(PECL memcache >= 0.2.0)
Memcache::increment — Increment item's value
Memcache::increment() increments value of an item by the specified value. If item specified by key was not numeric and cannot be converted to a number, it will change its value to value. Memcache::increment() does not create an item if it doesn't already exist.
Also you can use memcache_increment() function.Note: Do not use Memcache::increment() with items that have been stored compressed because subsequent calls to Memcache::get() will fail.
Key of the item to increment.
Increment the item by value.
Returns new items value on success or FALSE on failure.
Example #1 Memcache::increment() example
<?php
/* procedural API */
$memcache_obj = memcache_connect('memcache_host', 11211);
/* increment counter by 2 */
$current_value = memcache_increment($memcache_obj, 'counter', 2);
/* OO API */
$memcache_obj = new Memcache;
$memcache_obj->connect('memcache_host', 11211);
/* increment counter by 3 */
$current_value = $memcache_obj->increment('counter', 3);
?>