-Weffc++ and Qt describes how the compile warning -Weffc++ goes together smoothly with Qt. The goal is to be able to compile cleanly at high warning levels [1], because we prefer compile errors to runtime errors [2].

In Qt Creator, select '(menu) Tools | (menu item) Options | (vertical tab) Designer | (horizontal tab) Class generation | (groupbox) Embedding of the UI class' and select 'Aggregation' (view a screenshot of the default setting).
Around each Qt #include suppress and allow -Weffc++
Initialize the member variable 'ui' in the dialog its constructor

There are some drawbacks following this way:

Class generation is not done in this way be default
Compiling will take longer

Download the Qt Creator project 'CppWeffcppAndQtAggregation' (zip)
Download the Qt Creator project 'CppWeffcppAndQtPointer' (zip) (this follows another, but failing, approach)

Technical facts

Application type(s)

Desktop application

Operating system(s) or programming environment(s)

Lubuntu 12.10 (quantal)

IDE(s):

Qt Creator 2.5.2

Project type:

GUI application

C++ standard:

C++98

Compiler(s):

G++ 4.7.2

Libraries used:

Qt: version 4.8.3 (32 bit)
STL: GNU ISO C++ Library, version 4.7.2

Qt project file: CppWeffcppAndQt.pro


QT       += core gui

QMAKE_CXXFLAGS += -Weffc++ -Werror

greaterThan(QT_MAJOR_VERSION, 4): QT += widgets

TARGET = CppWeffcppAndQt

TEMPLATE = app

SOURCES += main.cpp\

        dialog.cpp

HEADERS  += dialog.h

FORMS    += dialog.ui

dialog.h


#ifndef DIALOG_H

#define DIALOG_H



#pragma GCC diagnostic ignored "-Weffc++"

#include "ui_dialog.h"

#pragma GCC diagnostic pop



class Dialog : public QDialog

{

  Q_OBJECT

  

public:

  explicit Dialog(QWidget *parent = 0);

  

private slots:

  void on_pushButton_clicked();



private:

  Ui::Dialog ui;

};



#endif // DIALOG_H

dialog.cpp


#include <vector>

#include <string>



#pragma GCC diagnostic ignored "-Weffc++"

#include "dialog.h"

#pragma GCC diagnostic pop



Dialog::Dialog(QWidget *parent) :

  QDialog(parent),

  ui(Ui::Dialog())

{

  ui.setupUi(this);

}



void Dialog::on_pushButton_clicked()

{

  const std::string s = ui.label->text().toStdString() + ".";



  ui.label->setText(QString(s.c_str()));

}

main.cpp




#pragma GCC diagnostic ignored "-Weffc++"

#include <QApplication>

#include "dialog.h"

#pragma GCC diagnostic pop



int main(int argc, char *argv[])

{

  QApplication a(argc, argv);

  Dialog w;

  w.show();

  return a.exec();

}

References

Herb Sutter, Andrei Alexandrescu. C++ coding standards: 101 rules, guidelines, and best practices. 2005. ISBN: 0-32-111358-6. Item 1: 'Compile cleanly at high warning levels'.
Herb Sutter, Andrei Alexandrescu. C++ coding standards: 101 rules, guidelines, and best practices. ISBN: 0-32-111358-6. Item 14: 'Prefer compile- and link-time errors to run-time errors'.

Go back to Richel Bilderbeek's C++ page.

Go back to Richel Bilderbeek's homepage.