std:: hash <std::error_code>

From cppreference.com

Defined in header `<system_error>`
template <> struct hash < std:: 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 .

Compiler support
Freestanding and hosted
Language
Standard library
Standard library headers
Named requirements
Feature test macros (C++20)
Language support library
Concepts library (C++20)
Metaprogramming library (C++11)
Diagnostics library
General utilities library
Strings library
Containers library
Iterators library
Ranges library (C++20)
Algorithms library
Numerics library
Localizations library
Input/output library
Filesystem library (C++17)
Regular expressions library (C++11)
Concurrency support library (C++11)
Execution support library (C++26)
Technical specifications
Symbols index
External libraries

Member functions
error_code::error_code
error_code::operator=
error_code::assign
Modifiers
error_code::clear
Observers
error_code::value
error_code::category
error_code::default_error_condition
error_code::message
error_code::operator bool
Non-member functions
operator== operator!= operator< operator<=> (until C++20) (until C++20) (C++20)
operator<<
Helper classes
is_error_code_enum
hash <std::error_code>