Просматривая источник Qt, кажется, что, когда вызывается слот из QMetaObject:: invokeMethod, можно указать тип возврата и получить возвращаемое значение. (Посмотрите на invokeMethod в справке Qt). Я не мог найти много примеров того, как это действительно используется в... Qt - Singleshot Timer with Lambda function as slot | qt… If a singleshot timer is required, it is quiet handy to have the slot as lambda function right in the place where the timer is declaredIn earlier Qt5 versions it has to be done with more boiler plate code: QTimer *timer = new QTimer(this); timer->setSingleShot(true) Кто послал сигнал в слот? | C++ (Qt) Кто послал сигнал в слот? - русский QT форум.Тролли пишут что данный путь нарушает "сигнал-слотовую-парадигму" . Кроме того, ссылка возвращаемая функцией будет "не валидна" в случае соединения объектов в разных потоках - смотрите Assistant. c++ signal - Qt:meaning of slot return value? - CODE… 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
Getting a return value from an emitted signal | Qt Forum
Okey, briefly, please understand that the doWork(QPixmap pic, QString str, int indx) function takes 3 arguments and emit valueChanged(pic, str,indx) signal also returns 3 arguments. But the problem is, the doWork() slot also contains a Qt Network request, which is connected to syncRequestFinished() slot. Function with Signals & Slots | Qt Forum Function with Signals & Slots Function with Signals & Slots @gabor53 You should read again about Qt signals/slots. They are used for asynchronous communication and to react on user interactions. ... If you want to assign a value returned from a function to a variable, well then, by all means, make the function return the proper type and ... PyQt slot return value | Qt Forum Looks like your connection to Qt Forum was lost, please wait while we try to reconnect. Slot with return value called via Signal between differen Threads | Qt … What you are seeing is undefined behaviour. 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.
QWindow Class | Qt GUI 5.12.3
Can Qt signals return a value - forums.wikitechy.com It captures the return value from the slots. Expand the code”testSlot2″, and return the last value from the connected slots of the signal. Qt Signals are a syntax sugared interface to the signaling pattern. Slots are the recipients of signal and direct connected signal-slot relationship. [Solved] Return value from dialog | Qt Forum
The return value of this method call is placed in returnValue. If the invocation is asynchronous, the return value cannot be evaluated. You can pass up to ten arguments (val0, val1, val2, val3, val4, val5, val6, val7, val8, and val9) to this method call. QGenericArgument and QGenericReturnArgument are internal helper classes.
It is possible for slots to return values to the QML caller ... QML functions appear as slots in Python, ... PySide; Developing with Qt::Qt Quick; Qt 4.8: QDialog Class Reference Public Functions; Public Slots; ... The QDialog class is the base class ... The Extension Example shows how to achieve extensible dialogs using Qt. Return Value ... 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. Signals & Slots | Qt Core 5.12.3 ... but we can always subclass widgets to add our own signals to them. A slot is a function ... Qt's signals and slots ... { return m_value; } public slots ...
How to Use the Signal/Slot Communication Mechanism? | ROOT a ...
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? According to the documentation the return value from a slot doesn't mean anything.Глядя через источник Qt, кажется, что, когда слот вызывается из QMetaObject :: InvokeMethod типа возвращаемого значения может быть определен и получено возвращаемое значение. Slot with return value called via Signal between differen... |… So the Return Value seems like just not received. Can someone tell me if this is "normal" QT behaivior? Im I doing or understanding somethingMake 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...
Boost.Signals - CiteSeerX Boost.Function, please note that the preferred syntactic form in Signals is equivalent to that of .... Just as slots can receive arguments, they can also return values. ...... Signals and Qt Signals and Slots, the relevant part of your .pro file might look. Have lambdas helped you write "better" C++? How? : cpp - Reddit Qt for example is massively simplified when you do not have to create yet another slot for a minor corner case. .... To add to other posts, it also helped encapsulate " helper functions" to some bigger more complex functions. ..... Instead I write a lambda that returns the value to assign and call it in-place: PySide/PyQt Tutorial: Creating Your Own Signals and Slots - Python ...