is C programming standard for all arm chips?

according to my knowledge : C is standard in arm when it comes to the core. but accessing peripherals vary widely from manufacturer to another.

questions:

if I used a book about "embedded C" but that book is using some microcontroller other than arm (e.g. AVR) will the book be useful for arm programming?

what about C book that is targeting desktop programming? my guess is that it will be OK but I will waste time learning some stuff that is not applicable to embedded e.g. system file access. correct?

any help in choosing a good C programming book for the sole purpose of arm programming will be greatly appreciated. my aim in this question is not to waste time learning something not needed or not the correct thing to spend my time on.