Category 

Type Trait Functions 

Syntax  

bool __is_empty( typename T ) 

Returns true if and only if T is an 'empty' type. 

Error if T is an incomplete type 

Definition of __is_empty is given in the table in Section 20.4.4.3 of the Working Draft. 

A type T is empty if T:

• is a class type but not a union type.
• has no non-static data members other than bit-fields of length 0
• has no virtual member functions
• has no virtual base classes
• has no base class which is not empty.