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Everything I know about good API design

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428 points ahamez | 1 comments | 24 Aug 25 19:10 UTC | HN request time: 0.206s | source
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dwattttt ◴[24 Aug 25 22:53 UTC] No.45008529[source]▶
The reminder to "never break userspace" is good, but people never bring up the other half of that statement: "we can and will break kernel APIs without warning".

It illustrates that the reminder isn't "never change an API in a way that breaks someone", it's the more nuanced "declare what's stable, and never break those".

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delta_p_delta_x ◴[24 Aug 25 23:37 UTC] No.45008791[source]▶
Even if the kernel doesn't break userspace, GNU libc does, all the time, so the net effect is that Linux userspace is broken regardless of the kernel maintainers' efforts. Put simply, programs and libraries compiled on/for newer libc are ABI-incompatible or straight-up do not run on older libc, so everything needs to be upgraded in lockstep.

It is a bit ironic and a little funny that Windows solved this problem a couple decades ago with redistributables.

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1. rcxdude ◴[25 Aug 25 02:13 UTC] No.45009576[source]▶
GNU libc has pretty good backwards compatibility, though, so if not you want to run on a broad range of versions, link against as old a version of libc as is practical (which does take some effort, annoyingly). It tends to be things like GUI libraries and such which are a bigger PITA, because they do break compatibility and the old versions stop being shipped in distros, and shipping them all with your app can still run into protocol compatibility issues.