nested4.c

this is a gcc file, you can download it and learn its usetility, for further detail please look at t

// From: [e-mail]
// Subject: extern "C" nested class
// Date: Fri, 13 Aug 1993 15:33:53 +0200
// Build don't link:

extern "C" {
  struct A {
    struct B { int j; } *x;
  };
}

void
foo () {
  A a;
  struct A::B *b;
  b = a.x;	// gets bogus error - type `B' is not a base type for type `B'
}