I am sure OP cannot understand the Unix file API without actually reading every line of its implementations (on each different architecture)! Or any function for that matter , what does sort do?? Impossible to know without reading the source. And I’m sure after reading the source you will know every detail of how it works and will never forget it.

It's hard for me to understand how you could work on software and not understand the qualitative difference between the Unix File API and some code that an AI spat out 5 minutes ago.