10.7. EGLIBC-2.18

The EGLIBC package contains the main C library. This library provides the basic routines for allocating memory, searching directories, opening and closing files, reading and writing files, string handling, pattern matching, arithmetic, and so on.

10.7.1. Installation of EGLIBC



Some packages outside of CLFS suggest installing GNU libiconv in order to translate data from one encoding to another. The project's home page (http://www.gnu.org/software/libiconv/) says “This library provides an iconv() implementation, for use on systems which don't have one, or whose implementation cannot convert from/to Unicode.” EGLIBC provides an iconv() implementation and can convert from/to Unicode, therefore libiconv is not required on a CLFS system.

At the end of the installation, the build system will run a sanity test to make sure everything installed properly. This script will attempt to test for a library that is only used in the test suite and is never installed. Prevent the script from testing for this library with the following command:

sed -i 's/\(&& $name ne\) "db1"/ & \1 "nss_test1"/' scripts/test-installation.pl

This same script performs its tests by attempting to compile test programs against certain libraries. However it does not specify the ld.so, and our toolchain is still configured to use the one in /tools. The following set of commands will force the script to use the complete path of the new ld.so that was just installed:

LINKER=$(readelf -l /tools/bin/bash | sed -n 's@.*interpret.*/tools\(.*\)]$@\1@p')
sed -i "s|libs -o|libs -L/usr/lib -Wl,-dynamic-linker=${LINKER} -o|" \
unset LINKER

The EGLIBC build system is self-contained and will install perfectly, even though the compiler specs file and linker are still pointing at /tools. The specs and linker cannot be adjusted before the EGLIBC install because the EGLIBC Autoconf tests would give false results and defeat the goal of achieving a clean build.

The EGLIBC documentation recommends building EGLIBC outside of the source directory in a dedicated build directory:

mkdir -v ../eglibc-build
cd ../eglibc-build

Prepare EGLIBC for compilation:

../eglibc-2.18/configure --prefix=/usr \
    --disable-profile --enable-kernel=2.6.32 --libexecdir=/usr/lib/eglibc \

The meaning of the new configure option:


This changes the location of the getconf utility from its default of /usr/libexec to /usr/lib/eglibc.

Compile the package:



The test suite for EGLIBC is considered critical. Do not skip it under any circumstance.

Before running the tests, copy a file from the source tree into our build tree to prevent a couple of test failures, then run the tests:

cp -v ../eglibc-2.18/iconvdata/gconv-modules iconvdata
make -k check 2>&1 | tee eglibc-check-log; grep Error eglibc-check-log

The EGLIBC test suite is highly dependent on certain functions of the host system, in particular the kernel. The posix/annexc test normally fails and you should see Error 1 (ignored) in the output. Apart from this, the EGLIBC test suite is always expected to pass. However, in certain circumstances, some failures are unavoidable. If a test fails because of a missing program (or missing symbolic link), or a segfault, you will see an error code greater than 127 and the details will be in the log. More commonly, tests will fail with Error 2 - for these, the contents of the corresponding .out file, e.g. posix/annexc.out may be informative. Here is a list of the most common issues:

  • The math tests sometimes fail. Certain optimization settings are known to be a factor here.

  • If you have mounted the CLFS partition with the noatime option, the atime test will fail. As mentioned in Section 2.4, “Mounting the New Partition”, do not use the noatime option while building CLFS.

  • When running on older and slower hardware, some tests can fail because of test timeouts being exceeded.

Though it is a harmless message, the install stage of EGLIBC will complain about the absence of /etc/ld.so.conf. Prevent this warning with:

touch /etc/ld.so.conf

Install the package:

make install

10.7.2. Internationalization

The locales that can make the system respond in a different language were not installed by the above command. Install them with:

make localedata/install-locales

To save time, an alternative to running the previous command (which generates and installs every locale listed in the eglibc-2.18/localedata/SUPPORTED file) is to install only those locales that are wanted and needed. This can be achieved by using the localedef command. Information on this command is located in the INSTALL file in the EGLIBC source. However, there are a number of locales that are essential in order for the tests of future packages to pass, in particular, the libstdc++ tests from GCC. The following instructions, instead of the install-locales target used above, will install the minimum set of locales necessary for the tests to run successfully:

mkdir -pv /usr/lib/locale
localedef -i cs_CZ -f UTF-8 cs_CZ.UTF-8
localedef -i de_DE -f ISO-8859-1 de_DE
localedef -i de_DE@euro -f ISO-8859-15 de_DE@euro
localedef -i en_HK -f ISO-8859-1 en_HK
localedef -i en_PH -f ISO-8859-1 en_PH
localedef -i en_US -f ISO-8859-1 en_US
localedef -i es_MX -f ISO-8859-1 es_MX
localedef -i fa_IR -f UTF-8 fa_IR
localedef -i fr_FR -f ISO-8859-1 fr_FR
localedef -i fr_FR@euro -f ISO-8859-15 fr_FR@euro
localedef -i it_IT -f ISO-8859-1 it_IT
localedef -i ja_JP -f EUC-JP ja_JP

Some locales installed by the make localedata/install-locales command above are not properly supported by some applications that are in CLFS and CBLFS. Because of the various problems that arise due to application programmers making assumptions that break in such locales, CLFS should not be used in locales that utilize multibyte character sets (including UTF-8) or right-to-left writing order. Numerous unofficial and unstable patches are required to fix these problems, and it has been decided by the CLFS developers not to support such complex locales at this time. This applies to the ja_JP and fa_IR locales as well—they have been installed only for GCC and Gettext tests to pass, and the watch program (part of the Procps package) does not work properly in them. Various attempts to circumvent these restrictions are documented in internationalization-related hints.

10.7.3. Configuring EGLIBC

The /etc/nsswitch.conf file needs to be created because, although EGLIBC provides defaults when this file is missing or corrupt, the EGLIBC defaults do not work well in a networked environment. The time zone also needs to be configured.

Create a new file /etc/nsswitch.conf by running the following:

cat > /etc/nsswitch.conf << "EOF"
# Begin /etc/nsswitch.conf

passwd: files
group: files
shadow: files

hosts: files dns
networks: files

protocols: files
services: files
ethers: files
rpc: files

# End /etc/nsswitch.conf

Install timezone data:

tar -xf ../tzdata2013g.tar.gz

mkdir -pv $ZONEINFO/{posix,right}

for tz in etcetera southamerica northamerica europe africa antarctica  \
          asia australasia backward pacificnew solar87 solar88 solar89 \
          systemv; do
    zic -L /dev/null   -d $ZONEINFO       -y "sh yearistype.sh" ${tz}
    zic -L /dev/null   -d $ZONEINFO/posix -y "sh yearistype.sh" ${tz}
    zic -L leapseconds -d $ZONEINFO/right -y "sh yearistype.sh" ${tz}

cp -v zone.tab iso3166.tab $ZONEINFO
zic -d $ZONEINFO -p America/New_York

The meaning of the zic commands:

zic -L /dev/null ...

This creates posix timezones, without any leap seconds. It is conventional to put these in both zoneinfo and zoneinfo/posix. It is necessary to put the POSIX timezones in zoneinfo, otherwise various test-suites will report errors. On an embedded system, where space is tight and you do not intend to ever update the timezones, you could save 1.9MB by not using the posix directory, but some applications or test-suites might give less good results

zic -L leapseconds ...

This creates right timezones, including leap seconds. On an embedded system, where space is tight and you do not intend to ever update the timezones, or care about the correct time, you could save 1.9MB by omitting the right directory.

zic ... -p ...

This creates the posixrules file. We use New York because POSIX requires the daylight savings time rules to be in accordance with US rules.

To determine the local time zone, run the following script:


After answering a few questions about the location, the script will output the name of the time zone (e.g., EST5EDT or Canada/Eastern). Then create the /etc/localtime file by running:

cp -v --remove-destination /usr/share/zoneinfo/[xxx] \

Replace [xxx] with the name of the time zone that tzselect provided (e.g., Canada/Eastern).

The meaning of the cp option:


This is needed to force removal of the already existing symbolic link. The reason for copying the file instead of using a symlink is to cover the situation where /usr is on a separate partition. This could be important when booted into single user mode.

10.7.4. Configuring The Dynamic Loader

By default, the dynamic loader (/lib/ld-linux.so.2) searches through /lib and /usr/lib for dynamic libraries that are needed by programs as they are run. However, if there are libraries in directories other than /lib and /usr/lib, these need to be added to the /etc/ld.so.conf file in order for the dynamic loader to find them. Two directories that are commonly known to contain additional libraries are /usr/local/lib and /opt/lib, so add those directories to the dynamic loader's search path.

Create a new file /etc/ld.so.conf by running the following:

cat > /etc/ld.so.conf << "EOF"
# Begin /etc/ld.so.conf


# End /etc/ld.so.conf

10.7.5. Contents of EGLIBC

Installed programs: catchsegv, gencat, getconf, getent, iconv, iconvconfig, ldconfig, ldd, lddlibc4, locale, localedef, makedb, mtrace, nscd, pcprofiledump, pldd, rpcgen, sln, sprof, tzselect, xtrace,zdump, and zic
Installed libraries: ld.so, libBrokenLocale.[a,so], libSegFault.so, libanl.[a,so], libbsd-compat.a, libc.[a,so], libc_nonshared.a, libcidn.[a,so], libcrypt.[a,so], libdl.[a,so], libg.a, libieee.a, libm.[a,so], libmcheck.a, libmemusage.so, libnsl.a, libnss_compat.so, libnss_dns.so, libnss_files.so, libnss_hesiod.so, libnss_nis.so, libnss_nisplus.so, libpcprofile.so, libpthread.[a,so], libpthread_nonshared.a, libresolv.[a,so], librpcsvc.a, librt.[a,so], libthread_db.so, and libutil.[a,so]
Installed directories: /usr/include/arpa, /usr/include/bits, /usr/include/gnu, /usr/include/net, /usr/include/netash, /usr/include/netatalk, /usr/include/netax25, /usr/include/neteconet, /usr/include/netinet, /usr/include/netipx, /usr/include/netiucv, /usr/include/netpacket, /usr/include/netrom, /usr/include/netrose, /usr/include/nfs, /usr/include/protocols, /usr/include/rpc, /usr/include/rpcsvc, /usr/include/sys, /usr/lib/gconv, /usr/lib/eglibc, /usr/lib/locale, /usr/share/i18n, /usr/share/zoneinfo, /var/cache/ldconfig

Short Descriptions


Can be used to create a stack trace when a program terminates with a segmentation fault


Generates message catalogues


Displays the system configuration values for file system specific variables


Gets entries from an administrative database


Performs character set conversion


Creates fastloading iconv module configuration files


Configures the dynamic linker runtime bindings


Reports which shared libraries are required by each given program or shared library


Assists ldd with object files


Tells the compiler to enable or disable the use of POSIX locales for built-in operations


Compiles locale specifications


Creates a simple database from textual input


Reads and interprets a memory trace file and displays a summary in human-readable format


A daemon that provides a cache for the most common name service requests


Dumps information generated by PC profiling


Lists dynamic shared objects used by running processes


Generates C code to implement the Remote Procecure Call (RPC) protocol


A statically linked program that creates symbolic links


Traces shared library procedure calls of a specified command


Reads and displays shared object profiling data


Asks the user about the location of the system and reports the corresponding time zone description


Traces the execution of a program by printing the currently executed function


The time zone dumper


The time zone compiler


The helper program for shared library executables


Used by programs, such as Mozilla, to solve broken locales


The segmentation fault signal handler


An asynchronous name lookup library


Provides the portability needed in order to run certain Berkey Software Distribution (BSD) programs under Linux


The main C library


Used internally by EGLIBC for handling internationalized domain names in the getaddrinfo() function


The cryptography library


The dynamic linking interface library


A runtime library for g++


The Institute of Electrical and Electronic Engineers (IEEE) floating point library


The mathematical library


Contains code run at boot


Used by memusage (included in EGLIBC, but not built in a base CLFS system as it has additional dependencies) to help collect information about the memory usage of a program


The network services library


The Name Service Switch libraries, containing functions for resolving host names, user names, group names, aliases, services, protocols, etc.


Contains profiling functions used to track the amount of CPU time spent in specific source code lines


The POSIX threads library


Contains functions for creating, sending, and interpreting packets to the Internet domain name servers


Contains functions providing miscellaneous RPC services


Contains functions providing most of the interfaces specified by the POSIX.1b Realtime Extension


Contains functions useful for building debuggers for multi-threaded programs


Contains code for “standard” functions used in many different Unix utilities