LDAP_MEMCACHE(3LDAP)LDAP_MEMCACHE(3LDAP)NAME
ldap_memcache, ldap_memcache_init, ldap_memcache_set, ldap_mem‐
cache_get, ldap_memcache_flush, ldap_memcache_destroy, ldap_mem‐
cache_update - LDAP client caching functions
SYNOPSIS
cc -flag ... file...-lldap [ -library ... ]
#include <ldap.h>
int ldap_memcache_init(unsigned long ttl, unsigned long size,
char **baseDNs,struct ldap_thread_fns *thread_fns,
LDAPMemCache **cachep
int ldap_memcache_set(LDAP *ld, LDAPMemCache **cache
int ldap_memcache_get(LDAP *ld, LDAPMemCache **cachep
void ldap_memcache_flush(LDAPMemCache *cache, char *dn, int scope
void ldap_memcache_destroy(LDAPMemCache *cache
void ldap_memcache_update(LDAPMemCache *cache
DESCRIPTION
Use the ldap_memcache functions to maintain an in-memory client side
cache to store search requests. Caching improves performance and
reduces network bandwidth when a client makes repeated requests. The
cache uses search criteria as the key to the cached items. When you
send a search request, the cache checks the search criteria to deter‐
mine if that request has been previously stored . If the request was
stored, the search results are read from the cache.
Make a call to ldap_memcache_init() to create the in-memory client side
cache. The function passes back a pointer to an LDAPMemCache structure,
which represents the cache. Make a call to the ldap_memcache_set()
function to associate this cache with an LDAP connection handle, an
LDAP structure. ttl is the the maximum amount of time (in seconds)
that an item can be cached. If a ttl value of 0 is passed, there is no
limit to the amount of time that an item can be cached. size is the
maximum amount of memory (in bytes) that the cache will consume. A zero
value of size means the cache has no size limit. baseDNS is an array
of the base DN strings representing the base DNs of the search
requests you want cached. If baseDNS is not NULL, only the search
requests with the specified base DNs will be cached. If baseDNS is
NULL, all search requests are cached. The thread_fns parameter takes
an ldap_thread_fns structure specifying the functions that you want
used to ensure that the cache is thread-safe. You should specify this
if you have multiple threads that are using the same connection handle
and cache. If you are not using multiple threads, pass NULL for this
parameter.
ldap_memcache_set() associates an in-memory cache that you have already
created by calling the ldap_memcache_init() function with an LDAP con‐
nection handle. The ld parameter should be the result of a successful
call to ldap_open(3LDAP). The cache parameter should be the result of
a cache created by the ldap_memcache_init() call. After you call this
function, search requests made over the specified LDAP connection will
use this cache. To disassociate the cache from the LDAP connection han‐
dle, make a call to the ldap_bind(3LDAP) or ldap_bind(3LDAP) function.
Make a call to ldap_memcache_set() if you want to associate a cache
with multiple LDAP connection handles. For example, call the ldap_mem‐
cache_get() function to get the cache associated with one connection,
then you can call this function and associate the cache with another
connection.
The ldap_memcache_get() function gets the cache associated with the
specified connection handle (LDAP structure). This cache is used by all
search requests made through that connection. When you call this func‐
tion, the function sets the cachep parameter as a pointer to the LDAP‐
MemCache structure that is associated with the connection handle.
ldap_memcache_flush() flushes search requests from the cache. If the
base DN of a search request is within the scope specified by the dn and
scope arguments, the search request is flushed from the cache. If no
DN is specified, the entire cache is flushed. The scope parameter,
along with the dn parameter, identifies the search requests that you
want flushed from the cache. This argument can have one of the follow‐
ing values:
LDAP_SCOPE_BASE
LDAP_SCOPE_ONELEVEL
LDAP_SCOPE_SUBTREE
ldap_memcache_destroy() frees the specified LDAPMemCache structure
pointed to by cache from memory. Call this function after you are done
working with a cache.
ldap_memcache_update() checks the cache for items that have expired
and removes them. This check is typically done as part of the way the
cache normally works. You do not need to call this function unless you
want to update the cache at this point in time. This function is only
useful in a multithreaded application, since it will not return until
the cache is destroyed.
PARAMETERS
ttl
The maximum amount of time (in seconds) that an item can
be cached
size
The maximum amount of memory (in bytes) that the cache
will consume.
baseDNs
An array of the base DN strings representing the base
DNs of the search requests you want cached
thread_fns
A pointer to the ldap_thread_fns structure structure.
cachep
A pointer to the LDAPMemCache structure
cache
The result of a cache created by the ldap_memcache_init()
call
ld
The result of a successful call to ldap_open(3LDAP)
dn
The search requests that you want flushed from the cache
scope
The search requests that you want flushed from the cache
ERRORS
The functions that have int return values return LDAP_SUCCESS if the
operation was successful. Otherwise, they return another LDAP error
code. See ldap_error(3LDAP) for a list of the LDAP error codes.
ATTRIBUTES
See attributes(5) for descriptions of the following attributes:
┌────────────────────┬─────────────────┐
│ ATTRIBUTE TYPE │ ATTRIBUTE VALUE │
├────────────────────┼─────────────────┤
│Interface Stability │ Evolving │
└────────────────────┴─────────────────┘
SEE ALSOldap_error(3LDAP), ldap_open(3LDAP), ldap_search(3LDAP), attributes(5)
Jan 6, 2003 LDAP_MEMCACHE(3LDAP)