MappingNotify Events

[Steven J Abner]

On Tue, Jun 17 2025 at 11:22:30 PM +0000, Steven J Abner 
<pheonix.sja at att.net> wrote:
> Or is it obvious that prior to run loop I create a XMappingEvent to 
> send with XRefreshKeyboardMapping(), with flush?

This is definitely not the solution! It solves the MappingNotify only 
to replace with a need for one to handle XCB_ALLOC_NAMED_COLOR event.

Looking at xcb_refresh_keyboard_mapping() the correct way to handle is 
to update my cached values. No messaging back to the server required.

I could not find the source code in libxcb for 
xcb_get_keyboard_mapping(). I am guessing that may be the server 
response it was looking for?

Here was my last attempt causing the event XCB_ALLOC_NAMED_COLOR:

/* session to hold global values */
void
_xcb_keysym_alloc(xcb_connection_t *connection) {

  const struct xcb_setup_t *setup = xcb_get_setup(connection);

  xcb_keycode_t min_keycode = setup->min_keycode;
  xcb_keycode_t max_keycode = setup->max_keycode;

  xcb_get_keyboard_mapping_reply_t *sym_table;
  xcb_get_keyboard_mapping_cookie_t cookie;
  cookie = xcb_get_keyboard_mapping(connection,
                                    min_keycode,
                                    max_keycode - min_keycode + 1);
    /* AFAICT owned by server */
  sym_table
    = xcb_get_keyboard_mapping_reply(connection, cookie, NULL);
    /* owned by server */
  session->keysyms = xcb_get_keyboard_mapping_keysyms(sym_table);
  session->sym_stride = sym_table->keysyms_per_keycode;
  session->sym_min = min_keycode;

/* Added for test purpose only. */
  {
  XMappingEvent event_map;
 event_map.type = MappingNotify;
 event_map.serial = 0;
 event_map.send_event = false;
 event_map.display = display;
 event_map.window = 0;
 event_map.request = MappingModifier;
 event_map.first_keycode = 0;
 event_map.count = 0;
  XRefreshKeyboardMapping(&event_map);
 event_map.request = MappingKeyboard;
 event_map.first_keycode = min_keycode;
 event_map.count = (max_keycode + 1) - min_keycode;
  XRefreshKeyboardMapping(&event_map);
  }
  xcb_flush(connection);
}

So solution as to what to do with a MappingNotify is just update values:

    case XCB_MAPPING_NOTIFY: { /* response_type 34 */
      xcb_mapping_notify_event_t *keymap
        = (xcb_mapping_notify_event_t*)nvt;
      if (keymap->request == XCB_MAPPING_KEYBOARD)
        _xcb_keysym_alloc(session->connection);
      break;
    }

That should even address when someone does actually call one of the 
trip functions to cause MappingNotify.

Thanks for listening, and if I'm wrong, please tell me :)
Steve