14 C Client Library for memcached (libmemcached, -lmemcached)
25 #include <libmemcached/memcached.h>
28 memcached_callback_set (memcached_st *ptr,
29 memcached_callback_t flag,
33 memcached_callback_get (memcached_st *ptr,
34 memcached_callback_t flag,
35 memcached_return_t *error);
44 libmemcached(3) can have callbacks set key execution points. These either
45 provide function calls at points in the code, or return pointers to
46 structures for particular usages.
48 memcached_callback_get() takes a callback flag and returns the structure or
49 function set by memcached_callback_set().
51 memcached_callback_set() changes the function/structure assigned by a
52 callback flag. No connections are reset.
54 You can use MEMCACHED_CALLBACK_USER_DATA to provide custom context if required for any
58 MEMCACHED_CALLBACK_CLEANUP_FUNCTION
60 When memcached_delete() is called this function will be excuted. At the
61 point of its execution all connections have been closed.
65 MEMCACHED_CALLBACK_CLONE_FUNCTION
67 When memcached_delete() is called this function will be excuted. At the
68 point of its execution all connections have been closed.
72 MEMCACHED_CALLBACK_PREFIX_KEY
74 You can set a value which will be used to create a domain for your keys.
75 The value specified here will be prefixed to each of your keys. The value can not
76 be greater then MEMCACHED_PREFIX_KEY_MAX_SIZE - 1 and will reduce MEMCACHED_MAX_KEY by
77 the value of your key. The prefix key is only applied to the primary key,
78 not the master key. MEMCACHED_FAILURE will be returned if no key is set. In the case
79 of a key which is too long MEMCACHED_BAD_KEY_PROVIDED will be returned.
81 If you set a value with the value being NULL then the prefix key is disabled.
84 MEMCACHED_CALLBACK_USER_DATA
86 This allows you to store a pointer to a specifc piece of data. This can be
87 retrieved from inside of memcached_fetch_execute(). Cloning a memcached_st
88 will copy the pointer to the clone.
92 MEMCACHED_CALLBACK_MALLOC_FUNCTION
94 DEPRECATED: use memcached_set_memory_allocators instead.
98 MEMCACHED_CALLBACK_REALLOC_FUNCTION
100 DEPRECATED: use memcached_set_memory_allocators instead.
104 MEMCACHED_CALLBACK_FREE_FUNCTION
106 DEPRECATED: use memcached_set_memory_allocators instead.
110 MEMCACHED_CALLBACK_GET_FAILURE
112 This function implements the read through cache behavior. On failure of retrieval this callback will be called.
113 You are responsible for populating the result object provided. This result object will then be stored in the server and
114 returned to the calling process. You must clone the memcached_st in order to
115 make use of it. The value will be stored only if you return
116 MEMCACHED_SUCCESS or MEMCACHED_BUFFERED. Returning MEMCACHED_BUFFERED will
117 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).
119 The prototype for this is:
120 memcached_return_t (\*memcached_trigger_key)(memcached_st \*ptr, char \*key, size_t key_length, memcached_result_st \*result);
124 MEMCACHED_CALLBACK_DELETE_TRIGGER
126 This function implements a trigger upon successful deletion of a key. The memcached_st structure will need to be cloned
127 in order to make use of it.
129 The prototype for this is:
130 typedef memcached_return_t (\*memcached_trigger_delete_key)(memcached_st \*ptr, char \*key, size_t key_length);
140 memcached_callback_get() return the function or structure that was provided.
141 Upon error, nothing is set, null is returned, and the memcached_return_t
142 argument is set to MEMCACHED_FAILURE.
144 memcached_callback_set() returns MEMCACHED_SUCCESS upon successful setting,
145 otherwise MEMCACHED_FAILURE on error.
153 To find out more information please check:
154 `https://launchpad.net/libmemcached <https://launchpad.net/libmemcached>`_
162 Brian Aker, <brian@tangent.org>
170 :manpage:`memcached(1)` :manpage:`libmemcached(3)` :manpage:`memcached_strerror(3)`