piece of code in mod_perl guide

[pascal barbedor]

hello,   I am reading mod_perl guide and i had a problem with a piece of code in chapter 9.7.4.2 about reloading configuration files. this is version jan 2001 but i have checked in the last one the piece of code is the same.   when running the code exactly, things don't work, even outside mod_perl environnment.   the sub below print  file is different even though I don't change the file.   I have located that if i change      $MODIFIED{$file} = -M _;   to  an explicit      $MODIFIED{$file} = -M $file;   in the last line, everything works fine.     since i do no test on any other file and I have understood that _ account s for the last file tested, I don't understand why it does work. I am on NT4 perl 5.6.1 try it yourself ! so strange !     thanks for any explanation     *********************************   for (1..10){   reread_conf("l:/asperl/site/lib/afpa/evolif/config.pm");   sleep 2;   }       our %MODIFIED; sub reread_conf{    my $file=shift;    return unless $file;    return unless -e $file and -r _;    if ($MODIFIED{$file} and $MODIFIED{$file}== -M _){    print  "same" ; }else {print "different";}    print "\n";    unless ($MODIFIED{$file} and $MODIFIED{$file}== -M _){          unless (my $result = do $file) {     warn ...        }     print "\nmod:",$MODIFIED{$file},' :', -M _,"\n";       $MODIFIED{$file} = -M _;    }   }