1 Installing the GNU C Library
2 ****************************
4 Before you do anything else, you should read the FAQ at
5 <https://sourceware.org/glibc/wiki/FAQ>. It answers common questions
6 and describes problems you may experience with compilation and
9 You will need recent versions of several GNU tools: definitely GCC
10 and GNU Make, and possibly others. *Note Tools for Compilation::,
13 Configuring and compiling the GNU C Library
14 ===========================================
16 The GNU C Library cannot be compiled in the source directory. You must
17 build it in a separate build directory. For example, if you have
18 unpacked the GNU C Library sources in '/src/gnu/glibc-VERSION', create a
19 directory '/src/gnu/glibc-build' to put the object files in. This
20 allows removing the whole build directory in case an error occurs, which
21 is the safest way to get a fresh start and should always be done.
23 From your object directory, run the shell script 'configure' located
24 at the top level of the source tree. In the scenario above, you'd type
26 $ ../glibc-VERSION/configure ARGS...
28 Please note that even though you're building in a separate build
29 directory, the compilation may need to create or modify files and
30 directories in the source directory.
32 'configure' takes many options, but the only one that is usually
33 mandatory is '--prefix'. This option tells 'configure' where you want
34 the GNU C Library installed. This defaults to '/usr/local', but the
35 normal setting to install as the standard system library is
36 '--prefix=/usr' for GNU/Linux systems and '--prefix=' (an empty prefix)
39 It may also be useful to pass 'CC=COMPILER' and 'CFLAGS=FLAGS'
40 arguments to 'configure'. 'CC' selects the C compiler that will be
41 used, and 'CFLAGS' sets optimization options for the compiler. Any
42 compiler options required for all compilations, such as options
43 selecting an ABI or a processor for which to generate code, should be
44 included in 'CC'. Options that may be overridden by the GNU C Library
45 build system for particular files, such as for optimization and
46 debugging, should go in 'CFLAGS'. The default value of 'CFLAGS' is '-g
47 -O2', and the GNU C Library cannot be compiled without optimization, so
48 if 'CFLAGS' is specified it must enable optimization. For example:
50 $ ../glibc-VERSION/configure CC="gcc -m32" CFLAGS="-O3"
52 The following list describes all of the available options for
56 Install machine-independent data files in subdirectories of
57 'DIRECTORY'. The default is to install in '/usr/local'.
59 '--exec-prefix=DIRECTORY'
60 Install the library and other machine-dependent files in
61 subdirectories of 'DIRECTORY'. The default is to the '--prefix'
62 directory if that option is specified, or '/usr/local' otherwise.
64 '--with-headers=DIRECTORY'
65 Look for kernel header files in DIRECTORY, not '/usr/include'. The
66 GNU C Library needs information from the kernel's header files
67 describing the interface to the kernel. The GNU C Library will
68 normally look in '/usr/include' for them, but if you specify this
69 option, it will look in DIRECTORY instead.
71 This option is primarily of use on a system where the headers in
72 '/usr/include' come from an older version of the GNU C Library.
73 Conflicts can occasionally happen in this case. You can also use
74 this option if you want to compile the GNU C Library with a newer
75 set of kernel headers than the ones found in '/usr/include'.
77 '--enable-kernel=VERSION'
78 This option is currently only useful on GNU/Linux systems. The
79 VERSION parameter should have the form X.Y.Z and describes the
80 smallest version of the Linux kernel the generated library is
81 expected to support. The higher the VERSION number is, the less
82 compatibility code is added, and the faster the code gets.
84 '--with-binutils=DIRECTORY'
85 Use the binutils (assembler and linker) in 'DIRECTORY', not the
86 ones the C compiler would default to. You can use this option if
87 the default binutils on your system cannot deal with all the
88 constructs in the GNU C Library. In that case, 'configure' will
89 detect the problem and suppress these constructs, so that the
90 library will still be usable, but functionality may be lost--for
91 example, you can't build a shared libc with old binutils.
93 '--with-nonshared-cflags=CFLAGS'
94 Use additional compiler flags CFLAGS to build the parts of the
95 library which are always statically linked into applications and
96 libraries even with shared linking (that is, the object files
97 contained in 'lib*_nonshared.a' libraries). The build process will
98 automatically use the appropriate flags, but this option can be
99 used to set additional flags required for building applications and
100 libraries, to match local policy. For example, if such a policy
101 requires that all code linked into applications must be built with
102 source fortification,
103 '--with-nonshared-cflags=-Wp,-D_FORTIFY_SOURCE=2' will make sure
104 that the objects in 'libc_nonshared.a' are compiled with this flag
105 (although this will not affect the generated code in this
106 particular case and potentially change debugging information and
109 '--with-rtld-early-cflags=CFLAGS'
110 Use additional compiler flags CFLAGS to build the early startup
111 code of the dynamic linker. These flags can be used to enable
112 early dynamic linker diagnostics to run on CPUs which are not
113 compatible with the rest of the GNU C Library, for example, due to
114 compiler flags which target a later instruction set architecture
117 '--with-timeoutfactor=NUM'
118 Specify an integer NUM to scale the timeout of test programs. This
119 factor can be changed at run time using 'TIMEOUTFACTOR' environment
123 Don't build shared libraries even if it is possible. Not all
124 systems support shared libraries; you need ELF support and
125 (currently) the GNU linker.
127 '--disable-default-pie'
128 Don't build glibc programs and the testsuite as position
129 independent executables (PIE). By default, glibc programs and tests
130 are created as position independent executables on targets that
131 support it. If the toolchain and architecture support it, static
132 executables are built as static PIE and the resulting glibc can be
133 used with the GCC option, -static-pie, which is available with GCC
134 8 or above, to create static PIE.
137 '--enable-cet=permissive'
138 Enable Intel Control-flow Enforcement Technology (CET) support.
139 When the GNU C Library is built with '--enable-cet' or
140 '--enable-cet=permissive', the resulting library is protected with
141 indirect branch tracking (IBT) and shadow stack (SHSTK). When CET
142 is enabled, the GNU C Library is compatible with all existing
143 executables and shared libraries. This feature is currently
144 supported on x86_64 and x32 with GCC 8 and binutils 2.29 or later.
145 With '--enable-cet', it is an error to dlopen a non CET enabled
146 shared library in CET enabled application. With
147 '--enable-cet=permissive', CET is disabled when dlopening a non CET
148 enabled shared library in CET enabled application.
150 NOTE: '--enable-cet' is only supported on x86_64 and x32.
152 '--enable-memory-tagging'
153 Enable memory tagging support if the architecture supports it.
154 When the GNU C Library is built with this option then the resulting
155 library will be able to control the use of tagged memory when
156 hardware support is present by use of the tunable
157 'glibc.mem.tagging'. This includes the generation of tagged memory
158 when using the 'malloc' APIs.
160 At present only AArch64 platforms with MTE provide this
161 functionality, although the library will still operate (without
162 memory tagging) on older versions of the architecture.
164 The default is to disable support for memory tagging.
167 Don't build libraries with profiling information. You may want to
168 use this option if you don't plan to do profiling.
170 '--enable-static-nss'
171 Compile static versions of the NSS (Name Service Switch) libraries.
172 This is not recommended because it defeats the purpose of NSS; a
173 program linked statically with the NSS libraries cannot be
174 dynamically reconfigured to use a different name database.
176 '--enable-hardcoded-path-in-tests'
177 By default, dynamic tests are linked to run with the installed C
178 library. This option hardcodes the newly built C library path in
179 dynamic tests so that they can be invoked directly.
181 '--disable-timezone-tools'
182 By default, time zone related utilities ('zic', 'zdump', and
183 'tzselect') are installed with the GNU C Library. If you are
184 building these independently (e.g. by using the 'tzcode' package),
185 then this option will allow disabling the install of these.
187 Note that you need to make sure the external tools are kept in sync
188 with the versions that the GNU C Library expects as the data
189 formats may change over time. Consult the 'timezone' subdirectory
192 '--enable-stack-protector'
193 '--enable-stack-protector=strong'
194 '--enable-stack-protector=all'
195 Compile the C library and all other parts of the glibc package
196 (including the threading and math libraries, NSS modules, and
197 transliteration modules) using the GCC '-fstack-protector',
198 '-fstack-protector-strong' or '-fstack-protector-all' options to
199 detect stack overruns. Only the dynamic linker and a small number
200 of routines called directly from assembler are excluded from this
204 Disable lazy binding for installed shared objects and programs.
205 This provides additional security hardening because it enables full
206 RELRO and a read-only global offset table (GOT), at the cost of
207 slightly increased program load times.
210 The file 'pt_chown' is a helper binary for 'grantpt' (*note
211 Pseudo-Terminals: Allocation.) that is installed setuid root to fix
212 up pseudo-terminal ownership on GNU/Hurd. It is not required on
213 GNU/Linux, and the GNU C Library will not use the installed
214 'pt_chown' program when configured with '--enable-pt_chown'.
217 By default, the GNU C Library is built with '-Werror'. If you wish
218 to build without this option (for example, if building with a newer
219 version of GCC than this version of the GNU C Library was tested
220 with, so new warnings cause the build with '-Werror' to fail), you
221 can configure with '--disable-werror'.
224 By default for x86_64, the GNU C Library is built with the vector
225 math library. Use this option to disable the vector math library.
227 '--disable-static-c++-tests'
228 By default, if the C++ toolchain lacks support for static linking,
229 configure fails to find the C++ header files and the glibc build
230 fails. '--disable-static-c++-link-check' allows the glibc build to
231 finish, but static C++ tests will fail if the C++ toolchain doesn't
232 have the necessary static C++ libraries. Use this option to skip
233 the static C++ tests. This option implies
234 '--disable-static-c++-link-check'.
236 '--disable-static-c++-link-check'
237 By default, if the C++ toolchain lacks support for static linking,
238 configure fails to find the C++ header files and the glibc build
239 fails. Use this option to disable the static C++ link check so
240 that the C++ header files can be located. The newly built libc.a
241 can be used to create static C++ tests if the C++ toolchain has the
242 necessary static C++ libraries.
245 Disable using 'scv' instruction for syscalls. All syscalls will
246 use 'sc' instead, even if the kernel supports 'scv'. PowerPC only.
248 '--build=BUILD-SYSTEM'
250 These options are for cross-compiling. If you specify both options
251 and BUILD-SYSTEM is different from HOST-SYSTEM, 'configure' will
252 prepare to cross-compile the GNU C Library from BUILD-SYSTEM to be
253 used on HOST-SYSTEM. You'll probably need the '--with-headers'
254 option too, and you may have to override CONFIGURE's selection of
255 the compiler and/or binutils.
257 If you only specify '--host', 'configure' will prepare for a native
258 compile but use what you specify instead of guessing what your
259 system is. This is most useful to change the CPU submodel. For
260 example, if 'configure' guesses your machine as 'i686-pc-linux-gnu'
261 but you want to compile a library for 586es, give
262 '--host=i586-pc-linux-gnu' or just '--host=i586-linux' and add the
263 appropriate compiler flags ('-mcpu=i586' will do the trick) to
266 If you specify just '--build', 'configure' will get confused.
268 '--with-pkgversion=VERSION'
269 Specify a description, possibly including a build number or build
270 date, of the binaries being built, to be included in '--version'
271 output from programs installed with the GNU C Library. For
272 example, '--with-pkgversion='FooBar GNU/Linux glibc build 123''.
273 The default value is 'GNU libc'.
276 Specify the URL that users should visit if they wish to report a
277 bug, to be included in '--help' output from programs installed with
278 the GNU C Library. The default value refers to the main
279 bug-reporting information for the GNU C Library.
281 '--enable-fortify-source'
282 '--enable-fortify-source=LEVEL'
283 Use -D_FORTIFY_SOURCE='LEVEL' to control hardening in the GNU C
284 Library. If not provided, 'LEVEL' defaults to highest possible
285 value supported by the build compiler.
287 Default is to disable fortification.
289 To build the library and related programs, type 'make'. This will
290 produce a lot of output, some of which may look like errors from 'make'
291 but aren't. Look for error messages from 'make' containing '***'.
292 Those indicate that something is seriously wrong.
294 The compilation process can take a long time, depending on the
295 configuration and the speed of your machine. Some complex modules may
296 take a very long time to compile, as much as several minutes on slower
297 machines. Do not panic if the compiler appears to hang.
299 If you want to run a parallel make, simply pass the '-j' option with
300 an appropriate numeric parameter to 'make'. You need a recent GNU
301 'make' version, though.
303 To build and run test programs which exercise some of the library
304 facilities, type 'make check'. If it does not complete successfully, do
305 not use the built library, and report a bug after verifying that the
306 problem is not already known. *Note Reporting Bugs::, for instructions
307 on reporting bugs. Note that some of the tests assume they are not
308 being run by 'root'. We recommend you compile and test the GNU C
309 Library as an unprivileged user.
311 Before reporting bugs make sure there is no problem with your system.
312 The tests (and later installation) use some pre-existing files of the
313 system such as '/etc/passwd', '/etc/nsswitch.conf' and others. These
314 files must all contain correct and sensible content.
316 Normally, 'make check' will run all the tests before reporting all
317 problems found and exiting with error status if any problems occurred.
318 You can specify 'stop-on-test-failure=y' when running 'make check' to
319 make the test run stop and exit with an error status immediately when a
322 To format the 'GNU C Library Reference Manual' for printing, type
323 'make dvi'. You need a working TeX installation to do this. The
324 distribution builds the on-line formatted version of the manual, as Info
325 files, as part of the build process. You can build them manually with
328 The library has a number of special-purpose configuration parameters
329 which you can find in 'Makeconfig'. These can be overwritten with the
330 file 'configparms'. To change them, create a 'configparms' in your
331 build directory and add values as appropriate for your system. The file
332 is included and parsed by 'make' and has to follow the conventions for
335 It is easy to configure the GNU C Library for cross-compilation by
336 setting a few variables in 'configparms'. Set 'CC' to the
337 cross-compiler for the target you configured the library for; it is
338 important to use this same 'CC' value when running 'configure', like
339 this: 'configure TARGET CC=TARGET-gcc'. Set 'BUILD_CC' to the compiler
340 to use for programs run on the build system as part of compiling the
341 library. You may need to set 'AR' to cross-compiling versions of 'ar'
342 if the native tools are not configured to work with object files for the
343 target you configured for. When cross-compiling the GNU C Library, it
344 may be tested using 'make check
345 test-wrapper="SRCDIR/scripts/cross-test-ssh.sh HOSTNAME"', where SRCDIR
346 is the absolute directory name for the main source directory and
347 HOSTNAME is the host name of a system that can run the newly built
348 binaries of the GNU C Library. The source and build directories must be
349 visible at the same locations on both the build system and HOSTNAME.
350 The 'cross-test-ssh.sh' script requires 'flock' from 'util-linux' to
351 work when GLIBC_TEST_ALLOW_TIME_SETTING environment variable is set.
353 It is also possible to execute tests, which require setting the date
354 on the target machine. Following use cases are supported:
355 * 'GLIBC_TEST_ALLOW_TIME_SETTING' is set in the environment in which
356 eligible tests are executed and have the privilege to run
357 'clock_settime'. In this case, nothing prevents those tests from
358 running in parallel, so the caller shall assure that those tests
359 are serialized or provide a proper wrapper script for them.
361 * The 'cross-test-ssh.sh' script is used and one passes the
362 '--allow-time-setting' flag. In this case, both sets
363 'GLIBC_TEST_ALLOW_TIME_SETTING' and serialization of test execution
364 are assured automatically.
366 In general, when testing the GNU C Library, 'test-wrapper' may be set
367 to the name and arguments of any program to run newly built binaries.
368 This program must preserve the arguments to the binary being run, its
369 working directory and the standard input, output and error file
370 descriptors. If 'TEST-WRAPPER env' will not work to run a program with
371 environment variables set, then 'test-wrapper-env' must be set to a
372 program that runs a newly built program with environment variable
373 assignments in effect, those assignments being specified as 'VAR=VALUE'
374 before the name of the program to be run. If multiple assignments to
375 the same variable are specified, the last assignment specified must take
376 precedence. Similarly, if 'TEST-WRAPPER env -i' will not work to run a
377 program with an environment completely empty of variables except those
378 directly assigned, then 'test-wrapper-env-only' must be set; its use has
379 the same syntax as 'test-wrapper-env', the only difference in its
380 semantics being starting with an empty set of environment variables
381 rather than the ambient set.
383 For AArch64 with SVE, when testing the GNU C Library, 'test-wrapper'
384 may be set to "SRCDIR/sysdeps/unix/sysv/linux/aarch64/vltest.py
385 VECTOR-LENGTH" to change Vector Length.
387 Installing the C Library
388 ========================
390 To install the library and its header files, and the Info files of the
391 manual, type 'make install'. This will build things, if necessary,
392 before installing them; however, you should still compile everything
393 first. If you are installing the GNU C Library as your primary C
394 library, we recommend that you shut the system down to single-user mode
395 first, and reboot afterward. This minimizes the risk of breaking things
396 when the library changes out from underneath.
398 'make install' will do the entire job of upgrading from a previous
399 installation of the GNU C Library version 2.x. There may sometimes be
400 headers left behind from the previous installation, but those are
401 generally harmless. If you want to avoid leaving headers behind you can
402 do things in the following order.
404 You must first build the library ('make'), optionally check it ('make
405 check'), switch the include directories and then install ('make
406 install'). The steps must be done in this order. Not moving the
407 directory before install will result in an unusable mixture of header
408 files from both libraries, but configuring, building, and checking the
409 library requires the ability to compile and run programs against the old
410 library. The new '/usr/include', after switching the include
411 directories and before installing the library should contain the Linux
412 headers, but nothing else. If you do this, you will need to restore any
413 headers from libraries other than the GNU C Library yourself after
414 installing the library.
416 You can install the GNU C Library somewhere other than where you
417 configured it to go by setting the 'DESTDIR' GNU standard make variable
418 on the command line for 'make install'. The value of this variable is
419 prepended to all the paths for installation. This is useful when
420 setting up a chroot environment or preparing a binary distribution. The
421 directory should be specified with an absolute file name. Installing
422 with the 'prefix' and 'exec_prefix' GNU standard make variables set is
425 The GNU C Library includes a daemon called 'nscd', which you may or
426 may not want to run. 'nscd' caches name service lookups; it can
427 dramatically improve performance with NIS+, and may help with DNS as
430 One auxiliary program, '/usr/libexec/pt_chown', is installed setuid
431 'root' if the '--enable-pt_chown' configuration option is used. This
432 program is invoked by the 'grantpt' function; it sets the permissions on
433 a pseudoterminal so it can be used by the calling process. If you are
434 using a Linux kernel with the 'devpts' filesystem enabled and mounted at
435 '/dev/pts', you don't need this program.
437 After installation you should configure the time zone ruleset and
438 install locales for your system. The time zone ruleset ensures that
439 timestamps are processed correctly for your location. The locales
440 ensure that the display of information on your system matches the
441 expectations of your language and geographic region.
443 The GNU C Library is able to use two kinds of localization
444 information sources, the first is a locale database named
445 'locale-archive' which is generally installed as
446 '/usr/lib/locale/locale-archive'. The locale archive has the benefit of
447 taking up less space and being very fast to load, but only if you plan
448 to install sixty or more locales. If you plan to install one or two
449 locales you can instead install individual locales into their self-named
450 directories e.g. '/usr/lib/locale/en_US.utf8'. For example to install
451 the German locale using the character set for UTF-8 with name 'de_DE'
452 into the locale archive issue the command 'localedef -i de_DE -f UTF-8
453 de_DE', and to install just the one locale issue the command 'localedef
454 --no-archive -i de_DE -f UTF-8 de_DE'. To configure all locales that
455 are supported by the GNU C Library, you can issue from your build
456 directory the command 'make localedata/install-locales' to install all
457 locales into the locale archive or 'make
458 localedata/install-locale-files' to install all locales as files in the
459 default configured locale installation directory (derived from
460 '--prefix' or '--localedir'). To install into an alternative system
461 root use 'DESTDIR' e.g. 'make localedata/install-locale-files
462 DESTDIR=/opt/glibc', but note that this does not change the configured
465 To configure the time zone ruleset, set the 'TZ' environment
466 variable. The script 'tzselect' helps you to select the right value.
467 As an example, for Germany, 'tzselect' would tell you to use
468 'TZ='Europe/Berlin''. For a system wide installation (the given paths
469 are for an installation with '--prefix=/usr'), link the time zone file
470 which is in '/usr/share/zoneinfo' to the file '/etc/localtime'. For
471 Germany, you might execute 'ln -s /usr/share/zoneinfo/Europe/Berlin
474 Recommended Tools for Compilation
475 =================================
477 We recommend installing the following GNU tools before attempting to
478 build the GNU C Library:
480 * GNU 'make' 4.0 or newer
482 As of release time, GNU 'make' 4.4.1 is the newest verified to work
483 to build the GNU C Library.
487 GCC 6.2 or higher is required. In general it is recommended to use
488 the newest version of the compiler that is known to work for
489 building the GNU C Library, as newer compilers usually produce
490 better code. As of release time, GCC 14.1 is the newest compiler
491 verified to work to build the GNU C Library.
493 For PowerPC 64-bits little-endian (powerpc64le), a GCC version with
494 support for '-mno-gnu-attribute', '-mabi=ieeelongdouble', and
495 '-mabi=ibmlongdouble' is required. Likewise, the compiler must
496 also support passing '-mlong-double-128' with the preceding
497 options. As of release, this implies GCC 7.4 and newer (excepting
498 GCC 7.5.0, see GCC PR94200). These additional features are
499 required for building the GNU C Library with support for IEEE long
502 For ARC architecture builds, GCC 8.3 or higher is needed.
504 For s390x architecture builds, GCC 7.1 or higher is needed (See gcc
507 For AArch64 architecture builds with mathvec enabled, GCC 10 or
508 higher is needed due to dependency on arm_sve.h.
510 For multi-arch support it is recommended to use a GCC which has
511 been built with support for GNU indirect functions. This ensures
512 that correct debugging information is generated for functions
513 selected by IFUNC resolvers. This support can either be enabled by
514 configuring GCC with '--enable-gnu-indirect-function', or by
515 enabling it by default by setting 'default_gnu_indirect_function'
516 variable for a particular architecture in the GCC source file
519 You can use whatever compiler you like to compile programs that use
522 Check the FAQ for any special compiler issues on particular
525 * GNU 'binutils' 2.25 or later
527 You must use GNU 'binutils' (as and ld) to build the GNU C Library.
528 No other assembler or linker has the necessary functionality at the
529 moment. As of release time, GNU 'binutils' 2.42 is the newest
530 verified to work to build the GNU C Library.
532 For PowerPC 64-bits little-endian (powerpc64le), 'objcopy' is
533 required to support '--update-section'. This option requires
534 binutils 2.26 or newer.
536 ARC architecture needs 'binutils' 2.32 or higher for TLS related
539 * GNU 'texinfo' 4.7 or later
541 To correctly translate and install the Texinfo documentation you
542 need this version of the 'texinfo' package. Earlier versions do
543 not understand all the tags used in the document, and the
544 installation mechanism for the info files is not present or works
545 differently. As of release time, 'texinfo' 7.1 is the newest
546 verified to work to build the GNU C Library.
548 * GNU 'awk' 3.1.2, or higher
550 'awk' is used in several places to generate files. Some 'gawk'
551 extensions are used, including the 'asorti' function, which was
552 introduced in version 3.1.2 of 'gawk'. As of release time, 'gawk'
553 version 5.3.0 is the newest verified to work to build the GNU C
556 * GNU 'bison' 2.7 or later
558 'bison' is used to generate the 'yacc' parser code in the 'intl'
559 subdirectory. As of release time, 'bison' version 3.8.2 is the
560 newest verified to work to build the GNU C Library.
564 Perl is not required, but if present it is used in some tests and
565 the 'mtrace' program, to build the GNU C Library manual. As of
566 release time 'perl' version 5.40.0 is the newest verified to work
567 to build the GNU C Library.
569 * GNU 'sed' 3.02 or newer
571 'Sed' is used in several places to generate files. Most scripts
572 work with any version of 'sed'. As of release time, 'sed' version
573 4.9 is the newest verified to work to build the GNU C Library.
575 * Python 3.4 or later
577 Python is required to build the GNU C Library. As of release time,
578 Python 3.12 is the newest verified to work for building and testing
583 The pretty printer tests drive GDB through test programs and
584 compare its output to the printers'. PExpect is used to capture
585 the output of GDB, and should be compatible with the Python version
586 in your system. As of release time PExpect 4.9.0 is the newest
587 verified to work to test the pretty printers.
589 * The Python 'abnf' module.
591 This module is optional and used to verify some ABNF grammars in
592 the manual. Version 2.2.0 has been confirmed to work as expected.
593 A missing 'abnf' module does not reduce the test coverage of the
596 * GDB 7.8 or later with support for Python 2.7/3.4 or later
598 GDB itself needs to be configured with Python support in order to
599 use the pretty printers. Notice that your system having Python
600 available doesn't imply that GDB supports it, nor that your
601 system's Python and GDB's have the same version. As of release
602 time GNU 'debugger' 14.2 is the newest verified to work to test the
605 Unless Python, PExpect and GDB with Python support are present, the
606 printer tests will report themselves as 'UNSUPPORTED'. Notice that
607 some of the printer tests require the GNU C Library to be compiled
608 with debugging symbols.
610 If you change any of the 'configure.ac' files you will also need
612 * GNU 'autoconf' 2.72 (exactly)
614 and if you change any of the message translation files you will need
616 * GNU 'gettext' 0.10.36 or later
618 As of release time, GNU 'gettext' version 0.22.4 is the newest
619 version verified to work to build the GNU C Library.
621 You may also need these packages if you upgrade your source tree using
622 patches, although we try to avoid this.
624 Specific advice for GNU/Linux systems
625 =====================================
627 If you are installing the GNU C Library on GNU/Linux systems, you need
628 to have the header files from a 3.2 or newer kernel around for
629 reference. These headers must be installed using 'make
630 headers_install'; the headers present in the kernel source directory are
631 not suitable for direct use by the GNU C Library. You do not need to
632 use that kernel, just have its headers installed where the GNU C Library
633 can access them, referred to here as INSTALL-DIRECTORY. The easiest way
634 to do this is to unpack it in a directory such as
635 '/usr/src/linux-VERSION'. In that directory, run 'make headers_install
636 INSTALL_HDR_PATH=INSTALL-DIRECTORY'. Finally, configure the GNU C
637 Library with the option '--with-headers=INSTALL-DIRECTORY/include'. Use
638 the most recent kernel you can get your hands on. (If you are
639 cross-compiling the GNU C Library, you need to specify
640 'ARCH=ARCHITECTURE' in the 'make headers_install' command, where
641 ARCHITECTURE is the architecture name used by the Linux kernel, such as
644 After installing the GNU C Library, you may need to remove or rename
645 directories such as '/usr/include/linux' and '/usr/include/asm', and
646 replace them with copies of directories such as 'linux' and 'asm' from
647 'INSTALL-DIRECTORY/include'. All directories present in
648 'INSTALL-DIRECTORY/include' should be copied, except that the GNU C
649 Library provides its own version of '/usr/include/scsi'; the files
650 provided by the kernel should be copied without replacing those provided
651 by the GNU C Library. The 'linux', 'asm' and 'asm-generic' directories
652 are required to compile programs using the GNU C Library; the other
653 directories describe interfaces to the kernel but are not required if
654 not compiling programs using those interfaces. You do not need to copy
655 kernel headers if you did not specify an alternate kernel header source
656 using '--with-headers'.
658 The Filesystem Hierarchy Standard for GNU/Linux systems expects some
659 components of the GNU C Library installation to be in '/lib' and some in
660 '/usr/lib'. This is handled automatically if you configure the GNU C
661 Library with '--prefix=/usr'. If you set some other prefix or allow it
662 to default to '/usr/local', then all the components are installed there.
664 As of release time, Linux version 6.6 is the newest stable version
665 verified to work to build the GNU C Library.
670 There are probably bugs in the GNU C Library. There are certainly
671 errors and omissions in this manual. If you report them, they will get
672 fixed. If you don't, no one will ever know about them and they will
673 remain unfixed for all eternity, if not longer.
675 It is a good idea to verify that the problem has not already been
676 reported. Bugs are documented in two places: The file 'BUGS' describes
677 a number of well known bugs and the central GNU C Library bug tracking
678 system has a WWW interface at <https://sourceware.org/bugzilla/>. The
679 WWW interface gives you access to open and closed reports. A closed
680 report normally includes a patch or a hint on solving the problem.
682 To report a bug, first you must find it. With any luck, this will be
683 the hard part. Once you've found a bug, make sure it's really a bug. A
684 good way to do this is to see if the GNU C Library behaves the same way
685 some other C library does. If so, probably you are wrong and the
686 libraries are right (but not necessarily). If not, one of the libraries
687 is probably wrong. It might not be the GNU C Library. Many historical
688 Unix C libraries permit things that we don't, such as closing a file
691 If you think you have found some way in which the GNU C Library does
692 not conform to the ISO and POSIX standards (*note Standards and
693 Portability::), that is definitely a bug. Report it!
695 Once you're sure you've found a bug, try to narrow it down to the
696 smallest test case that reproduces the problem. In the case of a C
697 library, you really only need to narrow it down to one library function
698 call, if possible. This should not be too difficult.
700 The final step when you have a simple test case is to report the bug.
701 Do this at <https://www.gnu.org/software/libc/bugs.html>.
703 If you are not sure how a function should behave, and this manual
704 doesn't tell you, that's a bug in the manual. Report that too! If the
705 function's behavior disagrees with the manual, then either the library
706 or the manual has a bug, so report the disagreement. If you find any
707 errors or omissions in this manual, please report them to the bug
708 database. If you refer to specific sections of the manual, please
709 include the section names for easier identification.