std::expected<T,E>:: error

From cppreference.com

constexpr const E & error ( ) const & noexcept ;	(1)	(since C++23)
constexpr E & error ( ) & noexcept ;	(2)	(since C++23)
constexpr const E && error ( ) const && noexcept ;	(3)	(since C++23)
constexpr E && error ( ) && noexcept ;	(4)	(since C++23)

Accesses the unexpected value contained in * this .

If has_value() is true , the behavior is undefined.

1,2)


          
           unex

3,4) std :: move (


         
          unex

)

This section is incomplete
Reason: no example

error_or	returns the unexpected value if present, another value otherwise (public member function)
operator-> operator*	accesses the expected value (public member function)
value	returns the expected value (public member function)
operator bool has_value	checks whether the object contains an expected value (public member function)

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
expected::expected
expected::~expected
expected::operator=
Observers
expected::operator-> expected::operator*
expected::operator bool expected::has_value
expected::value
expected::error
expected::value_or
expected::error_or
Monadic operations
expected::and_then
expected::or_else
expected::transform
expected::transform_error
Modifiers
expected::emplace
expected::swap
Non-member functions
operator== (std::expected)
swap (std::expected)
Helper classes
unexpected
bad_expected_access
unexpect_t unexpect