For what sort of 'systems programming' projects is C++ clearly superior to C?

Question

C++ is billed as a 'systems programming language'. Yet many 'systems' projects use plain C; when they use C++, sometimes it is only for very simple classes which could easily be replaced by C structs. What kind of 'systems' projects does C++ really shine in?

Answer 1

Well, in my line of work I maintain and develop a program that operates a relatively complex piece of medical machinery. These machines support a large number of hardware configurations. So, we define an interface (implemented as a DLL) for each piece of unique hardware.

In code, these are treated opaquely through the use of an interface (iVideo, iMotion, whatever) and the underlying implementation is irrelevant. This makes changing hardware or adding new components very easy as none of the component specific code ever needs to be changed in the larger context of the application.