Qt signal slot main thread

You could use the same technique to communicate the results back, but it would probably make more sense to add a signal to the worker object that is emitted when it's done. Attach this signal to a slot of some object living in your main thread and Qt will again take care to execute the slot in the main thread, not in the worker thread. Messaging and Signaling in C++ - Meeting C++ This allows to use 3rd party libraries which use these terms, e.g. boost::signal. Qt signal/slot implementation is thread safe, so that you can use it to send messages between different QThreads, this is especially important, as anything UI related should run in the main thread of Qt, anything that could block your UI should not run in this ...

In main GUI thread I have timer for show that GUI thread works. So qDebug() works fine and prints messages from my thread. Also timer from GUI thread works fine and prints message inside textEdit GUI field. Now when printMessage signal is emited, GUI thread executes slot method: user interface - Qt signaling across threads, one is GUI ... The owner thread makes a difference only when a slot is connected to a signal with the connection type other than Qt::DirectConnection. Then Qt will ensure that the slot runs on the owner thread, but for that the owner thread must be running an event loop with QThread::exec(). Emitting a Qt::signal from worker thread makes the UI ... When you emit a signal, Qt acquires relevant source and destination object mutexes, and compares the receiving object's thread() to QThread::currentThread(). If they are identical, the slot/functor is called immediately: it happens in the body of the signal, so the slot is called before the signal returns.

the thing is that the SLOT update_gui() is defined in the main window header and implemented in the .cpp, but it never gets to execute. I have tried attaching Qt::DirectConnection, and the gui updates, but when worker is finished... the whole program closes. I've looked this but didn't worked for me...

Qt Signals/Slots and Threads I'm new to GUI programming and multithreading. I am in the process of creating a real-time app that receivesI would like the thread to notify the main thread that there is a new screen available and I was thinking a signal/slots method would work the best for this. Как работает механизм signal-slot QT, если нужно... —… Всем привет! Сам по себе принцып работы сигнал-слот в qt мне понятен (когда один объект передаёт сигнал в слот дургого объекта в одном потоке). Совсем запутался, когда попытался разобраться, как же мне из объекта, находящегося в одном потоке... Qt - Multi window signal slot connection | qt Tutorial Connecting overloaded signals/slots. Multi window signal slot connection.SQL on Qt. Threading and Concurrency. Using Style Sheets Effectively.There is a MainWindow class that controls the Main Window view. A second window controlled by Website class.

c++ - Qt: Signal main thread - Stack Overflow

[QT] signals/slots между тредами не понимаю —…

[SOLVED] Qt: Main thread signal + worker thread slot. [SOLVED] Qt: Main thread signal + worker thread slot. This topic has been deleted. Only users with topic management privileges can see it. ronM71. last edited by . Say I wanted to have a worker thread that has slots for signals emmited from the main application thread.

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. Lock Free Multithreading in Qt – Dave Smith's Blog This might sound somewhat uninteresting at first, but it means you can have your own signals and slots outside the main thread. The Trolls created a new way to connect signals to slots such that signals can actually cross thread boundaries. I can now emit a signal in one thread and receive it in a slot in a different thread. Qt thread: simple, complete and stable (with full sources on ... Thread is surely one of the most discussed topic on Qt forums. Meanwhile, I never managed to find a simple example which describes how to simply do what I want to do: run a thread to do things and interrupt it if necessary (for example if the GUI is closed). Qt: wait for a signal in synchronously mode

PySide: problem with starting QThread with a signal when using ...

Communicating with the Main Thread | C++ GUI ... - InformIT The Image Pro application shows how Qt's signals and slots mechanism makes it easy to communicate with the main thread from a secondary thread. Implementing the secondary thread is trickier, because we must protect our member variables using a mutex, and we must put the thread to sleep and wake it up appropriately using a wait condition. QThreads general usage - Qt Wiki Usage with Worker class. This wrapper provides the signals, slots and methods to easily use the thread object within a Qt project. To use it, prepare a QObject subclass with all your desired functionality in it. Then create a new QThread instance, push the QObject onto it using moveToThread (QThread*) of the QObject instance and call start ()... PyQt/Threading,_Signals_and_Slots - Python Wiki

Qt слот сигнала над потоком, это безопасный способ? slot_triggered_by_signal_from_thread_B(){ foreach(myObject* i, map->childItems){ i->do_some_thing(); } } Безопасно ли это?Это безопасно до тех пор, пока вы используете подключение автоматического или очереди типа conncetion между нитями с тех пор слот будет... Qt Framework Events Signals Threads 2. Content Threading in QT QT Reentrancy vs QT ThreadSafe GUI and Non-GUI Threads Events and Event Loop Mechanism, restriction of using Events Integration in S60 Signals and Slots API and usage Implementation details 3. Threading in QT QT framework provide APIs similar to Posix Base class is... New Signal Slot Syntax - Qt Wiki This page was used to describe the new signal and slot syntax during its development. The feature is now released with Qt 5. Grafické programy v Qt 4 - 1 (úvod, hello world)