memcached_prepend_by_key(3)

1MEMCACHED_PREPEND_BY_KEY(3)  libmemcached-awesome  MEMCACHED_PREPEND_BY_KEY(3)
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NAME

6       memcached_prepend_by_key - Appending to or Prepending Data
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SYNOPSIS

9       #include <libmemcached-1.0/memcached.h>
10              Compile and link with -lmemcached
11
12       memcached_return_t   memcached_prepend(memcached_st  *ptr,  const  char
13       *key, size_t key_length, const char *value, size_t value_length, time_t
14       expiration, uint32_t flags)
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16       memcached_return_t memcached_append(memcached_st *ptr, const char *key,
17       size_t key_length, const char *value, size_t value_length, time_t expi‐
18       ration, uint32_t flags)
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20       memcached_return_t  memcached_prepend_by_key(memcached_st  *ptr,  const
21       char *group_key,  size_t  group_key_length,  const  char  *key,  size_t
22       key_length,  const char *value, size_t value_length, time_t expiration,
23       uint32_t flags)
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25       memcached_return_t  memcached_append_by_key(memcached_st  *ptr,   const
26       char  *group_key,  size_t  group_key_length,  const  char  *key, size_t
27       key_length, const char *value, size_t value_length, time_t  expiration,
28       uint32_t flags)
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30              Parameters
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32                     • ptr -- pointer to an initialized memcached_st struct
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34                     • group_key -- key namespace
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36                     • group_key_length -- length of the key namespace without
37                       any terminating zero
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39                     • key -- the key
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41                     • key_length -- length of the key without any terminating
42                       zero
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44                     • value -- the value to append/prepend
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46                     • value_length  --  the  length  of the value without any
47                       terminating zero
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49                     • expiration -- expiration as a unix timestamp or as rel‐
50                       ative expiration time in seconds
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52                     • flags -- 16 bit flags
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54              Returns
55                     memcached_return_t indicating success
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DESCRIPTION

58       memcached_prepend() and memcached_append are used to modify information
59       on a server. All methods take a key, and key_length to  store  the  ob‐
60       ject.  Keys are currently limited to 250 characters when using either a
61       version of memcached which is 1.4 or below, or when using the text pro‐
62       tocol.  You  must  supply both a value and a length. Optionally you may
63       set an expiration time for the object and a 16 bit value (it  is  meant
64       to  be  used as a bitmap). flags is a 4 byte space that is stored along
65       the main value. Many sub libraries make use of this field, so  in  most
66       cases users should avoid making use of it.
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68       memcached_prepend()  places  a segment of data before the last piece of
69       data stored. Currently expiration and key are not used in the server.
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71       memcached_append() places a segment of data at  the  end  of  the  last
72       piece  of data stored. Currently expiration and key are not used in the
73       server.
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75       memcached_prepend_by_key() and memcached_append_by_key()  methods  both
76       behave  in  a  similar manner as the non key methods. The difference is
77       that they use their group_key parameter to map  objects  to  particular
78       servers.
79
80       If  you  are looking for performance, memcached_set() with non-blocking
81       IO is the fastest way to store data on the server.
82
83       All of  the  above  functions  are  tested  with  the  MEMCACHED_BEHAV‐
84       IOR_USE_UDP behavior enabled. However, when using these operations with
85       this behavior on, there are limits to the size  of  the  payload  being
86       sent  to the server.  The reason for these limits is that the Memcached
87       Server does not allow multi-datagram requests and  the  current  server
88       implementation  sets  a  datagram  size  to 1400 bytes. Due to protocol
89       overhead, the actual limit of the user supplied data is less than  1400
90       bytes  and depends on the protocol in use as, well as the operation be‐
91       ing executed. When running with the binary  protocol,  MEMCACHED_BEHAV‐
92       IOR_BINARY_PROTOCOL,  the  size of the key,value, flags and expiry com‐
93       bined may not exceed 1368 bytes. When running with the ASCII  protocol,
94       the  exact  limit  fluctuates depending on which function is being exe‐
95       cuted and whether the function is a cas operation or not.  For  non-cas
96       ASCII  set operations, there are at least 1335 bytes available to split
97       among the key, key_prefix, and value; for cas  ASCII  operations  there
98       are  at  least  1318 bytes available to split among the key, key_prefix
99       and value. If the total size of the command,  including  overhead,  ex‐
100       ceeds 1400 bytes, a MEMCACHED_WRITE_FAILURE will be returned.
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RETURN VALUE

103       All  methods  return a value of type memcached_return_t. On success the
104       value will be MEMCACHED_SUCCESS.
105
106       Use memcached_strerror() to translate this value to a printable string.
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NAME

SYNOPSIS

DESCRIPTION

RETURN VALUE

SEE ALSO