Qt slot function return value

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. Signals & Slots — Qt for Python In Qt, we have an alternative to the callback technique: We use signals and slots. A signal is emitted when a particular event occurs. Qt’s widgets have many predefined signals, but we can always subclass widgets to add our own signals to them. A slot is a function that is …

QMetaMethod Class | Qt 4.8 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. QMetaMethod Class | Qt Core 5.12.3 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.

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.

How to Expose a Qt C++ Class with Signals and Slots to QML - Felgo This guide shows how to enhance your C++ class with signals and slots for ... In other words, we want to trigger functions in QML when the C++ property changes. .... No further adjustments are required to receive the return value in QML. Qt ... Signals and Slots | Introduction to GUI Programming with Python and Qt Feb 8, 2008 ... In C++/Qt, slots are methods that must be declared with a special syntax; ... If the values are the same, we do nothing and return; otherwise, we apply .... If we use the SIGNAL() function with a signalSignature (a possibly empty ... Lambda Expressions and Qt 4.x - Silmor.de Writing a complete function just for a custom sorting is quite cumbersome and .... are copied (the lambda knows its context by value instead of by reference), but ... If you need the paramters or need a return type for the slot/lambda you have to ...

How to Expose a Qt C++ Class with Signals and Slots to QML

QDialog Class Reference - SourceForge.net

Qt: Signals & Slots | return 0; }

How Qt Signals and Slots Work - Part 2 - Qt5 New Syntax Functor method). The first one is the one that is much closer to the old syntax: you connect a signal from the sender to a slot in a receiver object. The two other overloads are connecting a signal to a static function or a functor object without a receiver. They are very similar and we will only analyze... Qt/C++ - Урок 024. Сигналы и слоты в Qt5 Сигналы и слоты используются для коммуникации между объектами в Qt. Механизм сигналов и слотов является центральной функцией в Qt, и вероятно это то, что отличает Qt по своему функционалу от других фреймворков.

How Qt Signals and Slots Work - Woboq

Qt 4.8: QMetaObject Class Reference The return value of the member function call is placed in ret. 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 the member function. QGenericArgument and QGenericReturnArgument are internal helper classes. QCoreApplication — Qt for Python Qt provides default library paths, but they can also be set using a qt.conf file. Paths specified in this file will override default values. Note that if the qt.conf file is in the directory of the application executable, it may not be found until a QCoreApplication is created. If it is not found when calling this function, the default library ... QDialog Class Reference - SourceForge.net

Qt.ConnectionType com.trolltech.qt.core Class Qt.ConnectionType ... the slot is invoked directly, as with Qt:: ... This function should return an integer value for the enum values of ... Signals & Slots | Qt 4.8 Signals and Slots. In Qt, we have an alternative to the callback technique: We use signals and slots. A signal is emitted when a particular event occurs. Qt's widgets have many predefined signals, but we can always subclass widgets to add our own signals to them. A slot is a function that is called in response to a particular signal.