Re: Question on updating to 29.1

[Basile Starynkevitch <basile@starynkevitch.net>]

On 8/17/23 18:17, PierGianLuca wrote:
> Hi everyone,
>
> I'm finally getting around to installing Emacs 29.1 (from the tarball, 
> on Ubuntu 20.04), and was looking at the options listed by Basile. I 
> have some questions or curiosities:
>
>> Basile Starynkevitch wrote:
>>
>>> './configure'  'CFLAGS=-O2 -g' 'CC=/usr/bin/gcc-13'
>>> '--with-native-compilation' '--with-json'
>>> '--enable-link-time-optimization' '--with-x-toolkit=gtk3'
>>> '--program-suffix=-trunk'
>
> – I don't have gcc-13, so I'll skip that.
>
> – "--with-native-compilation" what does this do? I imagine it's 
> something not specifically related to Emacs.


In recent GNU emacs (30) there is a possibility to compile the Elisp 
code to machine code, using libgccjit.

And libgccjit is a "pseudo"' just in time compiler in recent GCC 
compiler. Documented in https://gcc.gnu.org/onlinedocs/jit/ and existing 
in GCC 12.

(Those wanting a real just in time compiler should consider using the 
GNU lightning library, see https://www.gnu.org/software/lightning/ ; it 
is not GCC related, smaller, but generates slower machine code than 
libgccjit).

>
> – "--with-json" ditto?


  I think it is related to understanding JSON. Using the jansson library 
see http://www.digip.org/jansson/ and https://github.com/akheron/jansson 
and https://www.json.org/json-en.html

>
> – "with-x-toolkit=gtk3" is this option already chosen by default? I 
> see that the Emacs install instructions say
>
> "If you use exclusively X, do not use the PGTK port.  There are a 
> number of respects in which the regular --with-x-toolkit=gtk build 
> works better"
>
> which sounds like "=gtk" is the default
>
>
> Thank you for any info you can share, and for your patience with 
> someone inexperienced with these kinds of installations!
>
> Luca



BTW, my pet open source project is the RefPerSys inference engine on 
https://github.com/RefPerSys/RefPerSys - contributors are welcome. See 
also some ideas from https://arxiv.org/pdf/1109.0779.pdf

-- 
Basile Starynkevitch                  <basile@starynkevitch.net>
(only mine opinions / les opinions sont miennes uniquement)
92340 Bourg-la-Reine, France
web page: starynkevitch.net/Basile/