These special variable types (objects) automatically increase as time elapses. This makes it easy to check if a certain time has elapsed, while allowing your program to perform other work or checks for user input. It is also very to handle multiple tasks requiring different delays.
Documentation on how to use this library is located in the wiki and also on the Arduino Playground.
Please report any bugs or issues you find on the issue tracker.
Initial code derived from Paul Stoffregen's elapsedMillis and elapsedMicros helper code for the Teensy USB developer board. Code contributes and initial examples created by John Plocher.