeeds, ldap_search_ext passes the message ID to the caller as a parameter when the operation returns successfully. Call ldap_result with the message ID to get the result of the operation.

An LDAP client application that needs to control the rate at which results are returned may specify the search request to provide a paged results control with size set to the desired page size and cookie set to the zero-length string. The page size specified may be greater than zero and less than the SizeLimit value specified in the search request.

If the page size is greater than or equal to the SizeLimit value option described in Session Options, the server should ignore the control because the request can be satisfied in a single page. If the server does not support this control, the server must return an error of unsupported Critical Extension if the client requested it as critical, otherwise the server should ignore the control. The remainder of this section assumes the server does not ignore the client's paged results control.

The client sends the server a search request with the simple paged results control, along with an empty previous enumeration key (also known as a "cookie") and the initial page size. The server then returns the number of entries specified by the page size and also returns a cookie issued on the next client request to get the next page of results. The client then issues a search, with the cookie included, optionally resetting the page size. The server then responds by returning the results, up to the specified number of entries. If you prefer to have the function return the results directly, use the synchronous routine ldap_search_ext_s.

Multithreading: Calls to ldap_search_ext are thread-safe.


Client: Included in Windows XP and Windows 2000 Professional.
Server: Included in Windows Server 2003 and Windows 2000 Server.
Redistributable: Requires Active Directory Client Extension on Windows NT 4.0 SP6a and Windows 95/98/Me.
Unicode: Implemented as Unicode and ANSI versions on all platforms.
Header: Declared in Winldap.h.
Library: Use Wldap32.lib.

See Also

Change Notifications in Active Directory, Extended Controls, Using Controls, Functions, ldap_result, ldap_search, ldap_search_ext_s, Session Options