使用 CRTP 时,我遇到了对象切片问题。以下模拟说明了我的问题。
#include <memory>
class CrtpGenr
{
};
template<class t_object>
class CrtpBase : public CrtpGenr
{
public:
static
auto create() -> std::unique_ptr<t_object> {
return(std::unique_ptr<t_object>(new t_object));
}
void funct1(){}
};
class CrtpDirv1 : public CrtpBase<CrtpDirv1>
{
public:
void funct2(){}
};
class CrtpDirv2 : public CrtpBase<CrtpDirv2>
{
public:
void funct2(){}
};
int main()
{
/*
// This works
std::unique_ptr<CrtpDirv1> crtp_obj = CrtpDirv1::create();
crtp_obj->funct1();
crtp_obj->funct2();
*/
std::unique_ptr<CrtpGenr> crtp_obj1 = static_cast<std::unique_ptr<CrtpGenr>>(CrtpDirv1::create());
std::unique_ptr<CrtpGenr> crtp_obj2 = static_cast<std::unique_ptr<CrtpGenr>>(CrtpDirv2::create());
crtp_obj1->funct1();
crtp_obj1->funct2();
return 0;
}
编译上面的代码给我以下错误:
main.cpp: In function 'int main()':
main.cpp:47:16: error: 'class CrtpGenr' has no member named 'funct1'
crtp_obj1->funct1();
^
main.cpp:48:16: error: 'class CrtpGenr' has no member named 'funct2'
crtp_obj1->funct2();
我希望能够将 CrtpDirv1 和 CrtpDirv2 类转换为 CrtpGenr。这样我就可以定义一个 CrtpGenr 类型的容器来保存 CrtpDirv1 或 CrtpDirv2 的对象。我究竟做错了什么?