(PECL gupnp >= 0.1.0)
gupnp_service_proxy_callback_set — Set service proxy callback for signal
$proxy
   , int $signal
   , mixed $callback
   [, mixed $arg
  ] )Set service proxy callback for signal.
proxy
     A service proxy identifier.
signal
     The value of signal.
GUPNP_SIGNAL_SUBSCRIPTION_LOST
         callback
     
       The callback function for the certain signal. Typically, callback function 
       takes on two parameters.  error parameter's message 
       being the first, and the arg is second.
      
arg
     
       User data for callback. 
      
   成功时返回 TRUE, 或者在失败时返回 FALSE.
  
Issues E_WARNING either with not valid callback function or with not valid signal.