ldap

LDAP(3)                    Library Functions Manual                    LDAP(3)

NAME
       ldap - OpenLDAP Lightweight Directory Access Protocol API

LIBRARY
       OpenLDAP LDAP (libldap, -lldap)

SYNOPSIS
       #include <ldap.h>

DESCRIPTION
       The  Lightweight  Directory  Access Protocol (LDAP) (RFC 4510) provides
       access to X.500 directory services.  These services may be  stand-alone
       or  part  of a distributed directory service.  This client API supports
       LDAP over TCP (RFC 4511), LDAP over TLS/SSL, and LDAP  over  IPC  (UNIX
       domain  sockets).  This API supports SASL (RFC 4513) and Start TLS (RFC
       4513) as well as a number of protocol extensions.  This API is  loosely
       based  upon  IETF/LDAPEXT  C LDAP API draft specification, a (orphaned)
       work in progress.

       The  OpenLDAP  Software  package  includes  a  stand-alone  server   in
       slapd(8), various LDAP clients, and an LDAP client library used to pro-
       vide programmatic access to the LDAP protocol. This man page  gives  an
       overview of the LDAP library routines.

       Both synchronous and asynchronous APIs are provided.  Also included are
       various routines to parse the results  returned  from  these  routines.
       These routines are found in the -lldap library.

       The basic interaction is as follows.  A session handle is created using
       ldap_initialize(3) and  set  the  protocol  version  to  3  by  calling
       ldap_set_option(3).  The underlying session is established first opera-
       tion is issued.  This would generally be a Start TLS or Bind operation,
       or  a Search operation to read attributes of the Root DSE.  A Start TLS
       operation is performed by calling ldap_start_tls_s(3).  A LDAP bind op-
       eration  is  performed  by  calling  ldap_sasl_bind(3)  or  one  of its
       friends.    A   Search    operation    is    performed    by    calling
       ldap_search_ext_s(3) or one of its friends.

       Subsequently, additional operations are performed by calling one of the
       synchronous or asynchronous routines  (e.g.,  ldap_compare_ext_s(3)  or
       ldap_compare_ext(3) followed by ldap_result(3)).  Results returned from
       these routines are interpreted by calling  the  LDAP  parsing  routines
       such as ldap_parse_result(3).  The LDAP association and underlying con-
       nection is terminated by calling ldap_unbind_ext(3).  Errors can be in-
       terpreted by calling ldap_err2string(3).

LDAP versions
       This  library  supports  version  3 of the Lightweight Directory Access
       Protocol (LDAPv3) as defined in RFC 4510.  It also supports  a  variant
       of version 2 of LDAP as defined by U-Mich LDAP and, to some degree, RFC
       1777.  Version 2 (all variants) are  considered  obsolete.   Version  3
       should be used instead.

       For backwards compatibility reasons, the library defaults to version 2.
       Hence, all new applications (and all actively maintained  applications)
       should  use ldap_set_option(3) to select version 3.  The library manual
       pages assume version 3 has been selected.

INPUT and OUTPUT PARAMETERS
       All character string input/output is expected to  be/is  UTF-8  encoded
       Unicode (version 3.2).

       Distinguished  names (DN) (and relative distinguished names (RDN) to be
       passed to the LDAP routines should conform to  RFC  4514  UTF-8  string
       representation.

       Search  filters to be passed to the search routines are to be construc-
       ted by hand and should conform to RFC 4515 UTF-8 string representation.

       LDAP URLs to be passed to routines are expected to conform to RFC  4516
       format.  The ldap_url(3) routines can be used to work with LDAP URLs.

       LDAP  controls  to  be  passed to routines can be manipulated using the
       ldap_controls(3) routines.

DISPLAYING RESULTS
       Results obtained from the search routines can be  output  by  hand,  by
       calling  ldap_first_entry(3) and ldap_next_entry(3) to step through the
       entries returned, ldap_first_attribute(3) and ldap_next_attribute(3) to
       step  through an entry's attributes, and ldap_get_values(3) to retrieve
       a given attribute's values.  Attribute values may or may  not  be  dis-
       playable.

UTILITY ROUTINES
       Also  provided are various utility routines.  The ldap_sort(3) routines
       are used to sort the entries and values returned via  the  ldap  search
       routines.

DEPRECATED INTERFACES
       A  number  of  interfaces are now considered deprecated.  For instance,
       ldap_add(3) is deprecated in favor of ldap_add_ext(3).  Deprecated  in-
       terfaces  generally  remain  in the library.  The macro LDAP_DEPRECATED
       can be defined to a non-zero  value  (e.g.,  -DLDAP_DEPRECATED=1)  when
       compiling  program designed to use deprecated interfaces.  It is recom-
       mended that developers writing new programs, or updating old  programs,
       avoid  use  of  deprecated  interfaces.  Over time, it is expected that
       documentation (and, eventually, support) for deprecated  interfaces  to
       be eliminated.

BER LIBRARY
       Also  included in the distribution is a set of lightweight Basic Encod-
       ing Rules routines.  These routines are used by the LDAP  library  rou-
       tines  to  encode and decode LDAP protocol elements using the (slightly
       simplified) Basic Encoding Rules defined by LDAP.  They  are  not  nor-
       mally  used  directly by an LDAP application program except in the han-
       dling of controls and extended  operations.   The  routines  provide  a
       printf  and scanf-like interface, as well as lower-level access.  These
       routines are discussed  in  lber-decode(3),  lber-encode(3),  lber-mem-
       ory(3), and lber-types(3).

INDEX
       ldap_initialize(3)  initialize  the LDAP library without opening a con-
                           nection to a server

       ldap_result(3)      wait for the result from an asynchronous operation

       ldap_abandon_ext(3) abandon (abort) an asynchronous operation

       ldap_add_ext(3)     asynchronously add an entry

       ldap_add_ext_s(3)   synchronously add an entry

       ldap_sasl_bind(3)   asynchronously bind to the directory

       ldap_sasl_bind_s(3) synchronously bind to the directory

       ldap_unbind_ext(3)  synchronously unbind from the LDAP server and close
                           the connection

       ldap_unbind(3) and ldap_unbind_s(3) are
                           equivalent to ldap_unbind_ext(3)

       ldap_memfree(3)     dispose of memory allocated by LDAP routines.

       ldap_compare_ext(3) asynchronously compare to a directory entry

       ldap_compare_ext_s(3)
                           synchronously compare to a directory entry

       ldap_delete_ext(3)  asynchronously delete an entry

       ldap_delete_ext_s(3)
                           synchronously delete an entry

       ld_errno(3)         LDAP error indication

       ldap_errlist(3)     list of LDAP errors and their meanings

       ldap_err2string(3)  convert LDAP error indication to a string

       ldap_extended_operation(3)
                           asynchronously perform an arbitrary extended opera-
                           tion

       ldap_extended_operation_s(3)
                           synchronously perform an arbitrary extended  opera-
                           tion

       ldap_first_attribute(3)
                           return first attribute name in an entry

       ldap_next_attribute(3)
                           return next attribute name in an entry

       ldap_first_entry(3) return first entry in a chain of search results

       ldap_next_entry(3)  return next entry in a chain of search results

       ldap_count_entries(3)
                           return number of entries in a search result

       ldap_get_dn(3)      extract the DN from an entry

       ldap_get_values_len(3)
                           return an attribute's values with lengths

       ldap_value_free_len(3)
                           free memory allocated by ldap_get_values_len(3)

       ldap_count_values_len(3)
                           return number of values

       ldap_modify_ext(3)  asynchronously modify an entry

       ldap_modify_ext_s(3)
                           synchronously modify an entry

       ldap_mods_free(3)   free  array  of  pointers to mod structures used by
                           ldap_modify_ext(3)

       ldap_rename(3)      asynchronously rename an entry

       ldap_rename_s(3)    synchronously rename an entry

       ldap_msgfree(3)     free results allocated by ldap_result(3)

       ldap_msgtype(3)     return the message type of a message from  ldap_re-
                           sult(3)

       ldap_msgid(3)       return  the  message  id of a message from ldap_re-
                           sult(3)

       ldap_search_ext(3)  asynchronously search the directory

       ldap_search_ext_s(3)
                           synchronously search the directory

       ldap_is_ldap_url(3) check a URL string to see if it is an LDAP URL

       ldap_url_parse(3)   break up an LDAP URL string into its components

       ldap_sort_entries(3)
                           sort a list of search results

       ldap_sort_values(3) sort a list of attribute values

       ldap_sort_strcasecmp(3)
                           case insensitive string comparison

SEE ALSO
       ldap.conf(5),         slapd(8),          draft-ietf-ldapext-ldap-c-api-
       xx.txt <http://www.ietf.org>

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.

       These  API manual pages are loosely based upon descriptions provided in
       the IETF/LDAPEXT C LDAP  API  Internet  Draft,  a  (orphaned)  work  in
       progress.

OpenLDAP                          2020/01/30                           LDAP(3)
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