int num_instances;

struct A
{
  A()
  {
    order = ++num_instances;
  }
  int order;
};

A a3;
A a2 __attribute__((init_priority(1000)));
A a1 __attribute__((init_priority(990)));

void setup()
{
  Serial.begin(115200);
}

void loop()
{
  int errors = 0;
  if (a1.order != 1) {
    Serial.print(F("Bad a1 order "));
    Serial.println(a1.order); // This must output 1
    ++errors;
  }
  if (a2.order != 2) {
    Serial.print(F("Bad a2 order "));
    Serial.println(a2.order); // This must output 2
    ++errors;
  }
  if (a3.order != 3) {
    Serial.print(F("Bad a3 order "));
    Serial.println(a3.order); // This must output 3
    ++errors;
  }
  if (!errors)
    Serial.println(F("Okay!"));
  delay(1000);
}