[#beman-optional-optional-03-operator_assign-01]
= xref:beman.adoc[beman]::xref:beman/optional.adoc[optional]::xref:beman/optional/optional-03.adoc[optional]::operator=
:relfileprefix: ../../../
:mrdocs:

Assignment operators

== Synopses

Declared in `<beman/optional/optional.hpp>`

Copy assigns the value from `rhs` if it has one.


[source,cpp,subs="verbatim,replacements,macros,-callouts"]
----
constexpr
xref:beman/optional/optional-03.adoc[optional]&
xref:beman/optional/optional-03/operator_assign-06.adoc[operator=](xref:beman/optional/optional-03.adoc[optional] const& other)
requires std::is_copy_constructible_v<T> && std::is_copy_assignable_v<T> &&
                     std::is_trivially_copy_constructible_v<T> && std::is_trivially_copy_assignable_v<T> = default;
----

[.small]#xref:beman/optional/optional-03/operator_assign-06.adoc[_» more..._]#

Copy assigns the value from `rhs` if it has one.


[source,cpp,subs="verbatim,replacements,macros,-callouts"]
----
constexpr
xref:beman/optional/optional-03.adoc[optional<T>]&
xref:beman/optional/optional-03/operator_assign-09.adoc[operator=](xref:beman/optional/optional-03.adoc[optional] const& rhs)
requires std::is_copy_constructible_v<T> && std::is_copy_assignable_v<T> &&
             (!std::is_trivially_copy_assignable_v<T>);
----

[.small]#xref:beman/optional/optional-03/operator_assign-09.adoc[_» more..._]#

Assigns the stored value from `rhs` if it has one, destroying the old value if there


[source,cpp,subs="verbatim,replacements,macros,-callouts"]
----
template<class U>
constexpr
xref:beman/optional/optional-03.adoc[optional<T>]&
xref:beman/optional/optional-03/operator_assign-08.adoc[operator=](xref:beman/optional/optional-03.adoc[optional<U>] const& rhs)
requires (detail::enable_assign_from_other<T, U, const U&>);
----

[.small]#xref:beman/optional/optional-03/operator_assign-08.adoc[_» more..._]#

Move assigns the value from `rhs` if it has one.


[source,cpp,subs="verbatim,replacements,macros,-callouts"]
----
constexpr
xref:beman/optional/optional-03.adoc[optional]&
xref:beman/optional/optional-03/operator_assign-0d.adoc[operator=](xref:beman/optional/optional-03.adoc[optional]&& other)
requires std::is_move_constructible_v<T> && std::is_move_assignable_v<T> &&
                     std::is_trivially_move_constructible_v<T> && std::is_trivially_move_assignable_v<T> = default;
----

[.small]#xref:beman/optional/optional-03/operator_assign-0d.adoc[_» more..._]#

Move assigns the value from `rhs` if it has one.


[source,cpp,subs="verbatim,replacements,macros,-callouts"]
----
constexpr
xref:beman/optional/optional-03.adoc[optional<T>]&
xref:beman/optional/optional-03/operator_assign-0b8.adoc[operator=](xref:beman/optional/optional-03.adoc[optional]&& rhs) noexcept(std::is_nothrow_move_constructible_v<T>)
requires std::is_move_constructible_v<T> && std::is_move_assignable_v<T> &&
             (!std::is_trivially_move_assignable_v<T>);
----

[.small]#xref:beman/optional/optional-03/operator_assign-0b8.adoc[_» more..._]#

Assigns the stored value from `rhs` if it has one, destroying the old value if there


[source,cpp,subs="verbatim,replacements,macros,-callouts"]
----
template<class U>
constexpr
xref:beman/optional/optional-03.adoc[optional<T>]&
xref:beman/optional/optional-03/operator_assign-07.adoc[operator=](xref:beman/optional/optional-03.adoc[optional<U>]&& rhs)
requires (detail::enable_assign_from_other<T, U, U>);
----

[.small]#xref:beman/optional/optional-03/operator_assign-07.adoc[_» more..._]#

Resets the optional to an empty state.


[source,cpp,subs="verbatim,replacements,macros,-callouts"]
----
constexpr
xref:beman/optional/optional-03.adoc[optional<T>]&
xref:beman/optional/optional-03/operator_assign-0f.adoc[operator=](xref:beman/optional/nullopt_t.adoc[nullopt_t] value) noexcept;
----

[.small]#xref:beman/optional/optional-03/operator_assign-0f.adoc[_» more..._]#

Assigns the stored value from `u,` destroying the old value if there


[source,cpp,subs="verbatim,replacements,macros,-callouts"]
----
template<class U = T>
constexpr
xref:beman/optional/optional-03.adoc[optional<T>]&
xref:beman/optional/optional-03/operator_assign-0b6.adoc[operator=](U&& u)
requires detail::enable_assign_forward<T, U>;
----

[.small]#xref:beman/optional/optional-03/operator_assign-0b6.adoc[_» more..._]#

== Return Value

optional&

== Template Parameters

[cols=2]
|===
| Name
| Description
| *U*
| 
|===

== Parameters

[cols=2]
|===
| Name
| Description
| *u*
| 
|===


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