Slaven Falandys

@h-2 The specialization of `std::hash` for `std::pair` does not exist in standard C++ library. You have to write it yourself. You can see that note on https://en.cppreference.com/w/cpp/utility/hash

Here is an example how to write specialization of `std::hash` for `std::pair`: ``` // This is similar to boost::hash_combine // template void hash_combine(std::size_t& seed, const T& v) { std::hash hasher;...

I have similar problem. Take this code snippet for example: ``` cxxopts::Options options("test", "A brief description"); options.add_options() ("b,bar", "Param bar", cxxopts::value()) ("d,debug", "Enable debugging", cxxopts::value()->default_value("false")) ("f,foo", "Param foo", cxxopts::value()->default_value("10")) ("h,help",...