git.m6w6.name Git - awesomized/libmemcached/blob - libmemcached/memcached_auto.rst

   1 Incrementing and Decrementing Values
   2 ====================================
   3
   4 SYNOPSIS
   5 --------
   6
   7 #include <libmemcached/memcached.h>
   8   Compile and link with -lmemcached
   9
  10 .. function:: memcached_return_t memcached_increment (memcached_st *ptr, const char *key, size_t key_length, uint32_t offset, uint64_t *value)
  11
  12 .. function:: memcached_return_t memcached_decrement (memcached_st *ptr, const char *key, size_t key_length, uint32_t offset, uint64_t *value)
  13
  14 .. function:: memcached_return_t memcached_increment_with_initial (memcached_st *ptr, const char *key, size_t key_length, uint64_t offset, uint64_t initial, time_t expiration, uint64_t *value)
  15
  16 .. function:: memcached_return_t memcached_decrement_with_initial (memcached_st *ptr, const char *key, size_t key_length, uint64_t offset, uint64_t initial, time_t expiration, uint64_t *value)
  17
  18 .. function:: memcached_return_t memcached_increment_by_key (memcached_st *ptr, const char *group_key, size_t group_key_length, const char *key, size_t key_length, uint32_t offset, uint64_t *value)
  19
  20 .. function:: memcached_return_t memcached_decrement_by_key (memcached_st *ptr, const char *group_key, size_t group_key_length, const char *key, size_t key_length, uint32_t offset, uint64_t *value)
  21
  22 .. function:: memcached_return_t memcached_increment_with_initial_by_key (memcached_st *ptr, const char *group_key, size_t group_key_length, const char *key, size_t key_length, uint64_t offset, uint64_t initial, time_t expiration, uint64_t *value)
  23
  24 .. function:: memcached_return_t memcached_decrement_with_initial_by_key (memcached_st *ptr, const char *group_key, size_t group_key_length, const char *key, size_t key_length, uint64_t offset, uint64_t initial, time_t expiration, uint64_t *value)
  25
  26     :param ptr: pointer to an initialized `memcached_st` struct
  27     :param group_key: key namespace
  28     :param group_key_length: length of the key namespace without any terminating zero
  29     :param key: the key
  30     :param key_length: length of the key without any terminating zero
  31     :param offset: offset to increment/decrement
  32     :param initial: initial value if `key` does not exist and `expiration` is not `MEMCACHED_EXPIRATION_NOT_ADD`
  33     :param expiration: expiration as a unix timestamp or as relative expiration time in seconds
  34     :param value: the resulting value after initialization/increment/decrement
  35     :returns: `memcached_return_t` indicating success
  36
  37 DESCRIPTION
  38 -----------
  39
  40 :manpage:`memcached(1)` servers have the ability to increment and decrement keys
  41 (overflow and underflow are not detected). This gives you the ability to use
  42 memcached to generate shared sequences of values.
  43
  44 `memcached_increment` takes a ``key`` and ``key_length`` and increments the
  45 value by the ``offset`` passed to it. The value is then returned via the
  46 uint32_t ``value`` pointer you pass to it.
  47
  48 `memcached_decrement` takes a ``key`` and ``key_length`` and decrements the
  49 value by the ``offset`` passed to it. The value is then returned via the
  50 uint32_t ``value`` pointer you pass to it.
  51
  52 `memcached_increment_with_initial` takes a ``key`` and ``key_length`` and
  53 increments the value by the ``offset`` passed to it. If the object specified by
  54 ``key`` does not exist, one of two things may happen: If the ``expiration``
  55 value is :c:macro:`MEMCACHED_EXPIRATION_NOT_ADD`, the operation will fail. For
  56 all other ``expiration`` values, the operation will succeed by seeding the value
  57 for that key with a initial value to expire with the provided expiration time.
  58 The ``flags`` will be set to zero. The value is then returned via the uint32_t
  59 ``value`` pointer you pass to it. ``memcached_increment_with_initial`` is only
  60 available when using the binary protocol.
  61
  62 `memcached_decrement_with_initial` takes a ``key`` and ``key_length`` and
  63 decrements the value by the ``offset`` passed to it. If the object specified by
  64 ``key`` does not exist, one of two things may happen: If the ``expiration``
  65 value is :c:macro:`MEMCACHED_EXPIRATION_NOT_ADD`, the operation will fail. For
  66 all other ``expiration`` values, the operation will succeed by seeding the value
  67 for that key with a initial value to expire with the provided expiration time.
  68 The ``flags`` will be set to zero. The value is then returned via the uint32_t
  69 ``value`` pointer you pass to it. `memcached_decrement_with_initial` is only
  70 available when using the binary protocol.
  71
  72 `memcached_increment_by_key`, `memcached_decrement_by_key`,
  73 `memcached_increment_with_initial_by_key`, and
  74 `memcached_decrement_with_initial_by_key` are master key equivalents of the
  75 above.
  76
  77 RETURN VALUE
  78 ------------
  79
  80 A value of type `memcached_return_t`  is returned.
  81 On success that value will be `MEMCACHED_SUCCESS`.
  82 Use `memcached_strerror` to translate this value to a printable string.
  83
  84 SEE ALSO
  85 --------
  86
  87 .. only:: man
  88
  89     :manpage:`memcached(1)`
  90     :manpage:`libmemcached(3)`
  91     :manpage:`memcached_strerror(3)`
  92
  93 .. only:: html
  94
  95     * :manpage:`memcached(1)`
  96     * :doc:`../libmemcached`
  97     * :doc:`memcached_strerror`