Em qui., 13 de out. de 2022 às 10:41, Iain Sandoe via SG15
<sg15_at_[hidden]> escreveu:
> I expect that this has been discussed before, and I’ve missed it somehow .. but several times during my implementation work on clang, it seemed to me that this problem would go away if importable header units were required to start with a keyword.
...
> Given an expectation that the user has to identify importable header units somehow, doing it in the source seems to me to be the neatest solution.
> what did I miss?

If the header themselves identify if they're importable or not it
means the build system needs to scan all headers (inside and outside
the project, directly and transitively included) for that keyword in
order to decide if a BMI needs to be produced or not. Particularly,
that has to happen before the module dependency scanning, because a
header becoming importable changes the overall shape of the dependency
graph.

If, OTOH, between the package management and the build system, that
information is available before-hand, and the list of importable
headers is provided before the dependency scanning, then the
dependency scanning knows to treat that include statement as an import
and then the header unit will have its dependencies scanned
independently.

Currently, I am of the opinion that identifying the importable headers
must be handled in metadata, before the build system even starts
anything.

daniel