(PECL memcached >= 0.1.0)
Memcached::getMulti — Retrieve multiple items
   Memcached::getMulti() is similar to
   Memcached::get(), but instead of a single key
   item, it retrieves multiple items the keys of which are specified in the
   keys array. If cas_tokens
   variable is provided, it is filled with the CAS token values for the found
   items.
   
Note:
Unlike Memcached::get() it is not possible to specify a read-through cache callback for Memcached::getMulti(), because the memcache protocol does not provide information on which keys were not found in the multi-key request.
   The flags parameter can be used to specify
   additional options for Memcached::getMulti(). Currently,
   the only available option is
   Memcached::GET_PRESERVE_ORDER that ensures that the
   keys are returned in the same order as they were requested in.
  
keysArray of keys to retrieve.
cas_tokensThe variable to store the CAS tokens for the found items.
flagsThe flags for the get operation.
   Returns the array of found items or FALSE on failure.
   Use Memcached::getResultCode() if necessary.
  
Example #1 Memcached::getMulti() example
<?php
$m = new Memcached();
$m->addServer('localhost', 11211);
$items = array(
    'key1' => 'value1',
    'key2' => 'value2',
    'key3' => 'value3'
);
$m->setMulti($items);
$result = $m->getMulti(array('key1', 'key3', 'badkey'), $cas);
var_dump($result, $cas);
?>
The above example will output something similar to:
array(2) {
  ["key1"]=>
  string(6) "value1"
  ["key3"]=>
  string(6) "value3"
}
array(2) {
  ["key1"]=>
  float(2360)
  ["key3"]=>
  float(2362)
}
Example #2 Memcached::GET_PRESERVE_ORDER example
<?php
$m = new Memcached();
$m->addServer('localhost', 11211);
$data = array(
    'foo' => 'foo-data',
    'bar' => 'bar-data',
    'baz' => 'baz-data',
    'lol' => 'lol-data',
    'kek' => 'kek-data',
);
$m->setMulti($data, 3600);
$null = null;
$keys = array_keys($data);
$keys[] = 'zoo';
$got = $m->getMulti($keys, $null, Memcached::GET_PRESERVE_ORDER);
foreach ($got as $k => $v) {
    echo "$k $v\n";
}
?>
The above example will output something similar to:
foo foo-data bar bar-data baz baz-data lol lol-data kek kek-data zoo