.
Thread 2 (Thread 0x7ff497d54640 (LWP 4131)):
#0  0x00007ff4a401919f in __GI___poll (fds=0x7ff497d52f88, nfds=1, timeout=-1) at ../sysdeps/unix/sysv/linux/poll.c:29
        sc_ret = -516
        sc_cancel_oldtype = 0
#1  0x00007ff4a08aec1a in  () at /lib/x86_64-linux-gnu/libxcb.so.1
#2  0x00007ff4a08b0ffa in xcb_wait_for_event () at /lib/x86_64-linux-gnu/libxcb.so.1
#3  0x00007ff4980b5e28 in  () at /lib/x86_64-linux-gnu/libQt5XcbQpa.so.5
#4  0x00007ff4a4548b51 in  () at /lib/x86_64-linux-gnu/libQt5Core.so.5
#5  0x00007ff4a396b430 in start_thread (arg=0x7ff497d54640) at pthread_create.c:473
        ret = <optimised out>
        pd = 0x7ff497d54640
        unwind_buf = {cancel_jmp_buf = {{jmp_buf = {140688496084544, 1966787042706342196, 140728704523614, 140728704523615, 0, 140688496084544, -1971941327522610892, -1971968295707197132}, mask_was_saved = 0}}, priv = {pad = {0x0, 0x0, 0x0, 0x0}, data = {prev = 0x0, cleanup = 0x0, canceltype = 0}}}
        not_first_call = 0
#6  0x00007ff4a4024cc3 in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:95
.
Thread 1 (Thread 0x7ff498eb6480 (LWP 3595)):
#0  0x00007ff4a476963f in  () at /lib/x86_64-linux-gnu/libQt5Core.so.5
#1  0x00007ff4a50fe5a6 in QGuiApplication::screenAdded(QScreen*) () at /lib/x86_64-linux-gnu/libQt5Gui.so.5
#2  0x00007ff4a50e3d80 in QWindowSystemInterface::handleScreenAdded(QPlatformScreen*, bool) () at /lib/x86_64-linux-gnu/libQt5Gui.so.5
#3  0x00007ff4980b9540 in QXcbConnection::initializeScreens() () at /lib/x86_64-linux-gnu/libQt5XcbQpa.so.5
#4  0x00007ff4980942a4 in QXcbConnection::QXcbConnection(QXcbNativeInterface*, bool, unsigned int, char const*) () at /lib/x86_64-linux-gnu/libQt5XcbQpa.so.5
#5  0x00007ff49809710f in QXcbIntegration::QXcbIntegration(QStringList const&, int&, char**) () at /lib/x86_64-linux-gnu/libQt5XcbQpa.so.5
#6  0x00007ff4b172c593 in  () at /usr/lib/x86_64-linux-gnu/qt5/plugins/platforms/libqxcb.so
#7  0x00007ff4a51029fc in QGuiApplicationPrivate::createPlatformIntegration() () at /lib/x86_64-linux-gnu/libQt5Gui.so.5
#8  0x00007ff4a5103e88 in QGuiApplicationPrivate::createEventDispatcher() () at /lib/x86_64-linux-gnu/libQt5Gui.so.5
#9  0x00007ff4a4738e46 in QCoreApplicationPrivate::init() () at /lib/x86_64-linux-gnu/libQt5Core.so.5
#10 0x00007ff4a5106e02 in QGuiApplicationPrivate::init() () at /lib/x86_64-linux-gnu/libQt5Gui.so.5
#11 0x00007ff4a8a97fed in QApplicationPrivate::init() () at /lib/x86_64-linux-gnu/libQt5Widgets.so.5
#12 0x00005571823d668b in SharedTools::QtSingleApplication::QtSingleApplication(QString const&, int&, char**) ()
#13 0x00005571822f730c in OCC::Application::Application(int&, char**) ()
#14 0x00005571822c33c7 in main ()