require Exporter;
@ISA = qw(Exporter);

@EXPORT =qw\fun1 fun2\;

@EXPORT_OK = qw\fun3\;

@EXPORT_FAIL= qw\fun4\;

sub fun1{print "\nfun1 in package " . __PACKAGE__ }
sub fun2{print "\nfun2 in package " . __PACKAGE__ }
sub fun3{print "\nfun3 in package " . __PACKAGE__ }
sub fun4{print "\nfun4 in package " . __PACKAGE__ }

##</code><code>##

use Module;
fun1;
fun2;
fun3;
fun4;

##</code><code>##

fun1 in package main
fun2 in package main
fun3 in package main
fun4 in package main

##</code><code>##

package Module;
require Exporter;
@ISA = qw(Exporter);
...

##</code><code>##

fun1 in package Module
fun2 in package Module