Version 2.43 of the GNU C Library "glibc" was released on Friday evening as the newest half-year feature update. This is a very feature packed update and even managed to be released ahead of the 1 February release plan.

Highlights of the GNU C Library glibc 2.43 release include:

- Support for more ISO C23 language features like the free_sized / free_aligned_sized / memset_explicit / memalignment functions, changes to some existing functions, support for the optional time bases of TIME_MONOTONIC / TIME_ACTIVE / TIME_THREAD_ACTIVE, and various other C23 features.

- [1]Support for the mseal function on Linux for sealing memory mappings during process execution to protect against permission changes, unmapping, relocations, or shrinking the size.

- Support for the openat2 function on Linux as an extension of openat with more features.

- Experimental support for building with the LLVM Clang compiler on Clang 18 or newer and for AArch64 or x86_64 Linux.

- Additional optimized math functions from the CORE-MATH project such as acosh / asinh / atanh / erf / erfc / lgamma / tgamma.

- Optimized implementations for fma, fmaf, remainder, remaindef, frexpf, frexp, frexpl (binary128), and frexpl (intel96). [2]The new FMA implementation is much faster . There are also some nice [3]FMA improvements on AMD Zen .

- [4]Glibc now enables 2MB transparent hugepages by default in malloc on AArch64.

- [5]Intel Nova Lake and Wildcat Lake processor detection .

- Unicode 17.0 support.

Downloads and more details on today's GNU C Library 2.43 release via [6]the info-gnu mailing list .



[1] https://www.phoronix.com/news/Glibc-Linux-mseal-Function

[2] https://www.phoronix.com/news/Glibc-New-Generic-FMA

[3] https://www.phoronix.com/news/Glibc-4x-FMA-Improvement-Zen

[4] https://www.phoronix.com/news/Glibc-malloc-2MB-THP-AArch64

[5] https://www.phoronix.com/news/Glibc-Nova-Lake-Wildcat-Lake

[6] https://lists.gnu.org/archive/html/info-gnu/2026-01/msg00005.html