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Changing an active deadline_timer's expiry time

Changing the expiry time of a timer while there are pending asynchronous waits causes those wait operations to be cancelled. To ensure that the action associated with the timer is performed only once, use something like this: used:

 void on_some_event()
 {
   if (my_timer.expires_from_now(seconds(5)) > 0)
   {
     // We managed to cancel the timer. Start new asynchronous wait.
     my_timer.async_wait(on_timeout);
   }
   else
   {
     // Too late, timer has already expired!
   }
 }

 void on_timeout(const boost::asio::error& e)
 {
   if (e != boost::asio::error::operation_aborted)
   {
     // Timer was not cancelled, take necessary action.
   }
 }

See also:
boost::asio::basic_deadline_timer
Copyright © 2003 - 2006 Christopher M. Kohlhoff

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