[jcelerier]

> Literally the entire reason for having a coding standard is to have a well-defined subset of the language you're using.

that's a perversion of what "standards" means. Standards are originally there to codify existing practice, not to put new practice into existence. "#pragma once" is common enough that it has its own wikipedia page : https://en.wikipedia.org/wiki/Pragma_once with the list of all supported compilers.