QException Class Reference

\inmodule QtCore More...

#include <qexception.h>

Inheritance diagram for QException:

Collaboration diagram for QException:

Public Member Functions
	QException ()=default
	Constructs a QException object.
	~QException () noexcept
	Destroys this QException object.
	QException (const QException &)=default
	Creates a copy of other.
QException &	operator= (const QException &)=default
	Copy-assigns other over this object.
virtual void	raise () const
	In your QException subclass, reimplement raise() like this:
virtual QException *	clone () const
	In your QException subclass, reimplement clone() like this:

Detailed Description

\inmodule QtCore

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

Since

5.0

Qt Concurrent supports throwing and catching exceptions across thread boundaries, provided that the exception inherits from QException and implements 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 \l{Qt Concurrent} functions will throw a QUnhandledException in the receiver thread.

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

• QFuture::waitForFinished()
• QFuture::result()
• QFuture::resultAt()
• QFuture::results() \endlist

Definition at line 21 of file qexception.h.

Constructor & Destructor Documentation

QException() [1/2]

QException::QException ( )

default

Constructs a QException object.

~QException()

QException::~QException ( )

noexcept

Destroys this QException object.

Definition at line 88 of file qexception.cpp.

QException() [2/2]

QException::QException ( const QException & other )

default

Creates a copy of other.

Note

Be careful when using this function, as you risk slicing.

See also

clone()

Member Function Documentation

clone()

QException * QException::clone ( ) const

virtual

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

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

Reimplemented in MyException, MyException, and QUnhandledException.

Definition at line 122 of file qexception.cpp.

operator=()

QException & QException::operator= ( const QException & other )

default

Copy-assigns other over this object.

Note

Be careful when using this function, as you risk slicing.

raise()

void QException::raise ( ) const

virtual

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

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

Reimplemented in MyException, MyException, and QUnhandledException.

Definition at line 116 of file qexception.cpp.

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The documentation for this class was generated from the following files:

• qtbase/src/corelib/thread/qexception.h (793309693aac24e7f88fc225408d92def638996e)
• qtbase/src/corelib/thread/qexception.cpp (793309693aac24e7f88fc225408d92def638996e)