Category 

Type Trait Functions 

Syntax 

bool __is_complete_type(T) 

Returns True if and only if T is a complete type at the point of the function call.  

This is a support function to help users track ill-formed code, not a distinct type trait required by the standard. This function is typically used in static_assert statements, because most other uses risk violating the ODR. Note that void and arrays of unknown bound are always incomplete types.