Details
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Bug
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Resolution: Invalid
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Not Evaluated
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None
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5.15.2, 6.4.2, 6.4.3
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None
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Linux/X11
Description
There are two samples. The only difference is with line "x1.result()", first waits for result of QFuture before runing next task, second will wait for result after scheduling both tasks. I check if executed thread is in specified thread pool. In Test1() task from QtConcurrent::run() is executed in the main thread, not that from thread pool. This can lead to deadlocks or other unexpected behavior. This should work like in Test2(). Reproducible always.
void MainWindow::Test1() { QThreadPool fThreadPool; qDebug() << "0 MAIN:" << fThreadPool.contains(QThread::currentThread()) << QThread::currentThread(); auto x1 = QtConcurrent::run(&fThreadPool, [&]() { qDebug() << "1 POOL:" << fThreadPool.contains(QThread::currentThread()) << QThread::currentThread(); return 1; }); qDebug() << "1 RESULT:" << x1.result(); auto x2 = QtConcurrent::run(&fThreadPool, [&]() { qDebug() << "2 POOL:" << fThreadPool.contains(QThread::currentThread()) << QThread::currentThread(); return 2; }); qDebug() << "2 RESULT:" << x2.result(); }
0 MAIN: false QThread(0x564b940bdc40) 1 POOL: true QThreadPoolThread(0x564b941bb280, name = "Thread (pooled)") 1 RESULT: 1 2 POOL: false QThread(0x564b940bdc40) 2 RESULT: 2
void MainWindow::Test2() { QThreadPool fThreadPool; qDebug() << "0 MAIN:" << fThreadPool.contains(QThread::currentThread()) << QThread::currentThread(); auto x1 = QtConcurrent::run(&fThreadPool, [&]() { qDebug() << "1 POOL:" << fThreadPool.contains(QThread::currentThread()) << QThread::currentThread(); return 1; }); auto x2 = QtConcurrent::run(&fThreadPool, [&]() { qDebug() << "2 POOL:" << fThreadPool.contains(QThread::currentThread()) << QThread::currentThread(); return 2; }); qDebug() << "1 RESULT:" << x1.result(); qDebug() << "2 RESULT:" << x2.result(); }
0 MAIN: false QThread(0x5623f34e0c40) 1 POOL: true QThreadPoolThread(0x5623f3565220, name = "Thread (pooled)") 1 RESULT: 1 2 POOL: true QThreadPoolThread(0x5623f36075e0, name = "Thread (pooled)") 2 RESULT: 2
Attachments
Issue Links
- duplicates
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- Closed
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