writeToFile:atomically: what does atomically mean?

Question

I am wondering what the atomically: parameter stands for in the writeToFile:atomically: method (-[NSArray writeToFile:atomically:] for

Answer 1

atomically

If YES, the data is written to a backup file, and then—assuming no errors occur—the backup file is renamed to the name specified by path; otherwise, the data is written directly to path.