The example says no mysticism but is using at least 4 undeclared variables. I’m not a C developer so I’m sure I’m completely wrong, but where do pledge, puts, EXIT SUCCESS/FAILURE come from?

I assume from importing stdlib etc, which probably give you additional variables to use, that you would need to know about explicitly. One thing I like about zeit.co’s micro server (js) was the argument about not using bodyparser and magically having res.body available, but using async/await and assigning it to a variable. This is popping up more with things like es module imports, render props in react, etc. They make it clear where variables come from and allow you to avoid stepping on existing variables. What other 10-100 variables can I step on potentially with global patterns as a new user?