SFML & Qt not working well together.

Pippin · wrote on 16 Sept 2015, 11:03

Hello,

long story short I have an sf::RenderWindow instance (public static variable of class GS) and depending on when I create it with sf::RenderWindow::create I get nothing or a segmentation fault.

If my code is as follows:

// ...
QApplication app(argc, argv);
// ...
std::cout << "foo" << std::endl;
GS::window.create(sf::VideoMode(GS::resWidth, GS::resHeight), "Some Window :D");
std::cout << "foo" << std::endl;
// ...

then I only get one foo and the program is stalled indefinitely at that point.

If my code is as follows:

// ...
GS::window.create(sf::VideoMode(GS::resWidth, GS::resHeight), "Some Window :D");
// ...
QApplication app(argc, argv);
// ...

then the window is created successfully (although there's nothing on it yet) and the program goes on. As the program progresses, valgrind spots a few problems:

(Menu.cpp:27 is QApplication app(argc, argv); and Menu.cpp:36 is return app.exec();)

==5347== Conditional jump or move depends on uninitialised value(s)
==5347==    at 0x1B8C14BA: ??? (in /usr/lib/x86_64-linux-gnu/libgtk-x11-2.0.so.0.2400.23)
==5347==    by 0x98425E6: ??? (in /usr/lib/x86_64-linux-gnu/libgobject-2.0.so.0.4002.0)
==5347==    by 0x985B087: g_signal_emit_valist (in /usr/lib/x86_64-linux-gnu/libgobject-2.0.so.0.4002.0)
==5347==    by 0x985C211: g_signal_emit_by_name (in /usr/lib/x86_64-linux-gnu/libgobject-2.0.so.0.4002.0)
==5347==    by 0x9849B38: g_object_set_valist (in /usr/lib/x86_64-linux-gnu/libgobject-2.0.so.0.4002.0)
==5347==    by 0x984A396: g_object_set (in /usr/lib/x86_64-linux-gnu/libgobject-2.0.so.0.4002.0)
==5347==    by 0x5FAAEE5: QGtkStylePrivate::initGtkWidgets() const (in /usr/lib/x86_64-linux-gnu/libQt5Widgets.so.5.2.1)
==5347==    by 0x5F2E07C: QStyleFactory::create(QString const&) (in /usr/lib/x86_64-linux-gnu/libQt5Widgets.so.5.2.1)
==5347==    by 0x5ECD98B: QApplication::style() (in /usr/lib/x86_64-linux-gnu/libQt5Widgets.so.5.2.1)
==5347==    by 0x5ECDCE4: QApplicationPrivate::initialize() (in /usr/lib/x86_64-linux-gnu/libQt5Widgets.so.5.2.1)
==5347==    by 0x5ECDD32: QApplicationPrivate::construct() (in /usr/lib/x86_64-linux-gnu/libQt5Widgets.so.5.2.1)
==5347==    by 0x5832B5: main (Menu.cpp:27)
==5347== 
==5347== Conditional jump or move depends on uninitialised value(s)
==5347==    at 0x9AF9320: g_utf8_offset_to_pointer (in /lib/x86_64-linux-gnu/libglib-2.0.so.0.4002.0)
==5347==    by 0x1B8C46A0: ??? (in /usr/lib/x86_64-linux-gnu/libgtk-x11-2.0.so.0.2400.23)
==5347==    by 0x1B8C4C2D: ??? (in /usr/lib/x86_64-linux-gnu/libgtk-x11-2.0.so.0.2400.23)
==5347==    by 0x1B8C4F1E: ??? (in /usr/lib/x86_64-linux-gnu/libgtk-x11-2.0.so.0.2400.23)
==5347==    by 0x98423B7: g_closure_invoke (in /usr/lib/x86_64-linux-gnu/libgobject-2.0.so.0.4002.0)
==5347==    by 0x9853556: ??? (in /usr/lib/x86_64-linux-gnu/libgobject-2.0.so.0.4002.0)
==5347==    by 0x985BA28: g_signal_emit_valist (in /usr/lib/x86_64-linux-gnu/libgobject-2.0.so.0.4002.0)
==5347==    by 0x985BCE1: g_signal_emit (in /usr/lib/x86_64-linux-gnu/libgobject-2.0.so.0.4002.0)
==5347==    by 0x1BA4863F: gtk_widget_realize (in /usr/lib/x86_64-linux-gnu/libgtk-x11-2.0.so.0.2400.23)
==5347==    by 0x1BA49917: gtk_widget_set_parent (in /usr/lib/x86_64-linux-gnu/libgtk-x11-2.0.so.0.2400.23)
==5347==    by 0x1B8F25B2: gtk_fixed_put (in /usr/lib/x86_64-linux-gnu/libgtk-x11-2.0.so.0.2400.23)
==5347==    by 0x9845486: g_cclosure_marshal_VOID__OBJECTv (in /usr/lib/x86_64-linux-gnu/libgobject-2.0.so.0.4002.0)
==5347== 
==5347== Conditional jump or move depends on uninitialised value(s)
==5347==    at 0x9AF934F: g_utf8_offset_to_pointer (in /lib/x86_64-linux-gnu/libglib-2.0.so.0.4002.0)
==5347==    by 0x1B8C46A0: ??? (in /usr/lib/x86_64-linux-gnu/libgtk-x11-2.0.so.0.2400.23)
==5347==    by 0x1B8C4C2D: ??? (in /usr/lib/x86_64-linux-gnu/libgtk-x11-2.0.so.0.2400.23)
==5347==    by 0x1B8C4F1E: ??? (in /usr/lib/x86_64-linux-gnu/libgtk-x11-2.0.so.0.2400.23)
==5347==    by 0x98423B7: g_closure_invoke (in /usr/lib/x86_64-linux-gnu/libgobject-2.0.so.0.4002.0)
==5347==    by 0x9853556: ??? (in /usr/lib/x86_64-linux-gnu/libgobject-2.0.so.0.4002.0)
==5347==    by 0x985BA28: g_signal_emit_valist (in /usr/lib/x86_64-linux-gnu/libgobject-2.0.so.0.4002.0)
==5347==    by 0x985BCE1: g_signal_emit (in /usr/lib/x86_64-linux-gnu/libgobject-2.0.so.0.4002.0)
==5347==    by 0x1BA4863F: gtk_widget_realize (in /usr/lib/x86_64-linux-gnu/libgtk-x11-2.0.so.0.2400.23)
==5347==    by 0x1BA49917: gtk_widget_set_parent (in /usr/lib/x86_64-linux-gnu/libgtk-x11-2.0.so.0.2400.23)
==5347==    by 0x1B8F25B2: gtk_fixed_put (in /usr/lib/x86_64-linux-gnu/libgtk-x11-2.0.so.0.2400.23)
==5347==    by 0x9845486: g_cclosure_marshal_VOID__OBJECTv (in /usr/lib/x86_64-linux-gnu/libgobject-2.0.so.0.4002.0)
==5347== 
==5347== Conditional jump or move depends on uninitialised value(s)
==5347==    at 0x9AF9320: g_utf8_offset_to_pointer (in /lib/x86_64-linux-gnu/libglib-2.0.so.0.4002.0)
==5347==    by 0x1B8C46A0: ??? (in /usr/lib/x86_64-linux-gnu/libgtk-x11-2.0.so.0.2400.23)
==5347==    by 0x1B8C4C2D: ??? (in /usr/lib/x86_64-linux-gnu/libgtk-x11-2.0.so.0.2400.23)
==5347==    by 0x1B8C4D0F: ??? (in /usr/lib/x86_64-linux-gnu/libgtk-x11-2.0.so.0.2400.23)
==5347==    by 0x1BE5ECE6: ??? (in /usr/lib/x86_64-linux-gnu/libgdk-x11-2.0.so.0.2400.23)
==5347==    by 0x9ACBCE4: g_main_context_dispatch (in /lib/x86_64-linux-gnu/libglib-2.0.so.0.4002.0)
==5347==    by 0x9ACC047: ??? (in /lib/x86_64-linux-gnu/libglib-2.0.so.0.4002.0)
==5347==    by 0x9ACC0EB: g_main_context_iteration (in /lib/x86_64-linux-gnu/libglib-2.0.so.0.4002.0)
==5347==    by 0x6EBB98B: QEventDispatcherGlib::processEvents(QFlags<QEventLoop::ProcessEventsFlag>) (in /usr/lib/x86_64-linux-gnu/libQt5Core.so.5.2.1)
==5347==    by 0x6E6D96A: QEventLoop::exec(QFlags<QEventLoop::ProcessEventsFlag>) (in /usr/lib/x86_64-linux-gnu/libQt5Core.so.5.2.1)
==5347==    by 0x6E740E0: QCoreApplication::exec() (in /usr/lib/x86_64-linux-gnu/libQt5Core.so.5.2.1)
==5347==    by 0x5833FB: main (Menu.cpp:36)
==5347== 
==5347== Conditional jump or move depends on uninitialised value(s)
==5347==    at 0x9AF934F: g_utf8_offset_to_pointer (in /lib/x86_64-linux-gnu/libglib-2.0.so.0.4002.0)
==5347==    by 0x1B8C46A0: ??? (in /usr/lib/x86_64-linux-gnu/libgtk-x11-2.0.so.0.2400.23)
==5347==    by 0x1B8C4C2D: ??? (in /usr/lib/x86_64-linux-gnu/libgtk-x11-2.0.so.0.2400.23)
==5347==    by 0x1B8C4D0F: ??? (in /usr/lib/x86_64-linux-gnu/libgtk-x11-2.0.so.0.2400.23)
==5347==    by 0x1BE5ECE6: ??? (in /usr/lib/x86_64-linux-gnu/libgdk-x11-2.0.so.0.2400.23)
==5347==    by 0x9ACBCE4: g_main_context_dispatch (in /lib/x86_64-linux-gnu/libglib-2.0.so.0.4002.0)
==5347==    by 0x9ACC047: ??? (in /lib/x86_64-linux-gnu/libglib-2.0.so.0.4002.0)
==5347==    by 0x9ACC0EB: g_main_context_iteration (in /lib/x86_64-linux-gnu/libglib-2.0.so.0.4002.0)
==5347==    by 0x6EBB98B: QEventDispatcherGlib::processEvents(QFlags<QEventLoop::ProcessEventsFlag>) (in /usr/lib/x86_64-linux-gnu/libQt5Core.so.5.2.1)
==5347==    by 0x6E6D96A: QEventLoop::exec(QFlags<QEventLoop::ProcessEventsFlag>) (in /usr/lib/x86_64-linux-gnu/libQt5Core.so.5.2.1)
==5347==    by 0x6E740E0: QCoreApplication::exec() (in /usr/lib/x86_64-linux-gnu/libQt5Core.so.5.2.1)
==5347==    by 0x5833FB: main (Menu.cpp:36)
==5347== 
==5347== Conditional jump or move depends on uninitialised value(s)
==5347==    at 0x9AF9320: g_utf8_offset_to_pointer (in /lib/x86_64-linux-gnu/libglib-2.0.so.0.4002.0)
==5347==    by 0x1B8C46A0: ??? (in /usr/lib/x86_64-linux-gnu/libgtk-x11-2.0.so.0.2400.23)
==5347==    by 0x1B8C4D28: ??? (in /usr/lib/x86_64-linux-gnu/libgtk-x11-2.0.so.0.2400.23)
==5347==    by 0x1BE5ECE6: ??? (in /usr/lib/x86_64-linux-gnu/libgdk-x11-2.0.so.0.2400.23)
==5347==    by 0x9ACBCE4: g_main_context_dispatch (in /lib/x86_64-linux-gnu/libglib-2.0.so.0.4002.0)
==5347==    by 0x9ACC047: ??? (in /lib/x86_64-linux-gnu/libglib-2.0.so.0.4002.0)
==5347==    by 0x9ACC0EB: g_main_context_iteration (in /lib/x86_64-linux-gnu/libglib-2.0.so.0.4002.0)
==5347==    by 0x6EBB98B: QEventDispatcherGlib::processEvents(QFlags<QEventLoop::ProcessEventsFlag>) (in /usr/lib/x86_64-linux-gnu/libQt5Core.so.5.2.1)
==5347==    by 0x6E6D96A: QEventLoop::exec(QFlags<QEventLoop::ProcessEventsFlag>) (in /usr/lib/x86_64-linux-gnu/libQt5Core.so.5.2.1)
==5347==    by 0x6E740E0: QCoreApplication::exec() (in /usr/lib/x86_64-linux-gnu/libQt5Core.so.5.2.1)
==5347==    by 0x5833FB: main (Menu.cpp:36)
==5347== 
==5347== Conditional jump or move depends on uninitialised value(s)
==5347==    at 0x9AF934F: g_utf8_offset_to_pointer (in /lib/x86_64-linux-gnu/libglib-2.0.so.0.4002.0)
==5347==    by 0x1B8C46A0: ??? (in /usr/lib/x86_64-linux-gnu/libgtk-x11-2.0.so.0.2400.23)
==5347==    by 0x1B8C4D28: ??? (in /usr/lib/x86_64-linux-gnu/libgtk-x11-2.0.so.0.2400.23)
==5347==    by 0x1BE5ECE6: ??? (in /usr/lib/x86_64-linux-gnu/libgdk-x11-2.0.so.0.2400.23)
==5347==    by 0x9ACBCE4: g_main_context_dispatch (in /lib/x86_64-linux-gnu/libglib-2.0.so.0.4002.0)
==5347==    by 0x9ACC047: ??? (in /lib/x86_64-linux-gnu/libglib-2.0.so.0.4002.0)
==5347==    by 0x9ACC0EB: g_main_context_iteration (in /lib/x86_64-linux-gnu/libglib-2.0.so.0.4002.0)
==5347==    by 0x6EBB98B: QEventDispatcherGlib::processEvents(QFlags<QEventLoop::ProcessEventsFlag>) (in /usr/lib/x86_64-linux-gnu/libQt5Core.so.5.2.1)
==5347==    by 0x6E6D96A: QEventLoop::exec(QFlags<QEventLoop::ProcessEventsFlag>) (in /usr/lib/x86_64-linux-gnu/libQt5Core.so.5.2.1)
==5347==    by 0x6E740E0: QCoreApplication::exec() (in /usr/lib/x86_64-linux-gnu/libQt5Core.so.5.2.1)
==5347==    by 0x5833FB: main (Menu.cpp:36)
==5347==

Then, the program ultimately encounters a segfault when using sf::RenderWindow::draw on an sf::Text instance. Here is what valgrind has to say about it:

==5347== Invalid read of size 8
==5347==    at 0x5055BA8: sf::Font::getTexture(unsigned int) const (in /usr/local/lib/libsfml-graphics.so.2.3.0)
==5347==    by 0x5081AF2: sf::Text::draw(sf::RenderTarget&, sf::RenderStates) const (in /usr/local/lib/libsfml-graphics.so.2.3.0)
==5347==    by 0x5076D38: sf::RenderTarget::draw(sf::Drawable const&, sf::RenderStates const&) (in /usr/local/lib/libsfml-graphics.so.2.3.0)
==5347==    by 0x52E909: BlitOtherStuff() (Functions.cpp:1577)
==5347==    by 0x52EC32: Loop() (Functions.cpp:1615)
==5347==    by 0x5126E6: GS::Run() (GS.cpp:2272)
==5347==    by 0x4E8ABC: OpeningInterface::GoSolitaire() (OpeningInterface.cpp:46)
==5347==    by 0x586100: OpeningInterface::qt_static_metacall(QObject*, QMetaObject::Call, int, void**) (moc_OpeningInterface.cpp:74)
==5347==    by 0x6E962A5: QMetaObject::activate(QObject*, int, int, void**) (in /usr/lib/x86_64-linux-gnu/libQt5Core.so.5.2.1)
==5347==    by 0x6238E41: QAbstractButton::clicked(bool) (in /usr/lib/x86_64-linux-gnu/libQt5Widgets.so.5.2.1)
==5347==    by 0x5FC2095: QAbstractButtonPrivate::emitClicked() (in /usr/lib/x86_64-linux-gnu/libQt5Widgets.so.5.2.1)
==5347==    by 0x5FC2BAD: QAbstractButtonPrivate::click() (in /usr/lib/x86_64-linux-gnu/libQt5Widgets.so.5.2.1)
==5347==  Address 0xffeffc4e8 is not stack'd, malloc'd or (recently) free'd
==5347== 
==5347== Invalid read of size 4
==5347==    at 0x5055BC4: sf::Font::getTexture(unsigned int) const (in /usr/local/lib/libsfml-graphics.so.2.3.0)
==5347==    by 0x5081AF2: sf::Text::draw(sf::RenderTarget&, sf::RenderStates) const (in /usr/local/lib/libsfml-graphics.so.2.3.0)
==5347==    by 0x5076D38: sf::RenderTarget::draw(sf::Drawable const&, sf::RenderStates const&) (in /usr/local/lib/libsfml-graphics.so.2.3.0)
==5347==    by 0x52E909: BlitOtherStuff() (Functions.cpp:1577)
==5347==    by 0x52EC32: Loop() (Functions.cpp:1615)
==5347==    by 0x5126E6: GS::Run() (GS.cpp:2272)
==5347==    by 0x4E8ABC: OpeningInterface::GoSolitaire() (OpeningInterface.cpp:46)
==5347==    by 0x586100: OpeningInterface::qt_static_metacall(QObject*, QMetaObject::Call, int, void**) (moc_OpeningInterface.cpp:74)
==5347==    by 0x6E962A5: QMetaObject::activate(QObject*, int, int, void**) (in /usr/lib/x86_64-linux-gnu/libQt5Core.so.5.2.1)
==5347==    by 0x6238E41: QAbstractButton::clicked(bool) (in /usr/lib/x86_64-linux-gnu/libQt5Widgets.so.5.2.1)
==5347==    by 0x5FC2095: QAbstractButtonPrivate::emitClicked() (in /usr/lib/x86_64-linux-gnu/libQt5Widgets.so.5.2.1)
==5347==    by 0x5FC2BAD: QAbstractButtonPrivate::click() (in /usr/lib/x86_64-linux-gnu/libQt5Widgets.so.5.2.1)
==5347==  Address 0x8b287f8b48000020 is not stack'd, malloc'd or (recently) free'd
==5347==

However, my SFML project works fine if I launch it entirely before QApplication app(argc, argv); or if I launch it in a separate program where I'm not using Qt at all. If somebody has any idea why SFML and Qt seem to conflict with each other, please share.

Thank you.