thank you. here is the difference between abs_path and rel2abs():

$ cd $HOME
$ ln -s /tmp softlink
$ perl softlink/mylog.pl
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main:: path/mylog.pl (23)> abs_path=/tmp/mylog.pl
main:: path/mylog.pl (26)> rel2abs=/home/maletin/softlink/mylog.pl
MyLog::init /home/maletin/MyLog.pm (11)> INIT
MyLog::path /home/maletin/MyLog.pm (16)> /home/maletin/MyLog.pm
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$ cat /tmp/mylog.pl

#! perl -w
# mylog.pl
# using a package that print it's absolute filename.

use strict;
use warnings;
use Log::Log4perl;
use Cwd qw( abs_path );
use lib $ENV{HOME};    # location of MyLog.pm
use MyLog;

my $conf = q(
log4perl.category.Log           = INFO, Screen
log4perl.appender.Screen        = Log::Log4perl::Appender::Screen
log4perl.appender.Screen.layout = Log::Log4perl::Layout::PatternLayout
log4perl.appender.Screen.layout.ConversionPattern = %l> %m %n
);

Log::Log4perl->init( \$conf );
my $log4perl_logger = Log::Log4perl->get_logger('Log');

my $abs_path = abs_path($0);
$log4perl_logger->info("abs_path=$abs_path");

my $rel2abs = File::Spec->rel2abs($0);
$log4perl_logger->info("rel2abs=$rel2abs");

MyLog->init($log4perl_logger);
MyLog->path();
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$ cat $HOME/MyLog.pm

package MyLog;

use strict;
use warnings;

my $my_logger = undef;

sub init {
    my ( $class, $logger ) = @_;
    $my_logger = $logger;
    $my_logger->info('INIT');
}

sub path {
    my $path = ( eval { caller(0) } )[1];
    $my_logger->info($path);
    return $path;
}

1;
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D:\>perl c:script.pl
D:\C:script.pl
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File::Spec::Win32's rel2abs is a wrapper around Cwd that solves this problem.