ldap_open(3) — Linux manual page


LDAP_OPEN(3)              Library Functions Manual              LDAP_OPEN(3)

NAME         top

       ldap_init,  ldap_initialize,  ldap_open - Initialize the LDAP library
       and open a connection to an LDAP server

LIBRARY         top

       OpenLDAP LDAP (libldap, -lldap)

SYNOPSIS         top

       #include <ldap.h>

       LDAP *ldap_open(host, port)
       char *host;
       int port;

       LDAP *ldap_init(host, port)
       char *host;
       int port;

       int ldap_initialize(ldp, uri)
       LDAP **ldp;
       char *uri;

       int ldap_connect(ldp)
       LDAP *ldp;

       int ldap_set_urllist_proc(ld, proc, params)
       LDAP *ld;
       LDAP_URLLIST_PROC *proc;
       void *params;

       int (LDAP_URLLIST_PROC)(ld, urllist, url, params);
       LDAP *ld;
       LDAPURLDesc **urllist;
       LDAPURLDesc **url;
       void *params;

       #include <openldap.h>

       int ldap_init_fd(fd, proto, uri, ldp)
       ber_socket_t fd;
       int proto;
       char *uri;
       LDAP **ldp;

DESCRIPTION         top

       ldap_open() opens a connection to an LDAP server and allocates an
       LDAP structure which is used to identify the connection and to
       maintain per-connection information.  ldap_init() allocates an LDAP
       structure but does not open an initial connection.  ldap_initialize()
       allocates an LDAP structure but does not open an initial connection.
       ldap_init_fd() allocates an LDAP structure using an existing
       connection on the provided socket.  One of these routines must be
       called before any operations are attempted.

       ldap_open() takes host, the hostname on which the LDAP server is
       running, and port, the port number to which to connect.  If the
       default IANA-assigned port of 389 is desired, LDAP_PORT should be
       specified for port.  The host parameter may contain a blank-separated
       list of hosts to try to connect to, and each host may optionally by
       of the form host:port.  If present, the :port overrides the port
       parameter to ldap_open().  Upon successfully making a connection to
       an LDAP server, ldap_open() returns a pointer to an opaque LDAP
       structure, which should be passed to subsequent calls to ldap_bind(),
       ldap_search(), etc. Certain fields in the LDAP structure can be set
       to indicate size limit, time limit, and how aliases are handled
       during operations; read and write access to those fields must occur
       by calling ldap_get_option(3) and ldap_set_option(3) respectively,
       whenever possible.

       ldap_init() acts just like ldap_open(), but does not open a
       connection to the LDAP server.  The actual connection open will occur
       when the first operation is attempted.

       ldap_initialize() acts like ldap_init(), but it returns an integer
       indicating either success or the failure reason, and it allows to
       specify details for the connection in the schema portion of the URI.
       The uri parameter may be a comma- or whitespace-separated list of
       URIs containing only the schema, the host, and the port fields.
       Apart from ldap, other (non-standard) recognized values of the schema
       field are ldaps (LDAP over TLS), ldapi (LDAP over IPC), and cldap
       (connectionless LDAP).  If other fields are present, the behavior is

       At this time, ldap_open() and ldap_init() are deprecated in favor of
       ldap_initialize(), essentially because the latter allows to specify a
       schema in the URI and it explicitly returns an error code.

       ldap_connect() causes a handle created by ldap_initialize() to
       connect to the server. This is useful in situations where a file
       descriptor is required before a request is performed.

       ldap_init_fd() allows an LDAP structure to be initialized using an
       already-opened connection. The proto parameter should be one of
       LDAP_PROTO_TCP, LDAP_PROTO_UDP, or LDAP_PROTO_IPC for a connection
       using TCP, UDP, or IPC, respectively. The value LDAP_PROTO_EXT may
       also be specified if user-supplied sockbuf handlers are going to be
       used. Note that support for UDP is not implemented unless libldap was
       built with LDAP_CONNECTIONLESS defined.  The uri parameter may
       optionally be provided for informational purposes.

       ldap_set_urllist_proc() allows to set a function proc of type
       LDAP_URLLIST_PROC that is called when a successful connection can be
       established.  This function receives the list of URIs parsed from the
       uri string originally passed to ldap_initialize(), and the one that
       successfully connected.  The function may manipulate the URI list;
       the typical use consists in moving the successful URI to the head of
       the list, so that subsequent attempts to connect to one of the URIs
       using the same LDAP handle will try it first.  If ld is null, proc is
       set as a global parameter that is inherited by all handlers within
       the process that are created after the call to
       ldap_set_urllist_proc().  By default, no LDAP_URLLIST_PROC is set.
       In a multithreaded environment, ldap_set_urllist_proc() must be
       called before any concurrent operation using the LDAP handle is

       Note: the first call into the LDAP library also initializes the
       global options for the library. As such the first call should be
       single-threaded or otherwise protected to insure that only one call
       is active. It is recommended that ldap_get_option() or
       ldap_set_option() be used in the program's main thread before any
       additional threads are created.  See ldap_get_option(3).

ERRORS         top

       If an error occurs, ldap_open() and ldap_init() will return NULL and
       errno should be set appropriately.  ldap_initialize() and
       ldap_init_fd() will directly return the LDAP code associated to the
       error (or LDAP_SUCCESS in case of success); errno should be set as
       well whenever appropriate.  ldap_set_urllist_proc() returns
       LDAP_OPT_ERROR on error, and LDAP_OPT_SUCCESS on success.

SEE ALSO         top

       ldap(3), ldap_bind(3), ldap_get_option(3), ldap_set_option(3),
       lber-sockbuf(3), errno(3)


       OpenLDAP Software is developed and maintained by The OpenLDAP Project
       <http://www.openldap.org/>.  OpenLDAP Software is derived from the
       University of Michigan LDAP 3.3 Release.

COLOPHON         top

       This page is part of the OpenLDAP (an open source implementation of
       the Lightweight Directory Access Protocol) project.  Information
       about the project can be found at ⟨http://www.openldap.org/⟩.  If you
       have a bug report for this manual page, see
       ⟨http://www.openldap.org/its/⟩.  This page was obtained from the
       project's upstream Git repository
       ⟨https://git.openldap.org/openldap/openldap.git⟩ on 2020-11-01.  (At
       that time, the date of the most recent commit that was found in the
       repository was 2020-10-30.)  If you discover any rendering problems
       in this HTML version of the page, or you believe there is a better or
       more up-to-date source for the page, or you have corrections or im‐
       provements to the information in this COLOPHON (which is not part of
       the original manual page), send a mail to man-pages@man7.org

OpenLDAP LDVERSION               RELEASEDATE                    LDAP_OPEN(3)

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