======millis()   ======

====Description   ====
Returns the number of milliseconds since the Arduino board began running the current program.  This number will overflow (go back to zero), after approximately 50 days.

====Parameters   ====
None

====Returns   ====
Number of milliseconds since the program started (''unsigned long'')

====Example   ====

<code arduino>
unsigned long time;

void setup(){
  Serial.begin(9600);
}
void loop(){
  Serial.print("Time: ");
  time = millis();
  //prints time since program started
  Serial.println(time);
  // wait a second so as not to send massive amounts of data
  delay(1000);
}
</code>

====Tip:   ====

Note that the parameter for millis is an unsigned long, errors may be generated if a programmer tries to do math with other datatypes such as ints. 

====See also   ====
* [[arduino:time:Micros]]
* [[arduino:time:Delay]]
* [[arduino:time:DelayMicroseconds]]


Source: arduino.cc