NAME
memcached_callback_get, memcached_callback_set - Get and set a callback
LIBRARY
C Client Library for memcached (libmemcached, -lmemcached)
SYNOPSIS
#include <memcached.h>
memcached_return_t
memcached_callback_set (memcached_st *ptr,
memcached_callback_t flag,
void *data);
void *
memcached_callback_get (memcached_st *ptr,
memcached_callback_t flag,
memcached_return_t *error);
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 have been closed.
MEMCACHED_CALLBACK_CLONE_FUNCTION
When memcached_delete() is called this function will be excuted. At
the point of its execution all connections have been closed.
MEMCACHED_CALLBACK_PREFIX_KEY
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.
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: use memcached_set_memory_allocators instead.
MEMCACHED_CALLBACK_REALLOC_FUNCTION
DEPRECATED: use memcached_set_memory_allocators instead.
MEMCACHED_CALLBACK_FREE_FUNCTION
DEPRECATED: 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 MEMCACHED_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
memcached_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:
<https://launchpad.net/libmemcached>
AUTHOR
Brian Aker, <brian@tangent.org>
SEE ALSO
memcached(1) libmemcached(3) memcached_strerror(3)
2010-01-07 memcached_callback_get.pop(3)