The C standard doesn't exactly "inherit" the 170 pages of the C language spec. As far as I know, the core C++ language (excluding the library) is defined entire

The C standard doesn't exactly "inherit" the 170 pages of the C language spec. As far as I know, the core C++ language (excluding the library) is defined entirely by the C++ standard, without reference to the C standard. It was certainly based on C, but the description doesn't depend on it. The C standard library is incorporated by reference (with a few tweaks) into the C++ standard. Of course the C++ standard library also includes a lot of material that isn't in the C standard library.