Following yesterday's release of [1]GNU Binutils 2.45 , the GNU C Library 2.42 released today.

GNU C Library 2.42 "glibc 2.42" is now available for this widely-used C library by Linux and other operating systems. Some of the highlights in today's Glibc 2.42 release include:

- Continued to implement additional ISO C23 functionality.

- Working on some early C2Y features, such as the uabs / ulabs / ullabs / uimaxabs unsigned abs functions.

- Glibc 2.42 on Linux now introduces the pthread_gettid_np function.

- The thread-local cache in malloc now supports caching of large blocks.

- When built with the new "--enable-sframe" option, [2]SFrame stack tracking support can be enabled .

- [3]FMA optimizations for Glibc's hyperbolic functions .

- Additional optimized math functions have been imported from CORE-MATH. The now better optimized functions are for acospif, asinpif, atanpif, atan2pif, cospif, sinpif, and tanpif.

- Glibc 2.42 now has built-in detection for Intel's Arrow Lake, Panther Lake, Clearwater Forest, and Diamond Rapids processors.

- Support for the IBM z17 platform.

- Various security and bug fixes.

More details on today's GNU C Library 2.42 release and all of the changes via [4]sourceware.org .



[1] https://www.phoronix.com/news/GNU-Binutils-2.45

[2] https://www.phoronix.com/news/SFrame-Merged-Glibc-2.42

[3] https://www.phoronix.com/news/glibc-Faster-Hyperbolic-FMA

[4] https://sourceware.org/pipermail/libc-alpha/2025-July/168994.html