Managing the servers used by memcached_st

SYNOPSIS

#include <libmemcached/memcached.h>
Compile and link with -lmemcached
uint32_t memcached_server_count(memcached_st *ptr)
Parameters:ptr -- pointer to initialized memcached_st struct
Returns:number of configured servers
memcached_return_t memcached_server_add(memcached_st *ptr, const char *hostname, in_port_t port)
Parameters:
  • ptr -- pointer to initialized memcached_st struct
  • hostname -- hostname or IP address of the TCP server to add
  • port -- port of the TCP server
Returns:

memcached_return_t indicating success
memcached_return_t memcached_server_add_udp(memcached_st *ptr, const char *hostname, in_port_t port)
Parameters:
  • ptr -- pointer to initialized memcached_st struct
  • hostname -- hostname or IP address of the UDP server to add
  • port -- port of the UDP server
Returns:

memcached_return_t indicating success
memcached_return_t memcached_server_add_unix_socket(memcached_st *ptr, const char *socket)
Parameters:
  • ptr -- pointer to initialized memcached_st struct
  • socket -- path to the UNIX socket of the server to add
Returns:

memcached_return_t indicating success
memcached_return_t memcached_server_push(memcached_st *ptr, const memcached_server_st *list)
Parameters:
  • ptr -- pointer to initialized memcached_st struct
  • list -- pre-configured list of servers to push
Returns:

memcached_return_t indicating success
const memcached_instance_st *memcached_server_by_key(memcached_st *ptr, const char *key, size_t key_length, memcached_return_t *error)
Parameters:
  • ptr -- pointer to initialized memcached_st struct
  • key -- key to hash and lookup a server
  • key_length -- length of key without any terminating zero
  • error -- pointer to memcached_return_t indicating success
Returns:

the server instance to be used for storing/retrieving key
const memcached_instance_st *memcached_server_get_last_disconnect(const memcached_st *ptr)
Parameters:ptr -- pointer to initialized memcached_st struct
Returns:the instance of the last server for which there was a connection problem
memcached_return_t memcached_server_cursor(const memcached_st *ptr, const memcached_server_fn *callback, void *context, uint32_t number_of_callbacks)
Parameters:
  • ptr -- pointer to initialized memcached_st struct
  • callback -- list of memcached_server_fn to be called for each server instance
  • context -- pointer to user supplied context for the callback
  • number_of_callbacks -- number of callbacks supplied
Returns:

memcached_return_t indicating success
typedef memcached_return_t (*memcached_server_fn)(const memcached_st *ptr, const memcached_instance_st *server, void *context)
Parameters:
  • ptr -- pointer to the memcached_st struct
  • server -- pointer to memcached_instance_st
  • context -- pointer to user supplied context
Returns:

memcached_return_t indicating success

DESCRIPTION

libmemcached performs operations on a list of hosts. The order of these hosts determine routing to keys. Functions are provided to add keys to memcached_st structures. To manipulate lists of servers see memcached_server_st.

memcached_server_count() provides you a count of the current number of servers being used by a memcached_st structure.

memcached_server_add() pushes a single TCP server into the memcached_st structure. This server will be placed at the end. Duplicate servers are allowed, so duplication is not checked. Executing this function with the MEMCACHED_BEHAVIOR_USE_UDP behavior set will result in a MEMCACHED_INVALID_HOST_PROTOCOL.

memcached_server_add_udp() pushes a single UDP server into the memcached_st structure. This server will be placed at the end. Duplicate servers are allowed, so duplication is not checked. Executing this function without setting the MEMCACHED_BEHAVIOR_USE_UDP behavior will result in a MEMCACHED_INVALID_HOST_PROTOCOL.

memcached_server_add_unix_socket() pushes a single UNIX socket into the memcached_st structure. This UNIX socket will be placed at the end. Duplicate servers are allowed, so duplication is not checked. The length of the filename must be one character less than MEMCACHED_MAX_HOST_LENGTH.

memcached_server_push() pushes an array of memcached_server_st into the memcached_st structure. These servers will be placed at the end. Duplicate servers are allowed, so duplication is not checked. A copy is made of structure so the list provided (and any operations on the list) are not saved.

memcached_server_by_key() allows you to provide a key and retrieve the server which would be used for assignment.

memcached_server_get_last_disconnect() returns a pointer to the last server for which there was a connection problem. It does not mean this particular server is currently dead but if the library is reporting a server is, the returned server is a very good candidate.

memcached_server_cursor() takes a memcached_st and loops through the list of hosts currently in the cursor calling the list of callback functions provided. You can optionally pass in a value via context which will be provided to each callback function. An error return from any callback will terminate the loop. memcached_server_cursor() is passed the original caller memcached_st in its current state.

RETURN VALUE

Varies, see particular functions.