clx-xinerama-test.lisp

;; (ql:quickload :clx)
(destructuring-bind (hostname display-id screen-id protocol)
    (xlib::get-default-display ":1")
  (let ((display (xlib:open-display hostname :display display-id :protocol protocol)))
    (xlib/xinerama:xinerama-is-active display)))

test-xinerama.c

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

// clang -std=c99 -pedantic -Werror -I/usr/include test-xinerama.c -o test-xinerama -lc -lX11 -lXinerama
#include <X11/Xlib.h>
#include <X11/extensions/Xinerama.h>

static Display *dpy;

int
main(int argc, char *argv[])
{
  dpy = XOpenDisplay(":1");
  if(!dpy) perror("Unable to open display.\n");

  bool xineramap;
  xineramap = XineramaIsActive(dpy);
  
  printf("Xinemara is active? %d\n", xineramap);
  
  return EXIT_SUCCESS;
}