Glibc 2 HOWTO

Table of Contents



  1. Introduction.

     1.1 About glibc 2.
     1.2 About this document.
     1.3 Recent changes in this document.

  2. Choosing your installation method.

  3. Getting the library.

  4. Installing as a test library.

     4.1 Compiling and installing.
        4.1.1 Prerequisites.
        4.1.2 Extracting the source.
        4.1.3 Configuring.
        4.1.4 Compiling and installing.
     4.2 Updating the dynamic loader.
     4.3 Configuring for gcc.
     4.4 Updating header file links.
     4.5 Testing your installation.

  5. Installing as the primary C library.

     5.1 Building the library from source.
        5.1.1 Prerequisites.
        5.1.2 Extracting the source.
        5.1.3 Configuring.
        5.1.4 Compiling.
     5.2 Preparing for installation.
     5.3 Installing from the binary package.
     5.4 Installing from the source.
     5.5 Updating the gcc specs.
     5.6 Testing your installation.

  6. Compiling with the non-primary libc.

     6.1 A warning when using non-primary libcs.
     6.2 Compiling programs with a test glibc.
     6.3 Compiling programs with libc 5 when glibc is primary library.

  7. Compiling C++ programs.

     7.1 Installing libg++ for a test glibc install.
     7.2 Installing libg++ for a primary glibc install.
     7.3 Compiling C++ programs with the non-primary libc.

  8. Problems.

     8.1 Host names do not resolve.

  9. Reporting bugs.

  10. Sample specs file.

  11. Miscellanea.

     11.1 Further information.
        11.1.1 Web pages.
        11.1.2 Newgroups.
        11.1.3 Mailing lists.
     11.2 Credits.
     11.3 Feedback.
     11.4 Copyright.


  ______________________________________________________________________

  1.  Introduction.



  1.1.  About glibc 2.


  Glibc 2 is the latest version of the GNU C Library. It currently runs
  unmodified on GNU Hurd systems and Linux i386, m68k, and alpha
  systems.  Support for Linux PowerPC, MIPS, Sparc, Sparc 64, and Arm
  will be in version 2.1.  In the future support for other architectures
  and operating systems will be added.

  On Linux, glibc 2 is used as the libc with major version 6, the
  successor of the Linux libc 5.  It is intended by the Linux libc
  developers to eventually replace libc 5.  As of 2.0.6, glibc is
  considered production quality.  Version 2.1 (due out in the near
  future) will be ready for main stream use along with adding more ports
  and features.

  There are three optional add-ons available for glibc 2:

     Crypt
        The UFC-crypt package.  It is seperate  because of export
        restrictions.

     LinuxThreads
        An implementation of the Posix 1003.1c "pthread" interface.

     Locale data
        Contains the data needed to build the locale data files to use
        the internationalization features of the glibc.

  The crypt and LinuxThreads add-ons are strongly recommended... not
  using them risks to be incompatible with the libraries of other
  systems.  (If you do not wish to use them, you must add the option
  --disable-sanity-checks when you run configure.)


  1.2.  About this document.


  This HOWTO covers installing the glibc 2 library on an existing Linux
  system.  It is tailored for users of Intel based systems currently
  using libc 5, but users of other systems and alternate libraries (such
  as glibc 1) should be able to use this information by substituting the
  proper filenames and architecture names in the appropriate places.

  The latest copy of this HOWTO can be found as part of the Linux
  Documentation Project <http://sunsite.unc.edu/LDP> or from
  <http://www.imaxx.net/~thrytis/glibc/Glibc2-HOWTO.html>.


  1.3.  Recent changes in this document.


  Differences between version 1.6 and 1.5:

  o  Fixed the install instructions of the binary glibc package.

  Differences between version 1.5 and 1.4:

  o  Indexing added Ed Bailey.

  o  Changed my email address.



  2.  Choosing your installation method.


  There are a few ways to install glibc.  You can install the libraries
  as a test, using the existing libraries as the default but letting you
  try the new libraries by using different options when compiling your
  program.  Installing in this way also makes it easy to remove glibc in
  the future (though any program linked with glibc will no longer work
  after the libraries are removed). Using glibc as a test library
  requires you to compile the libraries from source.  There is no binary
  distribution for installing libraries this way.  This installation is
  described in ``Installing as a test library''.

  The other way described in this document to install is using glibc as
  your primary library.  All new programs that you compile on your
  system will use glibc, though you can link programs with your old
  libraries using different options while compiling.  You can either
  install the libraries from binaries, or compile the library yourself.
  If you want to change optimization or configuration options, or use an
  add-on which is not distributed as a binary package, you must get the
  source distribution and compile.  This installation procedure is
  described in ``Installing as the primary C library''.

  Frodo Looijaard describes yet another way of installing glibc.  His
  method involves installing glibc as a secondary library and setting up
  a cross compiler to compile using glibc.  The installation procedure
  for this method is more complicated then the test library install
  described in this document, but allows for easier compiling when
  linking to glibc.  This method is described in his Installing glibc-2
  on Linux <http://huizen.dds.nl/~frodol/glibc/> document.

  If you are currently running Debian 1.3 but do not want to upgrade to
  the unstable version of Debian to use glibc, the Debian libc5 to libc6
  Mini-HOWTO <http://www.gate.net/~storm/FAQ/libc5-libc6-Mini-
  HOWTO.html> describes how to use Debian packages to upgrade your
  system.

  If you are installing glibc 2 on an important system, you might want
  to use the test install.  Even if there are no bugs, some programs
  will need to be modified before they will compile due to changes in
  function prototypes and types.



  3.  Getting the library.


  The glibc 2 consists of the glibc package and three optional add-on
  packages, LinuxThreads, Locale, and Crypt.  The source can be found at

  o  <ftp://prep.ai.mit.edu/pub/gnu/glibc-2.0.6.tar.gz>

  o  <ftp://prep.ai.mit.edu/pub/gnu/glibc-linuxthreads-2.0.6.tar.gz>

  o  <ftp://prep.ai.mit.edu/pub/gnu/glibc-localedata-2.0.6.tar.gz>

  o  <ftp://prep.ai.mit.edu/pub/gnu/glibc-crypt-2.0.6.tar.gz>

  It will take about 150 MB of disk space for the full compile and
  install.  The basic binary install of just the core library package is
  about 50 MB.

  Binary packages for 2.0.6 are not available.  Version 2.0.4 binary
  packages are available for i386 and m68k, and version 2.0.1 for the
  alpha can be found at

  o  Intel x86:

  o  <ftp://prep.ai.mit.edu/pub/gnu/glibc-2.0.4.bin.i386.tar.gz>

  o  <ftp://prep.ai.mit.edu/pub/gnu/glibc-crypt-2.0.4.bin.i386.tar.gz>

  o  Alpha:

  o  <ftp://prep.ai.mit.edu/pub/gnu/glibc-2.0.1.bin.alpha-linux.tar.gz>

  o  <ftp://prep.ai.mit.edu/pub/gnu/glibc-crypt-2.0.1.bin.alpha-
     linux.tar.gz>

  o  m68k:

  o  <ftp://prep.ai.mit.edu/pub/gnu/glibc-2.0.4-m68k-linux.bin.tar.gz>

  o  <ftp://prep.ai.mit.edu/pub/gnu/glibc-crypt-2.0.4-m68k-
     linux.bin.tar.gz>

     There are export restrictions on the crypt add-on.  Non-US users
     should get it from  <ftp://ftp.ifi.uio.no/pub/gnu>.

  If you are running a Red Hat distribution, you can get rpms for glibc
  2 from <ftp://ftp.redhat.com/pub/redhat/>.  Glibc 2 is the primary C
  library for the new Red Hat distribution 5.0.

  If you are running a Debian distribution, you can get the packages for
  glibc 2 from  <ftp://ftp.debian.org/debian/dists/unstable/main/>.  The
  files are named libc6.  Glibc 2 is now part of the base package of the
  hamm version of Debian, and will be the primary libc when Debian 2.0
  is released.



  4.  Installing as a test library.


  This section covers installing glibc 2 as a test library.  Anything
  you compile will be linked to your existing libraries unless you give
  some extra parameters to link to the new libraries.  It appears that
  the paths are compiled into quite a few files, so you probably have to
  install the library from source.


  4.1.  Compiling and installing.



  4.1.1.  Prerequisites.



  o  About 150 MB free disk space

  o  GNU make 3.75

  o  gcc >= 2.7.2 (better 2.7.2.1)

  o  binutils 2.8.1 (for alpha you need a snapshot)


  o  bash 2.0

  o  autoconf 2.12 (if you change configure.in)

  o  texinfo 3.11

  On an i586@133 with 64 MB of RAM, it takes about 3 hours to compile
  with full libraries with add-ons.  On a loaded i686@200, it takes
  about half an hour.


  4.1.2.  Extracting the source.


  You need to extract the source from the archives so you can compile
  it.  The best way to do this is:


        tar xzf glibc-2.0.6.tar.gz
        cd glibc-2.0.6
        tar xzf ../glibc-linuxthreads-2.0.6.tar.gz
        tar xzf ../glibc-crypt-2.0.6.tar.gz
        tar xzf ../glibc-localedata-2.0.6.tar.gz



  This will put linuxthreads, crypt, and localedata directories in the
  glibc-2.0.6 directory where configure can find these add-ons.


  4.1.3.  Configuring.


  In the glibc-2.0.6 directory, create a directory named compile, and cd
  into it.  All work will be done in this directory, which will simplify
  cleaning up.  (The developers have not been very concerned with
  getting 'make clean' perfect yet.)


        mkdir compile
        cd compile



  Run ../configure.  To use the add-on packages, you need to specify
  them with --enable-add-ons, such as --enable-add-ons=linux-
  threads,crypt,localedata.  You also need to choose a destination
  directory to install to.  /usr/i486-linuxglibc2 is a good choice.  The
  configure line for this would be:


        ../configure --enable-add-ons=linuxthreads,crypt,localedata --prefix=/usr/i486-linuxglibc2



  4.1.4.  Compiling and installing.



  To compile and verify, run:


        make
        make check



  If the 'make check' succeeds, install the library as root (while still
  in the compile/ directory):


        make install



  4.2.  Updating the dynamic loader.



  1. Create a link from the new ld.so to /lib/ld-linux.so.2:


        ln -s /usr/i486-linuxglibc2/lib/ld-linux.so.2 /lib/ld-linux.so.2



  This is the only library where the location is fixed once a program is
  linked, and using a link in /lib will ease upgrading to glibc as your
  primary C library when the stable version is released.

  2. Edit /etc/ld.so.conf.  You need to add path to the lib directory
     the new libraries reside in at the end of the file, which will be
     <prefix>/lib, such as /usr/i486-linuxglibc2/lib for the choice
     above.  After you have modified /etc/ld.so.conf, run


        ldconfig -v



  4.3.  Configuring for gcc.

  The last step of installation is updating /usr/lib/gcc-lib so gcc
  knows how to use the new libraries.  First you need to duplicate the
  existing configuration.  To find out which configuration is current,
  use the -v option of gcc:


        % gcc -v
        Reading specs from /usr/lib/gcc-lib/i486-unknown-linux/2.7.2.2/specs
        gcc version 2.7.2.2



  In this case, i486-unknown-linux is the system, and 2.7.2.2 is the
  version.  You need to copy the /usr/lib/gcc-lib/<system> to the new
  test system directory:


        cd /usr/lib/gcc-lib/
        cp -r i486-unknown-linux i486-linuxglibc2



  Change into your new test system directory and version directory


        cd /usr/lib/gcc-lib/i486-linuxglibc2/2.7.2.2



  and edit the file specs found in this directory.  In this file, change
  /lib/ld-linux.so.1 to /lib/ld-linux.so.2.  You also need to remove all
  expressions %{...:-lgmon} in the file, since glibc does not use the
  gmon library for profiling.  A sample specs file can be found in the
  ``Sample specs file'' section.


  4.4.  Updating header file links.


  You need create links in your new include directory to other include
  directories:


        cd /usr/i486-linuxglibc2/include
        ln -s /usr/src/linux/include/linux
        ln -s /usr/src/linux/include/asm
        ln -s /usr/X11R6/include/X11



  You might also have other libraries such as ncurses which need their
  header files put in this directory.  You should copy or link the files
  from /usr/include.  (Some libraries may need to be recompiled with
  glibc2 in order to work with it.  In these cases, just compile and
  install the package to /usr/i486-linuxglibc2.)


  4.5.  Testing your installation.


  To test the installation, create the following program in a file
  glibc.c:


        #include <stdio.h>

        main()
        {
            printf("hello world!\n");
        }


  and compile with the options of "-b <base install directory> -nostdinc
  -I<install directory>/include -I/usr/lib/gcc-lib/<new system dir>/<gcc
  version>/include":


        % gcc -b i486-linuxglibc2 -nostdinc -I/usr/i486-linuxglibc2/include -I/usr/lib/gcc-lib/i486-linuxglibc2/2.7.2.2/include glibc.c -o glibc



  Use ldd to verify the program was linked with glibc2, and not your old
  libc:


        % ldd glibc
        libc.so.6 => /usr/i486-linuxglibc2/lib/libc-2.0.6.so (0x4000d000)
        /lib/ld-linux.so.2 => /lib/ld-linux.so.2 (0x40000000)



  If it compiles, the links check out, and it generates "hello world!"
  when run, the installation succeeded.



  5.  Installing as the primary C library.


  This section covers installing glibc 2 as your primary C library.  Any
  new programs you compile will be linked with this library, unless you
  use special compile options to link with another version.

  If you are are using Redhat or Debian and have downloaded the
  appropriate rpm or deb files, see the Redhat or Debian installion
  instructions.  You can then skip this section.



  5.1.  Building the library from source.


  This section explains how to compile glibc 2 and add-ons from the
  sources.  You must compile the library if you want to change
  optimization or configuration options or use a package you do not have
  the binaries for.


  5.1.1.  Prerequisites.



  o  About 150 MB free disk space

  o  GNU make 3.75

  o  gcc >= 2.7.2 (better 2.7.2.1)

  o  binutils 2.8.1 (for alpha you need a snapshot)

  o  bash 2.0


  o  autoconf 2.12 (if you change configure.in)

  o  texinfo 3.11

  On an i586@133 with 64 MB of RAM, it takes about 3 hours to compile
  with full libraries with add-ons.  On a loaded i686@200, it takes
  about half an hour.


  5.1.2.  Extracting the source.


  You need to extract the source from the archives so you can compile
  it.  The best way to do this is:


        tar xzf glibc-2.0.6.tar.gz
        cd glibc-2.0.6
        tar xzf ../glibc-linuxthreads-2.0.6.tar.gz
        tar xzf ../glibc-crypt-2.0.6.tar.gz
        tar xzf ../glibc-localedata-2.0.6.tar.gz



  This will put linuxthreads, crypt, and localedata directories in the
  glibc-2.0.6 directory where configure can find these add-ons.


  5.1.3.  Configuring.


  In the glibc-2.0.6 directory, create a directory named compile, and cd
  into it.  All work will be done in this directory, which will simplify
  cleaning up.  (The developers have not been very concerned with
  getting 'make clean' perfect yet.)


       mkdir compile
       cd compile



  Run ../configure.  To use the add-on packages, you need to specify
  them with --enable-add-ons, such as --enable-add-ons=linux-
  threads,crypt,localedata.  You probably will also want to specify
  paths where it will be installed.  To match the standard linux distri-
  butions, specify --prefix=/usr.  (When a prefix of /usr is specified
  on a linux system, configure knows to adjust other paths to place
  libc.so and other important libraries in /lib.)  The whole configure
  line would be:


        ../configure --enable-add-ons=linuxthreads,crypt,localedata --prefix=/usr



  5.1.4.  Compiling.


  To compile and verify, run:

   make
   make check



  5.2.  Preparing for installation.


  Now you need to move some files around to prepare for the new library,
  whether you are installing from source or binaries.  Any new program
  compiled will be linked to glibc, but old programs which are not
  statically linked will still depend on libc 5, so you can not just
  overwrite the old version.


  1. Create a new directory to hold the old files to:


        mkdir -p /usr/i486-linuxlibc5/lib



  2. The old header files must be evacuated from /usr/include:


        mv /usr/include /usr/i486-linuxlibc5/include



  3. Create a new include directory and set up the links to other
     include directories:


        mkdir /usr/include

        ln -s /usr/src/linux/include/linux /usr/include/linux
        ln -s /usr/src/linux/include/asm /usr/include/asm
        ln -s /usr/X11R6/include/X11 /usr/include/X11
        ln -s /usr/lib/g++-include /usr/include/g++



  The links may need adjusting according to your distribution.  At least
  Slackware puts g++ headers in /usr/local/g++-include, while Debian
  puts the headers in /usr/include/g++, and links /usr/lib/g++-include
  to /usr/include/g++.  In the later case, you probably will want to
  move the original g++ include directory back to /usr/include.

  4. Restore any extra header files and links.  Some non-standard
     libraries such as ncurses put files in /usr/include or put a link
     to their include directories in the /usr/include.  These files and
     links need to be restored in order to use the extra libraries
     properly.

  5. Add your new library directory (such as /usr/i486-linuxlibc5/lib)
     at the top of your /etc/ld.so.conf file.  You should have ld.so
     1.8.8 or better installed to avoid getting strange messages once
     glibc is installed.

  6. Move/copy all the old C libraries into the new directory.


        mv /usr/lib/libbsd.a /usr/i486-linuxlibc5/lib
        mv /usr/lib/libc.a /usr/i486-linuxlibc5/lib
        mv /usr/lib/libgmon.a /usr/i486-linuxlibc5/lib
        mv /usr/lib/libm.a /usr/i486-linuxlibc5/lib
        mv /usr/lib/libmcheck.a /usr/i486-linuxlibc5/lib
        mv /usr/lib/libc.so /usr/i486-linuxlibc5/lib
        mv /usr/lib/libm.so /usr/i486-linuxlibc5/lib
        cp /lib/libm.so.5.* /usr/i486-linuxlibc5/lib
        cp /lib/libc.so.5.* /usr/i486-linuxlibc5/lib



  libm.so.5 and libc.so.5 should be copied and not moved if /usr is a
  seperate partition from /, because they are required by programs used
  to start linux and must be located on the root drive partition.

  7. Move the /usr/lib/*.o files into the new directory.


        mv /usr/lib/crt1.o /usr/i486-linuxlibc5/lib
        mv /usr/lib/crti.o /usr/i486-linuxlibc5/lib
        mv /usr/lib/crtn.o /usr/i486-linuxlibc5/lib
        mv /usr/lib/gcrt1.o /usr/i486-linuxlibc5/lib



  8. Update your library cache after your libraries are moved.


        ldconfig -v



  5.3.  Installing from the binary package.


  If you are installing glibc from precompiled binaries, you first want
  to check what is in the package before you install the binaries:


        tar -tzvvf glibc-2.0.bin.i386.tar.gz
        tar -tzvvf glibc-crypt-2.0.bin.i386.tar.gz



  If you are happy with that, you can install glibc with:

   cd /
   tar -xzf glibc-2.0.bin.i386.tar.gz
   tar -xzf glibc-crypt-2.0.bin.i386.tar.gz
   ldconfig -v



  If you have a different architecture or version, substitute the proper
  file names.

  The most recent glibc version is generally not available as a binary
  package, and it is strongly recommended that you run the most recent
  version to avoid bugs.  If you can not build the library yourself,
  grab a binary package of glibc from one of the distributions that is
  based on glibc (e.g. RedHat) and install this.


  5.4.  Installing from the source.


  To install the library from source, run as root from the compile/
  directory:


        make install
        ldconfig -v



  5.5.  Updating the gcc specs.


  The final step of the installation (for both binary and source
  installs) is to update the gcc specs file so you can link your
  programs properly. To determine which specs file is the one used by
  gcc, use:


        % gcc -v
        reading specs from /usr/lib/gcc-lib/i486-unknown-linux/2.7.2.2/specs
        gcc version 2.7.2.2



  In this case, i486-unknown-linux is the system, and 2.7.2.2 is the
  version.  You need to copy the /usr/lib/gcc-lib/<system> to the old
  system directory:


        cd /usr/lib/gcc-lib/
        cp -r i486-unknown-linux i486-linuxlibc5



  Change into the original directory and version directory

   cd /usr/lib/gcc-lib/i486-unknown-linux/2.7.2.2



  and edit the file specs found in this directory.  In this file, change
  /lib/ld-linux.so.1 to /lib/ld-linux.so.2.  You also need to remove all
  expressions %{...:-lgmon} in the file, since glibc does not use the
  gmon library for profiling.  A sample specs file can be found in the
  ``Sample specs file'' section.



  5.6.  Testing your installation.


  To test the installation, create the following program in a file
  glibc.c:


        #include <stdio.h>

        main()
        {
            printf("hello world!\n");
        }



  and compile the program.


        % gcc glibc.c -o glibc



  Use ldd to verify the program was linked with glibc2, and not your old
  libc:


        % ldd glibc
        libc.so.6 => /lib/libc.so.6 (0x4000e000)
        /lib/ld-linux.so.2 => /lib/ld-linux.so.2 (0x40000000)



  If this compiles and generates "hello world!" when run, the installa-
  tion was successful.



  6.  Compiling with the non-primary libc.


  There are times you will want to use an alternate library to compile
  your programs with.  This section explains how to accomplish this,
  using the directories and installation names used in the examples in
  the previous two sections.  Remember to change the names to fit your
  setup.


  6.1.  A warning when using non-primary libcs.

  Before compiling any programs which is used in the system boot
  process, remember that if the program is dynamically linked and is
  used before the non-root partitions are mounted, all linked libraries
  must be on the root partition.  Following the installation process in
  the previous section for installing glibc as your primary C library,
  the old libc is left in /lib, which will be on your root partition.
  This means all of your programs will still work during booting.
  However, if /usr is on a different partition and you install glibc as
  a test library in /usr/i486-linuxglibc2, any new programs you compile
  with glibc will not work until your /usr partition is mounted.


  6.2.  Compiling programs with a test glibc.

  To compile a program with a test-install glibc, you need to reset the
  include paths to point to the glibc includes.  Specifying "-nostdinc"
  will negate the normal paths, and "-I/usr/i486-linuxglibc2/include"
  will point to the glibc includes.  You will also need to specify the
  gcc includes, which are found in /usr/lib/gcc-
  lib/i486-linuxglibc2/2.7.2.2/include (assuming you installed the test
  lib in i486-linuxglibc2 with gcc version 2.7.2.2).

  To link a program with a test-install glibc, you need to specify the
  gcc setup.  This is done by using the option "-b i486-linuxglibc2".

  For most programs, you can specify these new options by adding them to
  the $CFLAGS and $LDFLAGS makefile options:


        CFLAGS = -nostdinc -I/usr/i486-linuxglibc2/include -I/usr/lib/gcc-lib/i486-linuxglibc2/2.7.2.2/include -b i486-linuxglibc2
        LDFLAGS = -b i486-linuxglibc2



  If you are using a configure script, define the $CFLAGS and $LDFLAGS
  shell variables (by using env/setenv for csh/tcsh, or set/export for
  sh/bash/etc) before running configure.  The makefiles generated by
  this should contain the proper $CFLAGS and $LDFLAGS.  Not all config-
  ure scripts will pick up the variables, so you should check after run-
  ning configure and edit the makefiles by hand if necessary.

  If the programs you are compiling only call gcc (and not cpp or
  binutils directly), you can use the following script to save having to
  specify all of the options each time:


        #!/bin/bash
        /usr/bin/gcc -b i486-linuxglibc2 -nostdinc \
                     -I/usr/i486-linuxglibc2/include \
                     -I/usr/lib/gcc-lib/i486-linuxglibc2/2.7.2.2/include "$@"



  You can then use this script instead of "gcc" when compiling.



  6.3.  Compiling programs with libc 5 when glibc is primary library.

  To compile a program with your old libraries when you have installed
  glibc as your main library, you need to reset the include paths to the
  old includes.  Specifying "-nostdinc" will negate the normal paths,
  and "-I/usr/i486-linuxlibc5/include" will point to the glibc includes.
  You must also specify "-I/usr/lib/gcc-
  lib/i486-linuxlibc5/2.7.2.2/include" to include the gcc specific
  includes.  Remember to adjust these paths based on the what you named
  the new directories and your gcc version.

  To link a program with your old libc, you need to specify the gcc
  setup.  This is done by using the option "-b i486-linuxlibc5".

  For most programs, you can specify these new options by appending them
  to the $CFLAGS and $LDFLAGS makefile options:


        CFLAGS = -nostdinc -I/usr/i486-linuxlibc5/include -I/usr/lib/gcc-lib/i486-linuxlibc5/2.7.2.2/include -b i486-linuxlibc5
        LDFLAGS = -b i486-linuxlibc5



  If you are using a configure script, define the $CFLAGS and $LDFLAGS
  shell variables (by using env/setenv for csh/tcsh, or set/export for
  sh/bash/etc) before running configure.  The makefiles generated by
  this should contain the proper $CFLAGS and $LDFLAGS.  Not all config-
  ure scripts will pick up the variables, so you should check after run-
  ning configure and edit the makefiles by hand if necessary.

  If the programs you are compiling only call gcc (and not cpp or
  binutils directly), you can use the following script to save having to
  specify all of the options each time:


        #!/bin/bash
        /usr/bin/gcc -b i486-linuxlibc5 -nostdinc \
                     -I/usr/i486-linuxlibc5/include \
                     -I/usr/lib/gcc-lib/i486-linuxlibc5/2.7.2.2/include "$@"



  You can then use this script instead of "gcc" when compiling.



  7.  Compiling C++ programs.


  Libg++ uses parts of the math library, so is link to libm.  Since your
  existing libg++ will be compiled with your old library, you will have
  to recompile libg++ with glibc or get a binary copy.  The latest
  source for libg++ along with a binary linked with glibc (for x86) can
  be found at <ftp://ftp.yggdrasil.com/private/hjl/>.


  7.1.  Installing libg++ for a test glibc install.

  If you have installed glibc as a test library, you need to install the
  files into the directory you installed glibc into (such as
  /usr/i486-linuxglibc2 for the example in the previous sections).  If
  you are installing from the binary package (which i would recommend,
  since i never had any luck compiling libg++ this way), you need to
  extract the files into a temporary directory and move all the usr/lib/
  files into the <install directory>/lib/ directory, the usr/include/
  files into the <install directory>/include/ directory (remember to
  delete your include/g++ link first!), and the usr/bin/ files into the
  <install directory>/bin/ directory.


  7.2.  Installing libg++ for a primary glibc install.

  If you have installed glibc as the primary library, you first need to
  move your old libg++ files into your old libc directory if you still
  want to be able to compile g++ programs with your old libc.  Probably
  the easiest way to do this is by installing a new copy of the libg++
  compiled with libc 5 as in the previous section, and then installing
  the glibc version normally.


  7.3.  Compiling C++ programs with the non-primary libc.

  If you are trying to compile a C++ program with a non-primary libc,
  you will need to include the g++ include dir, which in the examples
  above would be /usr/i486-linuxglibc2/include/g++ for a test glibc
  install or /usr/i486-linuxlibc5/include/g++ for a primary glibc
  install.  This can usually be done by appending the $CXXFLAGS
  variable:


        CXXFLAGS = -nostdinc -I/usr/i486-linuxglibc2/include -I/usr/lib/gcc-lib/i486-linuxglibc2/2.7.2.2/include -I/usr/i486-linuxlibc5/include/g++ -b i486-linuxglibc2



  8.  Problems.


  The glibc package contains a FAQ with additional information that you
  should check if you are having problems.  An online version is also
  available at  <http://www.imaxx.net/~thrytis/glibc/glibc-FAQ.html>.
  Below are some tips for solving problems which are not covered in the
  FAQ or are covered here in more detail.


  8.1.  Host names do not resolve.


  Glibc 2 uses a different method than libc 5 in looking up host names.
  The glibc name server switch (NSS) code looks for a file
  /etc/nsswitch.conf.  If host names are not resolving for you when
  using a glibc 2 application and your /etc/resolv.conf is configured
  correctly, check if you have the /etc/nsswitch.conf file.  If you do
  not have this file, you can create one containing the line:


        hosts:        files dns



  It will now look for /etc/resolv.conf to find the nameservers.


  You should look at the section of the libc info pages describing the
  nsswitch.conf file for more details.



  9.  Reporting bugs.


  If you think the lib is buggy, please read first the FAQ. It might be
  that others had the same problem and there's an easy solution. You
  should also check the section "Recommended Tools to Install the GNU C
  Library" in the INSTALL file since some bugs are bugs of the tools and
  not of glibc.

  Once you've found a bug, make sure it's really a bug. A good way to do
  this is to see if the GNU C library behaves the same way some other C
  library does. If so, probably you are wrong and the libraries are
  right (but not necessarily). If not, one of the libraries is probably
  wrong.

  Next, go to  <http://www-gnats.gnu.org:8080/cgi-bin/wwwgnats.pl>, and
  look through the bug database.  Check here to verify the problem has
  not already be reported. You should also look at the file BUGS
  (distributed with libc) to check for known bugs.

  Once you're sure you've found a new bug, try to narrow it down to the
  smallest test case that reproduces the problem. In the case of a C
  library, you really only need to narrow it down to one library
  function call, if possible.  This should not be too difficult.

  The final step when you have a simple test case is to report the bug.
  When reporting a bug, send your test case, the results you got, the
  results you expected, what you think the problem might be (if you've
  thought of anything), your system type, the versions of the GNU C
  library, the GNU CC compiler, and the GNU Binutils which you are
  using.  Also include the files config.status and config.make which are
  created by running configure; they will be in whatever directory was
  current when you ran configure.

  All bug reports for the GNU C library should be sent using the
  glibcbug shell script which comes with the GNU libc to <bugs@gnu.org>
  (the older address  <bugs@gnu.ai.mit.edu> is still working), or
  submitted through the GNATS web interface at <http://www-
  gnats.gnu.org:8080/cgi-bin/wwwgnats.pl>.

  Suggestions and questions should be sent to the mailing list at <bugs-
  glibc@prep.ai.mit.edu>.  If you don't read the gnewsgroup
  gnu.bug.glibc, you can subscribe to the list by asking  <bug-glibc-
  request@prep.ai.mit.edu>.

  Please DO NOT send bug report for the GNU C library to <bug-
  gcc@prep.ai.mit.edu>.  That list is for bug reports for GNU CC.  GNU
  CC and the GNU C library are separate entities maintained by separate
  people.



  10.  Sample specs file.


  Included here is a sample specs file for glibc 2 which is used by gcc
  for compiling and linking.  It should be found in the directory
  /usr/lib/gcc-lib/<new system dir>/<gcc version>.  If you are running
  an x86 system, you probably can copy this section to the file exactly.


   *asm:
   %{V} %{v:%{!V:-V}} %{Qy:} %{!Qn:-Qy} %{n} %{T} %{Ym,*} %{Yd,*} %{Wa,*:%*}

   *asm_final:
   %{pipe:-}

   *cpp:
   %{fPIC:-D__PIC__ -D__pic__} %{fpic:-D__PIC__ -D__pic__} %{!m386:-D__i486__} %{posix:-D_POSIX_SOURCE} %{pthread:-D_REENTRANT}

   *cc1:
   %{profile:-p}

   *cc1plus:


   *endfile:
   %{!shared:crtend.o%s} %{shared:crtendS.o%s} crtn.o%s

   *link:
   -m elf_i386 %{shared:-shared}   %{!shared:     %{!ibcs:       %{!static:   %{rdynamic:-export-dynamic}      %{!dynamic-linker:-dynamic-linker /lib/ld-linux.so.2}}
  %{static:-static}}}

   *lib:
   %{!shared: %{pthread:-lpthread}  %{profile:-lc_p} %{!profile: -lc}}

   *libgcc:
   -lgcc

   *startfile:
   %{!shared:      %{pg:gcrt1.o%s} %{!pg:%{p:gcrt1.o%s}                        %{!p:%{profile:gcrt1.o%s}
   %{!profile:crt1.o%s}}}}    crti.o%s %{!shared:crtbegin.o%s} %{shared:crtbeginS.o%s}

   *switches_need_spaces:


   *signed_char:
   %{funsigned-char:-D__CHAR_UNSIGNED__}

   *predefines:
   -D__ELF__ -Dunix -Di386 -Dlinux -Asystem(unix) -Asystem(posix) -Acpu(i386) -Amachine(i386)

   *cross_compile:
   0

   *multilib:
   . ;



  11.  Miscellanea.



  11.1.  Further information.



  11.1.1.  Web pages.



  o  FSF's GNU C Library Home Page
     <http://www.gnu.org/software/libc/libc.html>
  o  Using GNU Libc 2 with Linux <http://www.imaxx.net/~thrytis/glibc/>

  o  Installing glibc-2 on Linux <http://huizen.dds.nl/~frodol/glibc/>.

  o  Debian libc5 to libc6 Mini-HOWTO
     <http://www.gate.net/~storm/FAQ/libc5-libc6-Mini-HOWTO.html>.


  11.1.2.  Newgroups.



  o  comp.os.linux.development.system

  o  comp.os.linux.development.apps

  o  linux.dev.kernel

  o  gnu.bugs.glibc


  11.1.3.  Mailing lists.



     Glibc 2 Linux discussion list.
        This list is intended for discussion among Linux users who have
        installed glibc2, the new GNU C libraries.  Topics might include
        compatibility issues and questions about the compilation of code
        in a Linux/glibc setting.  To subscribe, send mail to
        Majordomo@ricardo.ecn.wfu.edu
        <mailto:Majordomo@ricardo.ecn.wfu.edu> with a body of "subscribe
        glibc-linux <your email address>.

        Archives for this mailing list can be found at
        <http://www.progressive-comp.com/Lists/?l=linux-
        glibc&r=1&w=2#linux-glibc>


  11.2.  Credits.


  Most of this information was stolen from the GNU Libc web page
  <http://www.gnu.org/software/libc/libc.html> and from Ulrich Drepper's
  <drepper@gnu.ai.mit.edu> glibc 2 announcement and his comments.
  Andreas Jaeger <aj@arthur.rhein-neckar.de> provided some of the
  Reporting bugs section.

  The following people have provided information and feedback for this
  document:

  o  Allex <allex@ms2.accmail.com.tw>

  o  Mark Brown <M.A.Brown-4@sms.ed.ac.uk>

  o  Ulrich Drepper <drepper@gnu.ai.mit.edu>

  o  Scott K. Ellis <ellis@valueweb.net>

  o  Aron Griffis <agriffis@coat.com>

  o  Andreas Jaeger <aj@arthur.rhein-neckar.de>

  o  Hank Leininger <hlein@progressive-comp.com>


  o  Frodo Looijaard <frodol@dds.nl>

  o  Ryan McGuire <rmcguire@freenet.columbus.oh.us>

  o  Shaya Potter <spotter@capaccess.org>

  o  Les Schaffer <godzilla@futuris.net>

  o  Andy Sewell <puck@pookhill.demon.co.uk>

  o  Gary Shea <shea@gtsdesign.com>

  o  Stephane <sr@adb.fr>

  o  Jan Vandenbos <jan@imaxx.net>

  o  Michael Wolf <wolfm@rpi.edu>

  Translations of this document are being done by:

  o  Chinese: Allex <allex@ms2.accmail.com.tw>

  o  French:  Olivier Tharan <tharan@int-evry.fr>

  o  Japanese:  Kazuyuki Okamoto <ikko-@pacific.rim.or.jp>



  11.3.  Feedback.


  Besides writing this HOWTO, maintaining the glibc 2 for Linux
  <http://www.imaxx.net/~thrytis/glibc> page, and using it on my
  machine, I have nothing to do with the glibc project.  I am far from
  knowledgeable on this topic, though I try to help with problems mailed
  to me.  I welcome any feedback, corrections, or suggestions you have
  to offer.  Please send them to ejg3@cornell.edu
  <mailto:ejg3@cornell.edu>.


  11.4.  Copyright.

  Copyright (c) 1997 by Eric Green.  This document may be distributed
  under the terms set forth in the LDP license.