main.cpp

#include <X11/Xlib.h>
#include <X11/Xutil.h>
#include <X11/Xos.h>

#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#include <sys/utsname.h>

int main(int argc, char **argv)
{
    Display *dpy = XOpenDisplay(NULL);
    if (dpy == NULL) {
        fprintf(stderr, "Cannot open display\n");
        exit(1);
    }

    int    s   = DefaultScreen(dpy);
    Window win = XCreateSimpleWindow(
        dpy, RootWindow(dpy, s), 10, 10, 660, 200, 1, BlackPixel(dpy, s), WhitePixel(dpy, s));
    XSelectInput(dpy, win, ExposureMask | KeyPressMask);
    XMapWindow(dpy, win);

    XStoreName(dpy, win, "Example X11 Window");

    Atom WM_DELETE_WINDOW = XInternAtom(dpy, "WM_DELETE_WINDOW", False);
    XSetWMProtocols(dpy, win, &WM_DELETE_WINDOW, 1);

    bool           uname_ok = false;
    struct utsname sname;
    int            ret = uname(&sname);
    if (ret != -1) {
        uname_ok = true;
    }

    XEvent e;
    while (1) {
        XNextEvent(dpy, &e);
        if (e.type == Expose) {
            // Draw screen?
        }

        if (e.type == KeyPress) {
            char   buf[128] = {0};
            KeySym keysym;
            int    len = XLookupString(&e.xkey, buf, sizeof buf, &keysym, NULL);
            if (keysym == XK_Escape)
                break;
        }

        if ((e.type == ClientMessage)
            && (static_cast<unsigned int>(e.xclient.data.l[0]) == WM_DELETE_WINDOW)) {
            break;
        }
    }

    XDestroyWindow(dpy, win);
    XCloseDisplay(dpy);
    return 0;
}