使用Posix时间的Boost中的线程超时

Question

I have created a number of threads in C++ using the Boost Threads library, I want to time-out all these threads, I can use the timed_join() in a loop, but this can make the total waiting time = number-of-threads * time-out-time.

for(int i = 0; i < number_of_threads; ++i)
{
   threads[i]->timed_join(boost::posix_time::seconds(timeout_time));
}

So, I'm thinking of using the builtin posix_time class to calculate the deadline for each thread. This way the total wait time is at most the given timeout-time.

What would be the simplest and most straightforward way to do this?

Answer 1

Use the overload of thread::timed_join that takes an absolute time (ie time point) instead of a duration. Make that absolute time deadline be the current time plus whatever timeout duration you desire. This will ensure that none of thread::timed_join calls in the loop will wait past the absolute time deadline.

In the latest version of Boost.Thread (as of Boost 1.50), Boost.Date_Time is now deprecated in favor of Boost.Chrono . This is to closer match the API of std::thread in C++11.

This example shows how to specify an absolute time deadline with either Boost.Chrono or Boost.DateTime:

using namespace boost;

#if BOOST_VERSION < 105000

// Use of Boost.DateTime in Boost.Thread is deprecated as of 1.50
posix_time::ptime deadline =
    posix_time::microsec_clock::local_time() +
    posix_time::seconds(timeoutSeconds);

#else

chrono::system_clock::time_point deadline =
    chrono::system_clock::now() + chrono::seconds(timeoutSeconds);

#endif

for(int i = 0; i < number_of_threads; ++i)
{
    threads[i]->timed_join(deadline);
}

This page in the documentation shows Boost.Date_Time example usages.

This page in the documentation is a tutorial on Boost.Chrono.

Answer 2

int64_t mseconds = 60*1000; // 60 seconds

simply use

threads[i]->timed_join(boost::posix_time::milliseconds(mseconds ))

you dont need to use absolute time