INSTALL

   1 Installing the GNU C Library
   2 ****************************
   3
   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
   7 installation.
   8
   9    You will need recent versions of several GNU tools: definitely GCC
  10 and GNU Make, and possibly others.  *Note Tools for Compilation::,
  11 below.
  12
  13 Configuring and compiling the GNU C Library
  14 ===========================================
  15
  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.
  22
  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
  25
  26      $ ../glibc-VERSION/configure ARGS...
  27
  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.
  31
  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)
  37 for GNU/Hurd systems.
  38
  39    It may also be useful to set the CC and CFLAGS variables in the
  40 environment when running 'configure'.  CC selects the C compiler that
  41 will be used, and CFLAGS sets optimization options for the compiler.
  42
  43    The following list describes all of the available options for
  44 'configure':
  45
  46 '--prefix=DIRECTORY'
  47      Install machine-independent data files in subdirectories of
  48      'DIRECTORY'.  The default is to install in '/usr/local'.
  49
  50 '--exec-prefix=DIRECTORY'
  51      Install the library and other machine-dependent files in
  52      subdirectories of 'DIRECTORY'.  The default is to the '--prefix'
  53      directory if that option is specified, or '/usr/local' otherwise.
  54
  55 '--with-headers=DIRECTORY'
  56      Look for kernel header files in DIRECTORY, not '/usr/include'.  The
  57      GNU C Library needs information from the kernel's header files
  58      describing the interface to the kernel.  The GNU C Library will
  59      normally look in '/usr/include' for them, but if you specify this
  60      option, it will look in DIRECTORY instead.
  61
  62      This option is primarily of use on a system where the headers in
  63      '/usr/include' come from an older version of the GNU C Library.
  64      Conflicts can occasionally happen in this case.  You can also use
  65      this option if you want to compile the GNU C Library with a newer
  66      set of kernel headers than the ones found in '/usr/include'.
  67
  68 '--enable-kernel=VERSION'
  69      This option is currently only useful on GNU/Linux systems.  The
  70      VERSION parameter should have the form X.Y.Z and describes the
  71      smallest version of the Linux kernel the generated library is
  72      expected to support.  The higher the VERSION number is, the less
  73      compatibility code is added, and the faster the code gets.
  74
  75 '--with-binutils=DIRECTORY'
  76      Use the binutils (assembler and linker) in 'DIRECTORY', not the
  77      ones the C compiler would default to.  You can use this option if
  78      the default binutils on your system cannot deal with all the
  79      constructs in the GNU C Library.  In that case, 'configure' will
  80      detect the problem and suppress these constructs, so that the
  81      library will still be usable, but functionality may be lost--for
  82      example, you can't build a shared libc with old binutils.
  83
  84 '--disable-shared'
  85      Don't build shared libraries even if it is possible.  Not all
  86      systems support shared libraries; you need ELF support and
  87      (currently) the GNU linker.
  88
  89 '--enable-static-pie'
  90      Enable static position independent executable (static PIE) support.
  91      Static PIE is similar to static executable, but can be loaded at
  92      any address without help from a dynamic linker.  All static
  93      programs as well as static tests are built as static PIE, except
  94      for those marked with no-pie.  The resulting glibc can be used with
  95      the GCC option, -static-pie, which is available with GCC 8 or
  96      above, to create static PIE.
  97
  98 '--disable-profile'
  99      Don't build libraries with profiling information.  You may want to
 100      use this option if you don't plan to do profiling.
 101
 102 '--enable-static-nss'
 103      Compile static versions of the NSS (Name Service Switch) libraries.
 104      This is not recommended because it defeats the purpose of NSS; a
 105      program linked statically with the NSS libraries cannot be
 106      dynamically reconfigured to use a different name database.
 107
 108 '--enable-hardcoded-path-in-tests'
 109      By default, dynamic tests are linked to run with the installed C
 110      library.  This option hardcodes the newly built C library path in
 111      dynamic tests so that they can be invoked directly.
 112
 113 '--disable-timezone-tools'
 114      By default, timezone related utilities ('zic', 'zdump', and
 115      'tzselect') are installed with the GNU C Library.  If you are
 116      building these independently (e.g.  by using the 'tzcode' package),
 117      then this option will allow disabling the install of these.
 118
 119      Note that you need to make sure the external tools are kept in sync
 120      with the versions that the GNU C Library expects as the data
 121      formats may change over time.  Consult the 'timezone' subdirectory
 122      for more details.
 123
 124 '--enable-stack-protector'
 125 '--enable-stack-protector=strong'
 126 '--enable-stack-protector=all'
 127      Compile the C library and all other parts of the glibc package
 128      (including the threading and math libraries, NSS modules, and
 129      transliteration modules) using the GCC '-fstack-protector',
 130      '-fstack-protector-strong' or '-fstack-protector-all' options to
 131      detect stack overruns.  Only the dynamic linker and a small number
 132      of routines called directly from assembler are excluded from this
 133      protection.
 134
 135 '--enable-bind-now'
 136      Disable lazy binding for installed shared objects.  This provides
 137      additional security hardening because it enables full RELRO and a
 138      read-only global offset table (GOT), at the cost of slightly
 139      increased program load times.
 140
 141 '--enable-pt_chown'
 142      The file 'pt_chown' is a helper binary for 'grantpt' (*note
 143      Pseudo-Terminals: Allocation.) that is installed setuid root to fix
 144      up pseudo-terminal ownership.  It is not built by default because
 145      systems using the Linux kernel are commonly built with the 'devpts'
 146      filesystem enabled and mounted at '/dev/pts', which manages
 147      pseudo-terminal ownership automatically.  By using
 148      '--enable-pt_chown', you may build 'pt_chown' and install it setuid
 149      and owned by 'root'.  The use of 'pt_chown' introduces additional
 150      security risks to the system and you should enable it only if you
 151      understand and accept those risks.
 152
 153 '--disable-werror'
 154      By default, the GNU C Library is built with '-Werror'.  If you wish
 155      to build without this option (for example, if building with a newer
 156      version of GCC than this version of the GNU C Library was tested
 157      with, so new warnings cause the build with '-Werror' to fail), you
 158      can configure with '--disable-werror'.
 159
 160 '--disable-mathvec'
 161      By default for x86_64, the GNU C Library is built with the vector
 162      math library.  Use this option to disable the vector math library.
 163
 164 '--enable-tunables'
 165      Tunables support allows additional library parameters to be
 166      customized at runtime.  This feature is enabled by default.  This
 167      option can take the following values:
 168
 169      'yes'
 170           This is the default if no option is passed to configure.  This
 171           enables tunables and selects the default frontend (currently
 172           'valstring').
 173
 174      'no'
 175           This option disables tunables.
 176
 177      'valstring'
 178           This enables tunables and selects the 'valstring' frontend for
 179           tunables.  This frontend allows users to specify tunables as a
 180           colon-separated list in a single environment variable
 181           'GLIBC_TUNABLES'.
 182
 183 '--enable-obsolete-nsl'
 184      By default, libnsl is only built as shared library for backward
 185      compatibility and the NSS modules libnss_compat, libnss_nis and
 186      libnss_nisplus are not built at all.  Use this option to enable
 187      libnsl with all depending NSS modules and header files.
 188
 189 '--disable-experimental-malloc'
 190      By default, a per-thread cache is enabled in 'malloc'.  While this
 191      cache can be disabled on a per-application basis using tunables
 192      (set glibc.malloc.tcache_count to zero), this option can be used to
 193      remove it from the build completely.
 194
 195 '--build=BUILD-SYSTEM'
 196 '--host=HOST-SYSTEM'
 197      These options are for cross-compiling.  If you specify both options
 198      and BUILD-SYSTEM is different from HOST-SYSTEM, 'configure' will
 199      prepare to cross-compile the GNU C Library from BUILD-SYSTEM to be
 200      used on HOST-SYSTEM.  You'll probably need the '--with-headers'
 201      option too, and you may have to override CONFIGURE's selection of
 202      the compiler and/or binutils.
 203
 204      If you only specify '--host', 'configure' will prepare for a native
 205      compile but use what you specify instead of guessing what your
 206      system is.  This is most useful to change the CPU submodel.  For
 207      example, if 'configure' guesses your machine as 'i686-pc-linux-gnu'
 208      but you want to compile a library for 586es, give
 209      '--host=i586-pc-linux-gnu' or just '--host=i586-linux' and add the
 210      appropriate compiler flags ('-mcpu=i586' will do the trick) to
 211      CFLAGS.
 212
 213      If you specify just '--build', 'configure' will get confused.
 214
 215 '--with-pkgversion=VERSION'
 216      Specify a description, possibly including a build number or build
 217      date, of the binaries being built, to be included in '--version'
 218      output from programs installed with the GNU C Library.  For
 219      example, '--with-pkgversion='FooBar GNU/Linux glibc build 123''.
 220      The default value is 'GNU libc'.
 221
 222 '--with-bugurl=URL'
 223      Specify the URL that users should visit if they wish to report a
 224      bug, to be included in '--help' output from programs installed with
 225      the GNU C Library.  The default value refers to the main
 226      bug-reporting information for the GNU C Library.
 227
 228    To build the library and related programs, type 'make'.  This will
 229 produce a lot of output, some of which may look like errors from 'make'
 230 but aren't.  Look for error messages from 'make' containing '***'.
 231 Those indicate that something is seriously wrong.
 232
 233    The compilation process can take a long time, depending on the
 234 configuration and the speed of your machine.  Some complex modules may
 235 take a very long time to compile, as much as several minutes on slower
 236 machines.  Do not panic if the compiler appears to hang.
 237
 238    If you want to run a parallel make, simply pass the '-j' option with
 239 an appropriate numeric parameter to 'make'.  You need a recent GNU
 240 'make' version, though.
 241
 242    To build and run test programs which exercise some of the library
 243 facilities, type 'make check'.  If it does not complete successfully, do
 244 not use the built library, and report a bug after verifying that the
 245 problem is not already known.  *Note Reporting Bugs::, for instructions
 246 on reporting bugs.  Note that some of the tests assume they are not
 247 being run by 'root'.  We recommend you compile and test the GNU C
 248 Library as an unprivileged user.
 249
 250    Before reporting bugs make sure there is no problem with your system.
 251 The tests (and later installation) use some pre-existing files of the
 252 system such as '/etc/passwd', '/etc/nsswitch.conf' and others.  These
 253 files must all contain correct and sensible content.
 254
 255    Normally, 'make check' will run all the tests before reporting all
 256 problems found and exiting with error status if any problems occurred.
 257 You can specify 'stop-on-test-failure=y' when running 'make check' to
 258 make the test run stop and exit with an error status immediately when a
 259 failure occurs.
 260
 261    The GNU C Library pretty printers come with their own set of scripts
 262 for testing, which run together with the rest of the testsuite through
 263 'make check'.  These scripts require the following tools to run
 264 successfully:
 265
 266    * Python 2.7.6/3.4.3 or later
 267
 268      Python is required for running the printers' test scripts.
 269
 270    * PExpect 4.0
 271
 272      The printer tests drive GDB through test programs and compare its
 273      output to the printers'.  PExpect is used to capture the output of
 274      GDB, and should be compatible with the Python version in your
 275      system.
 276
 277    * GDB 7.8 or later with support for Python 2.7.6/3.4.3 or later
 278
 279      GDB itself needs to be configured with Python support in order to
 280      use the pretty printers.  Notice that your system having Python
 281      available doesn't imply that GDB supports it, nor that your
 282      system's Python and GDB's have the same version.
 283
 284 If these tools are absent, the printer tests will report themselves as
 285 'UNSUPPORTED'.  Notice that some of the printer tests require the GNU C
 286 Library to be compiled with debugging symbols.
 287
 288    To format the 'GNU C Library Reference Manual' for printing, type
 289 'make dvi'.  You need a working TeX installation to do this.  The
 290 distribution builds the on-line formatted version of the manual, as Info
 291 files, as part of the build process.  You can build them manually with
 292 'make info'.
 293
 294    The library has a number of special-purpose configuration parameters
 295 which you can find in 'Makeconfig'.  These can be overwritten with the
 296 file 'configparms'.  To change them, create a 'configparms' in your
 297 build directory and add values as appropriate for your system.  The file
 298 is included and parsed by 'make' and has to follow the conventions for
 299 makefiles.
 300
 301    It is easy to configure the GNU C Library for cross-compilation by
 302 setting a few variables in 'configparms'.  Set 'CC' to the
 303 cross-compiler for the target you configured the library for; it is
 304 important to use this same 'CC' value when running 'configure', like
 305 this: 'CC=TARGET-gcc configure TARGET'.  Set 'BUILD_CC' to the compiler
 306 to use for programs run on the build system as part of compiling the
 307 library.  You may need to set 'AR' to cross-compiling versions of 'ar'
 308 if the native tools are not configured to work with object files for the
 309 target you configured for.  When cross-compiling the GNU C Library, it
 310 may be tested using 'make check
 311 test-wrapper="SRCDIR/scripts/cross-test-ssh.sh HOSTNAME"', where SRCDIR
 312 is the absolute directory name for the main source directory and
 313 HOSTNAME is the host name of a system that can run the newly built
 314 binaries of the GNU C Library.  The source and build directories must be
 315 visible at the same locations on both the build system and HOSTNAME.
 316
 317    In general, when testing the GNU C Library, 'test-wrapper' may be set
 318 to the name and arguments of any program to run newly built binaries.
 319 This program must preserve the arguments to the binary being run, its
 320 working directory and the standard input, output and error file
 321 descriptors.  If 'TEST-WRAPPER env' will not work to run a program with
 322 environment variables set, then 'test-wrapper-env' must be set to a
 323 program that runs a newly built program with environment variable
 324 assignments in effect, those assignments being specified as 'VAR=VALUE'
 325 before the name of the program to be run.  If multiple assignments to
 326 the same variable are specified, the last assignment specified must take
 327 precedence.  Similarly, if 'TEST-WRAPPER env -i' will not work to run a
 328 program with an environment completely empty of variables except those
 329 directly assigned, then 'test-wrapper-env-only' must be set; its use has
 330 the same syntax as 'test-wrapper-env', the only difference in its
 331 semantics being starting with an empty set of environment variables
 332 rather than the ambient set.
 333
 334 Installing the C Library
 335 ========================
 336
 337 To install the library and its header files, and the Info files of the
 338 manual, type 'make install'.  This will build things, if necessary,
 339 before installing them; however, you should still compile everything
 340 first.  If you are installing the GNU C Library as your primary C
 341 library, we recommend that you shut the system down to single-user mode
 342 first, and reboot afterward.  This minimizes the risk of breaking things
 343 when the library changes out from underneath.
 344
 345    'make install' will do the entire job of upgrading from a previous
 346 installation of the GNU C Library version 2.x.  There may sometimes be
 347 headers left behind from the previous installation, but those are
 348 generally harmless.  If you want to avoid leaving headers behind you can
 349 do things in the following order.
 350
 351    You must first build the library ('make'), optionally check it ('make
 352 check'), switch the include directories and then install ('make
 353 install').  The steps must be done in this order.  Not moving the
 354 directory before install will result in an unusable mixture of header
 355 files from both libraries, but configuring, building, and checking the
 356 library requires the ability to compile and run programs against the old
 357 library.  The new '/usr/include', after switching the include
 358 directories and before installing the library should contain the Linux
 359 headers, but nothing else.  If you do this, you will need to restore any
 360 headers from libraries other than the GNU C Library yourself after
 361 installing the library.
 362
 363    You can install the GNU C Library somewhere other than where you
 364 configured it to go by setting the 'DESTDIR' GNU standard make variable
 365 on the command line for 'make install'.  The value of this variable is
 366 prepended to all the paths for installation.  This is useful when
 367 setting up a chroot environment or preparing a binary distribution.  The
 368 directory should be specified with an absolute file name.  Installing
 369 with the 'prefix' and 'exec_prefix' GNU standard make variables set is
 370 not supported.
 371
 372    The GNU C Library includes a daemon called 'nscd', which you may or
 373 may not want to run.  'nscd' caches name service lookups; it can
 374 dramatically improve performance with NIS+, and may help with DNS as
 375 well.
 376
 377    One auxiliary program, '/usr/libexec/pt_chown', is installed setuid
 378 'root' if the '--enable-pt_chown' configuration option is used.  This
 379 program is invoked by the 'grantpt' function; it sets the permissions on
 380 a pseudoterminal so it can be used by the calling process.  If you are
 381 using a Linux kernel with the 'devpts' filesystem enabled and mounted at
 382 '/dev/pts', you don't need this program.
 383
 384    After installation you might want to configure the timezone and
 385 locale installation of your system.  The GNU C Library comes with a
 386 locale database which gets configured with 'localedef'.  For example, to
 387 set up a German locale with name 'de_DE', simply issue the command
 388 'localedef -i de_DE -f ISO-8859-1 de_DE'.  To configure all locales that
 389 are supported by the GNU C Library, you can issue from your build
 390 directory the command 'make localedata/install-locales'.
 391
 392    To configure the locally used timezone, set the 'TZ' environment
 393 variable.  The script 'tzselect' helps you to select the right value.
 394 As an example, for Germany, 'tzselect' would tell you to use
 395 'TZ='Europe/Berlin''.  For a system wide installation (the given paths
 396 are for an installation with '--prefix=/usr'), link the timezone file
 397 which is in '/usr/share/zoneinfo' to the file '/etc/localtime'.  For
 398 Germany, you might execute 'ln -s /usr/share/zoneinfo/Europe/Berlin
 399 /etc/localtime'.
 400
 401 Recommended Tools for Compilation
 402 =================================
 403
 404 We recommend installing the following GNU tools before attempting to
 405 build the GNU C Library:
 406
 407    * GNU 'make' 3.79 or newer
 408
 409      You need the latest version of GNU 'make'.  Modifying the GNU C
 410      Library to work with other 'make' programs would be so difficult
 411      that we recommend you port GNU 'make' instead.  *Really.*  We
 412      recommend GNU 'make' version 3.79.  All earlier versions have
 413      severe bugs or lack features.
 414
 415    * GCC 4.9 or newer
 416
 417      GCC 4.9 or higher is required.  In general it is recommended to use
 418      the newest version of the compiler that is known to work for
 419      building the GNU C Library, as newer compilers usually produce
 420      better code.  As of release time, GCC 7.1 is the newest compiler
 421      verified to work to build the GNU C Library.
 422
 423      For PowerPC 64-bits little-endian (powerpc64le), GCC 6.2 or higher
 424      is required.  This compiler version is the first to provide the
 425      features required for building the GNU C Library with support for
 426      '_Float128'.
 427
 428      For multi-arch support it is recommended to use a GCC which has
 429      been built with support for GNU indirect functions.  This ensures
 430      that correct debugging information is generated for functions
 431      selected by IFUNC resolvers.  This support can either be enabled by
 432      configuring GCC with '--enable-gnu-indirect-function', or by
 433      enabling it by default by setting 'default_gnu_indirect_function'
 434      variable for a particular architecture in the GCC source file
 435      'gcc/config.gcc'.
 436
 437      You can use whatever compiler you like to compile programs that use
 438      the GNU C Library.
 439
 440      Check the FAQ for any special compiler issues on particular
 441      platforms.
 442
 443    * GNU 'binutils' 2.25 or later
 444
 445      You must use GNU 'binutils' (as and ld) to build the GNU C Library.
 446      No other assembler or linker has the necessary functionality at the
 447      moment.  As of release time, GNU 'binutils' 2.27 is the newest
 448      verified to work to build the GNU C Library.
 449
 450    * GNU 'texinfo' 4.7 or later
 451
 452      To correctly translate and install the Texinfo documentation you
 453      need this version of the 'texinfo' package.  Earlier versions do
 454      not understand all the tags used in the document, and the
 455      installation mechanism for the info files is not present or works
 456      differently.  As of release time, 'texinfo' 6.0 is the newest
 457      verified to work to build the GNU C Library.
 458
 459    * GNU 'awk' 3.1.2, or higher
 460
 461      'awk' is used in several places to generate files.  Some 'gawk'
 462      extensions are used, including the 'asorti' function, which was
 463      introduced in version 3.1.2 of 'gawk'.  As of release time, 'gawk'
 464      version 4.1.3 is the newest verified to work to build the GNU C
 465      Library.
 466
 467    * GNU 'bison' 2.7 or later
 468
 469      'bison' is used to generate the 'yacc' parser code in the 'intl'
 470      subdirectory.
 471
 472    * Perl 5
 473
 474      Perl is not required, but it is used if present to test the
 475      installation.  We may decide to use it elsewhere in the future.
 476
 477    * GNU 'sed' 3.02 or newer
 478
 479      'Sed' is used in several places to generate files.  Most scripts
 480      work with any version of 'sed'.  As of release time, 'sed' version
 481      4.2.2 is the newest verified to work to build the GNU C Library.
 482
 483 If you change any of the 'configure.ac' files you will also need
 484
 485    * GNU 'autoconf' 2.69 (exactly)
 486
 487 and if you change any of the message translation files you will need
 488
 489    * GNU 'gettext' 0.10.36 or later
 490
 491 You may also need these packages if you upgrade your source tree using
 492 patches, although we try to avoid this.
 493
 494 Specific advice for GNU/Linux systems
 495 =====================================
 496
 497 If you are installing the GNU C Library on GNU/Linux systems, you need
 498 to have the header files from a 3.2 or newer kernel around for
 499 reference.  (For the ia64 architecture, you need version 3.2.18 or newer
 500 because this is the first version with support for the 'accept4' system
 501 call.)  These headers must be installed using 'make headers_install';
 502 the headers present in the kernel source directory are not suitable for
 503 direct use by the GNU C Library.  You do not need to use that kernel,
 504 just have its headers installed where the GNU C Library can access them,
 505 referred to here as INSTALL-DIRECTORY.  The easiest way to do this is to
 506 unpack it in a directory such as '/usr/src/linux-VERSION'.  In that
 507 directory, run 'make headers_install
 508 INSTALL_HDR_PATH=INSTALL-DIRECTORY'.  Finally, configure the GNU C
 509 Library with the option '--with-headers=INSTALL-DIRECTORY/include'.  Use
 510 the most recent kernel you can get your hands on.  (If you are
 511 cross-compiling the GNU C Library, you need to specify
 512 'ARCH=ARCHITECTURE' in the 'make headers_install' command, where
 513 ARCHITECTURE is the architecture name used by the Linux kernel, such as
 514 'x86' or 'powerpc'.)
 515
 516    After installing the GNU C Library, you may need to remove or rename
 517 directories such as '/usr/include/linux' and '/usr/include/asm', and
 518 replace them with copies of directories such as 'linux' and 'asm' from
 519 'INSTALL-DIRECTORY/include'.  All directories present in
 520 'INSTALL-DIRECTORY/include' should be copied, except that the GNU C
 521 Library provides its own version of '/usr/include/scsi'; the files
 522 provided by the kernel should be copied without replacing those provided
 523 by the GNU C Library.  The 'linux', 'asm' and 'asm-generic' directories
 524 are required to compile programs using the GNU C Library; the other
 525 directories describe interfaces to the kernel but are not required if
 526 not compiling programs using those interfaces.  You do not need to copy
 527 kernel headers if you did not specify an alternate kernel header source
 528 using '--with-headers'.
 529
 530    The Filesystem Hierarchy Standard for GNU/Linux systems expects some
 531 components of the GNU C Library installation to be in '/lib' and some in
 532 '/usr/lib'.  This is handled automatically if you configure the GNU C
 533 Library with '--prefix=/usr'.  If you set some other prefix or allow it
 534 to default to '/usr/local', then all the components are installed there.
 535
 536 Reporting Bugs
 537 ==============
 538
 539 There are probably bugs in the GNU C Library.  There are certainly
 540 errors and omissions in this manual.  If you report them, they will get
 541 fixed.  If you don't, no one will ever know about them and they will
 542 remain unfixed for all eternity, if not longer.
 543
 544    It is a good idea to verify that the problem has not already been
 545 reported.  Bugs are documented in two places: The file 'BUGS' describes
 546 a number of well known bugs and the central GNU C Library bug tracking
 547 system has a WWW interface at <https://sourceware.org/bugzilla/>.  The
 548 WWW interface gives you access to open and closed reports.  A closed
 549 report normally includes a patch or a hint on solving the problem.
 550
 551    To report a bug, first you must find it.  With any luck, this will be
 552 the hard part.  Once you've found a bug, make sure it's really a bug.  A
 553 good way to do this is to see if the GNU C Library behaves the same way
 554 some other C library does.  If so, probably you are wrong and the
 555 libraries are right (but not necessarily).  If not, one of the libraries
 556 is probably wrong.  It might not be the GNU C Library.  Many historical
 557 Unix C libraries permit things that we don't, such as closing a file
 558 twice.
 559
 560    If you think you have found some way in which the GNU C Library does
 561 not conform to the ISO and POSIX standards (*note Standards and
 562 Portability::), that is definitely a bug.  Report it!
 563
 564    Once you're sure you've found a bug, try to narrow it down to the
 565 smallest test case that reproduces the problem.  In the case of a C
 566 library, you really only need to narrow it down to one library function
 567 call, if possible.  This should not be too difficult.
 568
 569    The final step when you have a simple test case is to report the bug.
 570 Do this at <http://www.gnu.org/software/libc/bugs.html>.
 571
 572    If you are not sure how a function should behave, and this manual
 573 doesn't tell you, that's a bug in the manual.  Report that too!  If the
 574 function's behavior disagrees with the manual, then either the library
 575 or the manual has a bug, so report the disagreement.  If you find any
 576 errors or omissions in this manual, please report them to the bug
 577 database.  If you refer to specific sections of the manual, please
 578 include the section names for easier identification.