Looks for the next valid integer in the incoming serial. The function terminates if it times out (see Serial.setTimeout()).

Serial.parseInt() inherits from the Stream utility class.

In particular:

  • Parsing stops when no characters have been read for a configurable time-out value, or a non-digit is read;
  • If no valid digits were read when the time-out (see Serial.setTimeout()) occurs, 0 is returned;




Serial.parseInt(lookahead, ignore)

Parameter Values

  • Serial: serial port object. See the list of available serial ports for each board on the Serial main page.
  • lookahead: the mode used to look ahead in the stream for an integer. Allowed data types: LookaheadMode. Allowed lookahead values:
    • SKIP_ALL: all characters other than digits or a minus sign are ignored when scanning the stream for an integer. This is the default mode.
    • SKIP_NONE: Nothing is skipped, and the stream is not touched unless the first waiting character is valid.
    • SKIP_WHITESPACE: Only tabs, spaces, line feeds, and carriage returns are skipped.
  • ignore: used to skip the indicated char in the search. Used for example to skip thousands divider. Allowed data types: char

Return Values

  • The next valid integer. Data type: long.


Serial functions are not only used for the communication between an Arduino board and Serial Monitor of Arduino IDE but also used for the communication between:

  • An Arduino board and other Arduino board
  • An Arduino board and other sensors/devices
  • An Arduino board and computer (any Serial software on computer)

See Also


Arduino UNO R3
Arduino Starter Kit
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