Perl has changed over time, gaining new features, new functions, increasing its flexibility, and reducing the impact on the C namespace environment (reduced pollution). The header file, typically ppport.h, written by this module attempts to bring some of the newer Perl features to older versions of Perl, so that you can worry less about keeping track of old releases, but users can still reap the benefit. Why you should use ppport.h in modern code: so that your code will work with the widest range of Perl interpreters possible, without significant additional work. Why you should attempt older code to fully use ppport.h: because the reduced pollution of newer Perl versions is an important thing, so important that the old polluting ways of original Perl modules will not be supported very far into the future, and your module will almost certainly break! By adapting to it now, you'll gain compatibility and a sense of having done the electronic ecology some good. WWW: https://metacpan.org/release/Devel-PPPort