On Thu, 28 Jan 2021 at 12:13, Jonathan Wakely via SG10 <[email protected]> wrote: > > > > On Wed, 27 Jan 2021 at 20:54, Barry Revzin via Liaison > <[email protected]> wrote: >> >> Eric Niebler actually asked this on StackOverflow a few years ago: >> https://stackoverflow.com/q/48045470/2069064 >> >> The accepted answer there is: >> >> #define PP_THIRD_ARG(a,b,c,...) c >> #define VA_OPT_SUPPORTED_I(...) PP_THIRD_ARG(__VA_OPT__(,),true,false,) >> #define VA_OPT_SUPPORTED VA_OPT_SUPPORTED_I(?) > > > Who is going to remember that without having to look it up though?
Is it going to be written so often that that becomes a major problem? > The #ifdef __VA_OPT__ solution was my first thought, it's unfortunate we > forbid it. If we can't have that then I think we do need a feature test > macro. The voodoo above will make most developers wish they were using Rust. If they're using VA_OPT, the cause is already lost. -- SG10 mailing list [email protected] https://lists.isocpp.org/mailman/listinfo.cgi/sg10
