23 General utilities library [utilities]

23.11 Smart pointers [smartptr]

23.11.1 Class template unique_­ptr [unique.ptr]

23.11.1.2 unique_­ptr for single objects [unique.ptr.single]

23.11.1.2.3 unique_­ptr assignment [unique.ptr.single.asgn]

unique_ptr& operator=(unique_ptr&& u) noexcept;
Requires: If D is not a reference type, D shall satisfy the requirements of MoveAssignable and assignment of the deleter from an rvalue of type D shall not throw an exception.
Otherwise, D is a reference type; remove_­reference_­t<D> shall satisfy the CopyAssignable requirements and assignment of the deleter from an lvalue of type D shall not throw an exception.
Effects: Transfers ownership from u to *this as if by calling reset(u.release()) followed by get_­deleter() = std​::​forward<D>(u.get_­deleter()).
Returns: *this.
template<class U, class E> unique_ptr& operator=(unique_ptr<U, E>&& u) noexcept;
Requires: If E is not a reference type, assignment of the deleter from an rvalue of type E shall be well-formed and shall not throw an exception.
Otherwise, E is a reference type and assignment of the deleter from an lvalue of type E shall be well-formed and shall not throw an exception.
Remarks: This operator shall not participate in overload resolution unless:
  • unique_­ptr<U, E>​::​pointer is implicitly convertible to pointer, and
  • U is not an array type, and
  • is_­assignable_­v<D&, E&&> is true.
Effects: Transfers ownership from u to *this as if by calling reset(u.release()) followed by get_­deleter() = std​::​forward<E>(u.get_­deleter()).
Returns: *this.
unique_ptr& operator=(nullptr_t) noexcept;
Effects: As if by reset().
Postconditions: get() == nullptr.
Returns: *this.