Build error when subclassing of subclassing from QObject

[crazygun22]

build error is happen when subclassing of subclassing from QObject.

is there any solution to avoid this problem?

this is source code & error

!http://crazygun22.g3.cc/ee.png(source code & error)!

[crazygun22]

this is my qt version

Qt Creator 3.3.0 (opensource)
Based on Qt 5.4.0 (MSVC 2010, 32 bit)

Built on Dec 8 2014 at 15:24:21

[dheerendra]

Do you need Q_OBJECT in 'sub' class ? This is the source of your error.

[crazygun22]

i need to send signal in both base and sub classes,
so i wrote the Q_OBJECT in both class.

if writing Q_OBJECT in both class is impossible, how can i send signal in both classes?

build error is also happen when writing emit function to send signal without Q_OBJECT in Sub class

-------------------------------Sub.h------------------------------------
class Sub : public Base
{
.......
signals:
void sendSigKey(const QString &key) const;
};

-------------------------------Sub.c---------------
void Sub::send()
{
emit sendSigKey("asdf");
}
--------------------------------Error------------
error: undefined reference to `Sub::sendSigKey(QString const&) const'

[euchkatzl]

Did you do a clean qmake ?

Delete your build folder
Run qmake
Build your project.

After that i think you have to remove the const qualifier in your constructor !

[SGaist]

Hi,

To add to my fellow, when adding/removing the Q_OBJECT macro you need to run qmake once to update the build part. Then it should build cleanly

[crazygun22]

thank you, SGaist

your reply sloved my problem.