I am encountering a segmentation fault in my C++ project and using gdb to traceback the cause.

Here is a minimal example that causes the segfault:

int main() {
    
    GameDataRef data = std::make_shared<GameData>();

    //ScreenState is an enum declared in a different file
    auto screenManager = new ScreenManager(ScreenState::MainMenu);
    
    while (data->window.isOpen()) {
        sf::Event event;
        sf::Keyboard keyboard;
        
        while (data->window.pollEvent(event)) {
            screenManager->handleEvents(event);
        }

        data->window.clear();

        screenManager->update();

        screenManager->draw();

        data->window.display();
    }

    delete screenManager;

    return 0;
}

Here is my ScreenManager.h file and relavent methods:

class ScreenManager {
public:
    ScreenManager(ScreenState initialState);

    void handleEvents(sf::Event event);
    void update();
    void draw() const;
    void pushState(ScreenState newState);
    void popState();

private:
    std::unique_ptr<Screens::Screen> createState(ScreenState state);

    std::stack<std::unique_ptr<Screens::Screen>> stateStack;
    ScreenState currentState;

    Settings settings;
    GameDataRef _data;
};

ScreenManager::ScreenManager(ScreenState initialState)
    : currentState(initialState) 
{
    pushState(initialState);
}

void ScreenManager::pushState(ScreenState newState) {
    stateStack.push(std::move(createState(currentState)));
    stateStack.top()->init(); 
}

std::unique_ptr<Screens::Screen> ScreenManager::createState(ScreenState state) {
    console->debug("Creating screen: " + std::to_string(static_cast<int>(state)));
    switch (state) {
        case ScreenState::MainMenu:
            return std::make_unique<Screens::MenuScreen>(_data);
        case ScreenState::Game:
            return std::make_unique<Screens::GameScreen>(_data, settings);
        case ScreenState::Pause:
            return std::make_unique<Screens::PauseScreen>(_data);
        case ScreenState::Settings:
           return std::make_unique<Screens::SettingsScreen>(_data, settings);
        default:
            throw std::runtime_error("Unknown screen state");
    }
}

The screen manager simply takes in an enum value and creates a screen unique_ptr then pushes it onto a stack. When init() is called it results in a segmentation fault.

Here is the trace back from gdb:

0x00007ffff7f30784 in std::_Rb_tree<unsigned int, std::pair<unsigned int const, sf::Font::Page>, std::_Select1st<std::pair<unsigned int const, sf::Font::Page> >, std::less<unsigned int>, std::allocator<std::pair<unsigned int const, sf::Font::Page> > >::_M_mbegin (this=0x470) at /usr/include/c++/12/bits/stl_tree.h:735
735     /usr/include/c++/12/bits/stl_tree.h: No such file or directory.

#0  0x00007ffff7f30784 in std::_Rb_tree<unsigned int, std::pair<unsigned int const, sf::Font::Page>, std::_Select1st<std::pair<unsigned int const, sf::Font::Page> >, std::less<unsigned int>, std::allocator<std::pair<unsigned int const, sf::Font::Page> > >::_M_mbegin (this=0x470) at /usr/include/c++/12/bits/stl_tree.h:735
#1  0x00007ffff7f2f6fe in std::_Rb_tree<unsigned int, std::pair<unsigned int const, sf::Font::Page>, std::_Select1st<std::pair<unsigned int const, sf::Font::Page> >, std::less<unsigned int>, std::allocator<std::pair<unsigned int const, sf::Font::Page> > >::_M_begin (this=0x470) at /usr/include/c++/12/bits/stl_tree.h:739
#2  0x00007ffff7f2fe66 in std::_Rb_tree<unsigned int, std::pair<unsigned int const, sf::Font::Page>, std::_Select1st<std::pair<unsigned int const, sf::Font::Page> >, std::less<unsigned int>, std::allocator<std::pair<unsigned int const, sf::Font::Page> > >::find (this=0x470, __k=@0x7fffffffd584: 60) at /usr/include/c++/12/bits/stl_tree.h:2531
#3  0x00007ffff7f2ef8b in std::map<unsigned int, sf::Font::Page, std::less<unsigned int>, std::allocator<std::pair<unsigned int const, sf::Font::Page> > >::find (this=0x470, __x=@0x7fffffffd584: 60)
    at /usr/include/c++/12/bits/stl_map.h:1218
#4  0x00007ffff7f2cff0 in sf::Font::loadPage (this=0x420, characterSize=60) at /home/buildbot-worker/debian-gcc-64/build/src/SFML/Graphics/Font.cpp:574
#5  0x00007ffff7f2cc2e in sf::Font::getTexture (this=0x420, characterSize=60) at /home/buildbot-worker/debian-gcc-64/build/src/SFML/Graphics/Font.cpp:479
--Type <RET> for more, q to quit, c to continue without paging--c
#6  0x00007ffff7f83854 in sf::Text::ensureGeometryUpdate (this=0x555555aa59a8) at /home/buildbot-worker/debian-gcc-64/build/src/SFML/Graphics/Text.cpp:403
#7  0x00007ffff7f8362f in sf::Text::getLocalBounds (this=0x555555aa59a8) at /home/buildbot-worker/debian-gcc-64/build/src/SFML/Graphics/Text.cpp:360
#8  0x00005555556fb45b in Screens::MenuScreen::init (this=0x555555aa5980) at src/Screens/MenuScreen.cpp:30
#9  0x00005555556fd3d1 in ScreenManager::pushState (this=0x555555aa5680, newState=ScreenState::MainMenu) at src/ScreenManager.cpp:52
#10 0x00005555556fcc88 in ScreenManager::ScreenManager (this=0x555555aa5680, initialState=ScreenState::MainMenu) at ...
#11 0x00005555556e6b65 in main () at

The traceback says it’s occurring because of some issues in SFML but I know the init() method works because this works fine (without ScreenManager):

int main() {
    // Create the main window
    GameDataRef data = std::make_shared<GameData>();

    std::stack<std::unique_ptr<Screens::Screen>> states;
    auto state = std::make_unique<Screens::MenuScreen>(data);
    states.push(std::move(state));
    states.top()->init();

    // Main loop
    while (data->window.isOpen()) {
        // Process events
        sf::Event event;
        while (data->window.pollEvent(event)) {
            // Close window: exit
            if (event.type == sf::Event::Closed) {
                data->window.close();
            }

        }
        data->window.clear();

        states.top()->draw();
         
        data->window.display();
    }

    return 0;
}

I don’t think gdb is tracing the source of the segmentation fault to the right place. If I comment out the init() method it still segfaults and traces it back instead to:

window->clear(sf::Color(206, 154, 245));

Again, these both work in the minimal example I provided. Exact same environment.

I’d really appreciate any insight on this.