getline while reading a file vs reading whole file and then splitting based on newline character

Question

I want to process each line of a file on a hard-disk now. Is it better to load a file as a whole and then split on basis of newline character (using boost), or is it better

Answer 1

If it's a small file on disk, it's probably more efficient to read the entire file and parse it line by line vs. reading one line at a time--that would take lot's of disk access.