std::variant<Types...>::~variant

Declarations

C++17

~variant()

C++20

constexpr ~variant()

If valueless_by_exception() is true, does nothing. Otherwise, destroys the currently contained value.

This destructor is trivial if std::is_trivially_destructible_v<T_i> is true for all T_i in Types....

Example

#include <variant>
#include <cstdio>
 
int main()
{
    struct X { ~X() { puts("X::~X();"); } };
    struct Y { ~Y() { puts("Y::~Y();"); } };
 
    {
        puts("entering block #1");
        std::variant<X,Y> var;
        puts("leaving block #1");
    }
 
    {
        puts("entering block #2");
        std::variant<X,Y> var{ std::in_place_index_t<1>{} }; // constructs var(Y)
        puts("leaving block #2");
    }
}

Result

entering block #1
leaving block #1
X::~X();
entering block #2
leaving block #2
Y::~Y();

Defect reports

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

DR	Applied to	Behavior as published	Correct behavior
P2231R1	C++20	the destructor was not constexpr while non-trivial destructors can be constexpr in C++20	made constexpr