| MEMCACHE_COMPRESSED(integer) | Used to turn on-the-fly data compression on with
       Memcache::set(), 
       Memcache::add() and
       Memcache::replace(). | 
     
      | MEMCACHE_HAVE_SESSION(integer) | 1 if this Memcache session handler is available, 0 otherwise. | 
     
      | MEMCACHE_USER1(integer) | Used to turn user-defined application flag on with
       Memcache::set(), 
       Memcache::add() and
       Memcache::replace(). | 
     
      | MEMCACHE_USER2(integer) | Used to turn user-defined application flag on with
       Memcache::set(), 
       Memcache::add() and
       Memcache::replace(). | 
     
      | MEMCACHE_USER3(integer) | Used to turn user-defined application flag on with
       Memcache::set(), 
       Memcache::add() and
       Memcache::replace(). | 
     
      | MEMCACHE_USER4(integer) | Used to turn user-defined application flag on with
       Memcache::set(), 
       Memcache::add() and
       Memcache::replace(). |