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主要作用是筛选出符合条件的项值结果集,并与之替换原有序列列表
blockingMap
可以直接修改容器的每一项
blockingMapped
不直接修改容器的每一项,而是将处理后的结果返回一个新的容器
blockingMappedReduced
ResultType QtConcurrent::blockingMappedRed…blockingFilter
主要作用是筛选出符合条件的项值结果集,并与之替换原有序列列表
blockingMap
可以直接修改容器的每一项
blockingMapped
不直接修改容器的每一项,而是将处理后的结果返回一个新的容器
blockingMappedReduced
ResultType QtConcurrent::blockingMappedReduced(const Sequence sequence, MapFunctor mapFunction, ReduceFunctor reduceFunction, QtConcurrent::ReduceOptions reduceOptions ReduceOptions(UnorderedReduce | SequentialReduce))Calls mapFunction once for each item in sequence. The return value of each mapFunction is passed to reduceFunction.
Note that while mapFunction is called concurrently, only one thread at a time will call reduceFunction. The order in which reduceFunction is called is determined by reduceOptions.按顺序为每个项目调用mapFunction一次。每个mapFunction的返回值被传递给reduceFunction。 请注意当mapFunction被并发调用时一次只有一个线程会调用reduceFunction。reduceFunction的调用顺序由reduceOptions决定。
注意blockingFilter、blockingMap、blockingMapped、blockingMappedReduced 这些函数将阻塞直到序列中的所有项都被处理完。当然他们也有异步版本QtConcurrent::map、QtConcurrent::mapped、QtConcurrent::mappedReduced只要把前面的block去掉就是对应的异步版本函数了。
示例代码
#include QCoreApplication
#include QtConcurrent
#include QDebugint Addfunc(const int arg)
{return arg 1;
};int multiplyFunc(const int num)
{return num * 10;
}void reducedFunction(int result, const int intermedia)
{result intermedia;
}int main(int argc, char *argv[])
{QCoreApplication a(argc, argv);//1blockingFilter 主要作用是筛选出符合条件的项值结果集,并与之替换原有序列列表QListint list0{2, 7, 6, 5, 10, 9, 8, 3, 4};QtConcurrent::blockingFilter(list0, [](int v) { return v 5; });qDebug() blockingFilter sequence list0;//(7, 6, 10, 9, 8)//2blockingMap 可以直接修改容器的每一项QListint list1 {1, 2, 3, 4, 5};QtConcurrent::blockingMap(list1, [](int num){num num * 10;});qDebug() blockingMap list1 list1;//(10, 20, 30, 40, 50)//3blockingMapped 不直接修改容器的每一项,而是将处理后的结果返回一个新的容器QListint list2 {3, 4, 5, 6, 7};list2 QtConcurrent::blockingMapped(list2, multiplyFunc);qDebug() blockingMapped list2 list2;//(30, 40, 50, 60, 70)//4按顺序为每个项目调用multiplyFunc一次,每个multiplyFunc的返回值被传递给reducedFunctionQListint list3 {6, 7, 8, 9, 10};int res QtConcurrent::blockingMappedReduced(list3, multiplyFunc, reducedFunction);qDebug() blockingMappedReduced res res;//400//--------------------------Asynchronous call--------------------------
#if 1//QtConcurrent::mapQListint sequence0{1, 2, 3, 4, 5, 6, 7};QFuturevoid future0 QtConcurrent::map(sequence0, Addfunc);QFutureWatchervoid *watcher new QFutureWatchervoid();QObject::connect(watcher, QFutureWatchervoid::finished, [](){qDebug() QtConcurrent::map sequence0;});//QtConcurrent::mappedQListint sequence1{1, 2, 3, 4, 5, 6, 7};QFutureint future1 QtConcurrent::mapped(sequence1, multiplyFunc);qDebug() QtConcurrent::mapped future1.results();//(10, 20, 30, 40, 50, 60, 70)//新的结果用QFuture::const_iterator或QFutureIterator进行访问QFutureIteratorint itr(future1);while (itr.hasNext()) {qDebug() itr itr.next();}//QtConcurrent::mappedReduced()类似于mapped()//区别在于将结果继续传递给一个新函数,并在新函数里再处理成一个单值QListint sequence2{1, 2, 3, 4, 5, 6, 7};QFutureint future2 QtConcurrent::mappedReduced(sequence2, multiplyFunc, reducedFunction);future2.waitForFinished();int result future2.result();qDebug() QtConcurrent::mappedReduced result;//280
#endifreturn a.exec();
}
