Qt signal slot with return value

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How Qt Signals and Slots Work - Part 2 - Qt5 New Syntax

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 - Part 3 - Queued and Inter ... DirectConnection: call the slot as seen in Part 1 */ So in this blog post we will see what exactly happens in queued_activate and other parts that were skipped for the BlockingQueuedConnection. Qt Event Loop. A QueuedConnection will post an event to the event loop to eventually be handled. How to Use QPushButton - Qt Wiki The following simple code snippet shows how to create and use QPushButton. It has been tested on Qt Symbian Simulator. An instance of QPushButton is created. Signal released() is connected to slot handleButton() which changes the text and the size of the button. To build and run the example: Create an empty folder c++ - Can Qt signals return a value? - Stack Overflow Boost.Signals allows various strategies of using the return values of slots to form the return value of the signal. E.g. adding them, forming a vector out of them, or returning the last one.. The common wisdom (expressed in the Qt documentation [EDIT: as well as some answers to this question ]) is that no such thing is possible with Qt signals.. However, when I run the moc on the following ...

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.

As you might have seen in the previous example, the slot was just declared as public and not as slot. Qt will indeed call directly the function pointer of the slot, and will not need moc introspection anymore. (It still needs it for the signal) But what we can also do is connecting to any function or functor: OpenTutorials_PyQt/signal_slot_03_custom_signal.py ... - GitHub

Using libsigc++ signals - Inkscape Wiki

8 Feb 2008 ... If the values are the same, we do nothing and return; otherwise, we apply the change and emit a signal to announce the change of state. GitHub - robertknight/qt-signal-tools: Utility classes related to Qt signal ... qt-signal-tools is a collection of utility classes related to signal and slots in Qt. It ... returns a default value if the object is destroyed before the wrapper is called. Boost.Signals - CiteSeerX Signals allows the user to specify the manner in which multiple return values ...... Signals and Qt Signals and Slots, the relevant part of your .pro file might look. Performance of a C++11 Signal System | Timj's bits and tests - Testbit

Last (c c- nextConnectionList )! A Small Example, a minimal C class declaration might read: class Counter public: Counter m_value 0; int value const return m_value; void setValue(int value private: int m_value; ; A small, qObject -based …

c++ - Qt: meaning of slot return value? - Stack Overflow 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. Getting a return value from an emitted signal | Qt Forum