mirror of
https://sourceware.org/git/glibc.git
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ebae2f5a6f
Commit68ab82f566added support for the scv syscall ABI on powerpc. Since then systems that have kernel and processor support started using scv. However adding the proper support for a new syscall ABI requires changes to several other projects (e.g. qemu, valgrind, strace, kernel), which are gradually receiving support. Meanwhile, having a way to disable scv on glibc at build time can be useful for distros that may encounter conflicts with projects that still do not support the scv ABI, buying time until proper support is added. This commit adds a --disable-scv option that disables scv support and uses sc for all syscalls, like before commit68ab82f566. Reviewed-by: Raphael M Zinsly <rzinsly@linux.ibm.com>
702 lines
34 KiB
Plaintext
702 lines
34 KiB
Plaintext
Installing the GNU C Library
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****************************
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Before you do anything else, you should read the FAQ at
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<https://sourceware.org/glibc/wiki/FAQ>. It answers common questions
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and describes problems you may experience with compilation and
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installation.
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You will need recent versions of several GNU tools: definitely GCC
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and GNU Make, and possibly others. *Note Tools for Compilation::,
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below.
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Configuring and compiling the GNU C Library
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===========================================
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The GNU C Library cannot be compiled in the source directory. You must
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build it in a separate build directory. For example, if you have
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unpacked the GNU C Library sources in '/src/gnu/glibc-VERSION', create a
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directory '/src/gnu/glibc-build' to put the object files in. This
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allows removing the whole build directory in case an error occurs, which
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is the safest way to get a fresh start and should always be done.
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From your object directory, run the shell script 'configure' located
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at the top level of the source tree. In the scenario above, you'd type
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$ ../glibc-VERSION/configure ARGS...
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Please note that even though you're building in a separate build
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directory, the compilation may need to create or modify files and
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directories in the source directory.
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'configure' takes many options, but the only one that is usually
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mandatory is '--prefix'. This option tells 'configure' where you want
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the GNU C Library installed. This defaults to '/usr/local', but the
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normal setting to install as the standard system library is
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'--prefix=/usr' for GNU/Linux systems and '--prefix=' (an empty prefix)
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for GNU/Hurd systems.
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It may also be useful to pass 'CC=COMPILER' and 'CFLAGS=FLAGS'
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arguments to 'configure'. 'CC' selects the C compiler that will be
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used, and 'CFLAGS' sets optimization options for the compiler. Any
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compiler options required for all compilations, such as options
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selecting an ABI or a processor for which to generate code, should be
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included in 'CC'. Options that may be overridden by the GNU C Library
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build system for particular files, such as for optimization and
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debugging, should go in 'CFLAGS'. The default value of 'CFLAGS' is '-g
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-O2', and the GNU C Library cannot be compiled without optimization, so
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if 'CFLAGS' is specified it must enable optimization. For example:
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$ ../glibc-VERSION/configure CC="gcc -m32" CFLAGS="-O3"
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The following list describes all of the available options for
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'configure':
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'--prefix=DIRECTORY'
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Install machine-independent data files in subdirectories of
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'DIRECTORY'. The default is to install in '/usr/local'.
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'--exec-prefix=DIRECTORY'
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Install the library and other machine-dependent files in
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subdirectories of 'DIRECTORY'. The default is to the '--prefix'
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directory if that option is specified, or '/usr/local' otherwise.
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'--with-headers=DIRECTORY'
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Look for kernel header files in DIRECTORY, not '/usr/include'. The
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GNU C Library needs information from the kernel's header files
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describing the interface to the kernel. The GNU C Library will
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normally look in '/usr/include' for them, but if you specify this
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option, it will look in DIRECTORY instead.
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This option is primarily of use on a system where the headers in
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'/usr/include' come from an older version of the GNU C Library.
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Conflicts can occasionally happen in this case. You can also use
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this option if you want to compile the GNU C Library with a newer
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set of kernel headers than the ones found in '/usr/include'.
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'--enable-kernel=VERSION'
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This option is currently only useful on GNU/Linux systems. The
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VERSION parameter should have the form X.Y.Z and describes the
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smallest version of the Linux kernel the generated library is
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expected to support. The higher the VERSION number is, the less
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compatibility code is added, and the faster the code gets.
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'--with-binutils=DIRECTORY'
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Use the binutils (assembler and linker) in 'DIRECTORY', not the
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ones the C compiler would default to. You can use this option if
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the default binutils on your system cannot deal with all the
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constructs in the GNU C Library. In that case, 'configure' will
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detect the problem and suppress these constructs, so that the
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library will still be usable, but functionality may be lost--for
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example, you can't build a shared libc with old binutils.
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'--with-nonshared-cflags=CFLAGS'
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Use additional compiler flags CFLAGS to build the parts of the
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library which are always statically linked into applications and
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libraries even with shared linking (that is, the object files
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contained in 'lib*_nonshared.a' libraries). The build process will
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automatically use the appropriate flags, but this option can be
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used to set additional flags required for building applications and
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libraries, to match local policy. For example, if such a policy
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requires that all code linked into applications must be built with
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source fortification,
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'--with-nonshared-cflags=-Wp,-D_FORTIFY_SOURCE=2' will make sure
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that the objects in 'libc_nonshared.a' are compiled with this flag
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(although this will not affect the generated code in this
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particular case and potentially change debugging information and
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metadata only).
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'--disable-shared'
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Don't build shared libraries even if it is possible. Not all
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systems support shared libraries; you need ELF support and
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(currently) the GNU linker.
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'--enable-static-pie'
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Enable static position independent executable (static PIE) support.
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Static PIE is similar to static executable, but can be loaded at
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any address without help from a dynamic linker. All static
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programs as well as static tests are built as static PIE, except
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for those marked with no-pie. The resulting glibc can be used with
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the GCC option, -static-pie, which is available with GCC 8 or
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above, to create static PIE. This option also implies that glibc
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programs and tests are created as dynamic position independent
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executables (PIE) by default.
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'--enable-cet'
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'--enable-cet=permissive'
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Enable Intel Control-flow Enforcement Technology (CET) support.
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When the GNU C Library is built with '--enable-cet' or
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'--enable-cet=permissive', the resulting library is protected with
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indirect branch tracking (IBT) and shadow stack (SHSTK). When CET
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is enabled, the GNU C Library is compatible with all existing
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executables and shared libraries. This feature is currently
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supported on i386, x86_64 and x32 with GCC 8 and binutils 2.29 or
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later. Note that when CET is enabled, the GNU C Library requires
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CPUs capable of multi-byte NOPs, like x86-64 processors as well as
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Intel Pentium Pro or newer. With '--enable-cet', it is an error to
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dlopen a non CET enabled shared library in CET enabled application.
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With '--enable-cet=permissive', CET is disabled when dlopening a
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non CET enabled shared library in CET enabled application.
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NOTE: '--enable-cet' has been tested for i686, x86_64 and x32 on
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non-CET processors. '--enable-cet' has been tested for i686,
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x86_64 and x32 on CET processors.
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'--enable-memory-tagging'
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Enable memory tagging support if the architecture supports it.
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When the GNU C Library is built with this option then the resulting
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library will be able to control the use of tagged memory when
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hardware support is present by use of the tunable
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'glibc.mem.tagging'. This includes the generation of tagged memory
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when using the 'malloc' APIs.
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At present only AArch64 platforms with MTE provide this
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functionality, although the library will still operate (without
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memory tagging) on older versions of the architecture.
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The default is to disable support for memory tagging.
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'--disable-profile'
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Don't build libraries with profiling information. You may want to
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use this option if you don't plan to do profiling.
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'--enable-static-nss'
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Compile static versions of the NSS (Name Service Switch) libraries.
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This is not recommended because it defeats the purpose of NSS; a
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program linked statically with the NSS libraries cannot be
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dynamically reconfigured to use a different name database.
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'--enable-hardcoded-path-in-tests'
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By default, dynamic tests are linked to run with the installed C
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library. This option hardcodes the newly built C library path in
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dynamic tests so that they can be invoked directly.
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'--disable-timezone-tools'
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By default, timezone related utilities ('zic', 'zdump', and
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'tzselect') are installed with the GNU C Library. If you are
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building these independently (e.g. by using the 'tzcode' package),
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then this option will allow disabling the install of these.
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Note that you need to make sure the external tools are kept in sync
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with the versions that the GNU C Library expects as the data
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formats may change over time. Consult the 'timezone' subdirectory
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for more details.
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'--enable-stack-protector'
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'--enable-stack-protector=strong'
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'--enable-stack-protector=all'
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Compile the C library and all other parts of the glibc package
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(including the threading and math libraries, NSS modules, and
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transliteration modules) using the GCC '-fstack-protector',
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'-fstack-protector-strong' or '-fstack-protector-all' options to
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detect stack overruns. Only the dynamic linker and a small number
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of routines called directly from assembler are excluded from this
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protection.
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'--enable-bind-now'
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Disable lazy binding for installed shared objects and programs.
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This provides additional security hardening because it enables full
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RELRO and a read-only global offset table (GOT), at the cost of
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slightly increased program load times.
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'--enable-pt_chown'
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The file 'pt_chown' is a helper binary for 'grantpt' (*note
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Pseudo-Terminals: Allocation.) that is installed setuid root to fix
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up pseudo-terminal ownership on GNU/Hurd. It is not required on
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GNU/Linux, and the GNU C Library will not use the installed
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'pt_chown' program when configured with '--enable-pt_chown'.
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'--disable-werror'
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By default, the GNU C Library is built with '-Werror'. If you wish
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to build without this option (for example, if building with a newer
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version of GCC than this version of the GNU C Library was tested
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with, so new warnings cause the build with '-Werror' to fail), you
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can configure with '--disable-werror'.
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'--disable-mathvec'
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By default for x86_64, the GNU C Library is built with the vector
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math library. Use this option to disable the vector math library.
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'--enable-tunables'
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Tunables support allows additional library parameters to be
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customized at runtime. This feature is enabled by default. This
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option can take the following values:
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'yes'
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This is the default if no option is passed to configure. This
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enables tunables and selects the default frontend (currently
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'valstring').
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'no'
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This option disables tunables.
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'valstring'
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This enables tunables and selects the 'valstring' frontend for
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tunables. This frontend allows users to specify tunables as a
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colon-separated list in a single environment variable
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'GLIBC_TUNABLES'.
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'--disable-crypt'
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Do not install the passphrase-hashing library 'libcrypt' or the
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header file 'crypt.h'. 'unistd.h' will still declare the function
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'crypt'. Using this option does not change the set of programs
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that may need to be linked with '-lcrypt'; it only means that the
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GNU C Library will not provide that library.
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This option is for hackers and distributions experimenting with
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independently-maintained implementations of libcrypt. It may
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become the default in a future release.
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'--disable-experimental-malloc'
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By default, a per-thread cache is enabled in 'malloc'. While this
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cache can be disabled on a per-application basis using tunables
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(set glibc.malloc.tcache_count to zero), this option can be used to
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remove it from the build completely.
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'--disable-scv'
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Disable using 'scv' instruction for syscalls. All syscalls will
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use 'sc' instead, even if the kernel supports 'scv'. PowerPC only.
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'--build=BUILD-SYSTEM'
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'--host=HOST-SYSTEM'
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These options are for cross-compiling. If you specify both options
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and BUILD-SYSTEM is different from HOST-SYSTEM, 'configure' will
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prepare to cross-compile the GNU C Library from BUILD-SYSTEM to be
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used on HOST-SYSTEM. You'll probably need the '--with-headers'
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option too, and you may have to override CONFIGURE's selection of
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the compiler and/or binutils.
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If you only specify '--host', 'configure' will prepare for a native
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compile but use what you specify instead of guessing what your
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system is. This is most useful to change the CPU submodel. For
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example, if 'configure' guesses your machine as 'i686-pc-linux-gnu'
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but you want to compile a library for 586es, give
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'--host=i586-pc-linux-gnu' or just '--host=i586-linux' and add the
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appropriate compiler flags ('-mcpu=i586' will do the trick) to
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'CC'.
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If you specify just '--build', 'configure' will get confused.
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'--with-pkgversion=VERSION'
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Specify a description, possibly including a build number or build
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date, of the binaries being built, to be included in '--version'
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output from programs installed with the GNU C Library. For
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example, '--with-pkgversion='FooBar GNU/Linux glibc build 123''.
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The default value is 'GNU libc'.
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'--with-bugurl=URL'
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Specify the URL that users should visit if they wish to report a
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bug, to be included in '--help' output from programs installed with
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the GNU C Library. The default value refers to the main
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bug-reporting information for the GNU C Library.
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To build the library and related programs, type 'make'. This will
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produce a lot of output, some of which may look like errors from 'make'
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but aren't. Look for error messages from 'make' containing '***'.
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Those indicate that something is seriously wrong.
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The compilation process can take a long time, depending on the
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configuration and the speed of your machine. Some complex modules may
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take a very long time to compile, as much as several minutes on slower
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machines. Do not panic if the compiler appears to hang.
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If you want to run a parallel make, simply pass the '-j' option with
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an appropriate numeric parameter to 'make'. You need a recent GNU
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'make' version, though.
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To build and run test programs which exercise some of the library
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facilities, type 'make check'. If it does not complete successfully, do
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not use the built library, and report a bug after verifying that the
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problem is not already known. *Note Reporting Bugs::, for instructions
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on reporting bugs. Note that some of the tests assume they are not
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being run by 'root'. We recommend you compile and test the GNU C
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Library as an unprivileged user.
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Before reporting bugs make sure there is no problem with your system.
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The tests (and later installation) use some pre-existing files of the
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system such as '/etc/passwd', '/etc/nsswitch.conf' and others. These
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files must all contain correct and sensible content.
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Normally, 'make check' will run all the tests before reporting all
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problems found and exiting with error status if any problems occurred.
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You can specify 'stop-on-test-failure=y' when running 'make check' to
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make the test run stop and exit with an error status immediately when a
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failure occurs.
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To format the 'GNU C Library Reference Manual' for printing, type
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'make dvi'. You need a working TeX installation to do this. The
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distribution builds the on-line formatted version of the manual, as Info
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files, as part of the build process. You can build them manually with
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'make info'.
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The library has a number of special-purpose configuration parameters
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which you can find in 'Makeconfig'. These can be overwritten with the
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file 'configparms'. To change them, create a 'configparms' in your
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build directory and add values as appropriate for your system. The file
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is included and parsed by 'make' and has to follow the conventions for
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makefiles.
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It is easy to configure the GNU C Library for cross-compilation by
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setting a few variables in 'configparms'. Set 'CC' to the
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cross-compiler for the target you configured the library for; it is
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important to use this same 'CC' value when running 'configure', like
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this: 'configure TARGET CC=TARGET-gcc'. Set 'BUILD_CC' to the compiler
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to use for programs run on the build system as part of compiling the
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library. You may need to set 'AR' to cross-compiling versions of 'ar'
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if the native tools are not configured to work with object files for the
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target you configured for. When cross-compiling the GNU C Library, it
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may be tested using 'make check
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test-wrapper="SRCDIR/scripts/cross-test-ssh.sh HOSTNAME"', where SRCDIR
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is the absolute directory name for the main source directory and
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HOSTNAME is the host name of a system that can run the newly built
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binaries of the GNU C Library. The source and build directories must be
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visible at the same locations on both the build system and HOSTNAME.
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The 'cross-test-ssh.sh' script requires 'flock' from 'util-linux' to
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work when GLIBC_TEST_ALLOW_TIME_SETTING environment variable is set.
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It is also possible to execute tests, which require setting the date
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on the target machine. Following use cases are supported:
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* 'GLIBC_TEST_ALLOW_TIME_SETTING' is set in the environment in which
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eligible tests are executed and have the privilege to run
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'clock_settime'. In this case, nothing prevents those tests from
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running in parallel, so the caller shall assure that those tests
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are serialized or provide a proper wrapper script for them.
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* The 'cross-test-ssh.sh' script is used and one passes the
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'--allow-time-setting' flag. In this case, both sets
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'GLIBC_TEST_ALLOW_TIME_SETTING' and serialization of test execution
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are assured automatically.
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In general, when testing the GNU C Library, 'test-wrapper' may be set
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to the name and arguments of any program to run newly built binaries.
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This program must preserve the arguments to the binary being run, its
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working directory and the standard input, output and error file
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descriptors. If 'TEST-WRAPPER env' will not work to run a program with
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environment variables set, then 'test-wrapper-env' must be set to a
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program that runs a newly built program with environment variable
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assignments in effect, those assignments being specified as 'VAR=VALUE'
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before the name of the program to be run. If multiple assignments to
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the same variable are specified, the last assignment specified must take
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precedence. Similarly, if 'TEST-WRAPPER env -i' will not work to run a
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program with an environment completely empty of variables except those
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directly assigned, then 'test-wrapper-env-only' must be set; its use has
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the same syntax as 'test-wrapper-env', the only difference in its
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semantics being starting with an empty set of environment variables
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rather than the ambient set.
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For AArch64 with SVE, when testing the GNU C Library, 'test-wrapper'
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may be set to "SRCDIR/sysdeps/unix/sysv/linux/aarch64/vltest.py
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VECTOR-LENGTH" to change Vector Length.
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Installing the C Library
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========================
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To install the library and its header files, and the Info files of the
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manual, type 'make install'. This will build things, if necessary,
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before installing them; however, you should still compile everything
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first. If you are installing the GNU C Library as your primary C
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library, we recommend that you shut the system down to single-user mode
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first, and reboot afterward. This minimizes the risk of breaking things
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when the library changes out from underneath.
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'make install' will do the entire job of upgrading from a previous
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installation of the GNU C Library version 2.x. There may sometimes be
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headers left behind from the previous installation, but those are
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generally harmless. If you want to avoid leaving headers behind you can
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do things in the following order.
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You must first build the library ('make'), optionally check it ('make
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check'), switch the include directories and then install ('make
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install'). The steps must be done in this order. Not moving the
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directory before install will result in an unusable mixture of header
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files from both libraries, but configuring, building, and checking the
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library requires the ability to compile and run programs against the old
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library. The new '/usr/include', after switching the include
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directories and before installing the library should contain the Linux
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headers, but nothing else. If you do this, you will need to restore any
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headers from libraries other than the GNU C Library yourself after
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installing the library.
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You can install the GNU C Library somewhere other than where you
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configured it to go by setting the 'DESTDIR' GNU standard make variable
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on the command line for 'make install'. The value of this variable is
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prepended to all the paths for installation. This is useful when
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setting up a chroot environment or preparing a binary distribution. The
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directory should be specified with an absolute file name. Installing
|
|
with the 'prefix' and 'exec_prefix' GNU standard make variables set is
|
|
not supported.
|
|
|
|
The GNU C Library includes a daemon called 'nscd', which you may or
|
|
may not want to run. 'nscd' caches name service lookups; it can
|
|
dramatically improve performance with NIS+, and may help with DNS as
|
|
well.
|
|
|
|
One auxiliary program, '/usr/libexec/pt_chown', is installed setuid
|
|
'root' if the '--enable-pt_chown' configuration option is used. This
|
|
program is invoked by the 'grantpt' function; it sets the permissions on
|
|
a pseudoterminal so it can be used by the calling process. If you are
|
|
using a Linux kernel with the 'devpts' filesystem enabled and mounted at
|
|
'/dev/pts', you don't need this program.
|
|
|
|
After installation you should configure the timezone and install
|
|
locales for your system. The time zone configuration ensures that your
|
|
system time matches the time for your current timezone. The locales
|
|
ensure that the display of information on your system matches the
|
|
expectations of your language and geographic region.
|
|
|
|
The GNU C Library is able to use two kinds of localization
|
|
information sources, the first is a locale database named
|
|
'locale-archive' which is generally installed as
|
|
'/usr/lib/locale/locale-archive'. The locale archive has the benefit of
|
|
taking up less space and being very fast to load, but only if you plan
|
|
to install sixty or more locales. If you plan to install one or two
|
|
locales you can instead install individual locales into their self-named
|
|
directories e.g. '/usr/lib/locale/en_US.utf8'. For example to install
|
|
the German locale using the character set for UTF-8 with name 'de_DE'
|
|
into the locale archive issue the command 'localedef -i de_DE -f UTF-8
|
|
de_DE', and to install just the one locale issue the command 'localedef
|
|
--no-archive -i de_DE -f UTF-8 de_DE'. To configure all locales that
|
|
are supported by the GNU C Library, you can issue from your build
|
|
directory the command 'make localedata/install-locales' to install all
|
|
locales into the locale archive or 'make
|
|
localedata/install-locale-files' to install all locales as files in the
|
|
default configured locale installation directory (derived from
|
|
'--prefix' or '--localedir'). To install into an alternative system
|
|
root use 'DESTDIR' e.g. 'make localedata/install-locale-files
|
|
DESTDIR=/opt/glibc', but note that this does not change the configured
|
|
prefix.
|
|
|
|
To configure the locally used timezone, set the 'TZ' environment
|
|
variable. The script 'tzselect' helps you to select the right value.
|
|
As an example, for Germany, 'tzselect' would tell you to use
|
|
'TZ='Europe/Berlin''. For a system wide installation (the given paths
|
|
are for an installation with '--prefix=/usr'), link the timezone file
|
|
which is in '/usr/share/zoneinfo' to the file '/etc/localtime'. For
|
|
Germany, you might execute 'ln -s /usr/share/zoneinfo/Europe/Berlin
|
|
/etc/localtime'.
|
|
|
|
Recommended Tools for Compilation
|
|
=================================
|
|
|
|
We recommend installing the following GNU tools before attempting to
|
|
build the GNU C Library:
|
|
|
|
* GNU 'make' 4.0 or newer
|
|
|
|
As of relase time, GNU 'make' 4.3 is the newest verified to work to
|
|
build the GNU C Library.
|
|
|
|
* GCC 6.2 or newer
|
|
|
|
GCC 6.2 or higher is required. In general it is recommended to use
|
|
the newest version of the compiler that is known to work for
|
|
building the GNU C Library, as newer compilers usually produce
|
|
better code. As of release time, GCC 10.2 is the newest compiler
|
|
verified to work to build the GNU C Library.
|
|
|
|
For PowerPC 64-bits little-endian (powerpc64le), a GCC version with
|
|
support for '-mno-gnu-attribute', '-mabi=ieeelongdouble', and
|
|
'-mabi=ibmlondouble' is required. Likewise, the compiler must also
|
|
support passing '-mlong-double-128' with the preceding options. As
|
|
of release, this implies GCC 7.4 and newer (excepting GCC 7.5.0,
|
|
see GCC PR94200). These additional features are required for
|
|
building the GNU C Library with support for IEEE long double.
|
|
|
|
For ARC architecture builds, GCC 8.3 or higher is needed.
|
|
|
|
For s390x architecture builds, GCC 7.1 or higher is needed (See gcc
|
|
Bug 98269).
|
|
|
|
For multi-arch support it is recommended to use a GCC which has
|
|
been built with support for GNU indirect functions. This ensures
|
|
that correct debugging information is generated for functions
|
|
selected by IFUNC resolvers. This support can either be enabled by
|
|
configuring GCC with '--enable-gnu-indirect-function', or by
|
|
enabling it by default by setting 'default_gnu_indirect_function'
|
|
variable for a particular architecture in the GCC source file
|
|
'gcc/config.gcc'.
|
|
|
|
You can use whatever compiler you like to compile programs that use
|
|
the GNU C Library.
|
|
|
|
Check the FAQ for any special compiler issues on particular
|
|
platforms.
|
|
|
|
* GNU 'binutils' 2.25 or later
|
|
|
|
You must use GNU 'binutils' (as and ld) to build the GNU C Library.
|
|
No other assembler or linker has the necessary functionality at the
|
|
moment. As of release time, GNU 'binutils' 2.35.1 is the newest
|
|
verified to work to build the GNU C Library.
|
|
|
|
For PowerPC 64-bits little-endian (powerpc64le), 'objcopy' is
|
|
required to support '--update-section'. This option requires
|
|
binutils 2.26 or newer.
|
|
|
|
ARC architecture needs 'binutils' 2.32 or higher for TLS related
|
|
fixes.
|
|
|
|
* GNU 'texinfo' 4.7 or later
|
|
|
|
To correctly translate and install the Texinfo documentation you
|
|
need this version of the 'texinfo' package. Earlier versions do
|
|
not understand all the tags used in the document, and the
|
|
installation mechanism for the info files is not present or works
|
|
differently. As of release time, 'texinfo' 6.7 is the newest
|
|
verified to work to build the GNU C Library.
|
|
|
|
* GNU 'awk' 3.1.2, or higher
|
|
|
|
'awk' is used in several places to generate files. Some 'gawk'
|
|
extensions are used, including the 'asorti' function, which was
|
|
introduced in version 3.1.2 of 'gawk'. As of release time, 'gawk'
|
|
version 5.1 is the newest verified to work to build the GNU C
|
|
Library.
|
|
|
|
* GNU 'bison' 2.7 or later
|
|
|
|
'bison' is used to generate the 'yacc' parser code in the 'intl'
|
|
subdirectory. As of release time, 'bison' version 3.7.4 is the
|
|
newest verified to work to build the GNU C Library.
|
|
|
|
* Perl 5
|
|
|
|
Perl is not required, but if present it is used in some tests and
|
|
the 'mtrace' program, to build the GNU C Library manual. As of
|
|
release time 'perl' version 5.32.0 is the newest verified to work
|
|
to build the GNU C Library.
|
|
|
|
* GNU 'sed' 3.02 or newer
|
|
|
|
'Sed' is used in several places to generate files. Most scripts
|
|
work with any version of 'sed'. As of release time, 'sed' version
|
|
4.8 is the newest verified to work to build the GNU C Library.
|
|
|
|
* Python 3.4 or later
|
|
|
|
Python is required to build the GNU C Library. As of release time,
|
|
Python 3.8.6 is the newest verified to work for building and
|
|
testing the GNU C Library.
|
|
|
|
* PExpect 4.0
|
|
|
|
The pretty printer tests drive GDB through test programs and
|
|
compare its output to the printers'. PExpect is used to capture
|
|
the output of GDB, and should be compatible with the Python version
|
|
in your system. As of release time PExpect 4.8 is the newest
|
|
verified to work to test the pretty printers.
|
|
|
|
* GDB 7.8 or later with support for Python 2.7/3.4 or later
|
|
|
|
GDB itself needs to be configured with Python support in order to
|
|
use the pretty printers. Notice that your system having Python
|
|
available doesn't imply that GDB supports it, nor that your
|
|
system's Python and GDB's have the same version. As of release
|
|
time GNU 'debugger' 10.1 is the newest verified to work to test the
|
|
pretty printers.
|
|
|
|
Unless Python, PExpect and GDB with Python support are present, the
|
|
printer tests will report themselves as 'UNSUPPORTED'. Notice that
|
|
some of the printer tests require the GNU C Library to be compiled
|
|
with debugging symbols.
|
|
|
|
If you change any of the 'configure.ac' files you will also need
|
|
|
|
* GNU 'autoconf' 2.69 (exactly)
|
|
|
|
and if you change any of the message translation files you will need
|
|
|
|
* GNU 'gettext' 0.10.36 or later
|
|
|
|
As of release time, GNU 'gettext' version 0.21 is the newest
|
|
version verified to work to build the GNU C Library.
|
|
|
|
You may also need these packages if you upgrade your source tree using
|
|
patches, although we try to avoid this.
|
|
|
|
Specific advice for GNU/Linux systems
|
|
=====================================
|
|
|
|
If you are installing the GNU C Library on GNU/Linux systems, you need
|
|
to have the header files from a 3.2 or newer kernel around for
|
|
reference. (For the ia64 architecture, you need version 3.2.18 or newer
|
|
because this is the first version with support for the 'accept4' system
|
|
call.) These headers must be installed using 'make headers_install';
|
|
the headers present in the kernel source directory are not suitable for
|
|
direct use by the GNU C Library. You do not need to use that kernel,
|
|
just have its headers installed where the GNU C Library can access them,
|
|
referred to here as INSTALL-DIRECTORY. The easiest way to do this is to
|
|
unpack it in a directory such as '/usr/src/linux-VERSION'. In that
|
|
directory, run 'make headers_install
|
|
INSTALL_HDR_PATH=INSTALL-DIRECTORY'. Finally, configure the GNU C
|
|
Library with the option '--with-headers=INSTALL-DIRECTORY/include'. Use
|
|
the most recent kernel you can get your hands on. (If you are
|
|
cross-compiling the GNU C Library, you need to specify
|
|
'ARCH=ARCHITECTURE' in the 'make headers_install' command, where
|
|
ARCHITECTURE is the architecture name used by the Linux kernel, such as
|
|
'x86' or 'powerpc'.)
|
|
|
|
After installing the GNU C Library, you may need to remove or rename
|
|
directories such as '/usr/include/linux' and '/usr/include/asm', and
|
|
replace them with copies of directories such as 'linux' and 'asm' from
|
|
'INSTALL-DIRECTORY/include'. All directories present in
|
|
'INSTALL-DIRECTORY/include' should be copied, except that the GNU C
|
|
Library provides its own version of '/usr/include/scsi'; the files
|
|
provided by the kernel should be copied without replacing those provided
|
|
by the GNU C Library. The 'linux', 'asm' and 'asm-generic' directories
|
|
are required to compile programs using the GNU C Library; the other
|
|
directories describe interfaces to the kernel but are not required if
|
|
not compiling programs using those interfaces. You do not need to copy
|
|
kernel headers if you did not specify an alternate kernel header source
|
|
using '--with-headers'.
|
|
|
|
The Filesystem Hierarchy Standard for GNU/Linux systems expects some
|
|
components of the GNU C Library installation to be in '/lib' and some in
|
|
'/usr/lib'. This is handled automatically if you configure the GNU C
|
|
Library with '--prefix=/usr'. If you set some other prefix or allow it
|
|
to default to '/usr/local', then all the components are installed there.
|
|
|
|
Reporting Bugs
|
|
==============
|
|
|
|
There are probably bugs in the GNU C Library. There are certainly
|
|
errors and omissions in this manual. If you report them, they will get
|
|
fixed. If you don't, no one will ever know about them and they will
|
|
remain unfixed for all eternity, if not longer.
|
|
|
|
It is a good idea to verify that the problem has not already been
|
|
reported. Bugs are documented in two places: The file 'BUGS' describes
|
|
a number of well known bugs and the central GNU C Library bug tracking
|
|
system has a WWW interface at <https://sourceware.org/bugzilla/>. The
|
|
WWW interface gives you access to open and closed reports. A closed
|
|
report normally includes a patch or a hint on solving the problem.
|
|
|
|
To report a bug, first you must find it. With any luck, this will be
|
|
the hard part. Once you've found a bug, make sure it's really a bug. A
|
|
good way to do this is to see if the GNU C Library behaves the same way
|
|
some other C library does. If so, probably you are wrong and the
|
|
libraries are right (but not necessarily). If not, one of the libraries
|
|
is probably wrong. It might not be the GNU C Library. Many historical
|
|
Unix C libraries permit things that we don't, such as closing a file
|
|
twice.
|
|
|
|
If you think you have found some way in which the GNU C Library does
|
|
not conform to the ISO and POSIX standards (*note Standards and
|
|
Portability::), that is definitely a bug. Report it!
|
|
|
|
Once you're sure you've found a bug, try to narrow it down to the
|
|
smallest test case that reproduces the problem. In the case of a C
|
|
library, you really only need to narrow it down to one library function
|
|
call, if possible. This should not be too difficult.
|
|
|
|
The final step when you have a simple test case is to report the bug.
|
|
Do this at <https://www.gnu.org/software/libc/bugs.html>.
|
|
|
|
If you are not sure how a function should behave, and this manual
|
|
doesn't tell you, that's a bug in the manual. Report that too! If the
|
|
function's behavior disagrees with the manual, then either the library
|
|
or the manual has a bug, so report the disagreement. If you find any
|
|
errors or omissions in this manual, please report them to the bug
|
|
database. If you refer to specific sections of the manual, please
|
|
include the section names for easier identification.
|