package MyLogger;

use strict;
use warnings;

sub new {
    
    if( $^O =~ /win32/i ){
        require MyLogger::Win32;
        return MyLogger::Win32->new;
    }
    else{
        require MyLogger::Default;
        return MyLogger::Default->new;
    }

}

1;

package MyLogger::Win32;

use strict;
use warnings;

use all_Win32_stuff;

sub new{
    my ($class) = @_;

    my $self = bless {}, $class;
    $self->{handle} = Win32::EventLog->new("Zaphod");
}

sub log {
      my ($self) = @_;
      my %win;

      $win{'Computer'} = "Eddy";
      $win{'Source'} = "Hard of Gold";
      $win{'Category'} = undef;
      $win{'EventID'} = 42;
      $win{'Data'} = undef;
      $win{'Strings'} = "Dont interrupt me, I computing real earth Tee!"

      $self->{handle}->Report(\%win);
}

...

package MyLogger::Default;

use strict;
use warnings;

use all_Unix_stuff;

sub new{
    my ($class) = @_;

    return bless {}, $class;
}

sub log {
         &syslog(LOG_DEBUG,"Where is Marvin??");
}

...