typeid operator
| typeid operator | Runtime type identification operator |
postfix-expr := typeid ( expression ) | typeid ( type-id ) |
The typeid operator returns a const reference to a type_info object that describes type-id or the type of expression. If expression is an lvalue (not a pointer) of a polymorphic class, the type_info of the most-derived class is returned. Otherwise, expression is not evaluated, and the type_info of its static type is returned.
Each distinct type has its own associated type_info object, but type synonyms (such as those created with typedef) have the same type_info object.
Example
template<typename T>
void debug(const T& obj)
{
std::clog << typeid(obj).name( ) << ':' << &obj << '\n';
}
See Also
expression, typedef, Chapter 3, <typeinfo>
