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

On 11/5/2016 10:52 PM, Marshall Clow wrote:

On Sat, Nov 5, 2016 at 5:38 PM, Edward Diener wrote:

...

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" ?

Everywhere we derive from std::unary_function or std::binary_function, manually define "result_type", "first_argument_type", etc.

Like this:

Change:

template<typename T> struct plus: binary_function { T operator() (const T& x, const T& y) { return x + y } };

to:

template<typename T> struct plus { typedef T first_argument_type; typedef T second_argument_type; typedef T result_type; T operator() (const T& x, const T& y) { return x + y } };

Thanks ! Sounds like the obvious choice.

-- Marshall