A little bit more than one year after 0.9.31, the uClibc project has recently released a new version of the famous C library, uClibc 0.9.32. For the record, uClibc is an alternative standard C library for embedded Linux systems, which features a smaller size than the usual glibc or eglibc, a high-level of configurability and support for non-MMU architectures. uClibc usage is mandatory on non-MMU architectures running a Linux kernel since the traditional glibc or eglibc do not support non-MMU architectures. On architectures with MMU, uClibc may also be interesting for its reduced size, and has been used in a large number of systems over the last years.
The 0.9.32 release brings one major new feature : the support of the Native Posix Threads Library for the most common architectures (ARM, MIPS, PowerPC, x86, x86_64, SuperH and SuperH 64). NPTL is a different way of implementing the pthread userspace API than the one previously used in Linux, called LinuxThreads. The kernel mechanisms needed to implement NPTL have been added in 2.6 and support in glibc has been added a long time ago. uClibc was lagging behind in this area, and the new release fills this gap. This feature does not bring any visible API change, but completely changes the internal implementation of the threading mechanism, with better performance and a behavior that is more similar to the one we have on glibc based hosts. For more details about the differences about NPTL and LinuxThreads, one can check Ulrich Drepper and Ingo Molnar’s paper on this topic: NPTL Design paper.
Another new feature of the 0.9.32 release is support for the C6x architecture, which is a DSP architecture from Texas Instruments, capable of running a Linux kernel (see http://linux-c6x.org). Having upstream support in uClibc allows this architecture to benefit from a nice standard C library.