14 C Client Library for memcached (libmemcached, -lmemcached)
21 #include <libmemcached/memcached.h>
23 .. c:function:: memcached_return_t memcached_callback_set (memcached_st *ptr, memcached_callback_t flag, void *data);
25 .. c:function:: void * memcached_callback_get (memcached_st *ptr, memcached_callback_t flag, memcached_return_t *error);
34 libmemcached(3) can have callbacks set key execution points. These either
35 provide function calls at points in the code, or return pointers to
36 structures for particular usages.
38 memcached_callback_get() takes a callback flag and returns the structure or
39 function set by memcached_callback_set().
41 memcached_callback_set() changes the function/structure assigned by a
42 callback flag. No connections are reset.
44 You can use MEMCACHED_CALLBACK_USER_DATA to provide custom context if required for any of the callbacks.
47 .. c:var:: MEMCACHED_CALLBACK_CLEANUP_FUNCTION
49 When memcached_delete() is called this function will be excuted. At the point of its execution all connections are closed.
53 .. c:var:: MEMCACHED_CALLBACK_CLONE_FUNCTION
55 When memcached_delete() is called this function will be excuted. At the
56 point of its execution all connections are closed.
60 .. c:var:: MEMCACHED_CALLBACK_PREFIX_KEY
62 You can set a value which will be used to create a domain for your keys.
63 The value specified here will be prefixed to each of your keys. The value can not be greater then MEMCACHED_PREFIX_KEY_MAX_SIZE - 1 and will reduce MEMCACHED_MAX_KEY by the value of your key.
65 The prefix key is only applied to the primary key, not the master key. MEMCACHED_FAILURE will be returned if no key is set. In the case of a key which is too long, MEMCACHED_BAD_KEY_PROVIDED will be returned.
67 If you set a value with the value being NULL then the prefix key is disabled.
70 .. c:var:: MEMCACHED_CALLBACK_USER_DATA
72 This allows you to store a pointer to a specifc piece of data. This can be
73 retrieved from inside of memcached_fetch_execute(). Cloning a memcached_st
74 will copy the pointer to the clone.
78 .. c:var:: MEMCACHED_CALLBACK_MALLOC_FUNCTION
80 DEPRECATED: use memcached_set_memory_allocators instead.
84 .. c:var:: MEMCACHED_CALLBACK_REALLOC_FUNCTION
86 DEPRECATED: use memcached_set_memory_allocators instead.
90 .. c:var:: MEMCACHED_CALLBACK_FREE_FUNCTION
92 DEPRECATED: use memcached_set_memory_allocators instead.
96 .. c:var:: MEMCACHED_CALLBACK_GET_FAILURE
98 This function implements the read through cache behavior. On failure of retrieval this callback will be called.
100 You are responsible for populating the result object provided. This result object will then be stored in the server and returned to the calling process.
102 You must clone the memcached_st in order to
103 make use of it. The value will be stored only if you return
104 MEMCACHED_SUCCESS or MEMCACHED_BUFFERED. Returning MEMCACHED_BUFFERED will
105 cause the object to be buffered and not sent immediatly (if this is the default behavior based on your connection setup this will happen automatically).
107 The prototype for this is:
108 memcached_return_t (\*memcached_trigger_key)(memcached_st \*ptr, char \*key, size_t key_length, memcached_result_st \*result);
112 .. c:var:: MEMCACHED_CALLBACK_DELETE_TRIGGER
114 This function implements a trigger upon successful deletion of a key. The memcached_st structure will need to be cloned in order to make use of it.
116 The prototype for this is: typedef memcached_return_t (\*memcached_trigger_delete_key)(memcached_st \*ptr, char \*key, size_t key_length);
126 memcached_callback_get() return the function or structure that was provided.
127 Upon error, nothing is set, null is returned, and the memcached_return_t
128 argument is set to MEMCACHED_FAILURE.
130 memcached_callback_set() returns MEMCACHED_SUCCESS upon successful setting,
131 otherwise MEMCACHED_FAILURE on error.
139 To find out more information please check:
140 `http://libmemcached.org/ <http://libmemcached.org/>`_
148 Brian Aker, <brian@tangent.org>
156 :manpage:`memcached(1)` :manpage:`libmemcached(3)` :manpage:`memcached_strerror(3)`