cppdraft_translate/cppdraft/optional/ref/observe.md

[optional.ref.observe]

22 General utilities library [utilities]

22.5 Optional objects [optional]

22.5.4 Partial specialization of optional for reference types [optional.optional.ref]

22.5.4.6 Observers [optional.ref.observe]

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constexpr T* operator->() const noexcept;

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Hardened preconditions: has_value() is true.

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Returns: val.

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constexpr T& operator*() const noexcept;

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Hardened preconditions: has_value() is true.

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Returns: *val.

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constexpr explicit operator bool() const noexcept;

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Returns: val != nullptr.

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constexpr bool has_value() const noexcept;

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Returns: val != nullptr.

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constexpr T& value() const;

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Effects: Equivalent to:return has_value() ? *val : throw bad_optional_access();

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template<class U = remove_cv_t<T>> constexpr remove_cv_t<T> value_or(U&& u) const;

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Let X be remove_cv_t.

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Mandates: is_constructible_v<X, T&> && is_convertible_v<U, X> is true.

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Effects: Equivalent to:return has_value() ? *val : static_cast(std::forward(u));