Re: [boost] Clang 4.0.0 MPL error in Boost next.hpp and prior.hpp

Subject: Re: [boost] Clang 4.0.0 MPL error in Boost next.hpp and prior.hpp
From: Edward Diener (eldiener_at_[hidden])
Date: 2017-03-25 18:54:25

On 3/25/2017 8:30 AM, Peter Dimov via Boost wrote:
> Paul A. Bristow wrote:
>
>> In file included from I:\modular-boost\boost/mpl/next.hpp:17:
>> I:\modular-boost\boost/mpl/next_prior.hpp:44:23: error: too many
>> arguments provided to function-like macro invocation
>> BOOST_MPL_AUX_NA_SPEC(1, next)
>>                       ^
>
> I tried to compile
>
> #include <boost/mpl/list.hpp>
> #include <boost/mpl/push_front.hpp>
>
> int main()
> {
>    namespace mpl = boost::mpl;
>
>    using L = mpl::list<>;
>    using L2 = mpl::push_front<L, void>;
> }
>
> with the build-in Clang/C2, hit
>
> 1>../boost-git/boost\boost/mpl/next_prior.hpp(44,1): error : pasting
> formed 'BOOST_PP_TUPLE_ELEM_O_3(', an invalid preprocessing token
> [-Winvalid-token-paste]
> 1>BOOST_MPL_AUX_NA_SPEC(1, next)
>
> Tried
>
> #define BOOST_PP_CONFIG_FLAGS() 1
>
> at the top, same. The "strict" PP configuration is used, it just doesn't
> work for some reason I couldn't figure out. It's possible that
> -fms-extensions also changes the preprocessor and this breaks PP, but
> without it, MS's headers don't compile.

There is also BOOST_PP_VARIADICS_MSVC, which provides lots of special 
VC++ variadics workarounds.

>
> If you tell MPL to not use PP though:
>
> #include <boost/mpl/aux_/config/preprocessor.hpp>
> #undef BOOST_MPL_CFG_NO_OWN_PP_PRIMITIVES
>
> this simple example works. I've no idea whether more complex ones will.
>
> But if you don't insist on an MS-compatible Clang and can stomach the
> old and busted 3.9, you can just use the Cygwin Clang. That's what I do.