Question

I’m looking for some easy to use cross-platform threading library written in C++.

What’s your opinion on boost::thread or Pthreads?
Does Pthreads run only on POSIX compliant systems?

What about the threading support in the Qt library?

Answer 1

Boost.Thread is the draft for the coming standard threading library of the C++ language. Knowing that, I prefer to use it as it provide some strong guarantees (because it becomes standard).

Update: Now that we have the standard threading libraries, some more precisions. Some boost constructs, like boost::shared_mutex, have not been standardised (but might be later). However the standard library exploit the move semantic better. Good to know before choosing a library. Also, using C++11 threading library requires a compiler that provides it. It’s not the case for all compilers today.

Update:
Now [Nov2012] most of the Standard compilers provide C++11 threading library. VS2012, GCC4.8 and Clang3.1 have support for threads and synchronization primitives and atomic operations.
For complete implementation you can also use just thread by Anthony Williams. It is C++11 compliant library supported on Windows/Mac and Linux.

Links for status of C++11 features with various compilers:

• GCC 4.8 – http://gcc.gnu.org/gcc-4.8/cxx0x_status.html
• Clang3.1 – http://clang.llvm.org/cxx_status.html
• VS2012 – http://msdn.microsoft.com/en-us/library/vstudio/hh567368.aspx