This directory contains the version 2.7 release of the GNU C Library. The GNU C Library is the standard system C library for all GNU systems, and is an important part of what makes up a GNU system. It provides the system API for all programs written in C and C-compatible languages such as C++ and Objective C; the runtime facilities of other programming languages use the C library to access the underlying operating system. In GNU/Linux systems, the C library works with the Linux kernel to implement the operating system behavior seen by user applications. In GNU/Hurd systems, it works with a microkernel and Hurd servers. The GNU C Library implements much of the POSIX.1 functionality in the GNU/Hurd system, using configurations i[34567]86-*-gnu. When working with Linux kernels, the GNU C Library version 2.4 is intended primarily for use with Linux kernel version 2.6.0 and later. We only support using the NPTL implementation of pthreads, which is now the default configuration. Most of the C library will continue to work on older Linux kernels and many programs will not require a 2.6 kernel to run correctly. However, pthreads and related functionality will not work at all on old kernels and we do not recommend using glibc 2.4 with any Linux kernel prior to 2.6. All Linux kernel versions prior to 2.6.16 are known to have some bugs that may cause some of the tests related to pthreads in "make check" to fail. If you see such problems, please try the test suite on the most recent Linux kernel version that you can use, before pursuing those bugs further. The old LinuxThreads add-on implementation of pthreads for older Linux kernels is no longer supported, and we are not distributing it with this release. Someone has volunteered to revive its maintenance unofficially for at least a short time for the benefit of those using Linux kernels older than 2.6, but a working version is not presently available. When it is in working condition, we will make it available alongside future glibc releases. LinuxThreads will not be supported. The GNU C Library supports these configurations for using Linux kernels: i[34567]86-*-linux-gnu x86_64-*-linux-gnu powerpc-*-linux-gnu powerpc64-*-linux-gnu s390-*-linux-gnu s390x-*-linux-gnu ia64-*-linux-gnu sparc*-*-linux-gnu sparc64*-*-linux-gnu alpha*-*-linux-gnu Requires Linux 2.6.9 for NPTL sh[34]-*-linux-gnu Requires Linux 2.6.11 The code for other CPU configurations supported by volunteers outside of the core glibc maintenance effort is contained in the separate `ports' add-on. You can find glibc-ports-2.7 distributed separately in the same place where you got the main glibc distribution files. Currently these configurations are known to work using the `ports' add-on: arm-*-linux-gnu Requires Linux 2.6.15 for NPTL, no SMP support arm-*-linux-gnueabi Requires Linux 2.6.16-rc1 for NPTL, no SMP mips-*-linux-gnu Requires Linux 2.6.12 for NPTL mips64-*-linux-gnu Requires Linux 2.6.12 for NPTL The ports distribution also contains code for other configurations that do not work or have not been maintained recently, but will be of use to anyone trying to make a new configuration work. If you are interested in doing a port, please contact the glibc maintainers; see http://www.gnu.org/software/libc/ for more information. See the file INSTALL to find out how to configure, build, and install the GNU C Library. You might also consider reading the WWW pages for the C library at http://www.gnu.org/software/libc/. The GNU C Library is (almost) completely documented by the Texinfo manual found in the `manual/' subdirectory. The manual is still being updated and contains some known errors and omissions; we regret that we do not have the resources to work on the manual as much as we would like. For corrections to the manual, please file a bug in the `manual' component, following the bug-reporting instructions below. Please be sure to check the manual in the current development sources to see if your problem has already been corrected. The file NOTES contains a description of the feature-test macros used in the GNU C library, explaining how you can tell the library what facilities you want it to make available. Please see http://www.gnu.org/software/libc/bugs.html for bug reporting information. We are now using the Bugzilla system to track all bug reports. This web page gives detailed information on how to report bugs properly. The GNU C Library is free software. See the file COPYING.LIB for copying conditions, and LICENSES for notices about a few contributions that require these additional notices to be distributed.