MEMCACHED_CALLBACK_GET(3) libmemcached MEMCACHED_CALLBACK_GET(3)
NAME
memcached_callback_get - libmemcached Documentation
Get and set a callback
SYNOPSIS
#include <libmemcached/memcached.h>
memcached_callback_t
memcached_return_t memcached_callback_set(memcached_st *ptr, memcached_callback_t flag, const void *data)
void * memcached_callback_get(memcached_st *ptr, memcached_callback_t flag, memcached_return_t *error)
Compile and link with -lmemcached
DESCRIPTION
libmemcached(3) can have callbacks set key execution points. These either provide function calls at points in the code, or return pointers
to structures for particular usages.
memcached_callback_get() takes a callback flag and returns the structure or function set by memcached_callback_set().
memcached_callback_set() changes the function/structure assigned by a callback flag. No connections are reset.
You can use MEMCACHED_CALLBACK_USER_DATA to provide custom context if required for any of the callbacks.
MEMCACHED_CALLBACK_CLEANUP_FUNCTION
When memcached_delete() is called this function will be excuted. At the point of its execution all connections are closed.
MEMCACHED_CALLBACK_CLONE_FUNCTION
When memcached_delete() is called this function will be excuted. At the point of its execution all connections are closed.
MEMCACHED_CALLBACK_PREFIX_KEY
See MEMCACHED_CALLBACK_NAMESPACE
MEMCACHED_CALLBACK_NAMESPACE
You can set a value which will be used to create a domain for your keys. 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.
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.
If you set a value with the value being NULL then the prefix key is disabled.
MEMCACHED_CALLBACK_USER_DATA
This allows you to store a pointer to a specifc piece of data. This can be retrieved from inside of memcached_fetch_execute(). Cloning a
memcached_st will copy the pointer to the clone.
MEMCACHED_CALLBACK_MALLOC_FUNCTION
Deprecated since version <0.32: Use memcached_set_memory_allocators instead.
MEMCACHED_CALLBACK_REALLOC_FUNCTION
Deprecated since version <0.32: Use memcached_set_memory_allocators instead.
MEMCACHED_CALLBACK_FREE_FUNCTION
Deprecated since version <0.32: Use memcached_set_memory_allocators instead.
MEMCACHED_CALLBACK_GET_FAILURE
This function implements the read through cache behavior. On failure of retrieval this callback will be called.
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.
You must clone the memcached_st in order to make use of it. The value will be stored only if you return MEMCACHED_SUCCESS or MEM-
CACHED_BUFFERED. Returning MEMCACHED_BUFFERED will 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).
The prototype for this is:
memcached_return_t (*memcached_trigger_key)(memcached_st *ptr, char *key, size_t key_length, memcached_result_st *result);
MEMCACHED_CALLBACK_DELETE_TRIGGER
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.
The prototype for this is:
typedef memcached_return_t (*memcached_trigger_delete_key)(memcached_st *ptr, char *key, size_t key_length);
RETURN
memcached_callback_get() return the function or structure that was provided. Upon error, nothing is set, null is returned, and the mem-
cached_return_t argument is set to MEMCACHED_FAILURE.
memcached_callback_set() returns MEMCACHED_SUCCESS upon successful setting, otherwise MEMCACHED_FAILURE on error.
HOME
To find out more information please check: http://libmemcached.org/
AUTHOR
Brian Aker, <brian@tangent.org>
SEE ALSO
memcached(1) libmemcached(3) memcached_strerror(3)
AUTHOR
Brian Aker
COPYRIGHT
2011, Brian Aker DataDifferential, http://datadifferential.com/
1.0.8 May 22, 2012 MEMCACHED_CALLBACK_GET(3)