Qt signal slot main thread

signals: void signalA(QString arg); private: Thread *thread; }; Когда я пытаюсь выполнить программу, слот не вызывается? если я добавлюQt::QueuedConnection работает, отправляя событие в цикл событий целевого потока (потока, где получатель QObject жизни).

c++ - Qt: Signal main thread - Stack Overflow Hi, since your worker-thread comes from another API you have to use this API's methods. But anyhow you managed to signal from this implementation. Would it be a solution to hold a pointer to your thread in your app, let thread signal the end of your thread, connect (to your Qt MainThread) and delete in slot. Qt signals and slots for newbies - Qt Wiki There are many problems with them. Qt offer new event-handling system - signal-slot connections. Imagine alarm clock. When alarm is ringing, signal is sending (emitting). And you're handling it as a slot. Every QObject class may have as many signals of slots as you want. You can emit signal only from that class, where signal is. You’re doing it wrong… - Qt Blog

Signals & Slots | Qt Core 5.12.3

Когда я начинал изучать библиотеку Qt, весьма полезным показался пример виджета, выводящего бегущую строку. Подобный пример описан в настоящей статье, на нем мы разберем: Механизм сигналов и слотов Qt; Организацию объектов Qt в древовидную структуру... Signals and slots - Wikipedia Signals and slots is a language construct introduced in Qt for communication between objects which makes it easy to implement the observer pattern while avoiding boilerplate code. The concept is that GUI widgets can send signals containing event information which can be received by other widgets... Qt: Сигналы и слоты (выдержка из документации Qt 4.x) Сигналы и слоты используются для связи между объектами. Механизм сигналов и слотов - это основная особенность Qt и, вероятно, основная часть Qt, которая больше всего отличается по функциональности от других библиотек. 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...

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Like with a QueuedConnection, an event is posted to the other thread's event loop. The event also contains a pointer to a QSemaphore. The thread that delivers the event will release the semaphore right after the slot has been called. Meanwhile, the thread that called the signal will acquire the semaphore in order to wait until the event is ... New Signal Slot Syntax - Qt Wiki Connecting in Qt 5. There are several ways to connect a signal in Qt 5. Old syntax. Qt 5 continues to support the old string-based syntax for connecting signals and slots defined in a QObject or any class that inherits from QObject (including QWidget) . connect( sender, SIGNAL( valueChanged( QString, QString ) ), receiver, SLOT( updateValue( QString ) ) );

Communicating with the Main Thread | C++ GUI ... - InformIT

Communicating with the Main Thread - InformIT Communicating with the Main Thread. When a Qt application starts, only one thread is running—the main thread. This is the only thread that is allowed to create the QApplication or QCoreApplication object and call exec() on it. After the call to exec(), this thread is either waiting for an event or processing an event. Threads and QObjects | Qt 5.12 Signals and Slots Across Threads. Qt supports these signal-slot connection types: Auto Connection (default) If the signal is emitted in the thread which the receiving object has affinity then the behavior is the same as the Direct Connection. Otherwise, the behavior is the same as the Queued Connection."

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Signals and Slots. Qt's signals and slots mechanism ensures that if you connect a signal to a slot, the slot will be called with the signal's parameters at the right time. Signals and slots can take any number of arguments of any type. They are completely type safe. Passing custom type pointers between threads via signals ... Hi, as topic partially described, I send pointers to my custom type object, which has 3 members (int, int and QVariant) via sig/slot between the main thread and the worker thread. I use the Controller - Worker approach from qt docs . Threads and QObjects | Qt 5.12

pyqt4 emiting signals in threads to slots in main thread. ... Segmentation fault while emitting signal from other thread in Qt-2. ... Signal/slot multithreading Qt. QThreads general usage - Qt Wiki The main thing in this example to keep in mind when using a QThread is that it's not a thread. It's a wrapper around a thread object. 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.