memcached_callback_get(3)

1..::docs::memcached_callback(3)  libmemcached  ..::docs::memcached_callback(3)
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NAME

6       memcached_callback_get, memcached_callback_set - Get and set a callback
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LIBRARY

9       C Client Library for memcached (libmemcached, -lmemcached)
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SYNOPSIS

12         #include <memcached.h>
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14         memcached_return
15           memcached_callback_set (memcached_st *ptr,
16                                   memcached_callback flag,
17                                   void *data);
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19         void *
20           memcached_callback_get (memcached_st *ptr,
21                                   memcached_callback flag,
22                                   memcached_return *error);
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DESCRIPTION

25       libmemcached(3) can have callbacks set key execution points. These
26       either provide function calls at points in the code, or return pointers
27       to structures for particular usages.
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29       memcached_callback_get() takes a callback flag and returns the
30       structure or function set by memcached_callback_set().
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32       memcached_callback_set() changes the function/structure assigned by a
33       callback flag. No connections are reset.
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35       You can use MEMCACHED_CALLBACK_USER_DATA to provide custom context if
36       required for any of the callbacks
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38       MEMCACHED_CALLBACK_CLEANUP_FUNCTION
39           When memcached_delete() is called this function will be excuted. At
40           the point of its execution all connections have been closed.
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42       MEMCACHED_CALLBACK_CLONE_FUNCTION
43           When memcached_delete() is called this function will be excuted. At
44           the point of its execution all connections have been closed.
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46       MEMCACHED_CALLBACK_PREFIX_KEY
47           You can set a value which will be used to create a domain for your
48           keys.  The value specified here will be prefixed to each of your
49           keys. The value can not be greater then
50           MEMCACHED_PREFIX_KEY_MAX_SIZE - 1 and will reduce MEMCACHED_MAX_KEY
51           by the value of your key. The prefix key is only applied to the
52           primary key, not the master key. MEMCACHED_FAILURE will be returned
53           if no key is set. In the case of a key which is too long
54           MEMCACHED_BAD_KEY_PROVIDED will be returned.
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56       MEMCACHED_CALLBACK_USER_DATA
57           This allows you to store a pointer to a specifc piece of data. This
58           can be retrieved from inside of memcached_fetch_execute(). Cloning
59           a memcached_st will copy the pointer to the clone.
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61       MEMCACHED_CALLBACK_MALLOC_FUNCTION
62           DEPRECATED: use memcached_set_memory_allocators instead.
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64       MEMCACHED_CALLBACK_REALLOC_FUNCTION
65           DEPRECATED: use memcached_set_memory_allocators instead.
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67       MEMCACHED_CALLBACK_FREE_FUNCTION
68           DEPRECATED: use memcached_set_memory_allocators instead.
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70       MEMCACHED_CALLBACK_GET_FAILURE
71           This function implements the read through cache behavior. On
72           failure of retrieval this callback will be called.  You are
73           responsible for populating the result object provided. This result
74           object will then be stored in the server and returned to the
75           calling process. You must clone the memcached_st in order to make
76           use of it. The value will be stored only if you return
77           MEMCACHED_SUCCESS or MEMCACHED_BUFFERED. Returning
78           MEMCACHED_BUFFERED will cause the object to be buffered and not
79           sent immediatly (if this is the default behavior based on your
80           connection setup this will happen automatically).
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82           The prototype for this is: memcached_return
83           (*memcached_trigger_key)(memcached_st *ptr, char *key, size_t
84           key_length, memcached_result_st *result);
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86       MEMCACHED_CALLBACK_DELETE_TRIGGER
87           This function implements a trigger upon successful deletion of a
88           key. The memcached_st structure will need to be cloned in order to
89           make use of it.
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91           The prototype for this is: typedef memcached_return
92           (*memcached_trigger_delete_key)(memcached_st *ptr, char *key,
93           size_t key_length);
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RETURN

96       memcached_callback_get() return the function or structure that was
97       provided.  Upon error, nothing is set, null is returned, and the
98       memcached_return argument is set to MEMCACHED_FAILURE.
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100       memcached_callback_set() returns MEMCACHED_SUCCESS upon successful
101       setting, otherwise MEMCACHED_FAILURE on error.
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HOME

104       To find out more information please check:
105       <http://tangent.org/552/libmemcached.html>
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AUTHOR

108       Brian Aker, <brian@tangent.org>
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