Simply try to close a GdkDisplay object.

#include <gtk/gtk.h>
                                                                               
                                                             int main(int argc,
char *argv[]) {
gtk_init (&argc, &argv);    
gdk_display_close(gdk_display_manager_get_default_display(gdk_display_manager_get()));
}

Program received signal SIGSEGV, Segmentation fault.
0x0065ea80 in gdk_x11_display_get_xdisplay () from /usr/lib/libgdk-x11-2.0.so.0
(gdb) where

+ Trace 48949