NAME

       memcached_append_by_key - Appending to or Prepending Data

SYNOPSIS

       #include <libmemcached-1.0/memcached.h>
              Compile and link with -lmemcached

       memcached_return_t   memcached_prepend(memcached_st   *ptr,   const   char   *key,  size_t
       key_length, const char *value, size_t value_length, time_t expiration, uint32_t flags)

       memcached_return_t memcached_append(memcached_st *ptr, const char *key, size_t key_length,
       const char *value, size_t value_length, time_t expiration, uint32_t flags)

       memcached_return_t  memcached_prepend_by_key(memcached_st  *ptr,  const  char  *group_key,
       size_t group_key_length, const char *key, size_t key_length,  const  char  *value,  size_t
       value_length, time_t expiration, uint32_t flags)

       memcached_return_t   memcached_append_by_key(memcached_st  *ptr,  const  char  *group_key,
       size_t group_key_length, const char *key, size_t key_length,  const  char  *value,  size_t
       value_length, time_t expiration, uint32_t flags)

              Parameters

                     • ptr -- pointer to an initialized memcached_st struct

                     • group_key -- key namespace

                     • group_key_length  --  length  of the key namespace without any terminating
                       zero

                     • key -- the key

                     • key_length -- length of the key without any terminating zero

                     • value -- the value to append/prepend

                     • value_length -- the length of the value without any terminating zero

                     • expiration -- expiration as a unix timestamp  or  as  relative  expiration
                       time in seconds

                     • flags -- 16 bit flags

              Returns
                     memcached_return_t indicating success

DESCRIPTION

       memcached_prepend()  and  memcached_append are used to modify information on a server. All
       methods take a key, and key_length to store the object. Keys are currently limited to  250
       characters  when  using either a version of memcached which is 1.4 or below, or when using
       the text protocol. You must supply both a value and a length. Optionally you  may  set  an
       expiration  time  for  the object and a 16 bit value (it is meant to be used as a bitmap).
       flags is a 4 byte space that is stored along the main value. Many sub libraries  make  use
       of this field, so in most cases users should avoid making use of it.

       memcached_prepend()  places  a  segment  of  data  before  the  last piece of data stored.
       Currently expiration and key are not used in the server.

       memcached_append() places a segment of data at the end of the last piece of  data  stored.
       Currently expiration and key are not used in the server.

       memcached_prepend_by_key()  and memcached_append_by_key() methods both behave in a similar
       manner as the non key methods. The difference is that they use their  group_key  parameter
       to map objects to particular servers.

       If  you  are  looking for performance, memcached_set() with non-blocking IO is the fastest
       way to store data on the server.

       All of the  above  functions  are  tested  with  the  MEMCACHED_BEHAVIOR_USE_UDP  behavior
       enabled.  However,  when using these operations with this behavior on, there are limits to
       the size of the payload being sent to the server.  The reason for these limits is that the
       Memcached   Server   does  not  allow  multi-datagram  requests  and  the  current  server
       implementation sets a datagram size to 1400 bytes. Due to protocol  overhead,  the  actual
       limit of the user supplied data is less than 1400 bytes and depends on the protocol in use
       as, well as  the  operation  being  executed.  When  running  with  the  binary  protocol,
       MEMCACHED_BEHAVIOR_BINARY_PROTOCOL,  the  size of the key,value, flags and expiry combined
       may not exceed 1368  bytes.  When  running  with  the  ASCII  protocol,  the  exact  limit
       fluctuates depending on which function is being executed and whether the function is a cas
       operation or not. For non-cas  ASCII  set  operations,  there  are  at  least  1335  bytes
       available  to  split  among the key, key_prefix, and value; for cas ASCII operations there
       are at least 1318 bytes available to split among the key, key_prefix  and  value.  If  the
       total    size    of   the   command,   including   overhead,   exceeds   1400   bytes,   a
       MEMCACHED_WRITE_FAILURE will be returned.

RETURN VALUE

       All methods return a value of type  memcached_return_t.  On  success  the  value  will  be
       MEMCACHED_SUCCESS.

       Use memcached_strerror() to translate this value to a printable string.

SEE ALSO

       memcached(1)   libmemcached(3)   memcached_strerror(3)  memcached_set(3)  memcached_add(3)
       memcached_cas(3) memcached_replace(3)