NAME¶
libmemcached - Introducing the C Client Library for memcached
SYNOPSIS¶
#include <libmemcached/memcached.h>
Compile and link with -lmemcached
----
libMemcached is an open source C/C++ client library and tools for the memcached
server (
http://memcached.org/). It has been designed to be light on
memory usage, thread safe, and provide full access to server side methods.
libMemcached was designed to provide the greatest number of options to use
Memcached. Some of the features provided:
- 1.
- Asynchronous and Synchronous Transport Support.
- 2.
- Consistent Hashing and Distribution.
- 3.
- Tunable Hashing algorithm to match keys.
- 4.
- Access to large object support.
- 5.
- Local replication.
- 6.
- A complete reference guide and documentation to the
API.
- 7.
- Tools to Manage your Memcached networks.
DESCRIPTION¶
"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://memcached.org/
libmemcached is a small, thread-safe client library for the memcached
protocol. The code has all been written to allow for both web and embedded
usage. It handles the work behind routing individual keys to specific servers
specified by the developer (and values are matched based on server order as
supplied by the user). It implements a modular and consistent method of object
distribution.
There are multiple implemented routing and hashing methods. See the
memcached_behavior_set() manpage for more information.
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.
Objects are stored on servers by hashing keys. The hash value maps the key to a
particular server. All clients understand how this hashing works, so it is
possibly to reliably both push data to a server and retrieve data from a
server.
Group keys can be optionally used to group sets of objects with servers.
Namespaces are supported, and can be used to partition caches so that multiple
applications can use the same memcached 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
COPYING to properly include libmemcached in your application.
PKG_CHECK_MODULES(DEPS, libmemcached >= 0.8.0) AC_SUBST(DEPS_CFLAGS)
AC_SUBST(DEPS_LIBS)
Some features of the library must be enabled through
memcached_behavior_set().
Hope you enjoy it!
CONSTANTS¶
A number of constants have been provided for in the library.
- MEMCACHED_DEFAULT_PORT
- The default port used by memcached(3).
- MEMCACHED_MAX_KEY
- Default maximum size of a key (which includes the null
pointer). Master keys have no limit, this only applies to keys used for
storage.
- MEMCACHED_MAX_KEY
- Default size of key (which includes the null pointer).
- MEMCACHED_STRIDE
- This is the "stride" used in the consistent hash
used between replicas.
- MEMCACHED_MAX_HOST_LENGTH
- Maximum allowed size of the hostname.
- LIBMEMCACHED_VERSION_STRING
- String value of libmemcached version such as
"1.23.4"
- LIBMEMCACHED_VERSION_HEX
- Hex value of the version number. "0x00048000"
This can be used for comparing versions based on number.
- MEMCACHED_PREFIX_KEY_MAX_SIZE
- Maximum length allowed for namespacing of a key.
THREADS AND PROCESSES¶
When using threads or forked processes it is important to keep one instance of
memcached_st per process or thread. Without creating your own locking
structures you can not share a single
memcached_st. However, you can
call
memcached_quit() on a
memcached_st and then use the
resulting cloned structure.
HOME¶
To find out more information please check:
http://libmemcached.org/
SEE ALSO¶
memcached(1) libmemcached_examples(3) libmemcached(1)
memcat(1) memcp(1) memflush(1) memrm(1)
memslap(1) memstat(1) memcached_fetch(3)
memcached_replace(3) memcached_server_list_free(3)
libmemcached_examples(3) memcached_clone(3)
memcached_free(3) memcached_server_add(3)
memcached_server_push(3) memcached_add(3)
memcached_get(3) memcached_server_count(3)
memcached_create(3) memcached_increment(3)
memcached_server_list(3) memcached_set(3)
memcached_decrement(3) memcached_mget(3)
memcached_server_list_append(3) memcached_strerror(3)
memcached_delete(3) memcached_quit(3)
memcached_server_list_count(3) memcached_verbosity(3)
memcached_server_add_unix_socket(3) memcached_result_create(3)
memcached_result_free(3) memcached_result_key_value(3)
memcached_result_key_length(3) memcached_result_value(3)
memcached_result_length(3) memcached_result_flags(3)
memcached_result_cas(3) memcached_result_st(3)
memcached_append(3) memcached_prepend(3)
memcached_fetch_result(3) memerror(1)
memcached_get_by_key(3) memcached_mget_by_key(3)
memcached_delete_by_key(3) memcached_fetch_execute(3)
memcached_callback_get(3) memcached_callback_set(3)
memcached_version(3) memcached_lib_version(3)
memcached_result_set_value(3) memcached_dump(3)
memdump(1) memcached_set_memory_allocators(3)
memcached_get_memory_allocators(3) memcached_get_user_data(3)
memcached_set_user_data(3)
AUTHOR¶
Brian Aker
COPYRIGHT¶
2011, Brian Aker DataDifferential,
http://datadifferential.com/