Signals and slots are loosely coupled: A class which emits a signal neither knows nor cares which slots receive the signal. 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. Signal slots across threads performance - Qt Forum when setting up the signal/slot calls to the thread. Reply to Signal slots across threads performance on Tue, 25 Feb 2014 17:43:03 GMT I am using a queued connection because I don't want the caller to perform the necessary computations in the caller's thread. Threading Basics | Qt 4.8 Qt Thread Basics; QObject and Threads; ... Connect the signals to the GUI thread's slots using queued signal/slot connections. ... Using the thread pool has a performance advantage because threads are not destroyed after they have finished running. They are kept in a pool and wait to be used again later.
Сигналы и слоты Qt C++ не срабатывали
Problem in implementing signal slot in a threaded dll application Problem in implementing signal slot in a threaded dll application ... After getting loaded by process my dll class will launch a qt thread which will be receiving data from server using QTcpSocket. based on some special data , it will emit some signal to the calling class. I have ... Performance Considerations And Suggestions | Qt 5.12 It is important to note that using a low-priority worker thread is recommended to minimize the risk of starving the GUI thread (which could result in worse perceived performance). Also, remember that synchronization and locking mechanisms can be a significant cause of slow performance, and so care should be taken to avoid unnecessary locking. Signals & Slots | Qt 4.8
You seem to have at least three problems: First, by the look of things, you don't have an event loop running in your Sensor thread. That is, you probably did not call exec() inside your run() implementation. That means that signal slot connections to slots in this object won't work.
It depends on connection type you specified via calling connect function. The only way when slot will be launched concurrently is if you specified Qt::DirectConnection AND emitting signal in thread different from slot's thread. c++ - Qt events and signal/slots - Stack Overflow The Qt documentation probably explains it best: In Qt, events are objects, derived from the abstract QEvent class, that represent things that have happened either within an application or as a result of outside activity that the application needs to know about. Signal slots across threads performance | Qt Forum
Qt Signals/Slots and Threads - dskims.com
Send commands or data to the worker object over queued signal-slot connections. Permanent Repeatedly perform an expensive operation in another thread, where the thread does not need to receive any signals or events. Threading Basics | Qt 4.8 Connect the signals to the GUI thread's slots using queued signal/slot connections. Permanent: Have an object living in another thread and let it perform different tasks upon request. This means communication to and from the worker thread is required. Derive a class from QObject and implement the necessary slots and signals, move the object to a thread with a running event loop and communicate with the object over queued signal/slot connections. Permanent: Have an object living in another ... Signal slots across threads performance - Qt Forum
signals: void signalA(QString arg); private: Thread *thread; }; Когда я пытаюсь выполнить программу, слот не вызывается? если я добавлюСоединения в очереди Qt не могут работать, если в принимающем потоке нет цикла обработки событий. Когда объект-получатель живет в...
You are doing the signal and slot across thread. Signal is sent from MyThread and Slot is main thread. Is there even main event loop started before you start your service thread ? I suspect that you may not be starting the event loop where the mainObject exist. Hence you are hitting the issue. 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.
what is the advantage & disadvantage of Qt's signal-slot mechanism compared to MFC's message mechanism? is there anything which Qt can do but MFC can't? or Qt can easily realize but MFC is very hard? Meanwhile, the efficience problem, which one is more efficient on Windows? thank you very much Signals & Slots | Qt Core 5.12.3 Signals and slots are loosely coupled: A class which emits a signal neither knows nor cares which slots receive the signal. 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. Why I dislike Qt signals/slots - elfery It's possible for the slot/second signal to have fewer arguments than the first. The signals are processed during Qt's event loop and, if the target is in another thread, the arguments are automatically serialized and sent to that thread's event queue. This is very nice to have, as you can imagine. The problem with connections. The issue I have ... Threading Basics | Qt 4.8