I need to read a sensor every five minutes, but since my sketch also has other tasks to do, I cannot just delay() between the readings. There is the Blink without delay tutorial suggesting I code along these lines:

void loop()
{
 unsigned long currentMillis = millis();
 // Read the sensor when needed.
 if (currentMillis - previousMillis > interval) {
 previousMillis = currentMillis;
 readSensor();
 }
 // Do other stuff...
}

The problem is that millis() is going to roll over back to zero after roughly 49.7 days. Since my sketch is intended to run for longer than that, I need to make sure the rollover does not make my sketch fail. I can easily detect the rollover condition(currentMillis < previousMillis), but I am not sure what to do then.

Thus my question: what would be the proper/simplest way to handle the millis() rollover?

I need to read a sensor every five minutes, but since my sketch also has other tasks to do, I cannot just delay() between the readings. There is the Blink without delay tutorial suggesting I code along these lines:

void loop()
{
 unsigned long currentMillis = millis();
 // Read the sensor when needed.
 if (currentMillis - previousMillis >= interval) {
 previousMillis = currentMillis;
 readSensor();
 }
 // Do other stuff...
}

The problem is that millis() is going to roll over back to zero after roughly 49.7 days. Since my sketch is intended to run for longer than that, I need to make sure the rollover does not make my sketch fail. I can easily detect the rollover condition(currentMillis < previousMillis), but I am not sure what to do then.

Thus my question: what would be the proper/simplest way to handle the millis() rollover?