``Memcached is a high-performance, distributed memory object caching
system, generic in nature, but intended for use in speeding up dynamic web
applications by alleviating database load.'' <http://danga.com/memcached/>
libmemcached is a small, thread-safe client library for the
memcached protocol. The code has all been written with an eye to allow
for both web and embedded usage. It handles the work behind routing
particular keys to specific servers that you specify (and values are
matched based on server order as supplied by you). It implements both
a modula and consistent method of object distribution.
There are multiple implemented routing and hashing methods. See the
All operations are performed against a "memcached_st" structure.
These structures can either be dynamically allocated or statically
allocated and then initialized by memcached_create(). Functions have been
written in order to encapsulate the "memcached_st". It is not
recommended that you operate directly against the structure.
Nearly all functions return a "memcached_return_t" value.
This value can be translated to a printable string with memcached_strerror(3).
Partitioning based on keys is supported in the library. Using the key partioning
functions it is possible to group sets of object onto servers.
"memcached_st" structures are thread-safe, but each thread must
contain its own structure (that is, if you want to share these among
threads you must provide your own locking). No global variables are
used in this library.
If you are working with GNU autotools you will want to add the following to
your configure.ac to properly include libmemcached in your application.
Default maximum size of a key (which includes the null pointer). Master keys
have no limit, this only applies to keys used for storage.
Default size of key (which includes the null pointer).
This is the ``stride'' used in the consistent hash used between replicas.
Maximum allowed size of the hostname.
String value of libmemcached version such as ``1.23.4''
Major version value. Such as 1.23.4, would be 1
Major version value. Such as 1.23.4, would be 23
Major version value. Such as 1.23.4, would be 4
THREADS AND PROCESSES
When using threads or forked processes it is important to keep an instance
of "memcached_st" per process or thread. Without creating your own locking
structures you can not share a single "memcached_st". You can though call
memcached_quit(3) on a "memcached_st" and then use the resulting cloned