GNU C Library 2.39 released

GNU C Library 2.39 released

Posted Feb 1, 2024 10:20 UTC (Thu) by anton (subscriber, #25547)
Parent article: GNU C Library 2.39 released

The announcement contains more interesting details than the release notes, but I found the following gem in the release notes:

Revert to original qsort implementation and apply subsequent mergesort changes with heapsort as fallback.[...]

• Attempts to make changes to qsort have shown deep application dependencies on undocumented behaviour.
• In order to preserver application compatibility we need to revert the less conservative changes.

That's a productive approach to the consequences of Hyrum's law, rather than the often advocated approach (by C compiler advocates and ext* file system maintainers) of breaking the applications because they supposedly are already broken, and that maintaining compatibility would be O_PONIES.

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GNU C Library 2.39 released

Posted Feb 1, 2024 16:32 UTC (Thu) by fw (subscriber, #26023) [Link]

It was also slower than the mergesort implementation. The sole benefit of the quicksort-based was that it did not use malloc. We still needed a fallback sorting algorithm in case quicksort degraded, so complexity isn't much reduced, either.