On 2025-12-13 16:34, Alejandro Colomar wrote:
#define ARRAY_OF_AT_LEAST(a,n) a[static n]
Please don't use [static n] ever. I want to remove it from the
standard, and I think I'm quite advanced in convincing the right people.
If you start using it, that could be negative to my efforts.
I put a similar macro into Gnulib more than a decade ago with Gnulib's
vla module, which does this:
#ifdef __STDC_NO_VLA__
# define VLA_ELEMS(n)
#else
# define VLA_ELEMS(n) static n
#endif
... the idea being that you can use the syntax 'int foo[VLA_ELEMS (10)]'
if you like. However, the only use I know of is the obsolescent program
Gnu RCS that the module was introduced for. The late Thien-Thi Nguyen
asked for VLA_ELEMS and used it mostly for documentation I think. See
the thread starting at
<https://lists.gnu.org/r/bug-gnulib/2014-08/msg00012.html>.
As I understand things, the main use of [static n] advocated by Jens
Gustedt is as as a not-immediately-obvious way to assert that a pointer
parameter is non-null. But for Gnulib-using software we use
_GL_ATTRIBUTE_NONNULL for that instead. Although there's also a
secondary use of [static n] to allow separately-compiled code to fetch
contents of arrays more aggressively, I'm not sure the small benefit of
that is worth the hassle.
I'd ask you to please avoid arrays of exactly n in general.
These are rare enough in GNU code (with its no-arbitrary-limits
philosophy) that it's not clear it's worth the hassle of a Gnulib macro.
