[boost] why is not boost::asio::deadline_timer.wait() blocking in this case?

From: Tan, Tom (Shanghai) (TTan_at_[hidden])
Date: 2008-06-06 04:58:11

While trying to understand the difference between wait() and async_wait,
I modified the tutorial example a little to test 2 timers at the same
time like this:

 

int test_timer()

{

    boost::asio::io_service io;

 

    size_t delay1 = 5;

    size_t delay2 = 3;

 

    boost::asio::deadline_timer t1(io,
boost::posix_time::seconds(delay1));

    boost::asio::deadline_timer t2(io,
boost::posix_time::seconds(delay2));

 

    boost::timer t;

    t2.wait();

    std::cout << t.elapsed() << " sec elapsed!\n";

 

    t1.wait();

    std::cout << t.elapsed() << " sec elapsed!\n";

 

    return 0;

}

 

I got this output:

3.004 sec elapsed!

5.007 sec elapsed!

However, I was expecting t2 and t1 to execute sequentially and thus
getting:

3.004 sec elapsed!

8 sec elapsed!

 

What was wrong with my understanding about synchronous waiting here?
Thanks.