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@TomBdil I didnt find anything to fix that still I just find this bug pending being resolved https://bugreports.qt.io/browse/QTBUG-102321

Thx. But can't help here - don't use a mac.

@tataeress ? he does not explain how to debug my plugin hosted by designer.exe..

@amitsgh No worries, it happens to everybody. And QML is notorious for not printing enough warnings so it's easy to miss such details.

@fcarney This worked for me (I pointed it at Qt Design Studio Reduced). The first time I started my program after applying these settings my PC blue-screened though. Just a heads up! (After rebooting it worked fine)

@mpergand @Paul-Colby Thanks very much,Finally my problem is solved. I defined a pure cpp layer call c function in it and ...i used this layer in other qt classes...

@QuocKhanh Yes, QObject::connect() can make cross-thread connections. Why you would want to do this with QSerialPort, or what you have done that "didn't work", would have to be explained by you.

@Perdrix It has dead simple integration with Visual Studio and when you later might want to use CMake for building it is also easy to use. libraw, libtiff and boost are available and it would simplify things quite a lot for newcomers.

Solution found. Issue closed. In *.pro file: DEFINES += SOME_VALUE Here full explanation https://stackoverflow.com/questions/3348711/add-a-define-to-qmake-with-a-value

@Xav12358 Then I'm afraid I don't know since it's some PyCharm debugger issue.

@Paul-Colby Thanx.

@mjsmithers said in const function causes garbage collection crashes with QMap.: experiment more with Qmap::value(), although it's not clear from the documentation if it returns a copy or a const reference. As per my previous, I think this is 100% clear?

@ChrisW67 said in How to execute command installed with snap: Then the relevant directory is not in the PATH inherited by your process. On my Ubuntu machine the /snap/bin directory is in the system-wide path. Which is as I wrote above. However, I do not see a connection between lpr and snap. On a generic Ubuntu machine lpr is a compatibility tool installed as a native application by CUPS: I agree, this has nothing to do with snap. It should be in /usr/bin. That should be on $PATH already. @Stormbringer1900 said in How to execute command installed with snap: If I try QProcess::execute("whereis lpr"); there's no reply. whereis itself is in /usr/bin/. If by any chance, somehow, /usr/bin is not on PATH then the whereis itself will fail to execute. What is the return result from QProcess::execute()? Did it write anything to stdout/err? Probably the first thing to try is echo $PATH # or possibly /bin/echo $PATH Compare calling via QProcess from Qt app against what it is in external shell where lpr etc. work.

@SimonSchroeder said in QThread infinite loop: //-----8<--------------------------------------------- QThread *thread = new QThread(); thread->start(); // could also be done later MyClass *obj = new MyClass(); obj->moveToThread(thread); QTimer *timer = new QTimer(); timer->setInterval(1000); QObject::connect(timer, &QTimer::timout, obj, &MyClass::periodicFunction); timer->moveToThread(thread); timer->start(); Multithreading is hard! The timer->start() should come before timer->moveToThread(). I would also establish the connection from the QTimer instance to MyClass instance before moving the later. It's paranoia in this case, but prevents connecting to deleted objects in some realistic scenarios.