Package My::Module;
require Exporter;
@My::Module::ISA    = qw(Exporter);
@My::Module::EXPORT = qw(the-function);

sub the-function {

print "Content-type: text/html\n\n";

print <<HTML;
Here are the HTTP REQUEST headers:
<p>
HTTP Request: $ENV{'REQUEST_METHOD'} $0 $ENV{'SERVER_PROTOCOL'}
<br>
Host: $ENV{'HTTP_HOST'}
<br>
User-Agent: $ENV{'HTTP_USER_AGENT'}
<br>
Accept: $ENV{'HTTP_ACCEPT_ENCODING'}
<br>
Accept-Language: $ENV{'HTTP_ACCEPT_LANGUAGE'}
<br>
Accept-Charset: $ENV{'HTTP_ACCEPT_CHARSET'}
<br>
Keep-Alive: $ENV{'HTTP_KEEP_ALIVE'}
<br>
Connection: $ENV{'HTTP_CONNECTION'}
<p>

SORRY -- I don't know how to show you the HTTP --RESPONSE-- Headers . . .

HTML
}
1;

Package Main;

#!/usr/bin/perl

use My::Module;

the-function();

__END__