INSTALL

   1 Appendix A Installing the GNU C Library
   2 ***************************************
   3
   4 Before you do anything else, you should read the file `FAQ' located at
   5 the top level of the source tree.  This file answers common questions
   6 and describes problems you may experience with compilation and
   7 installation.  It is updated more frequently than this manual.
   8
   9    Features can be added to GNU Libc via "add-on" bundles.  These are
  10 separate tar files, which you unpack into the top level of the source
  11 tree.  Then you give `configure' the `--enable-add-ons' option to
  12 activate them, and they will be compiled into the library.  As of the
  13 2.2 release, one important component of glibc is distributed as
  14 "official" add-ons: the linuxthreads add-on.  Unless you are doing an
  15 unusual installation, you should get this.
  16
  17    Support for POSIX threads is maintained by someone else, so it's in a
  18 separate package.  It is only available for GNU/Linux systems, but this
  19 will change in the future.  Get it from the same place you got the main
  20 bundle; the file is `glibc-linuxthreads-VERSION.tar.gz'.
  21
  22    You will need recent versions of several GNU tools: definitely GCC
  23 and GNU Make, and possibly others.  *Note Tools for Compilation::,
  24 below.
  25
  26 A.1 Configuring and compiling GNU Libc
  27 ======================================
  28
  29 GNU libc can be compiled in the source directory, but we strongly advise
  30 building it in a separate build directory.  For example, if you have
  31 unpacked the glibc sources in `/src/gnu/glibc-2.3', create a directory
  32 `/src/gnu/glibc-build' to put the object files in.  This allows
  33 removing the whole build directory in case an error occurs, which is the
  34 safest way to get a fresh start and should always be done.
  35
  36    From your object directory, run the shell script `configure' located
  37 at the top level of the source tree.  In the scenario above, you'd type
  38
  39      $ ../glibc-2.3/configure ARGS...
  40
  41    Please note that even if you're building in a separate build
  42 directory, the compilation needs to modify a few files in the source
  43 directory, especially some files in the manual subdirectory.
  44
  45 `configure' takes many options, but you can get away with knowing only
  46 two: `--prefix' and `--enable-add-ons'.  The `--prefix' option tells
  47 `configure' where you want glibc installed. This defaults to
  48 `/usr/local'.  The `--enable-add-ons' option tells `configure' to use
  49 all the add-on bundles it finds in the source directory.  Since
  50 important functionality is provided in add-ons, you should always
  51 specify this option.
  52
  53    It may also be useful to set the CC and CFLAGS variables in the
  54 environment when running `configure'.  CC selects the C compiler that
  55 will be used, and CFLAGS sets optimization options for the compiler.
  56
  57    The following list describes all of the available options for
  58 `configure':
  59
  60 `--prefix=DIRECTORY'
  61      Install machine-independent data files in subdirectories of
  62      `DIRECTORY'.  The default is to install in `/usr/local'.
  63
  64 `--exec-prefix=DIRECTORY'
  65      Install the library and other machine-dependent files in
  66      subdirectories of `DIRECTORY'.  The default is to the `--prefix'
  67      directory if that option is specified, or `/usr/local' otherwise.
  68
  69 `--with-headers=DIRECTORY'
  70      Look for kernel header files in DIRECTORY, not `/usr/include'.
  71      Glibc needs information from the kernel's private header files.
  72      Glibc will normally look in `/usr/include' for them, but if you
  73      specify this option, it will look in DIRECTORY instead.
  74
  75      This option is primarily of use on a system where the headers in
  76      `/usr/include' come from an older version of glibc.  Conflicts can
  77      occasionally happen in this case.  Note that Linux libc5 qualifies
  78      as an older version of glibc.  You can also use this option if you
  79      want to compile glibc with a newer set of kernel headers than the
  80      ones found in `/usr/include'.
  81
  82 `--enable-add-ons[=LIST]'
  83      Enable add-on packages in your source tree.  If this option is
  84      specified with no list, it enables all the add-on packages it
  85      finds.  If you do not wish to use some add-on packages that you
  86      have present in your source tree, give this option a list of the
  87      add-ons that you _do_ want used, like this:
  88      `--enable-add-ons=linuxthreads'
  89
  90 `--enable-kernel=VERSION'
  91      This option is currently only useful on GNU/Linux systems.  The
  92      VERSION parameter should have the form X.Y.Z and describes the
  93      smallest version of the Linux kernel the generated library is
  94      expected to support.  The higher the VERSION number is, the less
  95      compatibility code is added, and the faster the code gets.
  96
  97 `--with-binutils=DIRECTORY'
  98      Use the binutils (assembler and linker) in `DIRECTORY', not the
  99      ones the C compiler would default to.  You can use this option if
 100      the default binutils on your system cannot deal with all the
 101      constructs in the GNU C library.  In that case, `configure' will
 102      detect the problem and suppress these constructs, so that the
 103      library will still be usable, but functionality may be lost--for
 104      example, you can't build a shared libc with old binutils.
 105
 106 `--without-fp'
 107      Use this option if your computer lacks hardware floating-point
 108      support and your operating system does not emulate an FPU.
 109
 110      these
 111
 112 `--disable-shared'
 113      Don't build shared libraries even if it is possible.  Not all
 114      systems support shared libraries; you need ELF support and
 115      (currently) the GNU linker.
 116
 117 `--disable-profile'
 118      Don't build libraries with profiling information.  You may want to
 119      use this option if you don't plan to do profiling.
 120
 121 `--enable-omitfp'
 122      Use maximum optimization for the normal (static and shared)
 123      libraries, and compile separate static libraries with debugging
 124      information and no optimization.  We recommend not doing this.
 125      The extra optimization doesn't gain you much, it may provoke
 126      compiler bugs, and you won't be able to trace bugs through the C
 127      library.
 128
 129 `--disable-versioning'
 130      Don't compile the shared libraries with symbol version information.
 131      Doing this will make the resulting library incompatible with old
 132      binaries, so it's not recommended.
 133
 134 `--enable-static-nss'
 135      Compile static versions of the NSS (Name Service Switch) libraries.
 136      This is not recommended because it defeats the purpose of NSS; a
 137      program linked statically with the NSS libraries cannot be
 138      dynamically reconfigured to use a different name database.
 139
 140 `--without-tls'
 141      By default the C library is built with support for thread-local
 142      storage if the used tools support it.  By using `--without-tls'
 143      this can be prevented though there generally is no reason since it
 144      creates compatibility problems.
 145
 146 `--build=BUILD-SYSTEM'
 147 `--host=HOST-SYSTEM'
 148      These options are for cross-compiling.  If you specify both
 149      options and BUILD-SYSTEM is different from HOST-SYSTEM, `configure'
 150      will prepare to cross-compile glibc from BUILD-SYSTEM to be used
 151      on HOST-SYSTEM.  You'll probably need the `--with-headers' option
 152      too, and you may have to override CONFIGURE's selection of the
 153      compiler and/or binutils.
 154
 155      If you only specify `--host', `configure' will prepare for a
 156      native compile but use what you specify instead of guessing what
 157      your system is. This is most useful to change the CPU submodel.
 158      For example, if `configure' guesses your machine as
 159      `i586-pc-linux-gnu' but you want to compile a library for 386es,
 160      give `--host=i386-pc-linux-gnu' or just `--host=i386-linux' and add
 161      the appropriate compiler flags (`-mcpu=i386' will do the trick) to
 162      CFLAGS.
 163
 164      If you specify just `--build', `configure' will get confused.
 165
 166    To build the library and related programs, type `make'.  This will
 167 produce a lot of output, some of which may look like errors from `make'
 168 but isn't.  Look for error messages from `make' containing `***'.
 169 Those indicate that something is seriously wrong.
 170
 171    The compilation process can take several hours.  Expect at least two
 172 hours for the default configuration on i586 for GNU/Linux.  For Hurd,
 173 times are much longer.  Some complex modules may take a very long time
 174 to compile, as much as several minutes on slower machines.  Do not
 175 panic if the compiler appears to hang.
 176
 177    If you want to run a parallel make, simply pass the `-j' option with
 178 an appropriate numeric parameter to `make'.  You need a recent GNU
 179 `make' version, though.
 180
 181    To build and run test programs which exercise some of the library
 182 facilities, type `make check'.  If it does not complete successfully,
 183 do not use the built library, and report a bug after verifying that the
 184 problem is not already known.  *Note Reporting Bugs::, for instructions
 185 on reporting bugs.  Note that some of the tests assume they are not
 186 being run by `root'.  We recommend you compile and test glibc as an
 187 unprivileged user.
 188
 189    Before reporting bugs make sure there is no problem with your system.
 190 The tests (and later installation) use some pre-existing files of the
 191 system such as `/etc/passwd', `/etc/nsswitch.conf' and others.  These
 192 files must all contain correct and sensible content.
 193
 194    To format the `GNU C Library Reference Manual' for printing, type
 195 `make dvi'.  You need a working TeX installation to do this.  The
 196 distribution already includes the on-line formatted version of the
 197 manual, as Info files.  You can regenerate those with `make info', but
 198 it shouldn't be necessary.
 199
 200    The library has a number of special-purpose configuration parameters
 201 which you can find in `Makeconfig'.  These can be overwritten with the
 202 file `configparms'.  To change them, create a `configparms' in your
 203 build directory and add values as appropriate for your system.  The
 204 file is included and parsed by `make' and has to follow the conventions
 205 for makefiles.
 206
 207    It is easy to configure the GNU C library for cross-compilation by
 208 setting a few variables in `configparms'.  Set `CC' to the
 209 cross-compiler for the target you configured the library for; it is
 210 important to use this same `CC' value when running `configure', like
 211 this: `CC=TARGET-gcc configure TARGET'.  Set `BUILD_CC' to the compiler
 212 to use for programs run on the build system as part of compiling the
 213 library.  You may need to set `AR' and `RANLIB' to cross-compiling
 214 versions of `ar' and `ranlib' if the native tools are not configured to
 215 work with object files for the target you configured for.
 216
 217 A.2 Installing the C Library
 218 ============================
 219
 220 To install the library and its header files, and the Info files of the
 221 manual, type `env LANGUAGE=C LC_ALL=C make install'.  This will build
 222 things, if necessary, before installing them; however, you should still
 223 compile everything first.  If you are installing glibc as your primary
 224 C library, we recommend that you shut the system down to single-user
 225 mode first, and reboot afterward.  This minimizes the risk of breaking
 226 things when the library changes out from underneath.
 227
 228    If you're upgrading from Linux libc5 or some other C library, you
 229 need to replace the `/usr/include' with a fresh directory before
 230 installing it.  The new `/usr/include' should contain the Linux
 231 headers, but nothing else.
 232
 233    You must first build the library (`make'), optionally check it
 234 (`make check'), switch the include directories and then install (`make
 235 install').  The steps must be done in this order.  Not moving the
 236 directory before install will result in an unusable mixture of header
 237 files from both libraries, but configuring, building, and checking the
 238 library requires the ability to compile and run programs against the old
 239 library.
 240
 241    If you are upgrading from a previous installation of glibc 2.0 or
 242 2.1, `make install' will do the entire job.  You do not need to remove
 243 the old includes - if you want to do so anyway you must then follow the
 244 order given above.
 245
 246    You may also need to reconfigure GCC to work with the new library.
 247 The easiest way to do that is to figure out the compiler switches to
 248 make it work again (`-Wl,--dynamic-linker=/lib/ld-linux.so.2' should
 249 work on GNU/Linux systems) and use them to recompile gcc.  You can also
 250 edit the specs file (`/usr/lib/gcc-lib/TARGET/VERSION/specs'), but that
 251 is a bit of a black art.
 252
 253    You can install glibc somewhere other than where you configured it
 254 to go by setting the `install_root' variable on the command line for
 255 `make install'.  The value of this variable is prepended to all the
 256 paths for installation.  This is useful when setting up a chroot
 257 environment or preparing a binary distribution.  The directory should be
 258 specified with an absolute file name.
 259
 260    Glibc 2.2 includes a daemon called `nscd', which you may or may not
 261 want to run.  `nscd' caches name service lookups; it can dramatically
 262 improve performance with NIS+, and may help with DNS as well.
 263
 264    One auxiliary program, `/usr/libexec/pt_chown', is installed setuid
 265 `root'.  This program is invoked by the `grantpt' function; it sets the
 266 permissions on a pseudoterminal so it can be used by the calling
 267 process.  This means programs like `xterm' and `screen' do not have to
 268 be setuid to get a pty.  (There may be other reasons why they need
 269 privileges.)  If you are using a 2.1 or newer Linux kernel with the
 270 `devptsfs' or `devfs' filesystems providing pty slaves, you don't need
 271 this program; otherwise you do.  The source for `pt_chown' is in
 272 `login/programs/pt_chown.c'.
 273
 274    After installation you might want to configure the timezone and
 275 locale installation of your system.  The GNU C library comes with a
 276 locale database which gets configured with `localedef'.  For example, to
 277 set up a German locale with name `de_DE', simply issue the command
 278 `localedef -i de_DE -f ISO-8859-1 de_DE'.  To configure all locales
 279 that are supported by glibc, you can issue from your build directory the
 280 command `make localedata/install-locales'.
 281
 282    To configure the locally used timezone, set the `TZ' environment
 283 variable.  The script `tzselect' helps you to select the right value.
 284 As an example, for Germany, `tzselect' would tell you to use
 285 `TZ='Europe/Berlin''.  For a system wide installation (the given paths
 286 are for an installation with `--prefix=/usr'), link the timezone file
 287 which is in `/usr/share/zoneinfo' to the file `/etc/localtime'.  For
 288 Germany, you might execute `ln -s /usr/share/zoneinfo/Europe/Berlin
 289 /etc/localtime'.
 290
 291 A.3 Recommended Tools for Compilation
 292 =====================================
 293
 294 We recommend installing the following GNU tools before attempting to
 295 build the GNU C library:
 296
 297    * GNU `make' 3.79 or newer
 298
 299      You need the latest version of GNU `make'.  Modifying the GNU C
 300      Library to work with other `make' programs would be so difficult
 301      that we recommend you port GNU `make' instead.  *Really.*  We
 302      recommend GNU `make' version 3.79.  All earlier versions have
 303      severe bugs or lack features.
 304
 305    * GCC 3.2 or newer
 306
 307      The GNU C library can only be compiled with the GNU C compiler
 308      family.  As of the 2.3 release, GCC 3.2 or higher is required.  As
 309      of this writing, GCC 3.2 is the compiler we advise to use.
 310
 311      You can use whatever compiler you like to compile programs that
 312      use GNU libc, but be aware that both GCC 2.7 and 2.8 have bugs in
 313      their floating-point support that may be triggered by the math
 314      library.
 315
 316      Check the FAQ for any special compiler issues on particular
 317      platforms.
 318
 319    * GNU `binutils' 2.13 or later
 320
 321      You must use GNU `binutils' (as and ld) to build the GNU C library.
 322      No other assembler or linker has the necessary functionality at the
 323      moment.
 324
 325    * GNU `texinfo' 3.12f
 326
 327      To correctly translate and install the Texinfo documentation you
 328      need this version of the `texinfo' package.  Earlier versions do
 329      not understand all the tags used in the document, and the
 330      installation mechanism for the info files is not present or works
 331      differently.
 332
 333    * GNU `awk' 3.0, or some other POSIX awk
 334
 335      `Awk' is used in several places to generate files.  The scripts
 336      should work with any POSIX-compliant `awk' implementation; `gawk'
 337      3.0 and `mawk' 1.3 are known to work.
 338
 339    * Perl 5
 340
 341      Perl is not required, but it is used if present to test the
 342      installation.  We may decide to use it elsewhere in the future.
 343
 344    * GNU `sed' 3.02 or newer
 345
 346      `Sed' is used in several places to generate files.  Most scripts
 347      work with any version of `sed'.  The known exception is the script
 348      `po2test.sed' in the `intl' subdirectory which is used to generate
 349      `msgs.h' for the test suite.  This script works correctly only
 350      with GNU `sed' 3.02.  If you like to run the test suite, you
 351      should definitely upgrade `sed'.
 352
 353
 354 If you change any of the `configure.in' files you will also need
 355
 356    * GNU `autoconf' 2.53 or higher
 357
 358 and if you change any of the message translation files you will need
 359
 360    * GNU `gettext' 0.10.36 or later
 361
 362 You may also need these packages if you upgrade your source tree using
 363 patches, although we try to avoid this.
 364
 365 A.4 Supported Configurations
 366 ============================
 367
 368 The GNU C Library currently supports configurations that match the
 369 following patterns:
 370
 371      alpha*-*-linux
 372      arm-*-linux
 373      cris-*-linux
 374      hppa-*-linux
 375      iX86-*-gnu
 376      iX86-*-linux
 377      ia64-*-linux
 378      m68k-*-linux
 379      mips*-*-linux
 380      powerpc-*-linux
 381      s390-*-linux
 382      s390x-*-linux
 383      sparc-*-linux
 384      sparc64-*-linux
 385      x86_64-*-linux
 386
 387    Former releases of this library (version 2.1 and/or 2.0) used to run
 388 on the following configurations:
 389
 390      arm-*-linuxaout
 391      arm-*-none
 392
 393    Very early releases (version 1.09.1 and perhaps earlier versions)
 394 used to run on the following configurations:
 395
 396      alpha-dec-osf1
 397      alpha-*-linuxecoff
 398      iX86-*-bsd4.3
 399      iX86-*-isc2.2
 400      iX86-*-isc3.N
 401      iX86-*-sco3.2
 402      iX86-*-sco3.2v4
 403      iX86-*-sysv
 404      iX86-*-sysv4
 405      iX86-force_cpu386-none
 406      iX86-sequent-bsd
 407      i960-nindy960-none
 408      m68k-hp-bsd4.3
 409      m68k-mvme135-none
 410      m68k-mvme136-none
 411      m68k-sony-newsos3
 412      m68k-sony-newsos4
 413      m68k-sun-sunos4.N
 414      mips-dec-ultrix4.N
 415      mips-sgi-irix4.N
 416      sparc-sun-solaris2.N
 417      sparc-sun-sunos4.N
 418
 419    Since no one has volunteered to test and fix these configurations,
 420 they are not supported at the moment.  They probably don't compile;
 421 they definitely don't work anymore.  Porting the library is not hard.
 422 If you are interested in doing a port, please contact the glibc
 423 maintainers.  Start at `http://www.gnu.org/software/libc/' and read the
 424 references there on how to go about getting involved and contacting the
 425 developers.
 426
 427    Valid cases of `iX86' include `i386', `i486', `i586', and `i686'.
 428 All of those configurations produce a library that can run on this
 429 processor and newer processors.  The GCC compiler by default generates
 430 code that's optimized for the machine it's configured for and will use
 431 the instructions available on that machine.  For example if your GCC is
 432 configured for `i686', gcc will optimize for `i686' and might issue
 433 some `i686' specific instructions.  To generate code for other models,
 434 you have to configure for that model and give GCC the appropriate
 435 `-march=' and `-mcpu=' compiler switches via CFLAGS.
 436
 437 A.5 Specific advice for GNU/Linux systems
 438 =========================================
 439
 440 If you are installing GNU libc on a GNU/Linux system, you need to have
 441 the header files from a 2.2 or newer kernel around for reference.  For
 442 some architectures, like ia64, sh and hppa, you need at least headers
 443 from kernel 2.3.99 (sh and hppa) or 2.4.0 (ia64).  You do not need to
 444 use that kernel, just have its headers where glibc can access at them.
 445 The easiest way to do this is to unpack it in a directory such as
 446 `/usr/src/linux-2.2.1'.  In that directory, run `make config' and
 447 accept all the defaults.  Then run `make include/linux/version.h'.
 448 Finally, configure glibc with the option
 449 `--with-headers=/usr/src/linux-2.2.1/include'.  Use the most recent
 450 kernel you can get your hands on.
 451
 452    An alternate tactic is to unpack the 2.2 kernel and run `make
 453 config' as above; then, rename or delete `/usr/include', create a new
 454 `/usr/include', and make symbolic links of `/usr/include/linux' and
 455 `/usr/include/asm' into the kernel sources.  You can then configure
 456 glibc with no special options.  This tactic is recommended if you are
 457 upgrading from libc5, since you need to get rid of the old header files
 458 anyway.
 459
 460    After installing GNU libc, you may need to remove or rename
 461 `/usr/include/linux' and `/usr/include/asm', and replace them with
 462 copies of `include/linux' and `include/asm-$ARCHITECTURE' taken from
 463 the Linux source package which supplied kernel headers for building the
 464 library.  ARCHITECTURE will be the machine architecture for which the
 465 library was built, such as `i386' or `alpha'.  You do not need to do
 466 this if you did not specify an alternate kernel header source using
 467 `--with-headers'.  The intent here is that these directories should be
 468 copies of, *not* symlinks to, the kernel headers used to build the
 469 library.
 470
 471    Note that `/usr/include/net' and `/usr/include/scsi' should *not* be
 472 symlinks into the kernel sources.  GNU libc provides its own versions
 473 of these files.
 474
 475    GNU/Linux expects some components of the libc installation to be in
 476 `/lib' and some in `/usr/lib'.  This is handled automatically if you
 477 configure glibc with `--prefix=/usr'.  If you set some other prefix or
 478 allow it to default to `/usr/local', then all the components are
 479 installed there.
 480
 481    If you are upgrading from libc5, you need to recompile every shared
 482 library on your system against the new library for the sake of new code,
 483 but keep the old libraries around for old binaries to use.  This is
 484 complicated and difficult.  Consult the Glibc2 HOWTO at
 485 `http://www.imaxx.net/~thrytis/glibc' for details.
 486
 487    You cannot use `nscd' with 2.0 kernels, due to bugs in the
 488 kernel-side thread support.  `nscd' happens to hit these bugs
 489 particularly hard, but you might have problems with any threaded
 490 program.
 491
 492 A.6 Reporting Bugs
 493 ==================
 494
 495 There are probably bugs in the GNU C library.  There are certainly
 496 errors and omissions in this manual.  If you report them, they will get
 497 fixed.  If you don't, no one will ever know about them and they will
 498 remain unfixed for all eternity, if not longer.
 499
 500    It is a good idea to verify that the problem has not already been
 501 reported.  Bugs are documented in two places: The file `BUGS' describes
 502 a number of well known bugs and the bug tracking system has a WWW
 503 interface at `http://sources.redhat.com/bugzilla/'.  The WWW interface
 504 gives you access to open and closed reports.  A closed report normally
 505 includes a patch or a hint on solving the problem.
 506
 507    To report a bug, first you must find it.  With any luck, this will
 508 be the hard part.  Once you've found a bug, make sure it's really a
 509 bug.  A good way to do this is to see if the GNU C library behaves the
 510 same way some other C library does.  If so, probably you are wrong and
 511 the libraries are right (but not necessarily).  If not, one of the
 512 libraries is probably wrong.  It might not be the GNU library.  Many
 513 historical Unix C libraries permit things that we don't, such as
 514 closing a file twice.
 515
 516    If you think you have found some way in which the GNU C library does
 517 not conform to the ISO and POSIX standards (*note Standards and
 518 Portability::), that is definitely a bug.  Report it!
 519
 520    Once you're sure you've found a bug, try to narrow it down to the
 521 smallest test case that reproduces the problem.  In the case of a C
 522 library, you really only need to narrow it down to one library function
 523 call, if possible.  This should not be too difficult.
 524
 525    The final step when you have a simple test case is to report the bug.
 526 Do this using the WWW interface to the bug database.
 527
 528    If you are not sure how a function should behave, and this manual
 529 doesn't tell you, that's a bug in the manual.  Report that too!  If the
 530 function's behavior disagrees with the manual, then either the library
 531 or the manual has a bug, so report the disagreement.  If you find any
 532 errors or omissions in this manual, please report them to the bug
 533 database.  If you refer to specific sections of the manual, please
 534 include the section names for easier identification.
 535