I build an application using Qt 5 Widgets on Kubuntu with a menu where I have connected the action with a function in my class StateMachine:
QObject::connect(
ui->actionOpen, &QAction::triggered, &sm, &StateMachine::open_file);
I am sorry that I cannot share all the code here, it is a commercial project.
This works fine with g++ 4.9 on Kubuntu. I now tried to compile this on openSUSE 13.1 which only has g++ 4.8 and I could not find headers for Qt 5 there. So I just tried to build it with Qt 4.8 which is available there in the default repository. Then I get this error:
/usr/include/QtGui/qaction.h: In constructor ‘MainWindow::MainWindow(QWidget*)’:
/usr/include/QtGui/qaction.h:228:10: error: ‘void QAction::triggered(bool)’ is protected
void triggered(bool checked = false);
^
/project/gui/mainwindow.cpp:26:35: error: within this context
ui->actionOpen, &QAction::triggered, &sm, &StateMachine::open_file);
^
/project/gui/mainwindow.cpp:26:75: error: no matching function for call to ‘MainWindow::connect(QAction*&, void (QAction::*)(bool), StateMachine*, void (StateMachine::*)())’
ui->actionOpen, &QAction::triggered, &sm, &StateMachine::open_file);
^
/project/gui/mainwindow.cpp:26:75: note: candidates are:
In file included from /usr/include/QtCore/QObject:1:0,
from /project/gui/AxisState.hpp:9,
from /project/gui/projectionview.h:7,
from /project/gui/mainwindow.h:5,
from /project/gui/mainwindow.cpp:3:
/usr/include/QtCore/qobject.h:204:17: note: static bool QObject::connect(const QObject*, const char*, const QObject*, const char*, Qt::ConnectionType)
static bool connect(const QObject *sender, const char *signal,
^
/usr/include/QtCore/qobject.h:204:17: note: no known conversion for argument 2 from ‘void (QAction::*)(bool)’ to ‘const char*’
/usr/include/QtCore/qobject.h:217:17: note: static bool QObject::connect(const QObject*, const QMetaMethod&, const QObject*, const QMetaMethod&, Qt::ConnectionType)
static bool connect(const QObject *sender, const QMetaMethod &signal,
^
/usr/include/QtCore/qobject.h:217:17: note: no known conversion for argument 2 from ‘void (QAction::*)(bool)’ to ‘const QMetaMethod&’
/usr/include/QtCore/qobject.h:337:13: note: bool QObject::connect(const QObject*, const char*, const char*, Qt::ConnectionType) const
inline bool QObject::connect(const QObject *asender, const char *asignal,
^
/usr/include/QtCore/qobject.h:337:13: note: no known conversion for argument 2 from ‘void (QAction::*)(bool)’ to ‘const char*’
In file included from /usr/include/QtGui/QAction:1:0,
from /project/gui/ui_mainwindow.h:13,
from /project/gui/mainwindow.cpp:5:
/usr/include/QtGui/qaction.h:228:10: error: ‘void QAction::triggered(bool)’ is protected
void triggered(bool checked = false);
^
I looked into the QAction 4.8 documentation and it looks like triggered(bool) is a public signal. Then I looked into the file /usr/include/QtGui/qaction.h and found that it looks like this:
protected:
bool event(QEvent *);
QAction(QActionPrivate &dd, QObject *parent);
public Q_SLOTS:
#ifdef QT3_SUPPORT
inline QT_MOC_COMPAT void setOn(bool b) { setChecked(b); }
#endif
void trigger() { activate(Trigger); }
void hover() { activate(Hover); }
void setChecked(bool);
void toggle();
void setEnabled(bool);
inline void setDisabled(bool b) { setEnabled(!b); }
void setVisible(bool);
Q_SIGNALS:
void changed();
void triggered(bool checked = false);
void hovered();
So it is in a Q_SIGNALS block, which does appear below a protected block, but those signals should be public.
How can I get this program to compile?
