Thread Support in Qt

Qt provides thread support in the form of platform-independent threading classes, a thread-safe way of posting events, and signal-slot connections across threads. This makes it easy to develop portable multithreaded Qt applications and take advantage of multiprocessor machines. Multithreaded programming is also a useful paradigm for performing time-consuming operations without freezing the user interface of an application.

Earlier versions of Qt offered an option to build the library without thread support. Since Qt 4.0, threads are always enabled.

Topics:

These articles assume that the reader has basic knowledge about multithreaded applications.

The Threading Classes

These classes are relevant to threaded applications.

Concurrent Filter and Filter-Reduce

Concurrent Map and Map-Reduce

Concurrent Run

QAtomicInteger

Platform-independent atomic operations on integers

QAtomicPointer

Template class that provides platform-independent atomic operations on pointers

Note: Qt's threading classes are implemented with native threading APIs; e.g., Win32 and pthreads. Therefore, they can be used with threads of the same native API.