Re: [boost] Visual Studio 2015 Update 3 has removed std::unary_function and std::binary_function

Subject: Re: [boost] Visual Studio 2015 Update 3 has removed std::unary_function and std::binary_function
From: Edward Diener (eldiener_at_[hidden])
Date: 2016-11-05 20:38:09

On 11/5/2016 3:21 PM, Marshall Clow wrote:
> ... if you build with /std:c++latest.
>
> See https://svn.boost.org/trac/boost/ticket/12586 for an example.
>
> Other vendors will be removing these types in C++17 mode in the future (or
> at least requiring a -D RETAIN_REMOVED_STUFF=1 or something like that)
>
> A quick grep for these terms found 153 instances of "std::unary_function"
> and 118 of "std::binary_function" across several libraries, including
> accumulators, algorithm, config, container, function, gil, graph, icl, mpi,
> msm, polygon, ptr_container, serialization, smart_ptr, tr1, unordered,
> utility - and probably others.
>
> I think that we ought to have a boost-wide solution for this (i.e, everyone
> should solve this the same way).
>
> I can think of three possibilities:
> * Deny, deny, deny: Boost doesn't work with C++17.  Not my recommendation.
> * Since std::unary|binary_function is an empty struct with a set of two (or
> three) typedefs, just define the typedefs everywhere.

What do you mean by "define the typedefs everywhere" ?

>  Note that the
> typedefs (result_type, first_argument_type, second_argument_type) were
> deemed to not be useful in C++17 due to the existence of advanced type
> traits, etc.
> * Define a boost:unary_function and boost::binary_function struct that
> mimics the one that was in namespace std, and change over to use that.
> * Something else.
>
> Comments?