Remove deprecated std::binary_function

[pavelkryukov]

std::binary_function was removed in C++17 and is no longer available while compiling with MS Visual Studio 2017

[fearsomepirate]

@pavelkryukov Have you tried using boost::functional::binary_function instead?

https://www.boost.org/doc/libs/1_71_0/boost/functional.hpp

[pavelkryukov]

I believe it should be deprecated as well since C++11 has type deduction and perfect forwarding.

[fearsomepirate]

Right, but this is failing integration checks. The minimum viable fix is probably to just replace std::binary_function with boost::functional::binary_function, and then those checks would probably stop failing.

[pavelkryukov]

The minimum viable fix is probably to just replace std::binary_function with boost::functional::binary_function,

This is not the way the issue has been fixed in other Boost libraries, for instance:

• Remove deprecated unary/binary_function. gil#191
• Remove deprecated std::binary_function mpi#51
• Remove std::*nary_function algorithm#18

and then those checks would probably stop failing.

Could you please point to the place where checks fail due to absence of std::binary_function inheritance?