#include <QtConcurrent/QtConcurrent>

The Qt Concurrent module extends the basic threading support found in Qt Core module and simplifies the development of code that can be executed in parallel on all available CPU cores.

Qt Concurrent模块延展了在Qt Core 中的基础线程支持模块并且简化了代码的发展：可以同时在所有的可用的cpu核上执行。

总结#include <QtConcurrent/QtConcurrent> 是支持多线程的头文件。