libcache(3) BSD Library Functions Manual libcache(3)NAMElibcache — the caching framework
SYNOPSIS
#include <cache.h>
DESCRIPTION
The libcache framework provides a facility for creating in memory data
caches. Each cache is a mutable dictionary that associates values with
their keys. A cache limits the number of values it keeps according to
available system memory and selects values to evict when the limit is
exceeded. Recently and frequently used values are less likely to be
selected for eviction.
Cache keys and values should be cast as pointers. The framework provides
a callback interface for supporting arbitrary types of keys and values
and implements callback functions for common types. See
cache_callbacks(3) for more information.
Clients retrieve a value previously added to a cache using the value's
key. When the client gets a value, the cache increments a reference
count on the value. When the client finishes with a value retrieved from
a cache they must release the value back to the cache. Referenced values
are considered in use and will not be evicted. The cache may evict
unreferenced values (e.g. to make room for other values or reduce its
size).
The number of values allowed in a cache at one time is managed by the
cache framework. Cache size will grow when the system has available mem‐
ory and shrink under memory pressure.
Libcache is thread-safe. It is not safe to call back into the cache API
from cache callback functions.
SEE ALSOcache_create(3), cache_set_and_retain(3)Darwin May 7, 2009 Darwin
