// transparent unions?

struct BoxedInt {
  int x;
};

typedef union {
  int *intPtr;
  struct BoxedInt *boxedPtr;
} CompatArgUnion __attribute__((__transparent_union__));

extern int compatFunc(int, CompatArgUnion);

int compatFunc(int firstArg, CompatArgUnion secondArg)
{
  return firstArg + *(secondArg.intPtr);
}


int main()
{ 
  int i = 6;
  struct BoxedInt b;
  int ret = 0;

  b.x = 7;

  // today I pass an int ptr
  ret += compatFunc(-6, &i);
  
  // tomorrow I pass a ptr to a struct with an embedded int
  ret += compatFunc(-7, &b);
  
  return ret;
}