use CGI;
my $cgi = new CGI;
#...more stuff not important to this discussion
print $cgi->header( -type => 'application/xml');
print '<?xml version.......blah blah'."\n";

##</code><code>##

use CGI;
my $cgi = new CGI;
#...more stuff not important to this discussion
print "Content-Type: application/xml\n".
      "\n".
      '<?xml version.......blah blah'."\n";