Equality operators
Declared in <beman/optional/optional.hpp>
Compares two nullopt_t objects for equality.
constexpr
bool
operator==(
nullopt_t lhs,
nullopt_t rhs) noexcept;
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Compares two optionals for equality.
template<
typename T,
typename U>
constexpr
bool
operator==(
optional<T> const& lhs,
optional<U> const& rhs)
requires detail::optional_eq_rel<T, U>;
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Compares an optional against nullopt.
template<class T>
constexpr
bool
operator==(
optional<T> const& lhs,
nullopt_t rhs) noexcept;
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Compares an engaged optional's value against a value for equality.
template<
typename T,
typename U>
constexpr
bool
operator==(
optional<T> const& lhs,
U const& rhs)
requires (!detail::is_optional<U>) && detail::optional_eq_rel<T, U>;
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Compares a value against an engaged optional's value for equality.
template<
typename T,
typename U>
constexpr
bool
operator==(
T const& lhs,
optional<U> const& rhs)
requires (!detail::is_optional<T>) && detail::optional_eq_rel<T, U>;
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true, since all nullopt_t objects compare equal.true if both are disengaged, or both are engaged and their contained values are equal.true if lhs is disengaged.true if lhs is engaged and its contained value equals rhs.true if rhs is engaged and lhs equals its contained value.| Name | Description |
|---|---|
| lhs | The left-hand nullopt_t object. |
| rhs | The right-hand nullopt_t object. |