#include <X11/Xlib.h>
#include <X11/Xutil.h>
#include <stdbool.h>
#include <stdlib.h>
#include <stdio.h>

#define KEYCODE 83

int main() {

   Display *display = XOpenDisplay(0);
   if(display == NULL)
      return -1;

   Window winRoot = XDefaultRootWindow(display);

   Window winFocus;
   int revert;
   XGetInputFocus(display, &winFocus, &revert);

   XKeyEvent event;
   event.display     = display;
   event.window      = winFocus;
   event.root        = winRoot;
   event.subwindow   = None;
   event.time        = CurrentTime;
   event.x           = 1;
   event.y           = 1;
   event.x_root      = 1;
   event.y_root      = 1;
   event.same_screen = True;
   event.keycode     = 83;
   event.state       = 0x10;

   event.type = KeyPress;

   XKeyEvent *e = &event;

    KeySym ks;
    int nbytes;
    char str[256+1];
    static char *buf;
    buf = malloc(8);

    nbytes = XLookupString (e, str, 256, &ks, NULL);
    printf("nbytes = %d\n", nbytes);
    printf("ks=  %d (%04x)\n", ks, ks);

    return 0;
}