git.m6w6.name Git - awesomized/libmemcached/blob - docs/source/libmemcached/memcached_result_st.rst

   1 ========================
   2 Working with result sets
   3 ========================
   4
   5 --------
   6 SYNOPSIS
   7 --------
   8
   9 #include <libmemcached/memcached_pool.h>
  10
  11 .. type:: memcached_result_st
  12
  13 .. function:: memcached_result_st * memcached_result_create (memcached_st *ptr, memcached_result_st *result)
  14
  15 .. function:: void memcached_result_free (memcached_result_st *result)
  16
  17 .. function:: const char * memcached_result_key_value (memcached_result_st *result)
  18
  19 .. function:: size_t memcached_result_key_length (const memcached_result_st *result)
  20
  21 .. function:: const char *memcached_result_value (memcached_result_st *ptr)
  22
  23 .. function:: char *memcached_result_take_value (memcached_result_st *ptr)
  24
  25 .. function:: size_t memcached_result_length (const memcached_result_st *ptr)
  26
  27 .. function:: uint32_t memcached_result_flags (const memcached_result_st *result)
  28
  29 .. function:: uint64_t memcached_result_cas (const memcached_result_st *result)
  30
  31 .. function:: memcached_return_t memcached_result_set_value (memcached_result_st *ptr, const char *value, size_t length)
  32
  33 .. function:: void memcached_result_set_flags (memcached_result_st *ptr, uint32_t flags)
  34
  35 .. function:: void memcached_result_set_expiration (memcached_result_st *ptr, time_t)
  36
  37 Compile and link with -lmemcachedutil -lmemcached
  38
  39 -----------
  40 DESCRIPTION
  41 -----------
  42
  43 libmemcached(3) can optionally return a :type:`memcached_result_st` which
  44 acts as a result object. The result objects have added benefits over the
  45 character pointer returns, in that they are forward compatible with new
  46 return items that future memcached servers may implement (the best current
  47 example of this is the CAS return item). The structures can also be reused,
  48 which will save on calls to malloc(3). It is suggested that you use result
  49 objects over char \* return functions.
  50
  51 The structure of :type:`memcached_result_st` has been encapsulated, you should
  52 not write code to directly access members of the structure.
  53
  54 :func:`memcached_result_create` will either allocate memory for a
  55 :type:`memcached_result_st` or will initialize a structure passed to it.
  56
  57 :func:`memcached_result_free` will deallocate any memory attached to the
  58 structure. If the structure was also allocated, it will deallocate it.
  59
  60 :func:`memcached_result_key_value` returns the key value associated with the
  61 current result object.
  62
  63 :func:`memcached_result_key_length` returns the key length associated with
  64 the current result object.
  65
  66 :func:`memcached_result_value` returns the result value associated with the
  67 current result object.
  68
  69 :func:`memcached_result_take_value` returns and hands over the result value
  70 associated with the current result object. You must call free() to release this
  71 value, unless you have made use of a custom allocator. Use of a custom
  72 allocator requires that you create your own custom free() to release it.
  73
  74 :func:`memcached_result_length` returns the result length associated with
  75 the current result object.
  76
  77 :func:`memcached_result_flags` returns the flags associated with the
  78 current result object.
  79
  80 :func:`memcached_result_cas` returns the cas associated with the
  81 current result object. This value will only be available if the server
  82 tests it.
  83
  84 :func:`memcached_result_set_value` takes a byte array and a size and sets
  85 the result to this value. This function is used for trigger responses.
  86
  87 :func:`memcached_result_set_flags` takes a result structure and stores a new
  88 value for the flags field.
  89
  90 :func:`memcached_result_set_expiration` takes a result structure and stores
  91 a new value for the expiration field (this is only used by read through
  92 triggers).
  93
  94 You may wish to avoid using memcached_result_create(3) with a
  95 stack based allocation. The most common issues related to ABI safety involve
  96 heap allocated structures.
  97
  98 ------
  99 RETURN
 100 ------
 101
 102 Varies, see particular functions. All structures must have
 103 :func:`memcached_result_free` called on them for cleanup purposes. Failure
 104 to do this will result in leaked memory.
 105
 106 --------
 107 SEE ALSO
 108 --------
 109
 110 .. only:: man
 111
 112   :manpage:`memcached(1)` :manpage:`libmemcached(3)` :manpage:`memcached_strerror(3)`