Comment by LegionMammal978
1 day ago
But to link against an old glibc version, you need to compile on an old distro, on a VM. And you'll have a rough time if some part of the build depends on a tool too new for your VM. It would be infinitely simpler if one could simply 'cross-compile' down to older symbol versions, but the tooling does not make this easy at all.
Check out `zig cc`. It let's you target specific glibc versions. It's a pretty amazing C toolchain.
https://andrewkelley.me/post/zig-cc-powerful-drop-in-replace...
It's actually doable without an old glibc as it was done by the Autopackage project: https://github.com/DeaDBeeF-Player/apbuild
That never took off though, containers are easier. Wirh distrobox and other tools this is quite easy, too.
> It would be infinitely simpler if one could simply 'cross-compile' down to older symbol versions, but the tooling does not make this easy at all.
It's definitely not easy, but it's possible: using the `.symver` assembly (pseudo-)directive you can specify the version of the symbol you want to link against.
Huh? Bullshit. You could totally compile and link in a container.
Ok, so you agree with him except where he says “in a VM” because you say you can also do it “in a container”.
Of course, you both leave out that you could do it “on real hardware”.
But none of this matters. The real point is that you have to compile on an old distro. If he left out “in a VM”, you would have had nothing to correct.
I'm not disagreeing that glibc symbol versioning could be better. I raised it because this is probably one of the few valid use cases for containers where they would have a large advantage over a heavyweight VM.
But it's like complaining that you might need a VM or container to compile your software for Win16 or Win32s. Nobody is using those anymore. Nor really old Linux distributions. And if they do, they're not really going to complain about having to use a VM or container.
As C/C++ programmer, the thing I notice is ... the people who complain about this most loudly are the web dev crowd who don't speak C/C++, when some ancient game doesn't work on their obscure Arch/Gentoo/Ubuntu distribution and they don't know how to fix it. Boo hoo.
But they'll happily take a paycheck for writing a bunch of shit Go/Ruby/PHP code that runs on Linux 24/7 without downtime - not because of the quality of their code, but due to the reliability of the platform at _that_ particular task. Go figure.
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