1 @c This is for making the `INSTALL' file for the distribution.
2 @c Makeinfo ignores it when processing the file from the include.
5 @node Installation, Maintenance, Library Summary, Top
6 @c %MENU% How to install the GNU C library
7 @appendix Installing the GNU C Library
9 Before you do anything else, you should read the file @file{FAQ} found
10 at the top level of the source tree. This file answers common questions
11 and describes problems you may experience with compilation and
12 installation. It is updated more frequently than this manual.
14 Features can be added to GNU Libc via @dfn{add-on} bundles. These are
15 separate tarfiles which you unpack into the top level of the source
16 tree. Then you give @code{configure} the @samp{--enable-add-ons} option
17 to activate them, and they will be compiled into the library. As of the
18 2.1 release, two important components of glibc are distributed as
19 ``official'' add-ons. Unless you are doing an unusual installation, you
22 Support for POSIX threads is maintained by someone else, so it's in a
23 separate package. It is only available for Linux systems, but this will
24 change in the future. Get it from the same place you got the main
25 bundle; the file is @file{glibc-linuxthreads-@var{VERSION}.tar.gz}.
26 Support for the @code{crypt} function is distributed separately because
27 of United States export restrictions. If you are outside the US or
28 Canada, you must get @code{crypt} support from a site outside the US,
29 such as @samp{ftp.gwdg.de}. @samp{ftp.gwdg.de} has the crypt
30 distribution in @code{pub/linux/glibc}.
31 @c Check this please someone:
32 (Most non-US mirrors of @samp{ftp.gnu.org} will have it too.) The file
33 you need is @file{glibc-crypt-@var{VERSION}.tar.gz}.
35 You will need recent versions of several GNU tools: definitely GCC and
36 GNU Make, and possibly others. @xref{Tools for Compilation}, below.
39 * Configuring and compiling:: How to compile and test GNU libc.
40 * Running make install:: How to install it once you've got it compiled.
41 * Tools for Compilation:: You'll need these first.
42 * Supported Configurations:: What it runs on, what it doesn't.
43 * Linux:: Specific advice for Linux systems.
44 * Reporting Bugs:: So they'll get fixed.
47 @node Configuring and compiling
48 @appendixsec Configuring and compiling GNU Libc
52 GNU libc can be compiled in the source directory, but we strongly advise to
53 build it in a separate build directory. For example, if you have unpacked
54 the glibc sources in @file{/src/gnu/glibc-2.1.0}, create a directory
55 @file{/src/gnu/glibc-build} to put the object files in. This allows to
56 remove the whole build directory in case an error occurs which is the
57 safest way to get a clean way and should always be done.
59 From your object directory, run the shell script @file{configure} found
60 at the top level of the source tree. In the scenario above, you'd type
63 $ ../glibc-2.1.0/configure @var{args...}
66 Please note that even if you're building in a separate build directory,
67 the compilation needs to modify a few files in the source
68 directory, especially some files in the manual subdirectory.
71 @code{configure} takes many options, but you can get away with knowing
72 only two: @samp{--prefix} and @samp{--enable-add-ons}. The
73 @code{--prefix} option tells configure where you want glibc installed.
74 This defaults to @file{/usr/local}. The @samp{--enable-add-ons} option
75 tells configure to use all the add-on bundles it finds in the source
76 directory. Since important functionality is provided in add-ons, you
77 should always specify this option.
79 It may also be useful to set the @var{CC} and @var{CFLAGS} variables in
80 the environment when running @code{configure}. @var{CC} selects the C
81 compiler that will be used, and @var{CFLAGS} sets optimization options
84 The following list describes all of the available options for @code{configure}:
87 @item --prefix=@var{directory}
88 Install machine-independent data files in subdirectories of
89 @file{@var{directory}}. The default is to install in @file{/usr/local}.
91 @item --exec-prefix=@var{directory}
92 Install the library and other machine-dependent files in subdirectories
93 of @file{@var{directory}}. The default is to the @samp{--prefix}
94 directory if that option is specified, or @file{/usr/local} otherwise.
96 @item --with-headers=@var{directory}
97 Look for kernel header files in @var{directory}, not
98 @file{/usr/include}. Glibc needs information from the kernel's private
99 header files. It will normally look in @file{/usr/include} for them,
100 but if you specify this option, it will look in @var{DIRECTORY} instead.
102 This option is primarily of use on a system where the headers in
103 @file{/usr/include} come from an older version of glibc. Conflicts can
104 occasionally happen in this case. Note that Linux libc5 qualifies as an
105 older version of glibc. You can also use this option if you want to
106 compile glibc with a newer set of kernel headers than the ones found in
109 @item --enable-add-ons[=@var{list}]
110 Enable add-on packages in your source tree. If this option is specified
111 with no list, it enables all the add-on packages it finds. If you do
112 not wish to use some add-on package that you have present in your source
113 tree, give this option a list of the add-ons that you @emph{do} want
114 used, like this: @samp{--enable-add-ons=crypt,linuxthreads}
116 @item --with-binutils=@var{directory}
117 Use the binutils (assembler and linker) in @file{@var{directory}}, not
118 the ones the C compiler would default to. You could use this option if
119 the default binutils on your system cannot deal with all the constructs
120 in the GNU C library. In that case, @code{configure} will detect the problem and
121 suppress these constructs, so that the library will still be usable, but
122 functionality may be lost---for example, you can't build a shared libc
126 Use this option if your computer lacks hardware floating-point support
127 and your operating system does not emulate an FPU.
129 @c disable static doesn't work currently
130 @c @item --disable-static
131 @c Don't build static libraries. Static libraries aren't that useful these
132 @c days, but we recommend you build them in case you need them.
134 @item --disable-shared
135 Don't build shared libraries even if it is possible. Not all systems support
136 shared libraries; you need ELF support and (currently) the GNU linker.
138 @item --disable-profile
139 Don't build libraries with profiling information. You may want to use
140 this option if you don't plan to do profiling.
142 @item --enable-omitfp
143 Use maximum optimization for the normal (static and shared)
144 libraries, and compile separate static libraries with debugging
145 information and no optimisation. We recommend against this. The extra
146 optimization doesn't gain you much, it may provoke compiler bugs, and
147 you won't be able to trace bugs through the C library.
149 @item --disable-versioning
150 Don't compile the shared libraries with symbol version information.
151 Doing this will make the resulting library incompatible with old
152 binaries, so it's not recommended.
154 @item --enable-static-nss
155 Compile static versions of the NSS (Name Service Switch) libraries.
156 This is not recommended because it defeats the purpose of NSS; a program
157 linked statically with the NSS libraries cannot be dynamically
158 reconfigured to use a different name database.
160 @item --build=@var{build-system}
161 @itemx --host=@var{host-system}
162 These options are for cross-compiling. If you specify both options and
163 @var{build-system} is different from @var{host-system}, @code{configure}
164 will prepare to cross-compile glibc from @var{build-system} to be used
165 on @var{host-system}. You'll probably need the @samp{--with-headers}
166 option too, and you may have to override @var{configure}'s selection of
167 the compiler and/or binutils.
169 If you only specify @samp{--host}, configure will prepare for a native
170 compile but use what you specify instead of guessing what your system is.
171 This is most useful to change the CPU submodel. For example, if
172 configure guesses your machine as @code{i586-pc-linux-gnu} but you want
173 to compile a library for 386es, give @samp{--host=i386-pc-linux-gnu} or
174 just @samp{--host=i386-linux} and add the appropriate compiler flags
175 (@samp{-mcpu=i386} will do the trick) to @var{CFLAGS}.
177 If you specify just @samp{--build}, configure will get confused.
180 To build the library and related programs, type @code{make}. This will
181 produce a lot of output, some of which may look like errors from
182 @code{make} but isn't. Look for error messages from @code{make}
183 containing @samp{***}. Those indicate that something is really wrong.
185 The compilation process takes several hours even on fast hardware.
186 Expect at least two hours for the default configuration on i586 for
187 Linux. For Hurd times are much longer. Except for EGCS 1.1 (and later
188 versions of EGCS), all supported versions of GCC have a problem which
189 causes them to take several minutes to compile certain files in the
190 iconvdata directory. Do not panic if the compiler appears to hang.
192 If you want to run a parallel make, you can't just give @code{make} the
193 @samp{-j} option, because it won't be passed down to the sub-makes.
194 Instead, edit the generated @file{Makefile} and uncomment the line
197 # PARALLELMFLAGS = -j 4
201 You can change the @samp{4} to some other number as appropriate for
202 your system. Instead of changing the @file{Makefile}, you could give
203 this option directly to @code{make} and call it as, for example,
204 @code{make PARALLELMFLAGS=-j4}. If you're building in the source
205 directory, you must use the latter approach since in this case no
206 new @file{Makefile} is generated for you to change.
208 To build and run test programs which exercise some of the library
209 facilities, type @code{make check}. If it does not complete
210 successfully, do not use the built library, and report a bug after
211 verifying that the problem is not already known. @xref{Reporting Bugs},
212 for instructions on reporting bugs. Note that some of the tests assume
213 they are not being run by @code{root}. We recommend you compile and
214 test glibc as an unprivileged user.
216 To format the @cite{GNU C Library Reference Manual} for printing, type
217 @w{@code{make dvi}}. You need a working @TeX{} installation to do this.
218 The distribution already includes the on-line formatted version of the
219 manual, as Info files. You can regenerate those with @w{@code{make
220 info}}, but it shouldn't be necessary.
222 @node Running make install
223 @appendixsec Installing the C Library
226 To install the library and its header files, and the Info files of the
227 manual, type @code{make install}. This will build things if necessary,
228 before installing them. However, you should still compile everything first.
229 If you are installing glibc as your primary C library, we recommend that you
230 shut the system down to single-user mode first, and reboot afterward.
231 This minimizes the risk of breaking things when the library changes out
234 If you are upgrading from a previous installation of glibc 2.0 or 2.1,
235 @samp{make install} will do the entire job. If you're upgrading from
236 Linux libc5 or some other C library, you need to rename the old
237 @file{/usr/include} directory before running @samp{make install},
238 or you will end up with a mixture of header files from both
239 libraries, and you won't be able to compile anything. You may also need
240 to reconfigure GCC to work with the new library. The easiest way to do
241 that is to figure out the compiler switches to make it work again
242 (@samp{-Wl,--dynamic-linker=/lib/ld-linux.so.2} should work on Linux
243 systems) and use them to recompile gcc. You can also edit the specs
244 file (@file{/usr/lib/gcc-lib/@var{TARGET}/@var{VERSION}/specs}), but
245 that is a bit of a black art.
247 You can install glibc somewhere other than where you configured it to go
248 by setting the @code{install_root} variable on the command line for
249 @samp{make install}. The value of this variable is prepended to all the
250 paths for installation. This is useful when setting up a chroot
251 environment or preparing a binary distribution.
253 Glibc 2.1 includes two daemons, @code{nscd} and @code{utmpd}, which you
254 may or may not want to run. @code{nscd} caches name service lookups; it
255 can dramatically improve performance with NIS+, and may help with DNS as
256 well. @code{utmpd} allows programs that use the old format for the
257 @file{utmp} file to coexist with new programs. For more information see
258 the file @file{login/README.utmpd}.
260 One auxiliary program, @file{/usr/libexec/pt_chown}, is installed setuid
261 @code{root}. This program is invoked by the @code{grantpt} function; it
262 sets the permissions on a pseudoterminal so it can be used by the
263 calling process. This means programs like @code{xterm} and
264 @code{screen} do not have to be setuid to get a pty. (There may be
265 other reasons why they need privileges.) If you are using a 2.1 or
266 newer Linux kernel with the @code{devptsfs} or @code{devfs} filesystems
267 providing pty slaves, you don't need this program; otherwise you do.
268 The source for @file{pt_chown} is in @file{login/programs/pt_chown.c}.
270 After installation you might want to configure the timezone and locale
271 installation of your system. The GNU C library comes with a locale
272 database which gets configured with @code{localedef}. For example, to
273 set up a German locale with name @code{de_DE}, simply issue the command
274 @samp{localedef -i de_DE -f ISO-8859-1 de_DE}. To configure all locales
275 that are supported by glibc, you can issue from your build directory the
276 command @samp{make localedata/install-locales}.
278 To configure the locally used timezone, you can either set the @code{TZ}
279 environment variable. The script @code{tzselect} helps you to select
280 the right value. As an example for Germany, tzselect would tell you to
281 use @samp{TZ='Europe/Berlin'}. For a system wide installation (the
282 given paths are for an installation with @samp{--prefix=/usr}), link the
283 timezone file which is in @file{/usr/share/zoneinfo} to the file
284 @file{/etc/localtime}. For Germany, you might execute @samp{ln -s
285 /usr/share/zoneinfo/Europe/Berlin /etc/localtime}.
287 @node Tools for Compilation
288 @appendixsec Recommended Tools for Compilation
289 @cindex installation tools
290 @cindex tools, for installing library
292 We recommend installing the following GNU tools before attempting to
293 build the GNU C library:
299 You need the latest version of GNU @code{make}. Modifying the GNU C
300 Library to work with other @code{make} programs would be so difficult that we
301 recommend you port GNU @code{make} instead. @strong{Really.} We
302 recommend version GNU @code{make} version 3.75 or 3.77. All earlier
303 versions have severe bugs or lack features. Version 3.76 is known to
304 have bugs which only show up in big projects like GNU @code{libc}.
305 Version 3.76.1 seems OK but some people have reported problems.
308 EGCS 1.1.1, 1.1 or 1.0.3, or GCC 2.8.1
310 The GNU C library can only be compiled with the GNU C compiler family.
311 As of the 2.1 release, EGCS 1.0.3 or higher is required. GCC 2.8.1 can
312 also be used (but see the FAQ for reasons why you might not want to).
313 Earlier versions simply are too buggy.
315 You can use whatever compiler you like to compile programs that use GNU
316 libc, but be aware that both GCC 2.7 and 2.8 have bugs in their
317 floating-point support that may be triggered by the math library.
319 On Alpha machines you need at least EGCS 1.1.1. Earlier versions don't
322 For PPC you might need some patches even on top of the last EGCS version.
326 GNU @code{binutils} 2.9.1, 2.9.1.0.16, or later 2.9.1.0.x release
328 You must use GNU binutils (as and ld) if you want to build a shared
329 library. Even if you don't, we recommend you use them anyway. No one
330 has tested compilation with non-GNU binutils in a long time.
332 The quality of binutils releases has varied a bit recently. The bugs
333 are in obscure features, but glibc uses quite a few of those. 2.9.1,
334 2.9.1.0.16, and later 2.9.1.0.x releases are known to work. Versions
335 after 2.8.1.0.23 may or may not work. Older versions definitely don't.
336 2.9.1.0.16 or higher is required on some platforms, like PPC and Arm.
338 For PPC you might need some patches even on top of the last binutils
339 version. See the FAQ.
342 GNU @code{texinfo} 3.12f
344 To correctly translate and install the Texinfo documentation you need
345 this version of the @code{texinfo} package. Earlier versions do not
346 understand all the tags used in the document, and the installation
347 mechanism for the info files is not present or works differently.
350 GNU @code{awk} 3.0, or some other POSIX awk
352 Awk is used in several places to generate files. The scripts should
353 work with any POSIX-compliant awk implementation; @code{gawk} 3.0 and
354 @code{mawk} 1.3 are known to work.
359 Perl is not required, but it is used if present to test the
360 installation. We may decide to use it elsewhere in the future.
365 If you change any of the @file{configure.in} files you will also need
369 GNU @code{autoconf} 2.12 or higher
373 and if you change any of the message translation files you will need
377 GNU @code{gettext} 0.10.35 or later (version 0.10.35 is a alpha release
378 and available via ftp from alpha.gnu.org/gnu)
382 You may also need these packages if you upgrade your source tree using
383 patches, although we try to avoid this.
385 @node Supported Configurations
386 @appendixsec Supported Configurations
387 @cindex configurations, all supported
389 The GNU C Library currently supports configurations that match the
395 arm-@var{*}-linuxaout
397 i@var{x}86-@var{*}-gnu
398 i@var{x}86-@var{*}-linux
400 powerpc-@var{*}-linux
402 sparc64-@var{*}-linux
405 Former releases of this library (version 1.09.1 and perhaps earlier
406 versions) used to run on the following configurations:
410 alpha-@var{*}-linuxecoff
411 i@var{x}86-@var{*}-bsd4.3
412 i@var{x}86-@var{*}-isc2.2
413 i@var{x}86-@var{*}-isc3.@var{n}
414 i@var{x}86-@var{*}-sco3.2
415 i@var{x}86-@var{*}-sco3.2v4
416 i@var{x}86-@var{*}-sysv
417 i@var{x}86-@var{*}-sysv4
418 i@var{x}86-force_cpu386-none
419 i@var{x}86-sequent-bsd
426 m68k-sun-sunos4.@var{n}
427 mips-dec-ultrix4.@var{n}
428 mips-sgi-irix4.@var{n}
429 sparc-sun-solaris2.@var{n}
430 sparc-sun-sunos4.@var{n}
433 Since no one has volunteered to test and fix these configurations,
434 they are not supported at the moment. They probably don't compile;
435 they definitely don't work anymore. Porting the library is not hard.
436 If you are interested in doing a port, please contact the glibc
437 maintainers by sending electronic mail to @email{bug-glibc@@gnu.org}.
439 Valid cases of @samp{i@var{x}86} include @samp{i386}, @samp{i486},
440 @samp{i586}, and @samp{i686}. All of those configurations produce a
441 library that can run on this processor and newer processors. The GCC
442 compiler by default generates code that's optimized for the machine it's
443 configured for and will use the instructions available on that machine.
444 For example if your GCC is configured for @samp{i686}, gcc will optimize
445 for @samp{i686} and might issue some @samp{i686} specific instructions.
446 To generate code for other models, you have to configure for that model
447 and give GCC the appropriate @samp{-march=} and @samp{-mcpu=} compiler
448 switches via @var{CFLAGS}.
451 @appendixsec Specific advice for Linux systems
452 @cindex upgrading from libc5
453 @cindex kernel header files
455 If you are installing GNU libc on a Linux system, you need to have
456 the header files from a 2.2 kernel around for reference. You do not
457 need to use the 2.2 kernel, just have its headers where glibc can access
458 at them. The easiest way to do this is to unpack it in a directory
459 such as @file{/usr/src/linux-2.2.1}. In that directory, run
460 @samp{make config} and accept all the defaults. Then run @samp{make
461 include/linux/version.h}. Finally, configure glibc with the option
462 @samp{--with-headers=/usr/src/linux-2.2.1/include}. Use the most recent
463 kernel you can get your hands on.
465 An alternate tactic is to unpack the 2.2 kernel and run @samp{make
466 config} as above. Then rename or delete @file{/usr/include}, create
467 a new @file{/usr/include}, and make the usual symbolic links of
468 @file{/usr/include/linux} and @file{/usr/include/asm} into the 2.2
469 kernel sources. You can then configure glibc with no special options.
470 This tactic is recommended if you are upgrading from libc5, since you
471 need to get rid of the old header files anyway.
473 Note that @file{/usr/include/net} and @file{/usr/include/scsi} should
474 @strong{not} be symlinks into the kernel sources. GNU libc provides its
475 own versions of these files.
477 Linux expects some components of the libc installation to be in
478 @file{/lib} and some in @file{/usr/lib}. This is handled automatically
479 if you configure glibc with @samp{--prefix=/usr}. If you set some other
480 prefix or allow it to default to @file{/usr/local}, then all the
481 components are installed there.
483 If you are upgrading from libc5, you need to recompile every shared
484 library on your system against the new library for the sake of new code,
485 but keep the old libraries around for old binaries to use. This is
486 complicated and difficult. Consult the Glibc2 HOWTO at
487 @url{http://www.imaxx.net/~thrytis/glibc} for details.
489 You cannot use @code{nscd} with 2.0 kernels, due to bugs in the
490 kernel-side thread support. @code{nscd} happens to hit these bugs
491 particularly hard, but you might have problems with any threaded
495 @appendixsec Reporting Bugs
496 @cindex reporting bugs
497 @cindex bugs, reporting
499 There are probably bugs in the GNU C library. There are certainly
500 errors and omissions in this manual. If you report them, they will get
501 fixed. If you don't, no one will ever know about them and they will
502 remain unfixed for all eternity, if not longer.
504 It is a good idea to verify that the problem has not already been
505 reported. Bugs are documented in two places: The file @file{BUGS}
506 describes a number of well known bugs and the bug tracking system has a
508 @url{http://www-gnats.gnu.org:8080/cgi-bin/wwwgnats.pl}. The WWW
509 interface gives you access to open and closed reports. The closed
510 reports normally include a patch or a hint on solving the problem.
512 To report a bug, first you must find it. Hopefully, this will be the
513 hard part. Once you've found a bug, make sure it's really a bug. A
514 good way to do this is to see if the GNU C library behaves the same way
515 some other C library does. If so, probably you are wrong and the
516 libraries are right (but not necessarily). If not, one of the libraries
517 is probably wrong. It might not be the GNU library. Many historical
518 Unix C libraries permit things that we don't, such as closing a file
521 If you think you have found some way in which the GNU C library does not
522 conform to the ISO and POSIX standards (@pxref{Standards and
523 Portability}), that is definitely a bug. Report it!
525 Once you're sure you've found a bug, try to narrow it down to the
526 smallest test case that reproduces the problem. In the case of a C
527 library, you really only need to narrow it down to one library
528 function call, if possible. This should not be too difficult.
530 The final step when you have a simple test case is to report the bug.
531 Do this using the @code{glibcbug} script. It is installed with libc, or
532 if you haven't installed it, will be in your build directory. Send your
533 test case, the results you got, the results you expected, and what you
534 think the problem might be (if you've thought of anything).
535 @code{glibcbug} will insert the configuration information we need to
536 see, and ship the report off to @email{bugs@@gnu.org}. Don't send
537 a message there directly; it is fed to a program that expects mail to be
538 formatted in a particular way. Use the script.
540 If you are not sure how a function should behave, and this manual
541 doesn't tell you, that's a bug in the manual. Report that too! If the
542 function's behavior disagrees with the manual, then either the library
543 or the manual has a bug, so report the disagreement. If you find any
544 errors or omissions in this manual, please report them to the Internet
545 address @email{bug-glibc-manual@@gnu.org}. If you refer to specific
546 sections of the manual, please include the section names for easier