std::optional::swap
From cppreference.com
| void swap( optional& other ) noexcept(/* see below */); |
(since C++17) | |
Swaps the contents with those of other.
- If neither *this nor
othercontain a value, the function has no effect.
- If only one of *this and
othercontains a value (let's call this objectinand the otherun), the contained value ofunis direct-initialized from std::move(*in), followed by destruction of the contained value ofinas if by in->T::~T(). After this call,indoes not contain a value;uncontains a value.
- If both *this and
othercontain values, the contained values are exchanged by calling using std::swap; swap(**this, *other).Tlvalues must satisfy Swappable.
Parameters
| other | - | the optional object to exchange the contents with
|
Return value
(none)
Exceptions
noexcept specification:
noexcept(std::is_nothrow_move_constructible_v<T> &&
std::is_nothrow_swappable_v<T>)
std::is_nothrow_swappable_v<T>)
In the case of thrown exception, the states of the contained values of *this and other are determined by the exception safety guarantees of swap of type T or T's move constructor, whichever is called. For both *this and other, if the object contained a value, it is left containing a value, and the other way round.
See also
| (C++17) |
specializes the std::swap algorithm (function) |