On Mon, May 12, 2025 at 1:09 PM Andrew Cooper <andrew.coop...@citrix.com> wrote: > > On 12/05/2025 12:59 pm, Jan Beulich wrote: > > On 05.05.2025 21:44, Stefano Stabellini wrote: > >> On Mon, 5 May 2025, Andrew Cooper wrote: > >>> In macros it is common to declare local variables using typeof(param) in > >>> order > >>> to ensure that side effects are only evaluated once. A consequence of > >>> this is > >>> double textural expansion of the parameter, which can get out of hand very > >>> quickly with nested macros. > >>> > >>> A GCC extension, __auto_type, is now avaialble in the new toolchain > >>> baseline > >>> and avoids the double textural expansion. > >> I think this is a good change > > +1 > > That looks like agreement. > > Now for the (new) controversial part. Since sending this, Linux has > decided to just #define auto __auto_type for C < 23, in order to start > writing C23 compatible code from now. It's more succinct, and has > better longevity. > > We might want to consider the same, although it will introduce a new > example of defining a keyword, which we'd have to call out in the > MISRA/Eclair config. > > If we're going to do this, we should do it from the outset. > > Thoughts? > > ~Andrew >
I vote for avoiding extensions when the same feature is implemented by standard, so yes for using "auto". Frediano
