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 |