Why isn't C/C++'s “#pragma once” an ISO standard?

Question

I am currently working on a big project and maintaining all those include guards makes me crazy! Writing it by hand is frustrating waste of time. Although many editors can g

Answer 1

You can probably avoid name collisions without resorting to random strings by setting the include guard to contain the name of the class and namespace that's in the file.

Besides, #pragma once is supported by both MS compilers and GCC for quite some time now so why does it bother you that it's not on the ISO standard?