slint-ui/slint · error

C++: NativeWindowHandle created with null xcb window handle

Error message

C++: NativeWindowHandle created with null xcb window handle

What it means

Error "C++: NativeWindowHandle created with null xcb window handle" thrown in slint-ui/slint.

Source

Thrown at api/cpp/platform.rs:814

            RawDisplayHandle::Windows(raw_window_handle::WindowsDisplayHandle::new()),
        ));
        Box::into_raw(Box::new(handle)) as CppRawHandleOpaque
    }

    #[unsafe(no_mangle)]
    pub unsafe extern "C" fn slint_new_raw_window_handle_x11_xcb(
        window: u32,
        visual_id: u32,
        connection: *mut c_void,
        screen: core::ffi::c_int,
    ) -> CppRawHandleOpaque {
        use raw_window_handle::{XcbDisplayHandle, XcbWindowHandle};
        let handle = CppRawHandle::from((
            RawWindowHandle::Xcb({
                let mut hnd = XcbWindowHandle::new(
                    window
                        .try_into()
                        .expect("C++: NativeWindowHandle created with null xcb window handle"),
                );
                hnd.visual_id = visual_id.try_into().ok();
                hnd
            }),
            RawDisplayHandle::Xcb(XcbDisplayHandle::new(
                core::ptr::NonNull::new(connection),
                screen,
            )),
        ));
        Box::into_raw(Box::new(handle)) as CppRawHandleOpaque
    }

    #[unsafe(no_mangle)]
    pub unsafe extern "C" fn slint_new_raw_window_handle_x11_xlib(
        window: core::ffi::c_ulong,
        visual_id: core::ffi::c_ulong,
        display: *mut c_void,
        screen: core::ffi::c_int,

View on GitHub (pinned to 3fd8f2ec03)

Solutions

1. Do not create a NativeWindowHandle with a null XCB window handle.
2. Obtain a valid X11 window id before calling.

When it happens

Trigger: Thrown at api/cpp/platform.rs:814 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of slint-ui/slint@3fd8f2ec03 (2026-08-19). Data as JSON: /api/errors/c44009771938f226. Report an issue: GitHub.