struct S1 {
  double val;
  int rank;
};

struct DoubleIntPair {
  double x;
  int y;
};

void convert(void * buf, int count) {
  struct DoubleIntPair * p = (struct DoubleIntPair *)buf;
  struct DoubleIntPair newbuf[count];
  for (int i=0; i<count; i++) {
    newbuf[i].x = p[i].x;
    newbuf[i].y = p[i].y;
  }
  for (int i=0; i<count; i++) {
    $assert(newbuf[i].x == 10.0*i);
    $assert(newbuf[i].y == i);
  }
}

int main(void) {
  int n = 5;
  struct S1 a[n];
  for (int i=0; i<n; i++) {
    a[i].val = 10.0*i;
    a[i].rank = i;
  }
  convert(a, n);
}