XNA - 如何确定哪个窗口具有焦点？

#include <X11/Xlib.h>
#include <X11/Xatom.h>
#include<stdio.h>

int main() {
    Display *display;
    Window focused_window;
    int revert_to;

    // 打开显示器连接
    display = XOpenDisplay(NULL);
    if (display == NULL) {
        fprintf(stderr, "Cannot open display\n");
        return 1;
    }

    // 获取当前具有焦点的窗口
    XGetInputFocus(display, &focused_window, &revert_to);

    // 获取窗口的属性
    XWindowAttributes attributes;
    XGetWindowAttributes(display, focused_window, &attributes);

    // 输出窗口的属性
    printf("Focused window ID: %ld\n", focused_window);
    printf("Window title: %s\n", attributes.name);
    printf("Window position: (%d, %d)\n", attributes.x, attributes.y);
    printf("Window size: (%d, %d)\n", attributes.width, attributes.height);

    // 关闭显示器连接
    XCloseDisplay(display);

    return 0;
}