--- name: "libmemcached_configuration" 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/libmemcached_configuration" --- # libmemcached\_configuration(3) libmemcached Documentation ## NAME libmemcached\_configuration - libmemcached Documentation ## SYNOPSIS - **#include \** Compile and link with -lmemcached - **memcached\_st \<#\_CPPv412memcached\_st\> \*memcached(const char \*string, size\_t string\_length)** - **Parameters** - • **string** -- configuration string - • **string\_length** -- length of the configuration string without any terminating zero - **Returns** allocated and initialized **memcached\_st** \<#\_CPPv412memcached\_st\> struct - **memcached\_return\_t \<#\_CPPv418memcached\_return\_t\> libmemcached\_check\_configuration(const char \*option\_string, size\_t length, char \*error\_buffer, size\_t error\_buffer\_size)** - **Parameters** - • **option\_string** -- configuration string - • **length** -- length of the configuration string without any terminating zero - • **error\_buffer** -- buffer used to store any error message - • **error\_buffer\_size** -- available size of the **error\_buffer** - **Returns** **memcached\_return\_t** \<#\_CPPv418memcached\_return\_t\> indicating success ## DESCRIPTION **libmemcached** implements a custom language for configuring and modifying servers. By passing in an option string you can generate a **memcached\_st** \<#\_CPPv412memcached\_st\> object that you can use in your application directly. ### General Options: - **--SERVER=\:\/?\** Provide a servername to be used by the client. Providing a weight will cause weighting to occur with all hosts with each server getting a default weight of 1. - **--SOCKET=\\"\/?\\\"** Provide a filepath to a UNIX socket file. Providing a weight will cause weighting to occur with all hosts with each server getting a default weight of 1. - **--VERIFY-KEY** Verify that keys that are being used fit within the design of the protocol being used. - **--REMOVE\_FAILED\_SERVERS** Enable the behavior **MEMCACHED\_BEHAVIOR\_REMOVE\_FAILED\_SERVERS** \<#\_CPPv4N20memcached\_behavior\_t40MEMCACHED\_BEHAVIOR\_REMOVE\_FAILED\_SERVERSE\>. - **--BINARY-PROTOCOL** Force all connections to use the binary protocol. - **--BUFFER-REQUESTS** Please see **MEMCACHED\_BEHAVIOR\_BUFFER\_REQUESTS** \<#\_CPPv4N20memcached\_behavior\_t34MEMCACHED\_BEHAVIOR\_BUFFER\_REQUESTSE\>. - **--CONFIGURE-FILE=** Provide a configuration file to be used to load requests. Beware that by using a configuration file **libmemcached** will reset **memcached\_st** \<#\_CPPv412memcached\_st\> based on information only contained in the file. - **--CONNECT-TIMEOUT=** See **memcached\_behavior\_set()** \<#\_CPPv422memcached\_behavior\_setP12memcached\_st20memcached\_behavior\_t8uint64\_t\> for **MEMCACHED\_BEHAVIOR\_CONNECT\_TIMEOUT** \<#\_CPPv4N20memcached\_behavior\_t34MEMCACHED\_BEHAVIOR\_CONNECT\_TIMEOUTE\>. - **--DISTRIBUTION=** Set the distribution model used by the client. See **memcached\_behavior\_set()** \<#\_CPPv422memcached\_behavior\_setP12memcached\_st20memcached\_behavior\_t8uint64\_t\> for more details. - **--HASH=** Set the hashing algorithm used for placing keys on servers. - **--HASH-WITH-NAMESPACE** When enabled the prefix key will be added to the key when determining which server to store the data in. - **--NOREPLY** Enable "no reply" for all calls that support this. It is highly recommended that you use this option with the binary protocol only. - **--NUMBER-OF-REPLICAS=** Set the number of servers that keys will be replicated to. - **--RANDOMIZE-REPLICA-READ** Select randomly the server within the replication pool to read from. - **--SORT-HOSTS** When adding new servers always calculate their distribution based on sorted naming order. - **--SUPPORT-CAS** See **memcached\_behavior\_set()** \<#\_CPPv422memcached\_behavior\_setP12memcached\_st20memcached\_behavior\_t8uint64\_t\> for **MEMCACHED\_BEHAVIOR\_SUPPORT\_CAS** \<#\_CPPv4N20memcached\_behavior\_t30MEMCACHED\_BEHAVIOR\_SUPPORT\_CASE\> - **--USE-UDP** See **memcached\_behavior\_set()** \<#\_CPPv422memcached\_behavior\_setP12memcached\_st20memcached\_behavior\_t8uint64\_t\> for **MEMCACHED\_BEHAVIOR\_USE\_UDP** \<#\_CPPv4N20memcached\_behavior\_t26MEMCACHED\_BEHAVIOR\_USE\_UDPE\> - **--NAMESPACE=** A namespace is a container that provides context for keys, only other requests that know the namespace can access these values. This is accomplished by prepending the namespace value to all keys. ### Memcached Pool Options: - **--POOL-MIN** Initial size of pool. - **--POOL-MAX** Maximize size of the pool. ### I/O Options: - **--TCP-NODELAY** See **memcached\_behavior\_set()** \<#\_CPPv422memcached\_behavior\_setP12memcached\_st20memcached\_behavior\_t8uint64\_t\> for **MEMCACHED\_BEHAVIOR\_TCP\_NODELAY** \<#\_CPPv4N20memcached\_behavior\_t30MEMCACHED\_BEHAVIOR\_TCP\_NODELAYE\> - **--TCP-KEEPALIVE** See **memcached\_behavior\_set()** \<#\_CPPv422memcached\_behavior\_setP12memcached\_st20memcached\_behavior\_t8uint64\_t\> for **MEMCACHED\_BEHAVIOR\_TCP\_KEEPALIVE** - **--RETRY-TIMEOUT=** See **memcached\_behavior\_set()** \<#\_CPPv422memcached\_behavior\_setP12memcached\_st20memcached\_behavior\_t8uint64\_t\> for **MEMCACHED\_BEHAVIOR\_RETRY\_TIMEOUT** \<#\_CPPv4N20memcached\_behavior\_t32MEMCACHED\_BEHAVIOR\_RETRY\_TIMEOUTE\> - **--SERVER-FAILURE-LIMIT=** See **memcached\_behavior\_set()** \<#\_CPPv422memcached\_behavior\_setP12memcached\_st20memcached\_behavior\_t8uint64\_t\> for **MEMCACHED\_BEHAVIOR\_SERVER\_FAILURE\_LIMIT** \<#\_CPPv4N20memcached\_behavior\_t39MEMCACHED\_BEHAVIOR\_SERVER\_FAILURE\_LIMITE\> - **--SND-TIMEOUT=** See **memcached\_behavior\_set()** \<#\_CPPv422memcached\_behavior\_setP12memcached\_st20memcached\_behavior\_t8uint64\_t\> for **MEMCACHED\_BEHAVIOR\_SND\_TIMEOUT** \<#\_CPPv4N20memcached\_behavior\_t30MEMCACHED\_BEHAVIOR\_SND\_TIMEOUTE\> - **--SOCKET-RECV-SIZE=** See **memcached\_behavior\_set()** \<#\_CPPv422memcached\_behavior\_setP12memcached\_st20memcached\_behavior\_t8uint64\_t\> for **MEMCACHED\_BEHAVIOR\_SOCKET\_RECV\_SIZE** \<#\_CPPv4N20memcached\_behavior\_t35MEMCACHED\_BEHAVIOR\_SOCKET\_RECV\_SIZEE\> - **--SOCKET-SEND-SIZE=** See **memcached\_behavior\_set()** \<#\_CPPv422memcached\_behavior\_setP12memcached\_st20memcached\_behavior\_t8uint64\_t\> for **MEMCACHED\_BEHAVIOR\_SOCKET\_SEND\_SIZE** \<#\_CPPv4N20memcached\_behavior\_t35MEMCACHED\_BEHAVIOR\_SOCKET\_SEND\_SIZEE\> - **--POLL-TIMEOUT=** Set the timeout used by **poll(3) \**. - **--IO-BYTES-WATERMARK=** - **--IO-KEY-PREFETCH=** - **--IO-MSG-WATERMARK=** - **--TCP-KEEPIDLE** - **--RCV-TIMEOUT=** ### Other Options: - **INCLUDE** Include a file in configuration. Unlike **--CONFIGURE-FILE=** this will not reset **memcached\_st** \<#\_CPPv412memcached\_st\>. - **RESET** Reset **memcached\_st** \<#\_CPPv412memcached\_st\> and continue to process. - **END** End configuration processing. - **ERROR** End configuration processing and throw an error. ## ENVIRONMENT - **LIBMEMCACHED** ## RETURN VALUE **memcached()** returns a pointer to the **memcached\_st** \<#\_CPPv412memcached\_st\> that was created (or initialized). On an allocation failure, it returns NULL. ## EXAMPLE ``` const char *config_string= "--SERVER=host10.example.com " "--SERVER=host11.example.com " "--SERVER=host10.example.com"; memcached_st *memc= memcached(config_string, strlen(config_string)); { // ... } memcached_free(memc); ``` ## SEE ALSO **[memcached(1)](/memcached/1.md) \** **[libmemcached(3)](/libmemcached/3.md) \** **[memcached\_strerror(3)](/memcached_strerror/3.md) \**