Direct base ‘QObject’ inaccessible in ‘myClass’ due to ambiguity
-
@// -- header file -------------------------------------------------
#ifndef MYCLASS_H
#define MYCLASS_H#include <QObject>
#include <QThread>class myClass : public QObject, public QThread
{
Q_OBJECT
public:
myClass(QObject *parent = 0);
};#endif // MYCLASS_H
// -- source file ------------------------------------------------
#include "myclass.h"myClass::myClass(QObject *parent) :
QObject(parent)
{
}
@// -- compiler output -----------------------------------------
myclass.h:9: warning: direct base ‘QObject’ inaccessible in ‘myClass’ due to ambiguity
myclass.cpp: undefined reference to `vtable for myClass'
error: collect2: ld returned 1 exit statuscan anyone tell why it fails to compile.???
and the solution. -
Hello.
You can not inherit from two QObjects.
Well, you should read "this":http://developer.qt.nokia.com/doc/qt-4.8/object.html
and then "this":http://developer.qt.nokia.com/doc/qt-4.8/metaobjects.html#meta-object-systemI asked myself the same questions once.
Object Model and The Meta-Object System are the answersbest regards
-
[quote author="aekam" date="1328613590"]is it because QThread already inherits QObject class, hence when i derive my class from QObject and QThread, compiler gets confuse to select right constructor for QObject...[/quote]
"Using the Meta-Object Compiler (moc)":http://developer.qt.nokia.com/doc/qt-4.8/moc.html#moc
...
Multiple Inheritance Requires QObject to Be First
If you are using multiple inheritance, moc assumes that the first inherited class is a subclass of QObject. Also, be sure that only the first inherited class is a QObject.
@
// correct
class SomeClass : public QObject, public OtherClass
{
...
};
@Virtual inheritance with QObject is not supported.