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cldap_open function

The cldap_open function establishes a session with an LDAP server over a connectionless User Datagram Protocol (UDP) service. This is an alternate to using TCP/IP.


LDAP* cldap_open(
  _In_  PCHAR HostName,
  _In_  ULONG PortNumber


HostName [in]

A pointer to a null-terminated string that contains a list of host names or dotted strings that represent the IP address of LDAP server hosts. Use a single space to separate the host names in the list. Each host name in the list may be followed by a port number. The optional port number is separated from the host itself with a colon (:). The LDAP run time attempts connection with the hosts in the order listed, stopping when a successful connection is made.

PortNumber [in]

The port number to be used. If no port number is specified, the default is port 389, which is defined as LDAP_PORT. If port numbers are included in the HostName parameter, this parameter is ignored.

Return value

If the function succeeds, a session handle, in the form of a pointer to an LDAP structure is returned. Free the session handle with a call to ldap_unbind when it is no longer required.

If the function fails, the return value is NULL. To get the error code, call LdapGetLastError or the Win32 function GetLastError.


The cldap_open function, unlike ldap_open, creates a connection block for UDP-based connectionless LDAP services. No TCP session is maintained. Like ldap_open, cldap_open allocates an LDAP structure to maintain state data for the session, and then attempts to make the connection before returning to the caller. The call returns a session handle, which you pass to subsequent LDAP function calls in the course of the session. When finished with the session, always free the allocated session handle by using ldap_unbind.

Using LDAP over UDP does not support binding and does not support TLS (SSL) or SASL.

Multithreading: Calls to cldap_open are thread-safe.

Note  When using cldap_open, the connection is opened by an anonymous user. The only available operations are those that an anonymous user can run.


Minimum supported client

Windows 2000 Professional [desktop apps only]

Minimum supported server

Windows 2000 Server [desktop apps only]







Unicode and ANSI names

cldap_openW (Unicode) and cldap_openA (ANSI)

See also




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