与现有变量的结构化绑定不可能？

Question

是否可以使用现有的变量作为与之相关的返回值的目标structured bindings？

auto f()
{
    return std::make_tuple(1,2.2);
}

int main()
{
    int x;
    double z;

    [ x, z ] = f();  // Did not work in gcc 7.1

    // structured bindings only work with "new" vars?
    auto [a, b] = f();  // works fine
}

Answer 1

如果要使用现有变量,则可以std::tie实现此目的.

std::tie(x, z) = f(); // only works with tuples however

结构化绑定引入了新标识符.不幸的是,没有什么能比得上std::tie一般的聚合.