Of the APIs covered in this chapter, only the Qt multithreading API can be considered to be truly high level. Although the other APIs (including C++11) have some higher-level concepts including thread pools and asynchronous runners which do not require one to use threads directly, Qt offers a full-blown signal-slot architecture, which makes inter-thread communication exceptionally easy.
As covered in this chapter, this ease also comes with a cost, namely, that of having to develop one's application to fit the Qt framework. This may not be acceptable depending on the project.
Which of these APIs is the right one depends on one's requirements. It is, however, relatively fair to say that using straight Pthreads, Windows threads, and kin does not make a lot of sense when one can use APIs such as C++11 threads, POCO, and so on, which ease the development process with no significant reduction in performance while also gaining extensive portability across platforms.
All the APIs...