Signals & Slots • Signal – Emitted when a particular event occurs (e.g., clicked()) – Qt widgets: predefined signals – Also create your own signals • Slot – Function called in response to a signal – Qt widgets: predefined slots (e.g., quit()) – Also create your own slots • Connection signals slots established by developer, c++ - Can Qt signals return a value? - Stack Overflow The constructor wires up two slots to the testSignal signal, and then emits the signal. It captures the return value from the slot(s) invoked. Unfortunately, you only get the last return value. If you evaluate the code above, you'll get: "testSlot2", the last return value from the connected slots of the signal. Getting a return value from an emitted signal | Qt Forum
methods and extending 'Qt' classes from R. Other packages build upon .... the values are double, a QSizeF instance is returned, otherwise an instance of .... These are typically signals and slots, although arbitrary methods/constructors are also ...
Slot return value - what if it would be not lost? | Qt Forum Note that you can trigger slots and get a return value. Look into the [[Doc:QMetaObject]] docs for details. OK, that is not the same as just emitting a signal and catch the return value (or, of course, values, if the signal was connected to multiple slots), but it may be useful nonetheless. Slot with return value called via Signal between differen Signals are not designed to give you the slots' return values, and there is no guarantee that your example will behave the same way in future versions of Qt. Make sure your code never tries to get the return value of a slot through a signal. Anyway, signal+slot connections do behave differently depending on the threads involved. 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 void and should not be used for this, even if they seem to do it. Emit a signal back seems easy. However, I'd like to know the result immediately. Or should I just call it as regular function instead of using the signal/slot Signals & Slots | Qt Core 5.9
foreach slot in connectedSlotsForSignal(signal): value = invoke slot with parameters from signal return value 明らかに、このプロセスではmocがもう少し役立ちます（初歩的な型チェックなど）が、絵を描くのに役立ちます。
Qt: Signals & Slots - PUC-Rio 1 Qt: Signals & Slots (Source: http://qt-project.org/doc/qt-4.8/signalsandslots.html ) Introduction Signals and slots are used for communication between objects. Interacting with QML Objects from C++ | Qt QML 5.9 Method parameters and return values passed from QML are always translated ... like any ordinary Qt C++ signal. In return, ... < < "Called the C++ slot with value: ... Qt 4.6: Signals and Slots - Club des développeurs Qt ...
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qt - My signal / slot connection does not work - Stack My signal / slot connection does not work. Always check return value of connect method (programmers should never ignore return values): Instead of. ... Qt Signals and slots mechanism blocked by a loop in main. 15. How to disconnect a signal with a slot temporarily in Qt? 0.
Qt: Signals & Slots - PUC-Rio
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. Need help passing a variable to another Form (Signals/Slots) @jsulm said in Need help passing a variable to another Form (Signals/Slots): @SnuggleKat Why don't you simply define the slot inside Dialog class? Exposing a member (opt_dia) as public to outside world is bad design. I'm aware it's bad design. That's why I asked what'd be the best way to instantiate it. Qt in Education The Qt object model and the signal slot ...
the vector _a is a list of arguments that is passed to qt_metacall. This is passed by QMetaObject::invokeMethod. So the return value in the moc generated code is saved and passed back to the caller. So for normal signal-slot interactions the return value is not used for anything at all. Can Qt signals return a value? - Stack Overflow OK. So, I did a little more investigating. Seems this is possible. I was able to emit a signal, and receive value from the slot the signal was ... How to send data through signal and slot? - Stack Overflow You're mixing C++ 'return' and Qt signal/slot. ... void bla() { emit doSomething( 3.1415926535); } signals: void doSomething(double value); }; class EventHandler: ...