std::hash<std::error_code> (3) - Linux Manuals

std::hash<std::error_code>: std::hash<std::error_code>

NAME

std::hash<std::error_code> - std::hash<std::error_code>

Synopsis

Defined in header <system_error>
template<> struct hash<error_code>; (since C++11)

The template specialization of std::hash for std::error_code allows users to obtain hashes of objects of type std::error_code.