[Boost-users] [interprocess] named_condition.timed_wait does not wait.

Subject: [Boost-users] [interprocess] named_condition.timed_wait does not wait.
From: Moritz (mokoman_at_[hidden])
Date: 2009-09-14 09:25:49

Hi all,

I am fighting with the named_condition again. Currently I am using
timed_wait but it does not behave like I expected. Sometimes it is okay
(triggers on the given timeout) but sometimes it just returns
immediately false (ignoring the timeout). Can someone give me a hint
what I am doing wrong?

Thanks in advance.

Here is a simplified version of what I try to do:

using namespace boost::interprocess;
using namespace boost::posix_time;

_process1_: (WRITER)

scoped_lock<named_mutex> lock(mtx1);

write_sth_to_shared_memory();
flag = true;
named_condition1.notify_all();
named_condition2.wait(lock);

_process2_: (READER)

scoped_lock<named_mutex> lock(mtx2);

while (true)
{
  while (!flag)
  {
    flag = check_flag();

    // set up timeout
    time_duration delay(milliseconds(200));
    ptime timeout = ptime(second_clock::universal_time());
    timeout += delay;
    // wait
    if (named_condition1.timed_wait(lock))
    {
       check_for_interrupt();
       break;
    }
    else
    {
       check_for_interrupt();
       continue;
    }
  }
  do_some_reading_from_shared_mem();
  named_condition2.notify(all);
}