Shared libraries [LWN.net]

Shared libraries

Posted Nov 25, 2025 19:16 UTC (Tue) by ssokolow (guest, #94568)
In reply to: Shared libraries by farnz
Parent article: APT Rust requirement raises questions

just as I can't use a random header file version in C, and rely on it working with a random shared library version

For varying definitions of "rely on"

https://abi-laboratory.pro/index.php?view=tracker

On top of that, while I'm demanding perfect tooling, moon-onna-stick, and free unicorns for everyone, I want tooling that allows me to knowingly break ABI as long as I provide the necessary shims to let people who linked against the older ABI to continue to work.

Knowing the Rust community, give it a decade and you'll probably have all that.

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Shared libraries

Posted Nov 26, 2025 10:00 UTC (Wed) by farnz (subscriber, #17727) [Link] (1 responses)

My definition of "rely on" is "the tooling gives me an error if I mismatch the shared library version and the header file". Very few C and C++ libraries make that guarantee - the only library I'm aware of that does make that guarantee is glibc, and they do a lot of work with symbol versioning to make that happen.

Shared libraries

Posted Nov 26, 2025 10:15 UTC (Wed) by ssokolow (guest, #94568) [Link]

I missed that you said "can't" instead of "can". Sorry.

I suspect anything which satisfies both your goals and the Rust devs' goals will be paired with some kind of link-time hackery to ensure that what would otherwise have been statically linked will refuse to start if the subset of the provided library that's being used is not 100% ABI compatible.

"'Just don't make mistakes' doesn't scale" is, after all, a core element of Rust's design philosophy.