I have two binary files (order of tens of MB) and I want to or every bit of these files. And of course, I want it to be as efficient as possible. So I have two ways in mind to do that, but I still think (I kinda feel) that should be a more efficient way that I do not know of. Given file a and b .. what I want to do is a = a|b 1. Loading two files, parse them in to two huge std::bitsets and or them together 2. loading two files byte by byte and or them if a huge for loop... Is there any other way to do that?