Re: [Boost-users] [asio] deadline_timer makes wrong delay when using date command

8 Sep 2009

      On Mon, 07 Sep 2009 15:03:00 +0200, Stefan Strasser
 wrote:
...
Am Monday 07 September 2009 13:24:58 schrieb Bjarne Laursen:
...
I have used a deadline_timer to generate a polling every 1 second.
Unfortunely when I use the linux date command the timing is curupted.  
(If
I set the clock back 1 min. I will be missing 60 pollings).
What can I do about that?
-Bjarne
I don't know how to solve that within asio but I also needed a timer  
like that
and didn't want to create a dependency on asio just for that, so I'm  
using
the following for now, which should also solve your problem (if you don't
also use asio for other purposes):
class cache_timer{
public:
  cache_timer(...)
      : resolution(...)
      , thread(boost::bind(&cache_timer::run,this))
{} //throw(thread_resource_error)
  void run(){
      while(!this_thread::interruption_requested()){
      	this_thread::sleep(resolution);
      	...
      }
  }
  ~cache_timer(){ //throw()
      this->thread.interrupt();
      this->thread.join();
  }
private:
  posix_time::time_duration resolution;
  boost::thread thread;
};
Thank you for the code. The thing is that I'm porting a central part of
rather large amount of code from windows (MSVC6) into a multi target
system, where the main target is linux.

The original code use a combination of WaitForMultipleObjectsEx and
GetTickCount to make a common destribution point for incoming data and
timers.
In addion a few user-modules used a function to give a CEvent and have my
framework call a member function if the event becomes set. It is typical
used to handle file/network/serial i/o, in windows.

I have now implemented the use of asio for this central waiting point and
it seem work well. Except for this problem. (And the shut down sequence,
but thats another issue I need to work with)

I don't know if the original windows system suffers from this problem
also, but I need to come up with a solution on the new.

Even if I need to give up the use of deadline_timer, I probably will
continue to use asio. I just thought that I had missed some simple setup
somewhere. It seem that the typical use of timers in asio (and given in
examples) is to make timeout for i/o operations. And as I see it, the use
of the date command will almost always make a program using asio fail.