X-Git-Url: https://git.m6w6.name/?a=blobdiff_plain;f=docs%2Fmemcached_get.pod;h=5faa2db9767107fb014917476ffcec3594f32506;hb=3430cb015fb0add207ff733f484dbb4a9fed3655;hp=1c95ec38ca22d3ce32234d52199fb09797987033;hpb=7d9255c986d5e9a395bd510ca7b01519736f33e1;p=m6w6%2Flibmemcached diff --git a/docs/memcached_get.pod b/docs/memcached_get.pod old mode 100755 new mode 100644 index 1c95ec38..5faa2db9 --- a/docs/memcached_get.pod +++ b/docs/memcached_get.pod @@ -1,6 +1,7 @@ =head1 NAME -memcached_get, memcached_mget, memcached_fetch +memcached_get, memcached_mget, memcached_fetch, memcached_mget_execute, +memcached_mget_execute_by_key - Get a value =head1 LIBRARY @@ -10,46 +11,144 @@ C Client Library for memcached (libmemcached, -lmemcached) #include - char *memcached_get (memcached_st *ptr, - char *key, size_t key_length, - size_t *value_length, - uint16_t *flags, - memcached_return *error); + memcached_result_st * + memcached_fetch_result (memcached_st *ptr, + memcached_result_st *result, + memcached_return_t *error); + + char * + memcached_get (memcached_st *ptr, + const char *key, size_t key_length, + size_t *value_length, + uint32_t *flags, + memcached_return_t *error); + + memcached_return_t + memcached_mget (memcached_st *ptr, + const char * const *keys, + const size_t *key_length, + size_t number_of_keys); + char * + memcached_get_by_key (memcached_st *ptr, + const char *master_key, size_t master_key_length, + const char *key, size_t key_length, + size_t *value_length, + uint32_t *flags, + memcached_return_t *error); + + memcached_return_t + memcached_mget_by_key (memcached_st *ptr, + const char *master_key, size_t master_key_length, + const char * const *keys, + const size_t *key_length, + size_t number_of_keys); + + char * + memcached_fetch (memcached_st *ptr, + char *key, size_t *key_length, + size_t *value_length, + uint32_t *flags, + memcached_return_t *error); + + memcached_return_t + memcached_fetch_execute (memcached_st *ptr, + memcached_execute_fn *callback, + void *context, + uint32_t number_of_callbacks); + + + memcached_return_t + memcached_mget_execute (memcached_st *ptr, + const char * const *keys, + const size_t *key_length, + size_t number_of_keys, + memcached_execute_fn *callback, + void *context, + uint32_t number_of_callbacks); + + memcached_return_t + memcached_mget_execute_by_key (memcached_st *ptr, + const char *master_key, + size_t master_key_length, + const char * const *keys, + const size_t *key_length, + size_t number_of_keys, + memcached_execute_fn *callback, + void *context, + uint32_t number_of_callbacks); - memcached_return - memcached_mget (memcached_st *ptr, - char **keys, size_t *key_length, - unsigned int number_of_keys); - - char *memcached_fetch (memcached_st *ptr, - char *key, size_t *key_length, - size_t *value_length, - uint16_t *flags, - memcached_return *error); =head1 DESCRIPTION memcached_get() is used to fetch an individual value from the server. You must pass in a key and its length to fetch the object. You must supply three pointer variables which will give you the state of the returned -object. A uint16_t pointer to contain whatever flags you stored with the value, +object. A uint32_t pointer to contain whatever flags you stored with the value, a size_t pointer which will be filled with size of of the object, and a -memcached_return pointer to hold any error. The object will be returned -upon success and NULL will be returned on failure. +memcached_return_t pointer to hold any error. The object will be returned +upon success and NULL will be returned on failure. Any object returned by +memcached_get() must be released by the caller application. memcached_mget() is used to select multiple keys at once. For multiple key operations it is always faster to use this function. This function always works asynchronously. memcached_fetch() is then used to retrieve any keys -found. No error is given on keys that are not found. - -memcached_fetch() is used to fetch an individual value from the server. +found. No error is given on keys that are not found. You must call either +memcached_fetch() or memcached_fetch_result() after a successful call to +memcached_mget(). You should continue to call these functions until they +return NULL (aka no more values). If you need to quit in the middle of a +memcached_get() call, execute a memcached_quit(). After you do this, you can +issue new queries against the server. + +memcached_fetch() is used to fetch an individual value from the server. memcached_mget() must always be called before using this method. You must pass in a key and its length to fetch the object. You must supply three pointer variables which will give you the state of the returned -object. A uint16_t pointer to contain whatever flags you stored with the value, +object. A uint32_t pointer to contain whatever flags you stored with the value, a size_t pointer which will be filled with size of of the object, and a -memcached_return pointer to hold any error. The object will be returned -upon success and NULL will be returned on failure. +memcached_return_t pointer to hold any error. The object will be returned +upon success and NULL will be returned on failure. MEMCACHD_END is returned +by the *error value when all objects that have been found are returned. +The final value upon MEMCACHED_END is null. Values returned by +memcached_fetch() musted be free'ed by the caller. memcached_fetch() will +be DEPRECATED in the near future, memcached_fetch_result() should be used +instead. + +memcached_fetch_result() is used to return a memcached_result_st(3) structure +from a memcached server. The result object is forward compatible with changes +to the server. For more information please refer to the memcached_result_st(3) +help. This function will dynamically allocate a result structure for you +if you do not pass one to the function. + +memcached_fetch_execute() is a callback function for result sets. Instead +of returning the results to you for processing, it passes each of the +result sets to the list of functions you provide. It passes to the function +a memcached_st that can be cloned for use in the called function (it can not +be used directly). It also passes a result set which does not need to be freed. +Finally it passes a "context". This is just a pointer to a memory reference +you supply the calling function. Currently only one value is being passed +to each function call. In the future there will be an option to allow this +to be an array. + +memcached_mget_execute() and memcached_mget_execute_by_key() is +similar to memcached_mget(), but it may trigger the supplied callbacks +with result sets while sending out the queries. If you try to perform +a really large multiget with memcached_mget() you may encounter a +deadlock in the OS kernel (we fail to write data to the socket because +the input buffer is full). memcached_mget_execute() solves this +problem by processing some of the results before continuing sending +out requests. Please note that this function is only available in the +binary protocol. + +memcached_get_by_key() and memcached_mget_by_key() behave in a similar nature +as memcached_get() and memcached_mget(). The difference is that they take +a master key that is used for determining which server an object was stored +if key partitioning was used for storage. + +All of the above functions are not supported when the C +has been set. Executing any of these functions with this behavior on will result in +C being returned or, for those functions which do not return +a C, the error function parameter will be set to +C. =head1 RETURN @@ -57,10 +156,14 @@ All objects returned must be freed by the calling application. memcached_get() and memcached_fetch() will return NULL on error. You must look at the value of error to determine what the actual error was. +MEMCACHED_KEY_TOO_BIG is set to error whenever memcached_fetch() was used +and the key was set larger then MEMCACHED_MAX_KEY, which was the largest +key allowed for the original memcached ascii server. + =head1 HOME To find out more information please check: -L +L =head1 AUTHOR