LDAP(3) Library Functions Manual LDAP(3)
ldap - OpenLDAP Lightweight Directory Access Protocol API
OpenLDAP LDAP (libldap, -lldap)
#include <ldap.h>
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
provide 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
operation 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 operation 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 connection is terminated by calling ldap_unbind_ext(3).
Errors can be interpreted by calling ldap_err2string(3).
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.
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
constructed 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.
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 displayable.
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.
A number of interfaces are now considered deprecated. For instance,
ldap_add(3) is deprecated in favor of ldap_add_ext(3). Deprecated
interfaces 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 recommended 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.
Also included in the distribution is a set of lightweight Basic
Encoding Rules routines. These routines are used by the LDAP library
routines to encode and decode LDAP protocol elements using the
(slightly simplified) Basic Encoding Rules defined by LDAP. They are
not normally used directly by an LDAP application program except in
the handling 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-memory(3), and lber-types(3).
ldap_initialize(3) initialize the LDAP library without opening a
connection 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
operation
ldap_extended_operation_s(3)
synchronously perform an arbitrary extended
operation
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_result(3)
ldap_msgid(3) return the message id of a message from
ldap_result(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
ldap.conf(5), slapd(8), draft-ietf-ldapext-ldap-c-api-
xx.txt <http://www.ietf.org>
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.
These API manual pages are loosely based upon descriptions provided
in the IETF/LDAPEXT C LDAP API Internet Draft, a (orphaned) work in
progress.
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
⟨git://git.openldap.org/openldap.git⟩ on 2017-07-05. 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 improvements 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(3)
Pages that refer to this page: ldapcompare(1), ldapdelete(1), ldapmodify(1), ldapmodrdn(1), ldapsearch(1), ldapurl(1), ldapwhoami(1), ldap_abandon(3), ldap_add(3), ldap_bind(3), ldap_compare(3), ldap_controls(3), ldap_delete(3), ldap_error(3), ldap_first_attribute(3), ldap_first_entry(3), ldap_first_message(3), ldap_first_reference(3), ldap_get_dn(3), ldap_get_option(3), ldap_get_values(3), ldap_memory(3), ldap_modify(3), ldap_modrdn(3), ldap_open(3), ldap_parse_reference(3), ldap_parse_result(3), ldap_rename(3), ldap_result(3), ldap_schema(3), ldap_search(3), ldap_sort(3), ldap_sync(3), ldap_tls(3), ldap_url(3), ldap.conf(5), ldif(5), slapd.backends(5), slapd.conf(5), slapd-config(5), slapd-ldap(5), slapd-monitor(5), slapd.overlays(5), slapo-ppolicy(5), slapacl(8), slapadd(8), slapauth(8), slapcat(8), slapd(8), slapdn(8), slapindex(8), slapmodify(8), slapschema(8), slaptest(8)