Qt in Education The Qt object model and the signal slot ... Qt events signals and slots properties memory management. The QObject QObject is the base class to most Qt classes. ... A slot is defined in one of the slots sections A slot can return values, but not through connections Any number of signals can be connected to a slot How to Expose a Qt C++ Class with Signals and Slots to QML In contrast to the previous example, our new class also uses a return value for the increment slot. No further adjustments are required to receive the return value in QML. Qt automatically maps basic C++ types to QML types for all method parameters and return values. PyQt/Sending Python values with signals and slots - Python ... Sending Python values with signals and slots. On the #pyqt channel on Freenode, Khertan asked about sending Python values via Qt's signals and slots mechanism. The following example uses the PyQt_PyObject value declaration with an old-style signal-slot connection, and again when the signal is emitted, to communicate a Python dictionary. qt_widgets::check_box::connection::Slots - Rust
13 Feb 2012 ... What do you do if you think you've correctly connected a signal to a slot ... If need be, ensure that connect succeeds by testing its return value (it ...
Your slots can return a value. However, if the slot is connected to a signal and called when the signal is emitted, the return value will be ignored. But the slot is a normal member function and can be called like any other function. In this case, the return value qt4 - Qt: Return value of signal works, why is the official ... E.g. with Qt::SingleConnection there is no risk of multiple slots, with Qt::BlockingQueuedConnection there is only one return value at a time. "Never have a return value" (doc) is different to use wisely IMHO. All the above true, there might How to send data through signal and slot? - Stack Overflow When you want to 'return' some value, you pass that value to signal, i. e. call 'emit signal_name(value_to_return)'. So you can treat signals as 'inverted' methods whose params are actually return values that are passed to Signals and Slots | Introduction to GUI Programming with ... PyQt is more versatile than C++/Qt in this regard, because we can connect not just to slots, but also to any callable, and from PyQt 4.2, it is possible to dynamically add "predefined" signals and slots to QObjects. Let's see how signals and slots
PySide/PyQt Tutorial: Creating Your Own Signals and Slots - Python ...
Getting a return value from an emitted signal | Qt Forum Getting a return value from an emitted signal ... If you need a return value, ... There's at least two things that can happen that can mess things up: Multiple slots ... Return value from slot in differnet thread | Qt Forum I'd like to get a return value that tells me in the main/GUI thread if everything is ok. I know that slots should be ... Return value from slot in differnet thread. Signals & Slots | Qt 4.8 Qt's signals and slots mechanism ensures that if you connect a signal to a ... { return m_value; } public slots: void setValue ... They can never have return types ... How Qt Signals and Slots Work - Woboq
Can Qt's moc be replaced by C++ reflection?
Signals and slots can take any number of arguments of any type. ... int value() const { return m_value; } public slots: void setValue(int value); signals: void ... 20 ways to debug Qt signals and slots | Sam Dutton's blog
The signals and slots mechanism is a central feature of Qt and probably the part that differs most from the features provided by other frameworks.Slots can be used for receiving signals, but they are also normal member functions. Just as an object does not know if anything receives its signals, a slot does...
I think that the return value for a slot is only available when the function is called directly (when it is a normal C++ function) or when using invokeMethod. I think this is really meant for internal Qt functions rather than for normal use in programs using Qt. Edit: For the sample case Qt: meaning of slot return value?
Qt 4.8: QDialog Class Reference