why UI will freeze when using the api createWindowContainer qt5.15.2， but other version of QT have no problem

[jimfar]

new test result

add: when the type of m_window is Qt3DWindow,the app will freeze ,and if the the type of m_window is QtWindow,the app will not freeze.

[jimfar]

QtWindow-->QWindow

[SGaist]

Hi,

Can you trigger that with a minimal compilable example ?

[jimfar]

how to do this? u mean Compile QT3D separately?

[jsulm]

@jimfar No, just create an application which reproduces this issues and as small as possible (no other parts of your application).

[jimfar]

#include <Qt3DExtras/Qt3DWindow>
void function1(QObject* receiver, int isrun, int b)
{
while (1)
{
Qtmsleep(1000);
}
}
#include <QApplication>
void maintest(int argc, char* argv[])
{
QApplication a(argc, argv);
Qt3DExtras::Qt3DWindow*_windows = new Qt3DExtras::Qt3DWindow();
QWidget *pv = QWidget::createWindowContainer(_windows );
QtConcurrent::run( function1, pv, 0, 0);
pv->show( );
int result1 = a.exec();
}
only when comment QWidget *pv = QWidget::createWindowContainer(_windows );，it will show the window，otherwise it will not show. and i found after pv->show( ), QThreadPool::globalInstance()->activeThreadCount() will goes from 1 to 16. but in QT5.13.2 ,it alway keep value 1. and QT5.13.2 doesnot have the same problem

[jimfar]

ok I think i found the problem , the Qt3DWindow of QT5.15.2 will set QThreadPool::globalInstance()->maxThreadCount() to 16 in somewhere, and also will create 16 activethread for itself. if faild will block the UI thread

[SGaist]

What do you get if you trigger your QtConcurrent run through a QTimer ?

[jimfar]

get the same result 。i use "QTimer::singleShot"

[SGaist]

Can you show the latest version of your code ?