What functions are disabled with noInterrupts()? The Arduino page for noInterrupts() says:


  Some functions will not work while interrupts are disabled, and incoming communication may be ignored.


While it may not be possible to give a complete listing of what would be disabled, having an incomplete list of functions which definitely are disabled would be useful.

I was thinking of calling a DHT sensor library which internally uses millis() while interrupts were disabled to avoid both bit banging and servicing interrupts simultaneously if possible (the interrupt would hold and be processed after).

Which functions are definitely disabled when interrupts are disabled?

What about incoming communication? My guess is that it would be slightly worse on the ATmega32U4 (eg Leonardo) as the one processor does USB and everything else as well.
From what I found turning off interrupts will definitely disable incrementing values of micros() and millis() This means that also every method that uses them like delay() will also not work correctly.

Of course manually attached interrupts using attachInterrupt() will also not work as intended.

According to comments by @Juraj Things that also will not work are Serial interrupts. Also libraries like Wire require interrupts for their logic.

EDIT: @EdgarBonet You are right, I removed incorrect info.