DB<243> $nan=sin(9**9**9)
 => "nan"

  DB<244>  looks_like_number($nan)
 => 8704

  DB<245> $nan eq "nan"
 => 1

  DB<246>  Scalar::Util::looks_like_number($nan)
 => 36

##</code><code>##

  DB<106> $nan=sin(9**9**9)
 => "nan"

  DB<107> print "NaN support here" if $nan != $nan
 => 1
NaN support here
  DB<108>