Effective Qt: Don’t be sub-class when subclassing

The first of my Effective Qt columns, “Don’t be sub-class when subclassing“, just went live on my site.

Here are the guidelines this item covers:

• When subclassing QObject (directly or indirectly), always add the Q_OBJECT macro, regardless of whether you also define signals or slots.
• Prefer to offer all base class constructors in subclasses, too.
• Prefer to offer the basic QObject constructor ( QObject * parent=0 ) when subclassing QObjects. Always offer the basic QWidget constructor ( QWidget * parent=0, Qt::WindowFlags f=0 ) when subclassing QWidget.
• Prefer to follow the Qt constructor pattern: When inheriting QObjects, end constructor argument lists in QObject * parent=0. When inheriting QWidgets, end constructor argument lists in QWidget * parent=0, Qt::WindowFlags f=0. Add additional arguments at the beginning of the argument list.

I hope to make this into a regular column, time permitting.

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