Hi, Am 14. August 2024 00:38:53 MESZ schrieb Xavier Del Campo Romero <xavi....@tutanota.com>: > I have been overseeing these last emails - thank you very much for your > efforts, Alex! I did not reply until now because I do not have prior > experience with gcc internals, so my feedback would probably have not > been that useful. > > Those emails from 2020 were in fact discussing two completely different > proposals at once: > > 1. Add _Lengthof + #include <stdlengthof.h> > 2. Allow static qualifier on compound literals > > Whereas proposal #2 made it into C23 (kudos to Jens Gustedt!),
this was together with Alex > and as > you already know by now, proposal #1 received some negative feedback, > suggesting _Typeof/typeof + some macro magic as a pragmatic workaround > instead. > > Since the proposal did not get much traction and I would had been > unable to contribute to gcc myself, I just gave up on it. IIRC the > deadline for new proposals closed soon after, anyway. > > But I am glad that someone with proper experience took the initiative. > I still think the proposal is relevant and has interesting use cases. > > > I have only added lengthof for now, not _Lengthof, as suggested by Jens. > > Depending on feedback, I'll propose the uglified version. > > Probably, all of us know why the uglified version is the usual approach > preferred by the C standard: we do not know how many applications would > break otherwise. > > However, we see that this trend is now changing with C23, so probably > it makes sense to define lengthof directly. When I suggested that the double-underscore version is sufficient, I was not thinking that there would be a paper to WG 14 so quickly. For integration into go and clang the double underscore is certainly enough. Then for a standardization that is another question. > As for the parentheses, I personally think lengthof should follow > similar rules compared to sizeof. > > Best regards, > > -- > Xavier Del Campo Romero > > > > Aug 13, 2024, 15:02 by a...@kernel.org: > > > Hi, > > > > On Tue, Aug 13, 2024 at 01:34:58AM GMT, Alejandro Colomar wrote: > > > >> I want to send an updated version of n2529. The original author didn't > >> respond to my mail, so I'll take over. I've been preparing a GCC patch > >> set for adding the feature to GCC, and have informed Clang developers > >> about it too. > >> > >> The title would be > >> > >> _Lengthof - New pointer-proof keyword to determine array length (v2) > >> > >> Can you please assign me a number for it? Thanks. > >> > > > > Attached is a draft for a paper (both the man(7) source and the > > generated PDF). > > > > I have only added lengthof for now, not _Lengthof, as suggested by Jens. > > Depending on feedback, I'll propose the uglified version. > > > > Cheers, > > Alex > > > > -- > > <https://www.alejandro-colomar.es/> > > > Jens -- Jens Gustedt - INRIA & ICube, Strasbourg, France
