Swaps twovariant objects.

• If both*this andrhs are valueless by exception, does nothing.
• Otherwise, if both*this andrhs hold the same alternative, callsswap(*std::get_if<i>(this),*std::get_if<i>(std::addressof(rhs))) wherei isindex(). If an exception is thrown, the state of the values depends on the exception safety of theswap function called.
• Otherwise, exchanges values ofrhs and*this. If an exception is thrown, the state of*this andrhs depends on exception safety of variant's move constructor.

The program is ill-formed unless typeT_i areSwappable andstd::is_move_constructible_v<T_i> istrue for allT_i inTypes....

[edit]Parameters

[edit]Return value

(none)

[edit]Exceptions

Ifthis->index()== rhs.index(), may throw any exception thrown byswap(*std::get_if<i>(this),*std::get_if<i>(std::addressof(rhs))) withi beingindex().

Otherwise, may throw any exception thrown by the move constructors of the alternatives currently held by*this andrhs.

[edit]Notes

[edit]Example

#include <iostream>#include <string>#include <variant> int main(){std::variant<int,std::string> v1{2}, v2{"abc"};std::visit([](auto&& x){std::cout<< x<<' ';}, v1);std::visit([](auto&& x){std::cout<< x<<'\n';}, v2);    v1.swap(v2);std::visit([](auto&& x){std::cout<< x<<' ';}, v1);std::visit([](auto&& x){std::cout<< x<<'\n';}, v2);}

2 abcabc 2

[edit]Defect reports

The following behavior-changing defect reports were applied retroactively to previously published C++ standards.

[edit]See also

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