Subject: Re: [wg14/wg21 liaison] Feature test macro for P0306 (__VA_OPT__)
From: Jonathan Wakely (cxx_at_[hidden])
Date: 2021-01-28 04:12:45
On Wed, 27 Jan 2021 at 20:54, Barry Revzin via Liaison <
> Eric Niebler actually asked this on StackOverflow a few years ago:
> 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?
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.
SG10 list run by email@example.com