Float

If an integer arithmetic expression overflows the limiting range, [-2^63 : 2^63] for 64-bit integers, the result is returned as a floating point value instead. This is not treated as an error. Example:
    gnuplot> set overflow float
    gnuplot> A = 2**62 - 1;  print A, A+A, A+A+A
    4611686018427387903 9223372036854775806 1.38350580552822e+19