diff --git a/gdk/x11/gdkdisplay-x11.c b/gdk/x11/gdkdisplay-x11.c
index cb09468cca..4d145a9956 100644
--- a/gdk/x11/gdkdisplay-x11.c
+++ b/gdk/x11/gdkdisplay-x11.c
@@ -1728,7 +1728,7 @@ _gdk_x11_display_open (const gchar *display_name)
   if (!gdk_running_in_sandbox ())
     {
       /* if sandboxed, we're likely in a pid namespace and would only confuse the wm with this */
-      pid_t pid = getpid ();
+      long pid = getpid ();
       XChangeProperty (display_x11->xdisplay,
                        display_x11->leader_window,
                        gdk_x11_get_xatom_by_name_for_display (display, "_NET_WM_PID"),
diff --git a/gdk/x11/gdkwindow-x11.c b/gdk/x11/gdkwindow-x11.c
index 764e39495f..f92a146be5 100644
--- a/gdk/x11/gdkwindow-x11.c
+++ b/gdk/x11/gdkwindow-x11.c
@@ -935,7 +935,7 @@ setup_toplevel_window (GdkWindow *window,
   if (!gdk_running_in_sandbox ())
     {
       /* if sandboxed, we're likely in a pid namespace and would only confuse the wm with this */
-      pid_t pid = getpid ();
+      long pid = getpid ();
       XChangeProperty (xdisplay, xid,
                        gdk_x11_get_xatom_by_name_for_display (x11_screen->display, "_NET_WM_PID"),
                        XA_CARDINAL, 32,