Question

Possible Duplicate:
Why do you have to put a 1; at the end of a Perl 5 module?

From this page Perl::Critic::Policy::Subroutines::RequireFinalReturn, this is a code sample

package Password;
# every time the user guesses the password wrong, its value
# is rotated by one character
my $password;
sub set_password {
    $password = shift;
}
sub check_password {
    my $guess = shift;
    if ($guess eq $password) {
        unlock_secrets();
    } else {
        $password = (substr $password, 1).(substr $password, 0, 1);
    }
}
1;

• Why is a 1; used at the end? What does that statement signify to the compiler?

I tried code with and without it. Result looks the same.

Answer 1

It’s because a Perl module has to return “true” in order for it to work as a module. If a module doesn’t return true, it’s assumed that its initialization failed and it’s equivalent to calling die. It’s not required if the code isn’t used as a module, though, so unless you try using the code example as a module as well, you won’t see the difference.

1; is just probably one of the most concise ways of returning true.

If you take a look at this site, you’ll see that people are being pretty creative with their return values.