git.m6w6.name Git - m6w6/libmemcached/blob - docs/memcached_get.pod

   1 =head1 NAME
   2
   3 memcached_get, memcached_mget, memcached_fetch
   4
   5 =head1 LIBRARY
   6
   7 C Client Library for memcached (libmemcached, -lmemcached)
   8
   9 =head1 SYNOPSIS
  10
  11   #include <memcached.h>
  12
  13   memcached_result_st *
  14   memcached_fetch_result(memcached_st *ptr,
  15                        memcached_result_st *result,
  16                        memcached_return *error);
  17
  18   char *memcached_get (memcached_st *ptr,
  19                        char *key, size_t key_length,
  20                        size_t *value_length,
  21                        uint16_t *flags,
  22                        memcached_return *error);
  23
  24   memcached_return
  25   memcached_mget (memcached_st *ptr,
  26                   char **keys, size_t *key_length,
  27                   unsigned int number_of_keys);
  28   char *
  29   memcached_get_by_key(memcached_st *ptr,
  30                        char *master_key, size_t master_key_length,
  31                        char *key, size_t key_length,
  32                        size_t *value_length,
  33                        uint16_t *flags,
  34                        memcached_return *error);
  35
  36   memcached_return
  37   memcached_mget_by_key(memcached_st *ptr,
  38                         char *master_key, size_t master_key_length,
  39                         char **keys, size_t *key_length,
  40                         unsigned int number_of_keys);
  41
  42   char *memcached_fetch (memcached_st *ptr,
  43                          char *key, size_t *key_length,
  44                          size_t *value_length,
  45                          uint16_t *flags,
  46                          memcached_return *error);
  47
  48 =head1 DESCRIPTION
  49
  50 memcached_get() is used to fetch an individual value from the server. You
  51 must pass in a key and its length to fetch the object. You must supply
  52 three pointer variables which will give you the state of the returned
  53 object.  A uint16_t pointer to contain whatever flags you stored with the value,
  54 a size_t pointer which will be filled with size of of the object, and a
  55 memcached_return pointer to hold any error. The object will be returned
  56 upon success and NULL will be returned on failure.
  57
  58 memcached_mget() is used to select multiple keys at once. For multiple key
  59 operations it is always faster to use this function. This function always
  60 works asynchronously. memcached_fetch() is then used to retrieve any keys
  61 found. No error is given on keys that are not found. You must call either
  62 memcached_fetch() or memcached_fetch_result() after a successful call to
  63 memcached_mget(). You should continue to call these functions until they
  64 return NULL (aka no more values). If you need to quit in the middle of a
  65 memcached_get() call, execute a memcached_quit(). After you do this, you can
  66 issue new queries against the server.
  67
  68 memcached_fetch() is used to fetch an individual value from the server.
  69 memcached_mget() must always be called before using this method.  You
  70 must pass in a key and its length to fetch the object. You must supply
  71 three pointer variables which will give you the state of the returned
  72 object.  A uint16_t pointer to contain whatever flags you stored with the value,
  73 a size_t pointer which will be filled with size of of the object, and a
  74 memcached_return pointer to hold any error. The object will be returned
  75 upon success and NULL will be returned on failure.
  76
  77 memcached_fetch_result() is used to return a memcached_result_st(3) structure
  78 from a memcached server. The result object is forward compatible with changes
  79 to the server. For more information please refer to the memcached_result_st(3)
  80 help. This function will dynamically allocate a result structure for you
  81 if you do not pass one to the function.
  82
  83 memcached_get_by_key() and memcached_mget_by_key() behave in a similar nature
  84 as memcached_get() and memcached_mget(). The difference is that they take
  85 a master key that is used for determining which server an object was stored
  86 if key partitioning was used for storage.
  87
  88 =head1 RETURN
  89
  90 All objects returned must be freed by the calling application.
  91 memcached_get() and memcached_fetch() will return NULL on error. You must
  92 look at the value of error to determine what the actual error was.
  93
  94 =head1 HOME
  95
  96 To find out more information please check:
  97 L<http://tangent.org/552/libmemcached.html>
  98
  99 =head1 AUTHOR
 100
 101 Brian Aker, E<lt>brian@tangent.orgE<gt>
 102
 103 =head1 SEE ALSO
 104
 105 memcached(1) libmemcached(3) memcached_strerror(3)
 106
 107 =cut
 108