portable threading APIs

Question

I know of three portable threading C++ APIs :

1. Qt
2. boost::thread
3. GNU Pth

Apart from possible licensing issues involved, how do these compare in:

• actual portability (mostly interested in Linux and Windows)
• capabilities
• programming ease-of-use
• support/development activity of the library

And: are there more like these that are well supported and used?

Answer 1

boost::thread is portable and actively supported, but most importantly it's going to be in the Standard C++0x Library. So I recommend this library for general-purpose threading.

Answer 2

QT's QThread is really straightforward, easy to use and cross platform, but it only makes sense if you are developing your whole user application already with Qt. You will not want to tie a heavy amount of Qt runtime DLLs to your app. just to get threading support.