(PECL memcache >= 0.2.0)
memcache_debug — Turn debug output on/off
$on_off): bool
   memcache_debug() turns on debug output if parameter
   on_off is equal to true and turns off if it's
   false.
   
Note:
memcache_debug() is accessible only if PHP was built with --enable-debug option and always returns
truein this case. Otherwise, this function has no effect and always returnsfalse.
on_off
       Turns debug output on if equals to true.
       Turns debug output off if equals to false.
      
   Returns true if PHP was built with --enable-debug option, otherwise
   returns false.