path: root/src/concurrent/doc/snippets/code/src_concurrent_qtconcurrenttask.cpp

// Copyright (C) 2020 The Qt Company Ltd.// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR BSD-3-Clause//! [0]QtConcurrent::task([]{qDebug("Hello, world!"); }).spawn();//! [0]//! [1]auto task = [](const QString &s){qDebug() << ("Hello, "+ s); };QtConcurrent::task(std::move(task)).withArguments("world!").spawn();//! [1]//! [2] QString s("Hello, ");QtConcurrent::task([](QString &s){ s.append("world!"); }).withArguments(std::ref(s)).spawn();//! [2]//! [3]auto future =QtConcurrent::task([]{return42; }).spawn();auto result = future.result();// result == 42//! [3]//! [4]std::is_invocable_v<std::decay_t<Task>,std::decay_t<Args>...>//! [4]//! [5] QVariant value(42);auto result =QtConcurrent::task([](const QVariant &var){return qvariant_cast<int>(var);}).withArguments(value).spawn().result();// result == 42//! [5]//! [6] QString result("Hello, world!");QtConcurrent::task(&QString::chop).withArguments(&result,8).spawn().waitForFinished();// result == "Hello"//! [6]//! [7]auto result =QtConcurrent::task(std::plus<int>()).withArguments(40,2).spawn().result()// result == 42//! [7]//! [8]struct CallableWithState {voidoperator()(int newState) { state = newState; }// ...};// ... CallableWithState object;QtConcurrent::task(std::ref(object)).withArguments(42).spawn().waitForFinished();// The object's state is set to 42//! [8]//! [9] QThreadPool pool;QtConcurrent::task([]{return42; }).onThreadPool(pool).spawn();//! [9]//! [10]QtConcurrent::task([]{return42; }).withPriority(10).spawn();//! [10]//! [11]QtConcurrent::task([]{qDebug("Hello, world!"); }).spawn(FutureResult::Ignore);//! [11]//! [12]voidincrement(QPromise<int> &promise,int i){ promise.addResult(i +1);}int result =QtConcurrent::task(&increment).withArguments(10).spawn().result();// result == 11//! [12]