My goal is to have a program that sleeps in the background but can be activated by the user via some "hotkey". From digging around the Xlib manual and the Xlib O'reilly manual, I gather that the correct way to to this is with XGrabKey. However my understanding of the process is incorrect as a simple proof of concept does not work.

My understanding is that if I call XGrabKey with the root window as the grab\_window, and owner\_events false, then whenever my hotkey is pressed the event will be sent *only* to the root window. If I then select KeyPress events from the root window, and then listen for X events, I should get a key press event when the hotkey is pressed. I've pasted a minimal example below.

What I expect is that when the program is run, regardless of what window has focus, if Ctrl+Shift+K is pressed, my program should output "Hot key pressed!" in the console, and then terminate.

Furthermore, it is my understanding that if the XGrabKey fails, the default error handler will display a message, and since it does not I am assuming that the call succeeds.

Obviously, my understanding is flawed somehow. Can anyone point me in the right direction? 

```
#include <iostream>
#include <X11/Xlib.h>
#include <X11/Xutil.h>

using namespace std;

int main()
{
    Display*    dpy     = XOpenDisplay(0);
    Window      root    = DefaultRootWindow(dpy);
    XEvent      ev;

    unsigned int    modifiers       = ControlMask | ShiftMask;
    int             keycode         = XKeysymToKeycode(dpy,XK_Y);
    Window          grab_window     =  root;
    Bool            owner_events    = False;
    int             pointer_mode    = GrabModeAsync;
    int             keyboard_mode   = GrabModeAsync;

    XGrabKey(dpy, keycode, modifiers, grab_window, owner_events, pointer_mode,
             keyboard_mode);

    XSelectInput(dpy, root, KeyPressMask );
    while(true)
    {
        bool shouldQuit = false;
        XNextEvent(dpy, &ev);
        switch(ev.type)
        {
            case KeyPress:
                cout << "Hot key pressed!" << endl;
                XUngrabKey(dpy,keycode,modifiers,grab_window);
                shouldQuit = true;

            default:
                break;
        }

        if(shouldQuit)
            break;
    }

    XCloseDisplay(dpy);
    return 0;
}

```