Hi Vincent - sure, I can add something about a recommended line length. Traditionally, it has always been <= 79 chars. Preferably more like 72. As you quote the Linux standards, it also is a "strongly preferred limit", that is, it's certainly not the case that every line in every source file is <80 chars, but it's the thing to shoot for.
It is not really a matter of how many characters one can squeeze onto a line in a big window, which is surely in the hundreds. Rather, the idea is for the source code to be maximally readable, and such immensely long lines are not easy for humans to grasp. Also, the sources should be readable in as many environments as possible, which also argues for <80. Thanks for writing, Karl
