[mananaysiempre]

> Given that glibc backward compatibility for all practical purposes is shorter than 10 years

As far as I’m able to tell[1], Glibc has never removed a versioned symbol as long as symbol versioning has existed, so the intended backwards compatibility is “forever”. No binary built against a(n unpatched) Glibc should fail to load on a later Glibc due to an absent Glibc symbol version. (Of course, if you play non-version-aware dynamic linker and dlsym() not dlvsym() things in libc, you lose; if you bundle an “updated” part of libc with the application[2], you lose; etc., so this may be true but still not entirely foolproof. And given how many things there are in libc, if you’re going to lose it’s probably going to be there.)

[1] E.g. https://sourceware.org/git/?p=glibc.git;a=history;f=stdlib/V...

[2] https://news.ycombinator.com/item?id=29479903