OK, I think I went off half-cocked there, and I later rather regretted replying. All I'm talking about is that you need the variables "day" and "today", which do nothing more than give you the midnight cue, and then express "date" as char. Any library method you use will give you that. I don't actually use a library at all, but simply stick with the method here
"getclock()" is simply my subroutine for getting the time, and "day" is the name of the variable that is produced therein.
I have never used my ESP32, and I was not aware that it requires a different library for SD. I think you know more about that than I do and, if you get what you expect from the various test examples, stick with it.
It seems that you have already modified my code, and I assume to good effect.
Sorry for the confusion!