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. However, the mechanism exists so that return values from slots can be accessed if the slot is called via invokeMethod. PyQt slot return value | Qt Forum Qt Development Language Bindings PyQt slot return value PyQt slot return value. This topic has been deleted. Only users with topic management privileges can see it. thumperj. last edited by . Any help with this would be appreciated, including hints on how to debug further. The pyqtSlot decorator takes a result as one of the parameters. Slot doesnt exist in connect function in C++/Qt project
This function returns 0 if no tests failed, or a value other than 0 if one or more tests failed or in case of unhandled exceptions. (Skipped tests do not influence the return value.)
QtScript – WebKit Any QObject-derived class instance can be exported to JavaScript this way, without the C++ class author having to do anything special; just declare his properties (Q_Property) and slots in the class declaration. QSpinBox Class | Qt Widgets 5.12 The QString overload provides the value with both prefix() and suffix(). The current value can be fetched with value() and set with setValue(). QMetaMethod Class | Qt Core 5.12.2 Because signals and slots can be dynamically invoked, you must enclose the arguments using the Q_ARG() and Q_Return_ARG() macros. Q_ARG() takes a type name and a const reference of that type; Q_Return_ARG() takes a type name and a non-const …
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.
How to Use Signals and Slots - Qt Wiki A developer can choose to connect to a signal by creating a function (a slot) and calling the connect() function to relate the signal to the slot. Qt's signals and slots mechanism does not require classes to have knowledge of each other, which makes it much easier to develop highly reusable classes. Qt signals and slots for newbies - Qt Wiki
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.
This page describes a few alternative approaches for connecting signals between QML and PySide. Simple illustrative examples about the signal connectivity are also provided in the pyside-examples repository.Browse the git tree directly or download a tarball of all examples and refer to the examples/declarative/signals directory. Qt 4.8: QDialog Class Reference The QDialog class is the base class of dialog windows. A dialog window is a top-level window mostly used for short-term tasks and brief communications with the user. QDialogs may be modal or modeless. QDialogs can provide a return value, and they can have default buttons. How Qt Signals and Slots Work - Woboq
Qt in Education The Qt object model and the signal slot concept
You seem to be in a confusion. Even though signals in Qt can indeed return values, this is rarely used, if ever. Namely because it doesn't make a lot of sense. What you probably want to do is not return but emit the image with a signal, this way you can connect it to a function that will receive the image and do something with it.
Automatic Connections: using Qt signals and slots the easy…