BEGIN {
  my $rel2abs = rel2abs $0;
  my $realpath = eval { realpath $rel2abs };
  unless ( defined $realpath ) {
    warn "$rel2abs";
    $rel2abs .= '.exe';
    $realpath = realpath $rel2abs;
  }

  my $myname = $0 = $realpath;
  #my $myname = $0 = realpath rel2abs $0;
  my $mybase = basename $0, qw(.t .pm .pl .perl .exe);
  my $mydir = dirname $0;

  die 'chdir() used too early' unless -f $0;  

  sub myname { $myname }
  sub mybase { $mybase }
  sub mydir  { $mydir  }

}