# std::optional<T>::operator->, std::optional<T>::operator*

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constexpr const T* operator->() const noexcept; | (1) | (since C++17)
constexpr T* operator->() noexcept; | (1) | (since C++17)
constexpr const T& operator*() const& noexcept; | (2) | (since C++17)
constexpr T& operator*() & noexcept; | (2) | (since C++17)
constexpr const T&& operator*() const&& noexcept; | (2) | (since C++17)
constexpr T&& operator*() && noexcept; | (2) | (since C++17)

Accesses the contained value.

1) Returns a pointer to the contained value.
2) Returns a reference to the contained value.

The behavior is undefined if *this does not contain a value.

### Parameters

(none)

### Return value

Pointer or reference to the contained value.

### Notes

This operator does not check whether the optional contains a value! You can do so manually by using has_value() or simply operator bool(). Alternatively, if checked access is needed, value() or value_or() may be used.

### Example

Run this code

    #include <optional>
    #include <iostream>
    #include <string>

    int main()
    {
        using namespace std::string_literals;

        std::optional<int> opt1 = 1;
        std::cout<< "opt1: " << *opt1 << '\n';

        *opt1 = 2;
        std::cout<< "opt1: " << *opt1 << '\n';

        std::optional<std::string> opt2 = "abc"s;
        std::cout<< "opt2: " << *opt2 << " size: " << opt2->size() << '\n';

        // You can "take" the contained value by calling operator* on an rvalue to optional

        auto taken = *std::move(opt2);
        std::cout << "taken: " << taken << " opt2: " << *opt2
                  << "size: " << opt2->size()  << '\n';
    }

Output:

    opt1: 1
    opt1: 2
    opt2: abc size: 3
    taken: abc opt2: size: 0

### Defect reports

The following behavior-changing defect reports were applied retroactively to previously published C++ standards.

DR | Applied to | Behavior as published | Correct behavior
--- | --- | --- | ---
LWG 2762 | C++17 | `operator->` and `operator*` might be potentially-throwing | made noexcept

### See also

value | returns the contained value (public member function)
value_or | returns the contained value if available, another value otherwise (public member function)

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