On 03/11/2022 16:19, Michael Matz via Gcc wrote:
Hello,
On Thu, 3 Nov 2022, Florian Weimer via Gcc wrote:
will not have propagated widely once GCC 13 releases, so rejecting
implicit ints in GCC 13 might be too early. GCC 14 might want to switch
to C23/C24 mode by default, activating auto support, if the standard
comes out in 2023 (which apparently is the plan).
Then we would go from
warning to changed semantics in a single release.
Comments?
I would argue that changing the default C mode to c23 in the year that
comes out (or even a year later) is too aggressive and early. Existing
sources are often compiled with defaults, and hence would change
semantics, which seems unattractive. New code can instead easily use
-std=c23 for a time.
E.g. c99/gnu99 (a largish deviation from gnu90) was never default and
gnu11 was made default only in 2014.
That's true - and the software world still has not recovered from the
endless mass of drivel that gcc (and other compilers) accepted in lieu
of decent C as a result of not changing to C99 as the standard.
Good C programmers put the standards flag explicitly in their makefile
(or other build system). Bad ones use whatever the compiler gives them
by default and believe "the compiler accepted it, it must be good code".
My vote would be to make "-std=c17 -Wall -Wextra -Wpedantic -Werror -O2"
the default flags. Force those who don't really know what they are
doing, to learn - it's not /that/ hard, and the effort pays off quickly.
(Or they can give up and move to Python.) Those who understand how to
use their tools can happily change the standards and warnings to suit
their needs.
And the person who first decided "implicit declaration of function"
should merely be a /warning/ should be sentenced to 10 years Cobol
programming.
It's probably a good thing that it is not I who decides the default
flags for gcc !
