type tyarit?

[Wu zhen hai]

How to implement is_class is_union is_enum?

Help!!!!

[coder777]

You need to #include <type_traits> . For example is_enum see:

http://www.cplusplus.com/reference/type_traits/is_enum/?kw=is_enum

[JLBorges]

For a possible implementation of std::is_class, see: http://en.cppreference.com/w/cpp/types/is_class

Also see: http://stackoverflow.com/a/11317409

[Wu zhen hai]

@coder777, not'how to use', but 'how to implement'?

[coder777]

'how to implement'?

You can't. These are basically compiler internals exposed. There might be other compiler internals (which depends of course on the compiler) used by these traits, but it makes not too much sense to use them non standard as they are.