Exit codes for errors would be nice.

[sicklittlemonkey]

I notice that AddFile already returns a result code but it isn't returned by Main.

Some others such as Set/ClearFileHighBit also return one but they can be run on multiple files, so a decision must be made as to error behaviour. Presumably the current behaviour of ignoring errors and attempting to process all files is desirable - though it could be an option.

But which error to return? The simplest way forward is to process all files and return zero, or the first or last non-zero code.