git.m6w6.name Git - m6w6/libmemcached/blob - docs/man/memcached_callback_set.3

   1 .TH "MEMCACHED_CALLBACK_SET" "3" "June 02, 2011" "0.47" "libmemcached"
   2 .SH NAME
   3 memcached_callback_set \- libmemcached Documentation
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  32 .
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  34 Get and set a callback
  35 .SH SYNOPSIS
  36 .sp
  37 #include <libmemcached/memcached.h>
  38 .INDENT 0.0
  39 .TP
  40 .B memcached_return_t memcached_callback_set (memcached_st *ptr, memcached_callback_t flag, void *data);
  41 .UNINDENT
  42 .INDENT 0.0
  43 .TP
  44 .B void * memcached_callback_get (memcached_st *ptr, memcached_callback_t flag, memcached_return_t *error);
  45 .UNINDENT
  46 .sp
  47 Compile and link with \-lmemcached
  48 .SH DESCRIPTION
  49 .sp
  50 libmemcached(3) can have callbacks set key execution points. These either
  51 provide function calls at points in the code, or return pointers to
  52 structures for particular usages.
  53 .sp
  54 memcached_callback_get() takes a callback flag and returns the structure or
  55 function set by memcached_callback_set().
  56 .sp
  57 memcached_callback_set() changes the function/structure assigned by a
  58 callback flag. No connections are reset.
  59 .sp
  60 You can use MEMCACHED_CALLBACK_USER_DATA to provide custom context if required for any of the callbacks.
  61 .INDENT 0.0
  62 .TP
  63 .B MEMCACHED_CALLBACK_CLEANUP_FUNCTION
  64 .UNINDENT
  65 .sp
  66 When memcached_delete() is called this function will be excuted. At the point of its execution all connections are closed.
  67 .INDENT 0.0
  68 .TP
  69 .B MEMCACHED_CALLBACK_CLONE_FUNCTION
  70 .UNINDENT
  71 .sp
  72 When memcached_delete() is called this function will be excuted. At the
  73 point of its execution all connections are closed.
  74 .INDENT 0.0
  75 .TP
  76 .B MEMCACHED_CALLBACK_PREFIX_KEY
  77 .UNINDENT
  78 .sp
  79 You can set a value which will be used to create a domain for your keys.
  80 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.
  81 .sp
  82 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.
  83 .sp
  84 If you set a value with the value being NULL then the prefix key is disabled.
  85 .INDENT 0.0
  86 .TP
  87 .B MEMCACHED_CALLBACK_USER_DATA
  88 .UNINDENT
  89 .sp
  90 This allows you to store a pointer to a specifc piece of data. This can be
  91 retrieved from inside of memcached_fetch_execute(). Cloning a memcached_st
  92 will copy the pointer to the clone.
  93 .INDENT 0.0
  94 .TP
  95 .B MEMCACHED_CALLBACK_MALLOC_FUNCTION
  96 .UNINDENT
  97 .sp
  98 DEPRECATED: use memcached_set_memory_allocators instead.
  99 .INDENT 0.0
 100 .TP
 101 .B MEMCACHED_CALLBACK_REALLOC_FUNCTION
 102 .UNINDENT
 103 .sp
 104 DEPRECATED: use memcached_set_memory_allocators instead.
 105 .INDENT 0.0
 106 .TP
 107 .B MEMCACHED_CALLBACK_FREE_FUNCTION
 108 .UNINDENT
 109 .sp
 110 DEPRECATED: use memcached_set_memory_allocators instead.
 111 .INDENT 0.0
 112 .TP
 113 .B MEMCACHED_CALLBACK_GET_FAILURE
 114 .UNINDENT
 115 .sp
 116 This function implements the read through cache behavior. On failure of retrieval this callback will be called.
 117 .sp
 118 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.
 119 .sp
 120 You must clone the memcached_st in order to
 121 make use of it. The value will be stored only if you return
 122 MEMCACHED_SUCCESS or MEMCACHED_BUFFERED. Returning MEMCACHED_BUFFERED will
 123 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).
 124 .sp
 125 The prototype for this is:
 126 memcached_return_t (*memcached_trigger_key)(memcached_st *ptr, char *key, size_t key_length, memcached_result_st *result);
 127 .INDENT 0.0
 128 .TP
 129 .B MEMCACHED_CALLBACK_DELETE_TRIGGER
 130 .UNINDENT
 131 .sp
 132 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.
 133 .sp
 134 The prototype for this is: typedef memcached_return_t (*memcached_trigger_delete_key)(memcached_st *ptr, char *key, size_t key_length);
 135 .SH RETURN
 136 .sp
 137 memcached_callback_get() return the function or structure that was provided.
 138 Upon error, nothing is set, null is returned, and the memcached_return_t
 139 argument is set to MEMCACHED_FAILURE.
 140 .sp
 141 memcached_callback_set() returns MEMCACHED_SUCCESS upon successful setting,
 142 otherwise MEMCACHED_FAILURE on error.
 143 .SH HOME
 144 .sp
 145 To find out more information please check:
 146 \fI\%http://libmemcached.org/\fP
 147 .SH AUTHOR
 148 .sp
 149 Brian Aker, <\fI\%brian@tangent.org\fP>
 150 .SH SEE ALSO
 151 .sp
 152 \fImemcached(1)\fP \fIlibmemcached(3)\fP \fImemcached_strerror(3)\fP
 153 .SH AUTHOR
 154 Brian Aker
 155 .SH COPYRIGHT
 156 2011, Brian Aker DataDifferential, http://datadifferential.com/
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