Hi Ben,
> On 21 Apr 2022, at 13:05, Ben Boeckel via Gcc <gcc@gcc.gnu.org> wrote:
>
> On Thu, Apr 21, 2022 at 06:05:52 +0200, Boris Kolpackov wrote:
>> I don't think it is. A header unit (unlike a named module) may export
>> macros which could affect further dependencies. Consider:
>>
>> import "header-unit.hpp"; // May or may not export macro FOO.
1. If you know how this was built, then you could do an -E -fdirectives-only
build (both
GCC and clang support this now) to obtain the macros.
2. I suppose we could invent a tool (or FE mode) to dump the macros exported
by a HU ***
>> #ifdef FOO
>> import "header-unit2.hpp"
>> #endif
>
> I agree that the header needs to be *found*, but scanning cannot require
> a pre-existing BMI for that header. A new mode likely needs to be laid
> down to get the information necessary (instead of just piggy-backing on
> `-E` behavior to get what I want).
perhaps that means (2)?
Iain
*** it’s kinda frustrating that this is hard infomation to get as a developer,
so
perhaps we can anticipate users wanting such output.
