memcached_callback_get(3)

1MEMCACHED_CALLBACK_GET(3)        libmemcached        MEMCACHED_CALLBACK_GET(3)
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NAME

6       memcached_callback_get - libmemcached Documentation
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8       Get and set a callback
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SYNOPSIS

11       #include <libmemcached/memcached.h>
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13       memcached_callback_t
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15       memcached_return_t            memcached_callback_set(memcached_st *ptr,
16       memcached_callback_t flag, const void *data)
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18       void            *             memcached_callback_get(memcached_st *ptr,
19       memcached_callback_t flag, memcached_return_t *error)
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21       Compile and link with -lmemcached
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DESCRIPTION

24       libmemcached(3)  can  have  callbacks  set  key execution points. These
25       either provide function calls at points in the code, or return pointers
26       to structures for particular usages.
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28       memcached_callback_get()  takes  a callback flag and returns the struc‐
29       ture or function set by memcached_callback_set().
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31       memcached_callback_set() changes the function/structure assigned  by  a
32       callback flag. No connections are reset.
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34       You  can  use MEMCACHED_CALLBACK_USER_DATA to provide custom context if
35       required for any of the callbacks.
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37       MEMCACHED_CALLBACK_CLEANUP_FUNCTION
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39       When memcached_delete() is called this function will be excuted. At the
40       point of its execution all connections are closed.
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42       MEMCACHED_CALLBACK_CLONE_FUNCTION
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44       When  memcached_delete()  is  called this function will be excuted.  At
45       the point of its execution all connections are closed.
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47       MEMCACHED_CALLBACK_PREFIX_KEY
48              See MEMCACHED_CALLBACK_NAMESPACE
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50       MEMCACHED_CALLBACK_NAMESPACE
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52       You can set a value which will be used to  create  a  domain  for  your
53       keys.   The value specified here will be prefixed to each of your keys.
54       The value can not be greater then MEMCACHED_PREFIX_KEY_MAX_SIZE - 1 and
55       will reduce MEMCACHED_MAX_KEY by the value of your key.
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57       The  prefix key is only applied to the primary key, not the master key.
58       MEMCACHED_FAILURE will be returned if no key is set. In the case  of  a
59       key which is too long, MEMCACHED_BAD_KEY_PROVIDED will be returned.
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61       If  you  set  a  value with the value being NULL then the prefix key is
62       disabled.
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64       MEMCACHED_CALLBACK_USER_DATA
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66       This allows you to store a pointer to a specifc piece of data. This can
67       be  retrieved  from inside of memcached_fetch_execute(). Cloning a mem‐
68       cached_st will copy the pointer to the clone.
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70       MEMCACHED_CALLBACK_MALLOC_FUNCTION
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72       Deprecated since  version  <0.32:  Use  memcached_set_memory_allocators
73       instead.
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75       MEMCACHED_CALLBACK_REALLOC_FUNCTION
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77       Deprecated  since  version  <0.32:  Use memcached_set_memory_allocators
78       instead.
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80       MEMCACHED_CALLBACK_FREE_FUNCTION
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82       Deprecated since  version  <0.32:  Use  memcached_set_memory_allocators
83       instead.
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85       MEMCACHED_CALLBACK_GET_FAILURE
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87       This function implements the read through cache behavior. On failure of
88       retrieval this callback will be called.
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90       You are responsible for populating the  result  object  provided.  This
91       result  object  will  then  be stored in the server and returned to the
92       calling process.
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94       You must clone the memcached_st in order to make use of it.  The  value
95       will   be   stored   only  if  you  return  MEMCACHED_SUCCESS  or  MEM‐
96       CACHED_BUFFERED. Returning MEMCACHED_BUFFERED will cause the object  to
97       be  buffered  and  not sent immediatly (if this is the default behavior
98       based on your connection setup this will happen automatically).
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100       The prototype for this is:
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102       memcached_return_t  (*memcached_trigger_key)(memcached_st  *ptr,   char
103       *key, size_t key_length, memcached_result_st *result);
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105       MEMCACHED_CALLBACK_DELETE_TRIGGER
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107       This  function  implements a trigger upon successful deletion of a key.
108       The memcached_st structure will need to be cloned in order to make  use
109       of it.
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111       The prototype for this is:
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113       typedef memcached_return_t (*memcached_trigger_delete_key)(memcached_st
114       *ptr, char *key, size_t key_length);
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RETURN

117       memcached_callback_get() return the function or structure that was pro‐
118       vided.  Upon  error,  nothing  is  set,  null is returned, and the mem‐
119       cached_return_t argument is set to MEMCACHED_FAILURE.
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121       memcached_callback_set() returns MEMCACHED_SUCCESS upon successful set‐
122       ting, otherwise MEMCACHED_FAILURE on error.
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HOME

125       To find out more information please check: http://libmemcached.org/
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AUTHOR

128       Brian Aker, <brian@tangent.org>
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AUTHOR

134       Brian Aker
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COPYRIGHT

137       2011-2013, Brian Aker DataDifferential, http://datadifferential.com/
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1421.0.18                         February 09, 2014     MEMCACHED_CALLBACK_GET(3)