This subclause describes the conventions used to specify this document, in addition to those conventions specified in C++ 2014 [description].
In addition to the elements defined in C++ 2014 [structure.specifications], descriptions of function semantics contain the following elements (as appropriate):
Completion signature: if the function initiates an asynchronous operation, specifies the signature of a completion handler used to receive the result of the operation.
Several classes defined in this document are nested classes. For a specified nested class A::B, an implementation is permitted to define A::B as a synonym for a class with equivalent functionality to class A::B. [ Note: When A::B is a synonym for another type A provides a nested type B, to emulate the injected class name. — end note ]