+static Bool error_handler_hit_p = False;
+
+static int
+ignore_all_errors_ehandler (Display *dpy, XErrorEvent *error)
+{
+ error_handler_hit_p = True;
+ return 0;
+}
+
+
+/* Returns True if successful, False if an X error occurred.
+ We need this because other programs might have done things to
+ our window that will cause XChangeWindowAttributes() to fail:
+ if that happens, we give up, destroy the window, and re-create
+ it.
+ */
+static Bool
+safe_XChangeWindowAttributes (Display *dpy, Window window,
+ unsigned long mask,
+ XSetWindowAttributes *attrs)
+{
+ XErrorHandler old_handler;
+ XSync (dpy, False);
+ error_handler_hit_p = False;
+ old_handler = XSetErrorHandler (ignore_all_errors_ehandler);
+
+ XChangeWindowAttributes (dpy, window, mask, attrs);
+
+ XSync (dpy, False);
+ XSetErrorHandler (old_handler);
+ XSync (dpy, False);
+
+ return (!error_handler_hit_p);
+}
+
+
+/* This might not be necessary, but just in case. */
+static Bool
+safe_XConfigureWindow (Display *dpy, Window window,
+ unsigned long mask, XWindowChanges *changes)
+{
+ XErrorHandler old_handler;
+ XSync (dpy, False);
+ error_handler_hit_p = False;
+ old_handler = XSetErrorHandler (ignore_all_errors_ehandler);
+
+ XConfigureWindow (dpy, window, mask, changes);
+
+ XSync (dpy, False);
+ XSetErrorHandler (old_handler);
+ XSync (dpy, False);
+
+ return (!error_handler_hit_p);
+}
+
+/* This might not be necessary, but just in case. */
+static Bool
+safe_XDestroyWindow (Display *dpy, Window window)
+{
+ XErrorHandler old_handler;
+ XSync (dpy, False);
+ error_handler_hit_p = False;
+ old_handler = XSetErrorHandler (ignore_all_errors_ehandler);
+
+ XDestroyWindow (dpy, window);
+
+ XSync (dpy, False);
+ XSetErrorHandler (old_handler);
+ XSync (dpy, False);
+
+ return (!error_handler_hit_p);
+}
+
+
+static Bool
+safe_XKillClient (Display *dpy, XID id)
+{
+ XErrorHandler old_handler;
+ XSync (dpy, False);
+ error_handler_hit_p = False;
+ old_handler = XSetErrorHandler (ignore_all_errors_ehandler);
+
+ XKillClient (dpy, id);
+
+ XSync (dpy, False);
+ XSetErrorHandler (old_handler);
+ XSync (dpy, False);
+
+ return (!error_handler_hit_p);
+}
+
+
+#ifdef HAVE_XF86VMODE
+static Bool
+safe_XF86VidModeGetViewPort (Display *dpy, int screen, int *xP, int *yP)
+{
+ Bool result;
+ XErrorHandler old_handler;
+ XSync (dpy, False);
+ error_handler_hit_p = False;
+ old_handler = XSetErrorHandler (ignore_all_errors_ehandler);
+
+ result = XF86VidModeGetViewPort (dpy, screen, xP, yP);
+
+ XSync (dpy, False);
+ XSetErrorHandler (old_handler);
+ XSync (dpy, False);
+
+ return (error_handler_hit_p
+ ? False
+ : result);
+}
+
+/* There is no "safe_XF86VidModeGetModeLine" because it fails with an
+ untrappable I/O error instead of an X error -- so one must call
+ safe_XF86VidModeGetViewPort first, and assume that both have the
+ same error condition. Thank you XFree, may I have another.
+ */
+
+#endif /* HAVE_XF86VMODE */
+
+