Re: MPS: Forwording symbols

["Gerd Möllmann" <gerd.moellmann@gmail.com>]

Helmut Eller <eller.helmut@gmail.com> writes:

> On Tue, Jun 18 2024, Gerd Möllmann wrote:
>
>>> Those in buffer.c are at least easy to understand. Strange: there are
>>> 4 IGC_OBJ_DUMPED_BUFFER_TEXT objects in the dump but only 3 buffers in
>>> Vbuffer_alist.
>>
>> Somehow there is never an end to surprises...
>
> An interesting comment in buffer.c:
>
>       /* The dumped buffers reference addresses of buffer text
> 	 recorded by temacs, that cannot be used by the dumped Emacs.
> 	 We map new memory for their text here.
>
> 	 Implementation notes: the buffers we carry from temacs are:
> 	 " prin1", "*scratch*", " *Minibuf-0*", "*Messages*", and
> 	 " *code-conversion-work*".  They are created by
> 	 init_buffer_once and init_window_once (which are not called
> 	 in the dumped Emacs), and by the first call to coding.c
> 	 routines.  Since FOR_EACH_LIVE_BUFFER only walks the buffers
> 	 in Vbuffer_alist, any buffer we carry from temacs that is
> 	 not in the alist (a.k.a. "magic invisible buffers") should
> 	 be handled here explicitly.  */
>       FOR_EACH_LIVE_BUFFER (tail, buffer)
>         {
> 	  struct buffer *b = XBUFFER (buffer);
> 	  b->text->beg = NULL;
> 	  enlarge_buffer_text (b, 0);
> 	}
>       /* The " prin1" buffer is not in Vbuffer_alist.  */
>       XBUFFER (Vprin1_to_string_buffer)->text->beg = NULL;
>       enlarge_buffer_text (XBUFFER (Vprin1_to_string_buffer), 0);
>
> The " *code-conversion-work*" buffer doesn't seem to exist anymore and
> the only non-empty buffer is *Messages*, which contains 374 bytes
> (pretty useless to have in the dump).  The quoted code is only used when
> dumped_with_unexec_p, but I was going to do almost the same.

Interesting, thanks!