The set-related functions within
libmemcached provide the same functionality
as the core functions supported by the
memcached protocol. The full definition for
the different functions is the same for all the base functions
(add, replace,
prepend, append). For
example, the function definition for
memcached_set() is:
memcached_return
memcached_set (memcached_st *ptr,
const char *key,
size_t key_length,
const char *value,
size_t value_length,
time_t expiration,
uint32_t flags);
The ptr is the
memcached_st structure. The
key and key_length
define the key name and length, and value
and value_length the corresponding value
and length. You can also set the expiration and optional
flags. For more information, see
Section 3.3.3.5, “Controlling libmemcached Behaviors”.
This table outlines the remainder of the set-related
libmemcached functions and the equivalent
core functions supported by the memcached
protocol.
libmemcached Function | Equivalent Core Function |
|---|---|
memcached_set(memc, key, key_length, value, value_length,
expiration, flags) | Generic set() operation. |
memcached_add(memc, key, key_length, value, value_length,
expiration, flags) | Generic add() function. |
memcached_replace(memc, key, key_length, value, value_length,
expiration, flags) | Generic replace(). |
memcached_prepend(memc, key, key_length, value, value_length,
expiration, flags) | Prepends the specified value before the current value
of the specified key. |
memcached_append(memc, key, key_length, value, value_length,
expiration, flags) | Appends the specified value after the current value
of the specified key. |
memcached_cas(memc, key, key_length, value, value_length,
expiration, flags, cas) | Overwrites the data for a given key as long as the corresponding
cas value is still the same within
the server. |
memcached_set_by_key(memc, master_key, master_key_length, key,
key_length, value, value_length, expiration,
flags) | Similar to the generic set(), but has the option of
an additional master key that can be used to identify
an individual server. |
memcached_add_by_key(memc, master_key, master_key_length, key,
key_length, value, value_length, expiration,
flags) | Similar to the generic add(), but has the option of
an additional master key that can be used to identify
an individual server. |
memcached_replace_by_key(memc, master_key, master_key_length,
key, key_length, value, value_length, expiration,
flags) | Similar to the generic replace(), but has the option
of an additional master key that can be used to
identify an individual server. |
memcached_prepend_by_key(memc, master_key, master_key_length,
key, key_length, value, value_length, expiration,
flags) | Similar to the memcached_prepend(), but has the
option of an additional master key that can be used to
identify an individual server. |
memcached_append_by_key(memc, master_key, master_key_length,
key, key_length, value, value_length, expiration,
flags) | Similar to the memcached_append(), but has the option
of an additional master key that can be used to
identify an individual server. |
memcached_cas_by_key(memc, master_key, master_key_length, key,
key_length, value, value_length, expiration,
flags) | Similar to the memcached_cas(), but has the option of
an additional master key that can be used to identify
an individual server. |
The by_key methods add two further
arguments that define the master key, to be used and applied
during the hashing stage for selecting the servers. You can
see this in the following definition:
memcached_return
memcached_set_by_key(memcached_st *ptr,
const char *master_key,
size_t master_key_length,
const char *key,
size_t key_length,
const char *value,
size_t value_length,
time_t expiration,
uint32_t flags);
All the functions return a value of type
memcached_return, which you can compare
against the MEMCACHED_SUCCESS constant.
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