Re: Breakpoint ignored.

[Eli Zaretskii <eliz@gnu.org>]

> From: Óscar_Fuentes <ofv@wanadoo.es>
> Date: Sun, 18 Oct 2009 04:55:52 +0200
> 
> C-h k á says `self-insert-command' is invoked, wich is a built-in
> function. So I follow the link to the source code to learn that the C
> function is Fself_insert_command, then invoke emacs and set a breakpoint
> on it, but gdb does not stop when a character is typed (and displayed),
> as if no breakpoint was active.
> 
> What I'm missing?

You are probably missing the fact that Emacs tries to optimize the
case of insertion of a single character.  See this part of keyboard.c:

	      else if (EQ (Vthis_command, Qself_insert_command)
		       /* Try this optimization only on char keystrokes.  */
		       && NATNUMP (last_command_event)
		       && CHAR_VALID_P (XFASTINT (last_command_event), 0))
		{
		  unsigned int c
		    = translate_char (Vtranslation_table_for_input,
				      XFASTINT (last_command_event));
		  int value;
		  if (NILP (Vexecuting_kbd_macro)
		      && !EQ (minibuf_window, selected_window))
		    {
		      if (!nonundocount || nonundocount >= 20)
			{
			  Fundo_boundary ();
			  nonundocount = 0;
			}
		      nonundocount++;
		    }

		  lose = ((XFASTINT (XWINDOW (selected_window)->last_modified)
			   < MODIFF)
			  || (XFASTINT (XWINDOW (selected_window)->last_overlay_modified)
			      < OVERLAY_MODIFF)
			  || (XFASTINT (XWINDOW (selected_window)->last_point)
			      != PT)
			  || MODIFF <= SAVE_MODIFF
			  || windows_or_buffers_changed
			  || !EQ (current_buffer->selective_display, Qnil)
			  || detect_input_pending ()
			  || !NILP (XWINDOW (selected_window)->column_number_displayed)
			  || !NILP (Vexecuting_kbd_macro));

		  value = internal_self_insert (c, 0);

		  if (value == 2)
		    nonundocount = 0;

                  frame_make_pointer_invisible ();

		  if (! NILP (Vpost_command_hook))
		    /* Put this before calling adjust_point_for_property
		       so it will only get called once in any case.  */
		    goto directly_done;

		  /* VALUE == 1 when AFTER-CHANGE functions are
		     installed which is the case most of the time
		     because FONT-LOCK installs one.  */
		  if (!lose && !value)
		    direct_output_for_insert (c);
		  goto directly_done;
		}