diff options
Diffstat (limited to 'examples/qtconcurrent/wordcount/doc/src/qtconcurrent-wordcount.qdoc')
-rw-r--r-- | examples/qtconcurrent/wordcount/doc/src/qtconcurrent-wordcount.qdoc | 44 |
1 files changed, 37 insertions, 7 deletions
diff --git a/examples/qtconcurrent/wordcount/doc/src/qtconcurrent-wordcount.qdoc b/examples/qtconcurrent/wordcount/doc/src/qtconcurrent-wordcount.qdoc index 2c5724bc85..adefdfdc59 100644 --- a/examples/qtconcurrent/wordcount/doc/src/qtconcurrent-wordcount.qdoc +++ b/examples/qtconcurrent/wordcount/doc/src/qtconcurrent-wordcount.qdoc @@ -1,15 +1,45 @@ -// Copyright (C) 2016 The Qt Company Ltd. +// Copyright (C) 2023 The Qt Company Ltd. // SPDX-License-Identifier: LicenseRef-Qt-Commercial OR GFDL-1.3-no-invariants-only /*! \example wordcount - \title QtConcurrent Word Count Example - \brief Demonstrates how to use the map-reduce algorithm. + \meta tags {threads, console} + \title Word Count \ingroup qtconcurrentexamples + \examplecategory {Data Processing & I/O} + \brief Demonstrates how to use the map-reduce algorithm. + + The Qt Concurrent \e {Word Count} example demonstrates the use of the + map-reduce algorithm when applied to the problem of counting words in a + collection of files. + + First, the Application starts a QFileDialog to select a starting + path, and then prints the output to the console. + + \include examples-run.qdocinc + + \section1 Comparing the operations + + Compare a single-threaded, sequential approach to counting the words in + the text files to a multithreaded approach with mappedReduced(): + + \dots + \snippet wordcount/main.cpp 1 + \dots + \snippet wordcount/main.cpp 2 + \dots + + The first argument to the \l {QtConcurrent::}{mappedReduced} function is the + container to operate on. The second argument is the mapping function + \c {countWords()}. It is called in parallel by multiple threads. The + third argument is the reducing function \c {reduce()}. It is called + once for each result returned by the mapping function, and generates the + final computation result. - The QtConcurrent Word Count example demonstrates the use of the map-reduce - algorithm when applied to the problem of counting words in a collection - of files. + The function returns a QFuture object of type \c WordCount. Call the + \l {QFuture::}{result} function immediately on this QFuture to block further + execution until the result becomes available. - This is a command-line application. + \note The mapping function must be thread-safe since it is called from + multiple threads. */ |