std::polymorphic<T, Allocator>::operator=
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constexpr polymorphic& operator=( const polymorphic& other );
(1)
(since C++26)
constexpr polymorphic& operator=( polymorphic&& other )
noexcept(/* see below */);
(2)
(since C++26)
noexcept(/* see below */);
Replaces contents of *this with the contents of other.
Let traits be std::allocator_traits <Allocator>:
1) If std::addressof (other) == this is true, does nothing. Otherwise, let need_update be traits::propagate_on_container_copy_assignment::value:
- If other is valueless, proceeds to the next step. Otherwise, constructs a new owned object in *this using traits::construct with *other as the argument, using the allocator update_alloc ? other.
allocalloc. - The previously owned object in *this (if any) is destroyed using traits::destroy and then the storage is deallocated.
After updating the object owned by *this, if need_update is true,
alloc is replaced with a copy of other.alloc . If
T is an incomplete type, the program is ill-formed.2) If std::addressof (other) == this is true, does nothing. Otherwise, let need_update be traits::propagate_on_container_move_assignment::value:
- If
allocallocis true, swaps the owned objects in *this and other; the owned object in other (if any) is then destroyed using traits::destroy and then the storage is deallocated. - Otherwise:
- If other is valueless, proceeds to the next step. Otherwise, constructs a new owned object in *this using traits::construct with std::move(*other) as the argument, using the allocator update_alloc ? other.
allocalloc. - The previously owned object in *this (if any) is destroyed using traits::destroy and then the storage is deallocated.
- If other is valueless, proceeds to the next step. Otherwise, constructs a new owned object in *this using traits::construct with std::move(*other) as the argument, using the allocator update_alloc ? other.
After updating the objects owned by *this and other, if need_update is true,
alloc is replaced with a copy of other.alloc . If all following conditions are satisfied, the program is ill-formed:
- std::allocator_traits <Allocator>::is_always_equal::value is false.
-
Tis an incomplete type.
Contents
[edit] Parameters
other
-
another
polymorphic object whose owned value (if exists) is used for assignment
[edit] Return value
*this
[edit] Exceptions
1) If any exception is thrown, there are no effects on *this.
2) If any exception is thrown, there are no effects on *this or other.
noexcept specification:
noexcept(std::allocator_traits <Allocator>::
propagate_on_container_move_assignment::value
[edit] Example
This section is incomplete
Reason: no example
Reason: no example