Re: On time64 and Large File Support

[Richard Purdie <richard.purdie@linuxfoundation.org>]

On Fri, 2022-11-11 at 08:38 +0000, Sam James wrote:
> In Gentoo, we've been planning out what we should do for time64 on glibc [0]
> and concluded that we need some support in glibc for a newer option. I'll outline
> why below.
> 
> Proposal: glibc gains two new build-time configure options:
> * --enable-hard-time64
> * --enable-hard-lfs
> 
> These would hard-enable the relevant #defines within glibc's headers and ensure that any
> binaries built with such a glibc have both Large File Support (LFS) and time64 support.
> 
> I've come to the conclusion it's infeasible to try handle the migration piecemeal. Various
> mismatches can and will occur (and while it's more likely with time64, it's possible with LFS
> too) [1].

As a data point, Yocto Project has been debating this a bit. Based upon
what I've seen so far, I reached a similar conclusion, that we probably
needed to "just switch". As a source based system, the situation is
quite different to distros with binary feeds though.

My questions are around how much warning we can give people where code
is doing something it shouldn't and I don't have a good feel for how
much risk we're putting onto users with existing runtimes.

Cheers,

Richard