Signal not found error solved by using old connect sythax. Why?

nwoki

Hi all!

As the title says, I've encountered a problem with Qt's signal/slots. I have a QQmlExtensionPlugin (Exercise) where I need to connect to its own signals in order to start/stop a timer. Now, I wanted to do it like I've been doing for some time now, with:

connect(this, &Exercise::statusChanged, this, &Exercise::startStopElapsedPausedTimer);

NOTE: arguments match (there aren't any)

but I encountered the following error during runtime:

QObject::connect: signal not found in Exercise
QObject::connect: signal not found in Exercise

After banging my head around and checking my code, I tried to change the signal/slot synthax with the following:

connect(this, SIGNAL(statusChanged()), this, SLOT(startStopElapsedPausedTimer()));

et voilà! No more connection error at runtime. Can anyone explain this to me? What's happening here? The wiki doesn't say anything about behaviour changes when adopting the new sythax

VRonin

could you show the definition of Exercise?

nwoki

The QQmlExtensionPlugin

.h

#ifndef EXERCISESETTINGSPLUGIN_H
#define EXERCISESETTINGSPLUGIN_H

#include <QtQml/QQmlExtensionPlugin>

class Q_DECL_EXPORT ExerciseSettingsPlugin : public QQmlExtensionPlugin
{
    Q_OBJECT
    Q_PLUGIN_METADATA(IID QQmlExtensionInterface_iid)

public:
    void registerTypes(const char *uri);
};

#endif // EXERCISESETTINGSPLUGIN_H

.cpp

#include "exercise.h"
#include "exercisesettingsplugin.h"

#include <QtQml/QQmlComponent>

void ExerciseSettingsPlugin::registerTypes(const char *uri)
{
    int versionMajor = 0;
    int versionMinor = 1;

    Q_UNUSED (versionMajor);
    Q_UNUSED (versionMinor);

    Q_ASSERT(uri == QLatin1String("nirvana.qml.exercisesettings"));
    qmlRegisterType<Exercise>(uri, versionMajor, versionMinor, "Exercise");
}

and Exercise .h

#ifndef EXERCISE_H
#define EXERCISE_H

#include <QtCore/QObject>

class Q_DECL_EXPORT Exercise : public QObject
{
    Q_OBJECT

    // list of properties

public:
    Exercise(QObject *parent = 0);
    Exercise(Exercise *ex);
    virtual ~Exercise();


Q_SIGNALS:
    void statusChanged();

private Q_SLOTS:
    void startStopElapsedPausedTimer();

private:
    void setupTimerConnections();


    class Private;
    Private * const d;
};

#endif // EXERCISE_H