On Friday, 19 June 2026 15:23:09 Pacific Daylight Time Steve Weinrich via Std-
Proposals wrote:
> Yes, currently there is no distinction between different types of input
> files to the compiler. But there could be.

But there aren't. Feel free start writing a paper for that. Expect a 6-year-
cycle to get it in, including explaining "why not modules" at every turn.

It's not worth for this discussion.

> As to the preprocessor, I believe they have long disappeared.

They have not. Distributed compilation systems and ccache rely on running the
preprocessor separately from the compiler. The output of the preprocessor
could be adapted to indicate what is what in your worldview, but again this
would require changes you don't need to address here.

Plus, it would make private extension methods incompatible with "unity build"
techniques that #include every .cpp (a poor man's LTO).

So just accept that this feature will exist in headers and word it such that
it's reasonable.

-- 
Thiago Macieira - thiago (AT) macieira.info - thiago (AT) kde.org
  Principal Engineer - Intel Data Center - Platform & Sys. Eng.