memcached_prepend(3)

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

6       memcached_prepend - Appending to or Prepending Data
7

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)
15
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)
29
30              Parameters
31
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.
67
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.
70
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.
74
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
84       MEMCACHED_BEHAVIOR_USE_UDP  behavior enabled. However, when using these
85       operations with this behavior on, there are limits to the size  of  the
86       payload  being sent to the server.  The reason for these limits is that
87       the Memcached Server does not allow  multi-datagram  requests  and  the
88       current  server  implementation sets a datagram size to 1400 bytes. Due
89       to protocol overhead, the actual limit of the  user  supplied  data  is
90       less than 1400 bytes and depends on the protocol in use as, well as the
91       operation being  executed.  When  running  with  the  binary  protocol,
92       MEMCACHED_BEHAVIOR_BINARY_PROTOCOL,  the  size  of the key,value, flags
93       and expiry combined may not exceed 1368 bytes. When  running  with  the
94       ASCII  protocol, the exact limit fluctuates depending on which function
95       is being executed and whether the function is a cas operation  or  not.
96       For  non-cas ASCII set operations, there are at least 1335 bytes avail‐
97       able to split among the key, key_prefix, and value; for cas ASCII oper‐
98       ations  there are at least 1318 bytes available to split among the key,
99       key_prefix and value. If the total size of the command, including over‐
100       head, exceeds 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.
107

NAME

SYNOPSIS

DESCRIPTION

RETURN VALUE

SEE ALSO