Learning threads on linux


Linux is a new platform to me. I've coded on Windows in c++ for a number of years and have become comfortable with multithreading on that platform.

Along comes C++11 at a time when I need to learn c++ on the linux platform.

Linux appears to use pthreads for the most part - okay there's also boost::threads and QT have their own threads too. But with C++11 comes std::thread, a whole new (cross platform and C++ standard) way to do threads.

So I guess I'll have to learn pthreads and std::threads. Ultimately, std::thread seems more important, but there's a lot of legacy code out there, so I'll have to know both.

For thread synchronization on windows, I would use WaitForMultipleObjects to wait for a number of tasks to complete before continuing with further work.

Does a similar synchronization mechanism exist for pthreads? std::threads?

I've had a look at pthread_join, and it seems to have the facility to only wait on one thread at a time. Am I missing another pthread call maybe?

std::thread is boost::thread accepted into C++11 with some extras. My understanding is that if boost::thread gets replaced in code with std::thread it should still compile and work.

boost::thread is based on pthreads design, providing thin C++ wrappers over thread, mutex and condition variables. Thread cancellation though was left outside the scope of C++11, since there was no agreement how it should work in C++.

So, by learning pthreads you also learn std::thread concepts. std::thread adds mostly syntax sugar and convenience functions on top of pthreads C API.

With regards to WaitForMultipleObjects(), neither pthreads nor std::thread provide anything similar to its bWaitAll=FALSE mode, however, it's routinely simulated using pipes and select() on UNIX, or more modern eventfd() and epoll() on Linux. bWaitAll=TRUE mode can be simulated by waiting on all tasks in turn, since it doesn't proceed until all objects are ready anyway.