[silentbicycle]

Which is weird, because it's actually a defining feature of modular programming.

Public/private access are used to specify an interface to arbitrary functionality. Other modules can call a public interface, but all private internals can be removed / modified freely.

[koenigdavidmj]

Yep, plenty of C modules do hacks to block access except through the defined API. Most are content simply to use void pointers in public header files, but some do nasty things like generating a random integer at library initialisation time and xor'ing all returned pointers by that number before returning it. (Eww.)