在联合中使用继承

Question

我想知道是否有人知道是否有可能以某种方式在联盟中使用继承.

在下面的示例中,TestFailsunion将不包含struct中的a变量Base,同时TestWorks确实有效.

struct Base { int a; };

union TestFails
{
    struct : public Base {};
    int b;
};

union TestWorks
{
    struct  { int a; };
    int b;
};

int main()
{
    TestWorks works;
    works.a = 0;

    TestFails fails;
    fails.a = 0;

    return 0;
}

您可以在此处测试代码:http://ideone.com/dUzpOR

Answer 1

不确定是否有帮助，但这有效：

struct Base { int a; };
struct Foo : Base { int b;};
union TestFailsNot {
    Base base;
    Foo foo;
    int b;
};

int main() {
    TestFailsNot failsNot;
    failsNot.foo.a = 0;    
    failsNot.base.a = 3; // maybe not what you want to do, but it works
}