(PECL memcached >= 0.1.0)
Memcached::prepend — Prepend data to an existing item
$key
   , string $value
   )
    Memcached::prepend() prepends the given
   value string to the value of an existing item. The
   reason that value is forced to be a string is
   that prepending mixed types is not well-defined.
  
Note:
If the
Memcached::OPT_COMPRESSIONis enabled, the operation will fail and a warning will be issued, because prepending compressed data to a value that is potentially already compressed is not possible.
key
     The key of the item to prepend the data to.
value
     The string to prepend.
   Returns TRUE on success or FALSE on failure.
   The  Memcached::getResultCode() will return
   Memcached::RES_NOTSTORED if the key does not exist.
  
Example #1 Memcached::prepend() example
<?php
$m = new Memcached();
$m->addServer('localhost', 11211);
$m->setOption(Memcached::OPT_COMPRESSION, false);
$m->set('foo', 'abc');
$m->prepend('foo', 'def');
var_dump($m->get('foo'));
?>
The above example will output:
string(6) "defabc"