--- name: "memcached_pool_pop" section: "3" platform: "linux" package: "libmemcached-awesome" version: "1.1.4-4" release: "Arch Linux 2026-11-01" platforms: ["linux"] url: "https://new.carta.tech/memcached_pool_pop" --- # memcached\_pool\_pop(3) libmemcached Documentation ## NAME memcached\_pool\_pop - libmemcached Documentation ## SYNOPSIS - **#include \** 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)** - **Parameters** - • **option\_string** -- configuration \<\> string - • **option\_string\_length** -- length of **options\_string** without any trailing zero byte - **Returns** allocated and initialized **memcached\_pool\_st** instance on success or nullptr on failure - **memcached\_st \<#\_CPPv412memcached\_st\> \*memcached\_pool\_destroy(memcached\_pool\_st \*pool)** - **Parameters** **pool** -- initialized **memcached\_pool\_st** instance to free - **Returns** pointer to the 'master' **memcached\_st** \<#\_CPPv412memcached\_st\> instance by legacy - **memcached\_st \<#\_CPPv412memcached\_st\> \*memcached\_pool\_fetch(memcached\_pool\_st \*pool, struct timespec \*relative\_time, memcached\_return\_t \<#\_CPPv418memcached\_return\_t\> \*rc)** Added in version 0.53: Synonym for memcached\_pool\_pop - **Parameters** - • **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** \<#\_CPPv418memcached\_return\_t\> - **Returns** pointer to an available **memcached\_st** \<#\_CPPv412memcached\_st\> instance - **memcached\_return\_t \<#\_CPPv418memcached\_return\_t\> memcached\_pool\_release(memcached\_pool\_st \*pool, memcached\_st \<#\_CPPv412memcached\_st\> \*mmc)** Added in version 0.53: Synonym for memcached\_pool\_push. - **Parameters** - • **pool** -- initialized **memcached\_pool\_st** instance - • **mmc** -- the **memcached\_st** \<#\_CPPv412memcached\_st\> instance to return to the pool - **Returns** **memcached\_return\_t** \<#\_CPPv418memcached\_return\_t\> indicating success - **memcached\_return\_t \<#\_CPPv418memcached\_return\_t\> memcached\_pool\_behavior\_set(memcached\_pool\_st \*pool, memcached\_behavior\_t \<#\_CPPv420memcached\_behavior\_t\> flag, uint64\_t data)** - **Parameters** - • **pool** -- initialized **memcached\_pool\_st** instance - • **flag** -- the behavior \<\> to change - • **value** -- the value to set for **flag** - **Returns** **memcached\_return\_t** \<#\_CPPv418memcached\_return\_t\> indicating success - **memcached\_return\_t \<#\_CPPv418memcached\_return\_t\> memcached\_pool\_behavior\_get(memcached\_pool\_st \*pool, memcached\_behavior\_t \<#\_CPPv420memcached\_behavior\_t\> flag, uint64\_t \*value)** - **Parameters** - • **pool** -- initialized **memcached\_pool\_st** instance - • **flag** -- the behavior \<\> to read - • **value** -- out pointer to receive the set value of **flag** - **Returns** **memcached\_return\_t** \<#\_CPPv418memcached\_return\_t\> indicating success - **memcached\_pool\_st \*memcached\_pool\_create(memcached\_st \<#\_CPPv412memcached\_st\> \*mmc, int initial, int max)** Deprecated since version 0.46: Use **memcached\_pool()** - **memcached\_st \<#\_CPPv412memcached\_st\> \*memcached\_pool\_pop(memcached\_pool\_st \*pool, bool block, memcached\_return\_t \<#\_CPPv418memcached\_return\_t\> \*rc)** Deprecated since version 0.53: Use **memcached\_pool\_fetch()** - **memcached\_return\_t \<#\_CPPv418memcached\_return\_t\> memcached\_pool\_push(memcached\_pool\_st \*pool, memcached\_st \<#\_CPPv412memcached\_st\> \*mmc)** Deprecated since version 0.53: Use **memcached\_pool\_release()** ## DESCRIPTION **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** \<#\_CPPv412memcached\_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** \<#\_CPPv412memcached\_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. ## RETURN VALUE **memcached\_pool\_destroy()** returns the pointer (and ownership) to the **memcached\_st** \<#\_CPPv412memcached\_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** \<#\_CPPv412memcached\_st\> structure from the pool (or NULL if an allocation cannot be satisfied). **memcached\_pool\_release()** returns **MEMCACHED\_SUCCESS** \<#\_CPPv4N18memcached\_return\_t17MEMCACHED\_SUCCESSE\> upon success. **memcached\_pool\_behavior\_get()** and **memcached\_pool\_behavior\_get()** return **MEMCACHED\_SUCCESS** \<#\_CPPv4N18memcached\_return\_t17MEMCACHED\_SUCCESSE\> upon success. **memcached\_pool\_fetch()** may return **MEMCACHED\_TIMEOUT** \<#\_CPPv4N18memcached\_return\_t17MEMCACHED\_TIMEOUTE\> if a timeout occurs while waiting for a free **memcached\_st** \<#\_CPPv412memcached\_st\> instance, **MEMCACHED\_NOTFOUND** \<#\_CPPv4N18memcached\_return\_t18MEMCACHED\_NOTFOUNDE\> if no **memcached\_st** \<#\_CPPv412memcached\_st\> instance was available, respectively. **Note:** 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** \<#\_CPPv4N18memcached\_return\_t27MEMCACHED\_INVALID\_ARGUMENTSE\> will be returned. ## SEE ALSO **[memcached(1)](/memcached/1.md) \** **[libmemcached(3)](/libmemcached/3.md) \** **[libmemcached\_configuration(3)](/libmemcached_configuration/3.md) \** **[memcached\_strerror(3)](/memcached_strerror/3.md) \**