union4.c

gcc-you can use this code to learn something about gcc, and inquire further into linux,

// Build don't link:
// Origin: Mark Mitchell <[e-mail]>
// Special g++ Options:

union A
{
  int i;
  int j;

  A () : i (3), j (2) {} // ERROR - multiple initializations
};

union B
{
  int i;
  union {
    int j;
  };

  B () : i (3), j (2) {} // ERROR - multiple initializations
};

union C
{
  union {
    struct {
      int i;
      int j;
    };
  };

  C () : i (3), j (2) {}
};