# beginning of program

eval {
    main();
};
if ( $@ ) {
    confess();
}

sub main {
...
}

##</code><code>##

#!/usr/bin/perl -w

use strict;
use Carp;

eval {
    main();
};
if ( $@ ) {
    confess();
}

exit;

sub main {
    print "hello world\n";
}