x                  The logarithmic gamma of the x argument.
    -HUGE_VAL          The x argument is a negative integer; errno is
                       set to ERANGE.
    NaN                The x argument is NaN; errno is set to EDOM.
    0                  Underflow occurred; errno is set to ERANGE.
    HUGE_VAL           Overflow occurred; errno is set to ERANGE.