Programming

 #include <X11/Xlib.h>
#include <stdio.h>
 
int main()
{
 
    Display* main_display;
 
    main_display = XOpenDisplay( NULL );
    if( !main_display )
    {
        printf( "Cannot open main display!\n" );
        return 1;
    }
 
    int display_num = XDefaultScreen( main_display );
    Window main_wnd =
        XCreateSimpleWindow( main_display, RootWindow( main_display, display_num ),
                                 0, 0, 100, 100, 1,
                             BlackPixel(main_display, display_num),
                             WhitePixel(main_display, display_num )
                           );
 
    Atom wm_delete_window = XInternAtom( main_display, "WM_DELETE_WINDOW", False );
    Atom wm_protocols = XInternAtom( main_display, "WM_PROTOCOLS", False );
    XSetWMProtocols( main_display, main_wnd, &wm_delete_window, 1 );
 
    XMapWindow( main_display, main_wnd );
 
    XEvent e;
    bool done = false;
    while( !done )
    {
        XNextEvent( main_display, &e );
 
        switch( e.type )
        {
        case ClientMessage:
              if( e.xclient.message_type == wm_protocols && e.xclient.data.l[0] == (long)wm_delete_window )
              {
                  printf( "WM_DELETE_WINDOW\n" );
                  done = true;
              }
 
              break;
 
 
        default :
            printf( "Unknown event #%d\n", e.type );
        }
    }
 
 
    XDestroyWindow( main_display, main_wnd );
 
    XCloseDisplay( main_display );
 
    printf( "done\n" );
 
    return 0;
}