1 ==============================================
2 Introducing the C Client Library for memcached
3 ==============================================
9 #include <libmemcached/memcached.h>
11 Compile and link with -lmemcached
19 "Memcached is a high-performance, distributed memory object caching
20 system, generic in nature, but intended for use in speeding up dynamic web
21 applications by alleviating database load." `http://danga.com/memcached/ <http://danga.com/memcached/>`_
23 \ **libmemcached**\ is a small, thread-safe client library for the
24 memcached protocol. The code has all been written with an eye to allow
25 for both web and embedded usage. It handles the work behind routing
26 particular keys to specific servers that you specify (and values are
27 matched based on server order as supplied by you). It implements both
28 a modula and consistent method of object distribution.
30 There are multiple implemented routing and hashing methods. See the
31 memcached_behavior_set() manpage.
33 All operations are performed against a \ ``memcached_st``\ structure.
34 These structures can either be dynamically allocated or statically
35 allocated and then initialized by memcached_create(). Functions have been
36 written in order to encapsulate the \ ``memcached_st``\ . It is not
37 recommended that you operate directly against the structure.
39 Nearly all functions return a \ ``memcached_return_t``\ value.
40 This value can be translated to a printable string with memcached_strerror(3).
42 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.
44 Group keys can be optionally used to group sets of objects with servers.
46 Namespaces are supported, and can be used to partition caches so that multiple applications can use the same memcached servers.
48 \ ``memcached_st``\ structures are thread-safe, but each thread must
49 contain its own structure (that is, if you want to share these among
50 threads you must provide your own locking). No global variables are
53 If you are working with GNU autotools you will want to add the following to
54 your COPYING to properly include libmemcached in your application.
56 PKG_CHECK_MODULES(DEPS, libmemcached >= 0.8.0)
60 Some features of the library must be enabled through memcached_behavior_set().
70 A number of constants have been provided for in the library.
73 .. c:var:: MEMCACHED_DEFAULT_PORT
75 The default port used by memcached(3).
79 .. c:var:: MEMCACHED_MAX_KEY
81 Default maximum size of a key (which includes the null pointer). Master keys
82 have no limit, this only applies to keys used for storage.
86 .. c:var:: MEMCACHED_MAX_KEY
88 Default size of key (which includes the null pointer).
92 .. c:var:: MEMCACHED_STRIDE
94 This is the "stride" used in the consistent hash used between replicas.
98 .. c:var:: MEMCACHED_MAX_HOST_LENGTH
100 Maximum allowed size of the hostname.
103 .. c:var:: LIBMEMCACHED_VERSION_STRING
105 String value of libmemcached version such as "1.23.4"
108 .. c:var:: LIBMEMCACHED_VERSION_HEX
110 Hex value of the version number. "0x00048000" This can be used for comparing versions based on number.
115 ---------------------
116 THREADS AND PROCESSES
117 ---------------------
120 When using threads or forked processes it is important to keep an instance
121 of \ ``memcached_st``\ per process or thread. Without creating your own locking
122 structures you can not share a single \ ``memcached_st``\ . You can though call
123 memcached_quit(3) on a \ ``memcached_st``\ and then use the resulting cloned
132 To find out more information please check:
133 `https://launchpad.net/libmemcached <https://launchpad.net/libmemcached>`_
141 :manpage:`memcached(1)` :manpage:`libmemcached_examples(3)` :manpage:`libmemcached(1)` :manpage:`memcat(1)` :manpage:`memcp(1)` :manpage:`memflush(1)` :manpage:`memrm(1)` :manpage:`memslap(1)` :manpage:`memstat(1)` :manpage:`memcached_fetch(3)` :manpage:`memcached_replace(3)` :manpage:`memcached_server_list_free(3)` :manpage:`libmemcached_examples(3)` :manpage:`memcached_clone(3)` :manpage:`memcached_free(3)`
142 :manpage:`memcached_server_add(3)` :manpage:`memcached_server_push(3)` :manpage:`memcached_add(3)` :manpage:`memcached_get(3)` :manpage:`memcached_server_count(3)` :manpage:`memcached_servers_parse(3)` :manpage:`memcached_create(3)` :manpage:`memcached_increment(3)` :manpage:`memcached_server_list(3)` :manpage:`memcached_set(3)`
143 :manpage:`memcached_decrement(3)` :manpage:`memcached_mget(3)` :manpage:`memcached_server_list_append(3)` :manpage:`memcached_strerror(3)` :manpage:`memcached_delete(3)` :manpage:`memcached_quit(3)` :manpage:`memcached_server_list_count(3)` :manpage:`memcached_verbosity(3)` :manpage:`memcached_server_add_unix_socket(3)` :manpage:`memcached_result_create(3)` :manpage:`memcached_result_free(3)`
144 :manpage:`memcached_result_key_value(3)` :manpage:`memcached_result_key_length(3)` :manpage:`memcached_result_value(3)` :manpage:`memcached_result_length(3)` :manpage:`memcached_result_flags(3)`
145 :manpage:`memcached_result_cas(3)` :manpage:`memcached_result_st(3)` :manpage:`memcached_append(3)` :manpage:`memcached_prepend(3)` :manpage:`memcached_fetch_result(3)`
146 :manpage:`memerror(1)` :manpage:`memcached_get_by_key(3)` :manpage:`memcached_mget_by_key(3)` :manpage:`memcached_delete_by_key(3)`
147 :manpage:`memcached_fetch_execute(3)` :manpage:`memcached_callback_get(3)` :manpage:`memcached_callback_set(3)` :manpage:`memcached_version(3)`
148 :manpage:`memcached_lib_version(3)` :manpage:`memcached_result_set_value(3)` :manpage:`memcached_dump(3)` :manpage:`memdump(1)`
149 :manpage:`memcached_set_memory_allocators(3)` :manpage:`memcached_get_memory_allocators(3)` :manpage:`memcached_get_user_data(3)` :manpage:`memcached_set_user_data(3)`