LDAP(3) OpenLDAP LDVERSION LDAP(3)
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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 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).
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
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LDAP(3) OpenLDAP LDVERSION LDAP(3)
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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 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.
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 displayable.
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).
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