Working with memcached pools


#include <libmemcachedutil-1.0/pool.h>
Compile and link with -lmemcachedutil -lmemcached
typedef struct memcached_pool_st memcached_pool_st
memcached_pool_st *memcached_pool(const char *option_string, size_t option_string_length)
  • option_string -- configuration string
  • option_string_length -- length of options_string without any trailing zero byte

allocated and initialized memcached_pool_st instance on success or nullptr on failure

memcached_st *memcached_pool_destroy(memcached_pool_st *pool)
Parameters:pool -- initialized memcached_pool_st instance to free
Returns:pointer to the 'master' memcached_st instance by legacy
memcached_st *memcached_pool_fetch(memcached_pool_st *pool, struct timespec *relative_time, memcached_return_t *rc)

New in version 0.53: Synonym for memcached_pool_pop

  • pool -- initialized memcached_pool_st instance
  • relative_time -- time to block thread and wait for a connection to become available when pool size is exceeded, unless nullptr
  • rc -- out pointer to memcached_return_t

pointer to an available memcached_st instance

memcached_return_t memcached_pool_release(memcached_pool_st *pool, memcached_st *mmc)

New in version 0.53: Synonym for memcached_pool_push.


memcached_return_t indicating success

memcached_return_t memcached_pool_behavior_set(memcached_pool_st *pool, memcached_behavior_t flag, uint64_t data)

memcached_return_t indicating success

memcached_return_t memcached_pool_behavior_get(memcached_pool_st *pool, memcached_behavior_t flag, uint64_t *value)

memcached_return_t indicating success

memcached_pool_st *memcached_pool_create(memcached_st *mmc, int initial, int max)

Deprecated since version 0.46: Use memcached_pool()

memcached_st *memcached_pool_pop(memcached_pool_st *pool, bool block, memcached_return_t *rc)

Deprecated since version 0.53: Use memcached_pool_fetch()

memcached_return_t memcached_pool_push(memcached_pool_st *pool, memcached_st *mmc)

Deprecated since version 0.53: Use memcached_pool_release()


memcached_pool() is used to create a connection pool of objects you may use to remove the overhead of using memcached_clone for short lived memcached_st objects. Please see libmemcached Configuration for details on the format of the configuration string.

memcached_pool_destroy() is used to destroy the connection pool created with memcached_pool_create() and release all allocated resources. It will return the pointer to the memcached_st structure passed as an argument to memcached_pool_create(), and returns the ownership of the pointer to the caller when created with memcached_pool_create(), otherwise NULL is returned..

memcached_pool_fetch() is used to fetch a connection structure from the connection pool. The relative_time argument specifies if the function should block and wait for a connection structure to be available if we try to exceed the maximum size. You need to specify time in relative time.

memcached_pool_release() is used to return a connection structure back to the pool.

memcached_pool_behavior_get() and memcached_pool_behavior_set() is used to get/set behavior flags on all connections in the pool.

Both memcached_pool_release() and memcached_pool_fetch() are thread safe.


memcached_pool_destroy() returns the pointer (and ownership) to the memcached_st structure used to create the pool. If connections are in use it returns NULL.

memcached_pool_pop() returns a pointer to a memcached_st structure from the pool (or NULL if an allocation cannot be satisfied).

memcached_pool_release() returns MEMCACHED_SUCCESS upon success.

memcached_pool_behavior_get() and memcached_pool_behavior_get() return MEMCACHED_SUCCESS upon success.

memcached_pool_fetch() may return MEMCACHED_TIMEOUT if a timeout occurs while waiting for a free memcached_st instance, MEMCACHED_NOTFOUND if no memcached_st instance was available, respectively.


If any method returns MEMCACHED_IN_PROGRESS then a lock on the pool could not be obtained.

If any of the parameters passed to any of these functions is invalid, MEMCACHED_INVALID_ARGUMENTS will be returned.