I am trying to replicate behaviour in a small PyQt application, but instead using C++.

In Qt6, the SQL server was connected and the database was successfully opened. However, when using the setTable method of QsqlTableModel, the error “QODBDriver:: record: Unable to allocate handle” appeared. code: { tabModel = new QSqlTableModel(this, DB); tabModel->setTable(QString(“Book”)); if (! tabModel->select()) { QMessageBox:: critical (this, “Error message”, “Opening database table error, Error message:n”+ tabModel->lastError().text()); qDebug() […]

I need to pass a large amount of data from the worker thread to the main thread. I tried to use the signal slot method to pass the variable reference, but I am not sure whether it will cause program exceptions due to the scope of the variable, because the parameter in the signal function is a local variable. Some people told me that it is possible, but some people told me that it is not possible. Please help me

When I use QT Creator, I am in. Pro file includes include.pri file, but when I really compiled, I reported an error, saying that I could not find the header file in the corresponding environment, the following is some of my code and the corresponding error information, I do not know how to solve this problem, and why this problem occurs.

I migrated our application from Qt5 to Qt6. The code of the main application is working fine after some code changes. But all the QT plugins that are in the application cannot be loaded because of undefined symbol: _ZN7GscreenD1Ev. Hope someone sees the error?

I implementing a custom QStyledItemDelegate and want to know decoration QRect in sizeHint() method to calculate correct size hint for my items.