memcache的启动参数

          "a:"  /* access mask for unix socket */          "p:"  /* TCP port number to listen on */          "s:"  /* unix socket path to listen on */          "U:"  /* UDP port number to listen on */          "m:"  /* max memory to use for items in megabytes */          "M"   /* return error on memory exhausted */          "c:"  /* max simultaneous connections */          "k"   /* lock down all paged memory */          "hi"  /* help, licence info */          "r"   /* maximize core file limit */          "v"   /* verbose */          "d"   /* daemon mode */          "l:"  /* interface to listen on */          "u:"  /* user identity to run as */          "P:"  /* save PID in file */          "f:"  /* factor? */          "n:"  /* minimum space allocated for key+value+flags */          "t:"  /* threads */          "D:"  /* prefix delimiter? */          "L"   /* Large memory pages */          "R:"  /* max requests per event */          "C"   /* Disable use of CAS */          "b:"  /* backlog queue limit */          "B:"  /* Binding protocol */          "I:"  /* Max item size */          "S"   /* Sasl ON */          "o:"  /* Extended generic options */