QException Class

The QException class provides a base class for exceptions that can transferred across threads. More...

Header:	#include <QException>
qmake:	QT += core
Since:	Qt 5.0
Inherited By:	QUnhandledException

This class was introduced in Qt 5.0.

List of all members, including inherited members

Public Functions

virtual QException *	clone() const
virtual void	raise() const

Detailed Description

Qt Concurrent supports throwing and catching exceptions across thread boundaries, provided that the exception inherit from QException and implement two helper functions:

 class MyException : public QException
 {
 public:
     void raise() const override { throw *this; }
     MyException *clone() const override { return new MyException(*this); }
 };

QException subclasses must be thrown by value and caught by reference:

 try  {
     QtConcurrent::blockingMap(list, throwFunction); // throwFunction throws MyException
 } catch (MyException &e) {
     // handle exception
 }

If you throw an exception that is not a subclass of QException, the Qt functions will throw a QUnhandledException in the receiver thread.

When using QFuture, transferred exceptions will be thrown when calling the following functions:

Member Function Documentation

`[virtual]` QException *QException::clone() const

In your QException subclass, reimplement clone() like this:

 MyException *MyException::clone() const { return new MyException(*this); }

`[virtual]` void QException::raise() const

In your QException subclass, reimplement raise() like this:

 void MyException::raise() const { throw *this; }

Contents