You are right, I will return with a complete example to explain the problem, but , unrelated to my specific use case, the problems you and someone else raised are non-problems from my perspective:

All builds are made in containers that I define and are by definition reproducible builds. There are pretty strong guarantees that a container-based reproducible build system guarantees the exact same environment, including the filesystem . Similarly, any security concers of Marcin are moot : any changes will be local to that container.
I agree that maybe containerized, reproducible build systems are not the norm in the c++ world, but still.

But thanks for the input.

On Tue, Mar 12, 2024, at 13:49, Matthew Taylor wrote:
> Granted, I'm not as familiar as some to the specific needs of writing a build system, but could you elaborate further on specifically what you want and specifically why it would be an improvement? Just adding constexpr to filesystem operations seems like it has a large area of confusion for the obvious reason of there being no guarantee that a program will be compiled and run on the same filesystem (as well as a few other reasons of varying obviousness).
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> Are you looking for a facility like #embed, to directly embed file data into your source code? Or are you thinking of the possibility of more complex file manipulation performed by the compiler?