ldap_init

LDAP_OPEN(3)               Library Functions Manual               LDAP_OPEN(3)

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

LIBRARY
       OpenLDAP LDAP (libldap, -lldap)

SYNOPSIS
       #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_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
       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 pro-
       vided socket.  One of these routines must be called before  any  opera-
       tions are attempted.

       ldap_open()  takes  host, the hostname on which the LDAP server is run-
       ning, 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. Cer-
       tain 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 in-
       dicating 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 contain-
       ing  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 undefined.

       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_init_fd() allows an LDAP structure to be initialized using an  al-
       ready-opened   connection.   The  proto  parameter  should  be  one  of
       LDAP_PROTO_TCP, LDAP_PROTO_UDP, or LDAP_PROTO_IPC for a connection  us-
       ing  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_URL-
       LIST_PROC that is called when a successful  connection  can  be  estab-
       lished.   This  function  receives the list of URIs parsed from the uri
       string originally passed to ldap_initialize(), and the  one  that  suc-
       cessfully  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  de-
       fault,  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 started.

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

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

OpenLDAP                          2020/01/30                      LDAP_OPEN(3)