The need for tcsetattr@GLIBC_2.42.1 and tcgetattr@GLIBC_2.42.1

[H. Peter Anvin]

On 2025-09-15 01:41, Florian Weimer wrote:
> I think we need symbol version to restrict the new tcsetattr and
> tcgetattre behavior to newly linked applications.  This would achieve
> near-perfect backwards compatibility with existing applications (but
> not those that use dlsym).  I assume this include various industrial
> control software that can't be recompiled.

I think you are fundamentally misunderstanding the nature of the recent
incompatibilities.

They are CROSS APPLICATION incompatibilities.

Basically, a broken application goes and modifies only part of the
kernel state, and expect it to work, based on what kernel state older
versions of glibc and *MOST* other applications simply didn't know about.

I fail to see any meaningful scenario that would gain from versioning
tcsetattr(), and literally no scenario at all that would gain from
versioning tcgetattr().

	-hpa