Concurrent Map and Map-Reduce

The QtConcurrent::map(), QtConcurrent::mapped() and QtConcurrent::mappedReduced() functions run computations in parallel on the items in a sequence such as a QList or a QVector. QtConcurrent::map() modifies a sequence in-place, QtConcurrent::mapped() returns a new sequence containing the modified content, and QtConcurrent::mappedReduced() returns a single result.

These functions are a part of the {Qt Concurrent} framework.

Each of the above functions has a blocking variant that returns the final result instead of a QFuture. You use them in the same way as the asynchronous variants.

Note that the result types above are not QFuture objects, but real result types (in this case, QList<QImage> and QImage).