why do some perl files end with 1;

nikhil.patil has asked for the wisdom of the Perl Monks concerning the following question:

Replies are listed 'Best First'.
Re: why do some perl files end with 1; by olus (Curate) on Feb 21, 2008 at 11:15 UTC
When a module is loaded (via use) the compiler will complain unless the last statement executed when it is loaded is true. For that reason, Perl modules end with `1;`	[reply] [d/l]
Re: why do some perl files end with 1; by moritz (Cardinal) on Feb 21, 2008 at 11:16 UTC
A module that is useed or required by other perl code needs to return a true value. That's what the `1;` is for. See perlmod for details.	[reply] [d/l]
Re: why do some perl files end with 1; by parv (Parson) on Feb 21, 2008 at 12:02 UTC
If you don't like 1, (after reading other replies) you can have any other true value, say 42, the strings 'undef' or 'zero', etc. I wonder what 0E0 would give ... nope, that doesn't work.	[reply]
Re^2: why do some perl files end with 1; by Limbic~Region (Chancellor) on Feb 21, 2008 at 15:14 UTC
parv, I am rather partial to: `'This statement is false.';` [download] Cheers - L~R	[reply] [d/l]
Re^3: why do some perl files end with 1; by Your Mother (Archbishop) on Feb 22, 2008 at 00:31 UTC
I share my favorite HEREDOC delimiter in the same spirit. `print <<"AsPhynCteRsAyswHat";` Another dev did write to ask me once.	[reply] [d/l]
Re^2: why do some perl files end with 1; by Narveson (Chaplain) on Feb 21, 2008 at 15:23 UTC
Module authors have the opportunity to use a string in this position. They could say `'Hello, world!';` `'Have a nice day!';` `'Thank you for using Acme::Foo!';` It's like a comment, except if the user deletes it, their program breaks. Some CPAN authors do use this opportunity to have a last word. Does anybody have a favorite example?	[reply] [d/l] [select]
Re^3: why do some perl files end with 1; by ferreira (Chaplain) on Feb 22, 2008 at 12:25 UTC
Some good ones. Explicit and correct: from List::Maker `1; # Magic true value required at end of module` Epitaph: at Acme::DonMartin `'This module is dedicated to Don Martin' ; 1931-2000` [download] Identify your package: from nuffin's packages: `__PACKAGE__;` Remarkable quote: at WWW::CPAN `"I didn't do it! -- Bart Simpson";` the end of Sex	[reply] [d/l] [select]
Re^3: why do some perl files end with 1; by John M. Dlugosz (Monsignor) on Feb 22, 2008 at 00:30 UTC
Favorite example: `return 1; # module loaded successfully` [download]	[reply] [d/l]