What are “extended integer types”?

Question

Quoting from the book I\'m reading:

1. signed char, signed short int, signed int, signed long int, signed long long int are called

Answer 1

Extended integer types are implementation-specific integer types that are provided as an extension. Because almost everything about such extensions is implementation-defined, the standard can’t say much about them. However, a C++09 proposal provides a framework for implementing such extensions in a way that doesn’t interfere with the behavior of standard compliant programs.

you should refer this,which covers everything about extended integer types.