I use printf debugging locally as well. Interactive debuggers and I just don't get on, and my test cases are built to start fast enough that it works out for me

I use printf debugging locally as well. Interactive debuggers and I just don't get on, and my test cases are built to start fast enough that it works out for me. Usually I have a 'debug_stderr' function of some sort that serialises + writes its argument and then returns it so I can stick it in the middle of expressions. (I do make sure that anybody learning from me understands that debuggers are not evil, they're just not my thing, and that shouldn't stop everybody else at least trying to learn to use them)