c++ - 使用模板类的 Cast 运算符

Question

我想重载一个转换运算符，我有以下代码:

template <typename _T>
class CTest
{
public :
    _T data;

    CTest(_T _data) : data(_data) {}
    ~CTest() {}

    operator _T(){ return data; }
};

和 MS Visual Studio 2005，给我以下错误:

warning C4003: not enough actual parameters for macro 'T' warning C4003: not enough actual parameters for macro '_T' error C2833: 'operator L' is not a recognized operator or type see reference to class template instantiation 'CTest<_T>' being compiled error C2059: syntax error : 'newline' error C2334: unexpected token(s) preceding '{'; skipping apparent function body error C2833: 'operator L' is not a recognized operator or type

如何正确声明operator _T()？

Answer 1

_T 是一个 WINAPI 宏(参见 Generic-Text Mappings in Tchar.h 或 Should I use _T or _TEXT on C++ string literals? ):将 _T 更改为 T。