This directory contains the sources of the GNU C Library. See the file "version.h" for what release version you have. 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 from version 2.4 on 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. The library is unlikely to build without NPTL, or to work on Linux kernels prior to 2.6. 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. 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. Also note that the shared version of the libgcc_s library must be installed for the pthread library to work correctly. The GNU C Library supports these configurations for using Linux kernels: i[4567]86-*-linux-gnu x86_64-*-linux-gnu powerpc-*-linux-gnu Hardware floating point required powerpc64-*-linux-gnu s390-*-linux-gnu s390x-*-linux-gnu sh[34]-*-linux-gnu Requires Linux 2.6.11 or newer sparc*-*-linux-gnu sparc64*-*-linux-gnu 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-VERSION distributed separately in the same place where you got the main glibc distribution files. Currently these configurations have code in the `ports' add-on: alpha*-*-linux-gnu Requires Linux 2.6.9 or newer for NPTL am33*-*-linux-gnu Not currently functional arm-*-linux-gnueabi Requires Linux 2.6.16-rc1 or newer for NPTL hppa-*-linux-gnu Requires Linux 2.6.9 or newer for NPTL ia64-*-linux-gnu m68k-*-linux-gnu mips-*-linux-gnu Requires Linux 2.6.12 or newer for NPTL mips64-*-linux-gnu Requires Linux 2.6.12 or newer for NPTL powerpc-*-linux-gnu Software floating point (--without-fp) tilegx-*-linux-gnu tilepro-*-linux-gnu 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. 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. License copyright years may be listed using range notation, e.g., 2000-2011, indicating that every year in the range, inclusive, is a copyrightable year that would otherwise be listed individually.