[Add an address that doesn't fail] On 2023-09-06 15:18, Alejandro Colomar wrote: > Hi Stefan, > > On 2023-09-06 15:00, Stefan Tauner wrote: >> Hi, >> >> last year a new syntax to indicate the (minimum) length of parameter >> arrays has been introduced to many function synposes with this commit: >> https://git.kernel.org/pub/scm/docs/man-pages/man-pages.git/commit/?id=c64cd13e002561c6802c6a1a1a8a640f034fea70 > > And these too: > <https://git.kernel.org/pub/scm/docs/man-pages/man-pages.git/commit/?id=1eed67e75deff662dffce3195e55e608809eaafd> > <https://git.kernel.org/pub/scm/docs/man-pages/man-pages.git/commit/?id=77f31ff920bc0abdf73ee4ece808ba4eeeff90a4> > >> >> The additional information is great but WTF is the "."? I have asked a >> few C-programming colleagues and skimmed through the c23 draft to no >> avail. Then I looked up the respective thread on the ML and there seems >> to be astonishingly little arguing about introducing such a new syntax >> that is not included in the C language. >> >> I've been teaching C at university level for almost 10 years and I >> think the dot is profoundly confusing to most readers and thus is >> actually harmful in documentation context. >> Of course it's not code but "just" documentation but its syntax is so >> similar that every C coder would be stumbled at least the first time >> they see it - unlike the case w/o the dot, which is legal C. I'd not >> add the static keyword though due to brevity but I would have strongly >> advocated against the dot if I'd have known earlier - but maybe I am >> alone with that opinion? > > Thanks for your feedback! > > We discussed the different options, and there seem to be two ways to do > it: legal C, or what we did: > > "legal" C: > char *fgets(char s[restrict size], int size, FILE *restrict stream); > > current manual: > char *fgets(char s[restrict .size], int size, FILE *restrict stream); > > The problem with the "legal" syntax, is that it doesn't mean what we > want it to mean. Let's compile a couple of files to see. > > $ cat a.c > void foo(char s[n], int n); > > $ cc -Wall -Wextra -c a.c > a.c:1:17: error: ‘n’ undeclared here (not in a function) > 1 | void foo(char s[n], int n); > | ^ > > $ cat b.c > int n = 3; > void foo(char s[n], int n); > > $ cc -Wall -Wextra -c b.c > > So, I we decided to go with an extension to the language, which doesn't > mean anything legal yet, and we can give it the precise meaning that we > want. This extension is currently not supported by any compiler, but > we're discussing the addition to GCC. The conversation was paused for > a few months, as I wanted to have more feedback, and time to think, but > I'll soon contact GCC developers again to continue the discussion. > > Cheers, > Alex > -- <http://www.alejandro-colomar.es/> GPG key fingerprint: A9348594CE31283A826FBDD8D57633D441E25BB5
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