git.m6w6.name Git - m6w6/libmemcached/blob - docs/source/libmemcached.rst

   1 ==============================================
   2 Introducing the C Client Library for memcached
   3 ==============================================
   4
   5 --------
   6 SYNOPSIS
   7 --------
   8
   9 #include <libmemcached/memcached.h>
  10   Compile and link with -lmemcached
  11
  12 =======
  13
  14 libMemcached is an open source C/C++ client library and tools for the memcached server (http://memcached.org/).
  15 It has been designed to be light on memory usage, thread safe, and provide full access to server side methods.
  16
  17 libMemcached was designed to provide the greatest number of options to use Memcached. Some of the features provided:
  18
  19 1. Asynchronous and Synchronous Transport Support.
  20 2. Consistent Hashing and Distribution.
  21 3. Tunable Hashing algorithm to match keys.
  22 4. Access to large object support.
  23 5. Local replication.
  24 6. A complete reference guide and documentation to the API.
  25 7. Tools to Manage your Memcached networks.
  26
  27 -----------
  28 DESCRIPTION
  29 -----------
  30
  31
  32 "Memcached is a high-performance, distributed memory object caching
  33 system, generic in nature, but intended for use in speeding up dynamic web
  34 applications by alleviating database load." `http://memcached.org/ <http://memcached.org/>`_
  35
  36 :program:`libmemcached` is a small, thread-safe client library for the
  37 memcached protocol. The code has all been written to allow
  38 for both web and embedded usage. It handles the work behind routing
  39 individual keys to specific servers specified by the developer (and values are
  40 matched based on server order as supplied by the user). It implements
  41 a modular and consistent method of object distribution.
  42
  43 There are multiple implemented routing and hashing methods. See the
  44 :c:func:`memcached_behavior_set` manpage for more information.
  45
  46 All operations are performed against a :c:type:`memcached_st` structure.
  47 These structures can either be dynamically allocated or statically
  48 allocated and then initialized by :c:func:`memcached_create`. Functions have
  49 been written in order to encapsulate the :c:type:`memcached_st`. It is not
  50 recommended that you operate directly against the structure.
  51
  52 Nearly all functions return a :c:type:`memcached_return_t` value.
  53 This value can be translated to a printable string with
  54 :c:type:`memcached_strerror`.
  55
  56 Objects are stored on servers by hashing keys. The hash value maps the key to a particular server.
  57 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.
  58
  59 Group keys can be optionally used to group sets of objects with servers.
  60
  61 Namespaces are supported, and can be used to partition caches so that multiple applications can use the same memcached servers.
  62
  63 :c:type:`memcached_st` structures are thread-safe, but each thread must
  64 contain its own structure (that is, if you want to share these among
  65 threads you must provide your own locking). No global variables are
  66 used in this library.
  67
  68 If you are working with GNU autotools you will want to add the following to
  69 your COPYING to properly include libmemcached in your application.
  70
  71 PKG_CHECK_MODULES(DEPS, libmemcached >= 0.8.0)
  72 AC_SUBST(DEPS_CFLAGS)
  73 AC_SUBST(DEPS_LIBS)
  74
  75 Some features of the library must be enabled through :c:func:`memcached_behavior_set`.
  76
  77
  78 ---------
  79 CONSTANTS
  80 ---------
  81
  82
  83 A number of constants have been provided for in the library.
  84
  85
  86 .. c:macro:: MEMCACHED_DEFAULT_PORT
  87
  88  The default port used by memcached(3).
  89
  90
  91 .. c:macro:: MEMCACHED_MAX_KEY
  92
  93  Default maximum size of a key (which includes the null pointer). Master keys
  94  have no limit, this only applies to keys used for storage.
  95
  96
  97 .. c:macro:: MEMCACHED_MAX_BUFFER
  98
  99  Default size of read/write buffers (which includes the null pointer).
 100
 101
 102 .. c:macro:: MEMCACHED_STRIDE
 103
 104  This is the "stride" used in the consistent hash used between replicas.
 105
 106
 107 .. c:macro:: MEMCACHED_MAX_HOST_LENGTH
 108
 109  Maximum allowed size of the hostname.
 110
 111
 112 .. c:macro:: LIBMEMCACHED_VERSION_STRING
 113
 114  String value of libmemcached version such as "1.23.4"
 115
 116
 117 .. c:macro:: LIBMEMCACHED_VERSION_HEX
 118
 119  Hex value of the version number. "0x00048000" This can be used for comparing versions based on number.
 120
 121
 122 .. c:macro:: MEMCACHED_PREFIX_KEY_MAX_SIZE
 123
 124  Maximum length allowed for namespacing of a key.
 125
 126
 127
 128 ---------------------
 129 THREADS AND PROCESSES
 130 ---------------------
 131
 132
 133 When using threads or forked processes it is important to keep one instance
 134 of :c:type:`memcached_st` per process or thread. Without creating your own
 135 locking structures you can not share a single :c:type:`memcached_st`. However,
 136 you can call :c:func:`memcached_quit` on a :c:type:`memcached_st` and then use the resulting cloned structure.
 137
 138
 139
 140 --------
 141 SEE ALSO
 142 --------
 143
 144 .. only:: man
 145
 146     :manpage:`memcached(1)`
 147     :manpage:`memaslap(1)`
 148     :manpage:`memcapable(1)`
 149     :manpage:`memcat(1)`
 150     :manpage:`memcp(1)`
 151     :manpage:`memdump(1)`
 152     :manpage:`memerror(1)`
 153     :manpage:`memexist(1)`
 154     :manpage:`memflush(1)`
 155     :manpage:`memparse(1)`
 156     :manpage:`memping(1)`
 157     :manpage:`memrm(1)`
 158     :manpage:`memslap(1)`
 159     :manpage:`memstat(1)`
 160     :manpage:`memtouch(1)`
 161     :manpage:`libhashkit(3)`
 162     :manpage:`libmemcached_configuration(3)`
 163     :manpage:`libmemcached_examples(3)`
 164     :manpage:`libmemcachedutil(3)`
 165     :manpage:`memcached_analyze(3)`
 166     :manpage:`memcached_append(3)`
 167     :manpage:`memcached_auto(3)`
 168     :manpage:`memcached_behavior(3)`
 169     :manpage:`memcached_callback(3)`
 170     :manpage:`memcached_cas(3)`
 171     :manpage:`memcached_create(3)`
 172     :manpage:`memcached_delete(3)`
 173     :manpage:`memcached_dump(3)`
 174     :manpage:`memcached_exist(3)`
 175     :manpage:`memcached_fetch(3)`
 176     :manpage:`memcached_flush(3)`
 177     :manpage:`memcached_flush_buffers(3)`
 178     :manpage:`memcached_generate_hash_value(3)`
 179     :manpage:`memcached_get(3)`
 180     :manpage:`memcached_last_error_message(3)`
 181     :manpage:`memcached_memory_allocators(3)`
 182     :manpage:`memcached_pool(3)`
 183     :manpage:`memcached_quit(3)`
 184     :manpage:`memcached_result_st(3)`
 185     :manpage:`memcached_return_t(3)`
 186     :manpage:`memcached_sasl(3)`
 187     :manpage:`memcached_servers(3)`
 188     :manpage:`memcached_server_st(3)`
 189     :manpage:`memcached_set(3)`
 190     :manpage:`memcached_set_encoding_key(3)`
 191     :manpage:`memcached_stats(3)`
 192     :manpage:`memcached_strerror(3)`
 193     :manpage:`memcached_touch(3)`
 194     :manpage:`memcached_user_data(3)`
 195     :manpage:`memcached_verbosity(3)`
 196     :manpage:`memcached_version(3)`
 197
 198 .. only:: html
 199
 200     * :manpage:`memcached(1)`
 201     * :doc:`bin/memaslap`
 202     * :doc:`bin/memcapable`
 203     * :doc:`bin/memcat`
 204     * :doc:`bin/memcp`
 205     * :doc:`bin/memdump`
 206     * :doc:`bin/memerror`
 207     * :doc:`bin/memexist`
 208     * :doc:`bin/memflush`
 209     * :doc:`bin/memparse`
 210     * :doc:`bin/memping`
 211     * :doc:`bin/memrm`
 212     * :doc:`bin/memslap`
 213     * :doc:`bin/memstat`
 214     * :doc:`bin/memtouch`
 215     * :doc:`libhashkit`
 216     * :doc:`libmemcached_configuration`
 217     * :doc:`libmemcached_examples`
 218     * :doc:`libmemcachedutil`
 219     * :doc:`memcached_analyze`
 220     * :doc:`memcached_append`
 221     * :doc:`memcached_auto`
 222     * :doc:`memcached_behavior`
 223     * :doc:`memcached_callback`
 224     * :doc:`memcached_cas`
 225     * :doc:`memcached_create`
 226     * :doc:`memcached_delete`
 227     * :doc:`memcached_dump`
 228     * :doc:`libmemcached/memcached_exist`
 229     * :doc:`libmemcached/memcached_fetch`
 230     * :doc:`memcached_flush`
 231     * :doc:`memcached_flush_buffers`
 232     * :doc:`memcached_generate_hash_value`
 233     * :doc:`memcached_get`
 234     * :doc:`libmemcached/memcached_last_error_message`
 235     * :doc:`memcached_memory_allocators`
 236     * :doc:`memcached_pool`
 237     * :doc:`memcached_quit`
 238     * :doc:`memcached_result_st`
 239     * :doc:`libmemcached/memcached_return_t`
 240     * :doc:`memcached_sasl`
 241     * :doc:`memcached_servers`
 242     * :doc:`memcached_server_st`
 243     * :doc:`memcached_set`
 244     * :doc:`libmemcached-1.0/memcached_set_encoding_key`
 245     * :doc:`memcached_stats`
 246     * :doc:`memcached_strerror`
 247     * :doc:`libmemcached-1.0/memcached_touch`
 248     * :doc:`memcached_user_data`
 249     * :doc:`memcached_verbosity`
 250     * :doc:`memcached_version`