Qt invoke slot another thread

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Threads Events QObjects - Qt Wiki A function is thread-safe if it's safe to invoke it from more than one thread at the same time even if the invocations reference shared data. Events and the event loop. Being an event-driven toolkit, events and event delivery play a central role in Qt architecture. Qt: Access GUI From Another Thread? - Allegro Apparently in Qt you can only access GUI elements from the GUI (main) thread. I need to use multiple threads to do work while keeping the GUI responsive, and yet the worker threads need to modify the GUI. Qt does provide an Event system that's thread-safe, but writing all those different events is not something I look forward to. Communicating with the Main Thread - InformIT

You start work in your thread by giving your worker object a slot. In the default implementation, your thread will get an event loop (run() calls exec()), so you can invoke a slot in it. You can invoke that slot by connecting a signal to it from the main thread, or by using QMetaObject::invokeMethod.

Both the signal and slot are defined in the same class and running under the main GUI thread, but I call the emit in another function which is being controlled by a boost thread type of thread. I am using Qt4 and Ubuntu 10.04 is my OS. This function is called from another thread which is emitting the signal. QThread, execute slot without signal | Qt Forum I have been researching about QThreads, and have found out that the best way to use thread is to inherit a QObject and then move that to another thread. Signals are important, because with a queued connection, I don't have to worry about locking anything.... Initialization in a new thread. | Qt Forum

Qt::QueuedConnection - Слот вызывается когда элемент управления возвращает управление в цикл обработки событий в потоке получателя.Поэтому сигнал передается в другой поток. В чем проблема-то: сперва передаем переменные, а потом запускаем поток. другими словами в...

I think mainObject is not created in main thread. It would have been created by another worker thread. That thread may not have even loop. Just to ensure that can you print QThread::currentThreadID() in main and also in initialise method ? Also you don't have to do anything for inserting the slot in to main thread event loop. logmessage from another thread to the mainwindow slot | Qt Forum... In Qt, whether signal-slot connection crosses a thread boundary or not does not matter - it works same regardless of threads. The only thing which might not work is when custom objects are sent - but then all that is needed is to properly register them. Qt warns about it at compile time - so it's not a problem in this case. invokeMethod in other thread | Qt Forum invokeMethod in other thread invokeMethod in other thread ... InitLoLaSocket is the signal of the emitting class whereas InitLoLaUDPsocket is the slot of the target class running in another thread. still thinking about the others ... Reply Quote 0. ... I suspect you want to provide a blocking queued call (i.e. Qt::BlockingQueuedConnection) ... multithreading - Segmentation fault while emitting signal from... Both the signal and slot are defined in the same class and running under the main GUI thread, but I call the emit in another function which is being controlled by a boost thread type of thread. I am using Qt4 and Ubuntu 10.04 is my OS. This function is called from another thread which is emitting the signal.

Crash course in Qt for C++ developers, Part 3 / Clean Qt

Thus, a developer who wishes to invoke slots in the new thread must use the worker-object approach; new slots should not be implemented directly into a subclassed QThread. When subclassing QThread, keep in mind that the constructor executes in the old thread while run () executes in the new thread. Qt meta-object Programming - CodeProject The general Qt paradigm is to "move" an object onto a worker thread and then create a signal / slot connection so that objects in worker thread "A" signal the UI objects and vice versa. Multithreading with Qt - conf.qtcon.org QThread QThread p.5 QThread is the central class in Qt to run code in a different thread It's a QObject subclass Not copiable/moveable Has signals to notify when the thread starts/finishes Asynchronous Database Access with Qt 4.x | Linux Journal Communicating between threads now becomes a matter of connecting signals from one thread to the slots in another, and the mutexing and thread-safety issues of exchanging data between threads are handled by Qt.