Qt 5 continues to support the old string-based syntax for connecting signals and slots defined in a QObject or any class that inherits from QObject (including QWidget) connect (sender, SIGNAL (valueChanged (QString, QString)), receiver, SLOT (updateValue (QString))); New: connecting to QObject member.

Signal And Slot Qt5 C++ Download

Case when the slot require more arguments than the signal but the extra arguments in the slot are all default arguments. For example, I can't connect my signal showMessage(QString) to QStatusBar::showMessage(QString, int=0) this way. I'll get a static assert 'The slot requires more arguments than the signal provides.' Qt5 alpha has been released. One of the features which I have been working on is a new syntax for signals and slot. This blog entry will present it. Another implementation of signals exists for ActionScript 3.0, inspired by C# events and signals/slots in Qt. Additionally, a delegate can be a local variable, much like a function pointer, while a slot in Qt must be a class member declared as such. The C based GObject system also provides similar functionality via GSignal.

Signal And Slot Qt C++

2012-09-04 04:59:19 UTC

Hi, there! I try to connect signals and slot in Qt 5 using new syntax. But I have a question: how to connect overloaded signals to special slots?
For example, I have the following code:
QSpinBox *spinBox = new QSpinBox(&window);
QSlider *slider = new QSlider(Qt::Horizontal, &window);
QObject::connect(slider, &QSlider::valueChanged, spinBox, &QSpinBox::setValue);
QObject::connect(spinBox, &QSpinBox::valueChanged, slider, &QSlider::setValue);
valueChanged() in QSpinBox is an overloaded signal. When I use qmake 2.01a to compile it, the error shows:
no matching function for call to 'QObject::connect(QSpinBox*&, <unresolved overloaded function type>, QSlider*&, void (QAbstractSlider::*)(int))'
How could I solve this?
In Qt 4 I could specialize the signal using SIGNAL(valueChanged(int)), how could I do in Qt 5?
Cheng Liang
Nanjing, China
http://www.devbean.info