Re: [boost] [config] request for BOOST_NO_FWD_STD_DECLARATION

Subject: Re: [boost] [config] request for BOOST_NO_FWD_STD_DECLARATION
From: Daniel James (dnljms_at_[hidden])
Date: 2011-02-16 07:52:46

On 16 February 2011 09:40, John Maddock <boost.regex_at_[hidden]> wrote:
>> libc++ does not allow forward declarations of types for std:: , as it uses
>> inline namespace to allow versioning.
>>
>> Forward declarations occur in many libraries (config, fusion,
>> interprocess). In each case I would like to just include the actual headers.
>>
>> I could just #define all cases for LIBCPP, but other libraries might move
>> to using inline namespaces in future, so I could introduce a macro?
>
> I think that sounds a reasonable addition, yes.  Do you have patches?

IMO it should be a macro that's defined when forward declaration is
possible rather than when it isn't. That way the default would be the
safer option. I now think it was a mistake to forward declare for
unknown setups in 'container_fwd.hpp'.

Daniel