package Foo;
use Exporter;
our @ISA = ( 'Exporter' );

##</code><code>##

package Foo;
use base 'Exporter';

##</code><code>##

# file Foo.pm

package Foo;
use strict;
use warnings;

use Exporter;
our @ISA       = ( 'Exporter' );
our @EXPORT_OK = ( 'sysread' );

sub sysread {
  warn "this is not the real thing\n";
}

1;
__END__

# file test.pl

use strict;
use warnings;

package Bar;
use Foo 'sysread';

warn "about to test sysread\n";
sysread;
__END__

% perl test.pl
about to test sysread
this is not the real thing