On 18/05/2023 23.07, Daniel Ruoso via SG15 wrote:
> Em qui., 18 de mai. de 2023 às 16:56, Tom Honermann
> <tom_at_[hidden]> escreveu:
>> I don’t know what you mean by this. There are multiple implementation strategies, some of which have been in use for many years.
>
> I mean importable headers as specified in C++20 is not implementable.

How so?

[module.import] p5 says

"An importable header is a member of an implementation-defined set of headers
that includes all importable C++ library headers (16.4.2.3). H shall identify
an importable header."

There is a to be-created core issue that says "set of headers" is intended to
cover source files as well, not just (standard library) headers.

Obviously, the "implementation-defined set" can be defined to just include
the importable C++ library headers, and no user-provided source files.
So, which part is "unimplementable" here?

Jens