(PECL memcached >= 0.1.0)
Memcached::add — 向一个新的key下面增加一个元素
Memcached::add()与Memcached::set()类似，但是如果
key已经在服务端存在，此操作会失败。
成功时返回 TRUE， 或者在失败时返回 FALSE。
如果key已经存在，Memcached::getResultCode()方法将会返回Memcached::RES_NOTSTORED。
Note that this operation is atomic, means that it's safe from race condition operation (since memcached is running in single process). You can use this method for locks and can be sure that two requests will not get "true" simultaneously using this method.
<?php
/**
* Created by PhpStorm.
* User: zhoujunwen
* Date: 15/6/17
* Time: 下午4:51
*/
$mem = new Memcached();
$mem->addServer('127.0.0.1',11211);
if( $mem->add("mystr","this is a memcache test!",3600)){
echo '原始数据缓存成功!';
}else{
echo '数据已存在：'.$mem->get("mystr");
}
?>