Intel Threading Building Blocks

From Intel:

Intel TBB is an award-winning runtime library that simplifies the writing of multi-threaded applications. Just like the C++ Standard Template Library (STL) extends the core language, Intel TBB offers C++ users a higher level abstraction for parallelism. To implement Intel TBB developers use familiar C++ templates and coding style, leaving the low-level threading details to the library. It is also portable between architectures and operating systems. While it's possible to write POSIX threads or Windows threads that will be as fast as Intel TBB, the lines of code will be significantly larger and will require maintenance to ensure future scalability. With Intel TBB, developers get the benefits of faster programming, scalable performance and easier to maintain code. Intel TBB is available in both a free open source version and a for-purchase commercial version with support for Windows, Linux, and Mac OS X operating systems.