path: root/manual/install.texi

@include macros.texi
@include pkgvers.texi

@ifclear plain
@node Installation, Maintenance, Library Summary, Top
@end ifclear

@c %MENU% How to install the GNU C Library
@appendix Installing @theglibc{}

Before you do anything else, you should read the FAQ at
@url{http://sourceware.org/glibc/wiki/FAQ}.  It answers common
questions and describes problems you may experience with compilation
and installation.

Features can be added to @theglibc{} via @dfn{add-on} bundles.  These are
separate tar files, which you unpack into the top level of the source
tree.  Then you give @code{configure} the @samp{--enable-add-ons} option
to activate them, and they will be compiled into the library.

You will need recent versions of several GNU tools: definitely GCC and
GNU Make, and possibly others.  @xref{Tools for Compilation}, below.

@ifclear plain
@menu
* Configuring and compiling::   How to compile and test GNU libc.
* Running make install::        How to install it once you've got it
 compiled.
* Tools for Compilation::       You'll need these first.
* Linux::                       Specific advice for GNU/Linux systems.
* Reporting Bugs::              So they'll get fixed.
@end menu
@end ifclear

@node Configuring and compiling
@appendixsec Configuring and compiling @theglibc{}
@cindex configuring
@cindex compiling

@Theglibc{} cannot be compiled in the source directory.  You must build
it in a separate build directory.  For example, if you have unpacked
the @glibcadj{} sources in @file{/src/gnu/glibc-@var{version}},
create a directory
@file{/src/gnu/glibc-build} to put the object files in.  This allows
removing the whole build directory in case an error occurs, which is
the safest way to get a fresh start and should always be done.

From your object directory, run the shell script @file{configure} located
at the top level of the source tree.  In the scenario above, you'd type

@smallexample
$ ../glibc-@var{version}/configure @var{args@dots{}}
@end smallexample

Please note that even though you're building in a separate build
directory, the compilation may need to create or modify files and
directories in the source directory.

@noindent
@code{configure} takes many options, but the only one that is usually
mandatory is @samp{--prefix}.  This option tells @code{configure}
where you want @theglibc{} installed.  This defaults to @file{/usr/local},
but the normal setting to install as the standard system library is
@samp{--prefix=/usr} for @gnulinuxsystems{} and @samp{--prefix=} (an
empty prefix) for @gnuhurdsystems{}.

It may also be useful to set the @var{CC} and @var{CFLAGS} variables in
the environment when running @code{configure}.  @var{CC} selects the C
compiler that will be used, and @var{CFLAGS} sets optimization options
for the compiler.

The following list describes all of the available options for
 @code{configure}:

@table @samp
@item --prefix=@var{directory}
Install machine-independent data files in subdirectories of
@file{@var{directory}}.  The default is to install in @file{/usr/local}.

@item --exec-prefix=@var{directory}
Install the library and other machine-dependent files in subdirectories
of @file{@var{directory}}.  The default is to the @samp{--prefix}
directory if that option is specified, or @file{/usr/local} otherwise.

@item --with-headers=@var{directory}
Look for kernel header files in @var{directory}, not
@file{/usr/include}.  @Theglibc{} needs information from the kernel's header
files describing the interface to the kernel.  @Theglibc{} will normally
look in @file{/usr/include} for them,
but if you specify this option, it will look in @var{DIRECTORY} instead.

This option is primarily of use on a system where the headers in
@file{/usr/include} come from an older version of @theglibc{}.  Conflicts can
occasionally happen in this case.  You can also use this option if you want to
compile @theglibc{} with a newer set of kernel headers than the ones found in
@file{/usr/include}.

@item --enable-add-ons[=@var{list}]
Specify add-on packages to include in the build.  If this option is
specified with no list, it enables all the add-on packages it finds in
the main source directory; this is the default behavior.  You may
specify an explicit list of add-ons to use in @var{list}, separated by
spaces or commas (if you use spaces, remember to quote them from the
shell).  Each add-on in @var{list} can be an absolute directory name
or can be a directory name relative to the main source directory, or
relative to the build directory (that is, the current working directory).
For example, @samp{--enable-add-ons=nptl,../glibc-libidn-@var{version}}.

@item --enable-kernel=@var{version}
This option is currently only useful on @gnulinuxsystems{}.  The
@var{version} parameter should have the form X.Y.Z and describes the
smallest version of the Linux kernel the generated library is expected
to support.  The higher the @var{version} number is, the less
compatibility code is added, and the faster the code gets.

@item --with-binutils=@var{directory}
Use the binutils (assembler and linker) in @file{@var{directory}}, not
the ones the C compiler would default to.  You can use this option if
the default binutils on your system cannot deal with all the constructs
in @theglibc{}.  In that case, @code{configure} will detect the
problem and suppress these constructs, so that the library will still be
usable, but functionality may be lost---for example, you can't build a
shared libc with old binutils.

@item --without-fp
Use this option if your computer lacks hardware floating-point support
and your operating system does not emulate an FPU.

@c disable static doesn't work currently
@c @item --disable-static
@c Don't build static libraries.  Static libraries aren't that useful these
@c days, but we recommend you build them in case you need them.

@item --disable-shared
Don't build shared libraries even if it is possible.  Not all systems
support shared libraries; you need ELF support and (currently) the GNU
linker.

@item --disable-profile
Don't build libraries with profiling information.  You may want to use
this option if you don't plan to do profiling.

@item --enable-static-nss
Compile static versions of the NSS (Name Service Switch) libraries.
This is not recommended because it defeats the purpose of NSS; a program
linked statically with the NSS libraries cannot be dynamically
reconfigured to use a different name database.

@item --enable-hardcoded-path-in-tests
By default, dynamic tests are linked to run with the installed C library.
This option hardcodes the newly built C library path in dynamic tests
so that they can be invoked directly.

@item --disable-timezone-tools
By default, timezone related utilities (@command{zic}, @command{zdump},
and @command{tzselect}) are installed with @theglibc{}.  If you are building
these independently (e.g. by using the @samp{tzcode} package), then this
option will allow disabling the install of these.

Note that you need to make sure the external tools are kept in sync with
the versions that @theglibc{} expects as the data formats may change over
time.  Consult the @file{timezone} subdirectory for more details.

@item --enable-lock-elision=yes
Enable lock elision for pthread mutexes by default.

@item --enable-stack-protector
@itemx --enable-stack-protector=strong
@itemx --enable-stack-protector=all
Compile the C library and all other parts of the glibc package
(including the threading and math libraries, NSS modules, and
transliteration modules) using the GCC @option{-fstack-protector},
@option{-fstack-protector-strong} or @option{-fstack-protector-all}
options to detect stack overruns.  Only the dynamic linker and a small
number of routines called directly from assembler are excluded from this
protection.

@pindex pt_chown
@findex grantpt
@item --enable-pt_chown
The file @file{pt_chown} is a helper binary for @code{grantpt}
(@pxref{Allocation, Pseudo-Terminals}) that is installed setuid root to
fix up pseudo-terminal ownership.  It is not built by default because
systems using the Linux kernel are commonly built with the @code{devpts}
filesystem enabled and mounted at @file{/dev/pts}, which manages
pseudo-terminal ownership automatically.  By using
@samp{--enable-pt_chown}, you may build @file{pt_chown} and install it
setuid and owned by @code{root}.  The use of @file{pt_chown} introduces
additional security risks to the system and you should enable it only if
you understand and accept those risks.

@item --disable-werror
By default, @theglibc{} is built with @option{-Werror}.  If you wish
to build without this option (for example, if building with a newer
version of GCC than this version of @theglibc{} was tested with, so
new warnings cause the build with @option{-Werror} to fail), you can
configure with @option{--disable-werror}.

@item --disable-mathvec
By default for x86_64, @theglibc{} is built with the vector math library.
Use this option to disable the vector math library.

@item --enable-tunables
Tunables support allows additional library parameters to be customized at
runtime.  This is an experimental feature and affects startup time and is thus
disabled by default.  This option can take the following values:

@table @code
@item no
This is the default if the option is not passed to configure. This disables
tunables.

@item yes
This is the default if the option is passed to configure. This enables tunables
and selects the default frontend (currently @samp{valstring}).

@item valstring
This enables tunables and selects the @samp{valstring} frontend for tunables.
This frontend allows users to specify tunables as a colon-separated list in a
single environment variable @env{GLIBC_TUNABLES}.
@end table

@item --build=@var{build-system}
@itemx --host=@var{host-system}
These options are for cross-compiling.  If you specify both options and
@var{build-system} is different from @var{host-system}, @code{configure}
will prepare to cross-compile @theglibc{} from @var{build-system} to be used
on @var{host-system}.  You'll probably need the @samp{--with-headers}
option too, and you may have to override @var{configure}'s selection of
the compiler and/or binutils.

If you only specify @samp{--host}, @code{configure} will prepare for a
native compile but use what you specify instead of guessing what your
system is.  This is most useful to change the CPU submodel.  For example,
if @code{configure} guesses your machine as @code{i686-pc-linux-gnu} but
you want to compile a library for 586es, give
@samp{--host=i586-pc-linux-gnu} or just @samp{--host=i586-linux} and add
the appropriate compiler flags (@samp{-mcpu=i586} will do the trick) to
@var{CFLAGS}.

If you specify just @samp{--build}, @code{configure} will get confused.

@item --with-pkgversion=@var{version}
Specify a description, possibly including a build number or build
date, of the binaries being built, to be included in
@option{--version} output from programs installed with @theglibc{}.
For example, @option{--with-pkgversion='FooBar GNU/Linux glibc build
123'}.  The default value is @samp{GNU libc}.

@item --with-bugurl=@var{url}
Specify the URL that users should visit if they wish to report a bug,
to be included in @option{--help} output from programs installed with
@theglibc{}.  The default value refers to the main bug-reporting
information for @theglibc{}.
@end table

To build the library and related programs, type @code{make}.  This will
produce a lot of output, some of which may look like errors from
@code{make} but aren't.  Look for error messages from @code{make}
containing @samp{***}.  Those indicate that something is seriously wrong.

The compilation process can take a long time, depending on the
configuration and the speed of your machine.  Some complex modules may
take a very long time to compile, as much as several minutes on slower
machines.  Do not panic if the compiler appears to hang.

If you want to run a parallel make, simply pass the @samp{-j} option
with an appropriate numeric parameter to @code{make}.  You need a recent
GNU @code{make} version, though.

To build and run test programs which exercise some of the library
facilities, type @code{make check}.  If it does not complete
successfully, do not use the built library, and report a bug after
verifying that the problem is not already known.  @xref{Reporting Bugs},
for instructions on reporting bugs.  Note that some of the tests assume
they are not being run by @code{root}.  We recommend you compile and
test @theglibc{} as an unprivileged user.

Before reporting bugs make sure there is no problem with your system.
The tests (and later installation) use some pre-existing files of the
system such as @file{/etc/passwd}, @file{/etc/nsswitch.conf} and others.
These files must all contain correct and sensible content.

Normally, @code{make check} will run all the tests before reporting
all problems found and exiting with error status if any problems
occurred.  You can specify @samp{stop-on-test-failure=y} when running
@code{make check} to make the test run stop and exit with an error
status immediately when a failure occurs.

The @glibcadj{} pretty printers come with their own set of scripts for testing,
which run together with the rest of the testsuite through @code{make check}.
These scripts require the following tools to run successfully:

@itemize @bullet
@item
Python 2.7.6/3.4.3 or later

Python is required for running the printers' test scripts.

@item PExpect 4.0

The 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.

@item
GDB 7.8 or later with support for Python 2.7.6/3.4.3 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.
@end itemize

@noindent
If these tools are absent, the printer tests will report themselves as
@code{UNSUPPORTED}.  Notice that some of the printer tests require @theglibc{}
to be compiled with debugging symbols.

To format the @cite{GNU C Library Reference Manual} for printing, type
@w{@code{make dvi}}.  You need a working @TeX{} installation to do
this.  The distribution builds the on-line formatted version of the
manual, as Info files, as part of the build process.  You can build
them manually with @w{@code{make info}}.

The library has a number of special-purpose configuration parameters
which you can find in @file{Makeconfig}.  These can be overwritten with
the file @file{configparms}.  To change them, create a
@file{configparms} in your build directory and add values as appropriate
for your system.  The file is included and parsed by @code{make} and has
to follow the conventions for makefiles.

It is easy to configure @theglibc{} for cross-compilation by
setting a few variables in @file{configparms}.  Set @code{CC} to the
cross-compiler for the target you configured the library for; it is
important to use this same @code{CC} value when running
@code{configure}, like this: @samp{CC=@var{target}-gcc configure
@var{target}}.  Set @code{BUILD_CC} to the compiler to use for programs
run on the build system as part of compiling the library.  You may need to
set @code{AR} to cross-compiling versions of @code{ar}
if the native tools are not configured to work with
object files for the target you configured for.  When cross-compiling
@theglibc{}, it may be tested using @samp{make check
test-wrapper="@var{srcdir}/scripts/cross-test-ssh.sh @var{hostname}"},
where @var{srcdir} is the absolute directory name for the main source
direct