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

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< cpp‎ | utility‎ | expected

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.

### Return value

1,2) `unex`
3,4) std::move(`unex`)

### Example

| This section is incomplete Reason: no example

### See also

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 boolhas_value | checks whether the object contains an expected value (public member function)

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