BOOK/chapter06/glibc.xml

   1 <?xml version="1.0" encoding="ISO-8859-1"?>
   2 <!DOCTYPE sect1 PUBLIC "-//OASIS//DTD DocBook XML V4.5//EN"
   3   "http://www.oasis-open.org/docbook/xml/4.5/docbookx.dtd" [
   4   <!ENTITY % general-entities SYSTEM "../general.ent">
   5   %general-entities;
   6 ]>
   7
   8 <sect1 id="ch-system-glibc" role="wrap">
   9   <?dbhtml filename="glibc.html"?>
  10
  11   <sect1info condition="script">
  12     <productname>glibc</productname>
  13     <productnumber>&glibc-version;</productnumber>
  14     <address>&glibc-url;</address>
  15   </sect1info>
  16
  17   <title>Glibc-&glibc-version;</title>
  18
  19   <indexterm zone="ch-system-glibc">
  20     <primary sortas="a-Glibc">Glibc</primary>
  21   </indexterm>
  22
  23   <sect2 role="package">
  24     <title/>
  25
  26     <para>The Glibc package contains the main C library. This library provides
  27     the basic routines for allocating memory, searching directories, opening and
  28     closing files, reading and writing files, string handling, pattern matching,
  29     arithmetic, and so on.</para>
  30
  31     <segmentedlist>
  32       <segtitle>&buildtime;</segtitle>
  33       <segtitle>&diskspace;</segtitle>
  34
  35       <seglistitem>
  36         <seg>&glibc-ch6-sbu;</seg>
  37         <seg>&glibc-ch6-du;</seg>
  38       </seglistitem>
  39     </segmentedlist>
  40
  41   </sect2>
  42
  43   <sect2 role="installation">
  44     <title>Installation of Glibc</title>
  45
  46     <note><para>The Glibc build system is self-contained and will install
  47     perfectly, even though the compiler specs file and linker are still
  48     pointing to <filename class="directory">/tools</filename>. The specs
  49     and linker cannot be adjusted before the Glibc install because the
  50     Glibc autoconf tests would give false results and defeat the goal
  51     of achieving a clean build.</para></note>
  52
  53     <para>Some of the Glibc programs use the non-FHS compilant
  54     <filename class="directory">/var/db</filename> directory to store
  55     their runtime data. Apply the following patch to make such programs
  56     store their runtime data in the FHS-compliant locations:</para>
  57
  58 <screen><userinput remap="pre">patch -Np1 -i ../&glibc-fhs-patch;</userinput></screen>
  59 <!--
  60     <para>Fix a minor security issue with glob functions:</para>
  61
  62 <screen><userinput remap="pre">patch -Np1 -i ../&glibc-glob-patch;</userinput></screen>
  63 -->
  64     <para>First create a compatibility symlink to avoid references to /tools in
  65     our final glibc:</para>
  66
  67 <screen><userinput remap="pre">ln -sfv /tools/lib/gcc /usr/lib</userinput></screen>
  68
  69     <para>Determine the GCC include directory and create a symlink for LSB
  70     compliance. Additionally, for x86_64, create a compatibility symlink
  71     required for the dynamic loader to function correctly:</para>
  72
  73 <screen><userinput remap="pre">case $(uname -m) in
  74     i?86)    GCC_INCDIR=/usr/lib/gcc/$(uname -m)-pc-linux-gnu/&gcc-version;/include
  75             ln -sfv ld-linux.so.2 /lib/ld-lsb.so.3
  76     ;;
  77     x86_64) GCC_INCDIR=/usr/lib/gcc/x86_64-pc-linux-gnu/&gcc-version;/include
  78             ln -sfv ../lib/ld-linux-x86-64.so.2 /lib64
  79             ln -sfv ../lib/ld-linux-x86-64.so.2 /lib64/ld-lsb-x86-64.so.3
  80     ;;
  81 esac</userinput></screen>
  82
  83     <para>Remove a file that may be left over from a previous build attempt:
  84     </para>
  85
  86 <screen><userinput remap="pre">rm -f /usr/include/limits.h</userinput></screen>
  87
  88     <para>The Glibc documentation recommends building Glibc
  89     in a dedicated build directory:</para>
  90
  91 <screen><userinput remap="pre">mkdir -v build
  92 cd       build</userinput></screen>
  93
  94     <para>Prepare Glibc for compilation:</para>
  95
  96 <screen><userinput remap="configure">CC="gcc -isystem $GCC_INCDIR -isystem /usr/include" \
  97 ../configure --prefix=/usr                          \
  98              --disable-werror                       \
  99              --enable-kernel=&min-kernel;                    \
 100              --enable-stack-protector=strong        \
 101              libc_cv_slibdir=/lib
 102 unset GCC_INCDIR</userinput></screen>
 103
 104    <variablelist>
 105       <title>The meaning of the options and new configure parameters:</title>
 106
 107       <varlistentry>
 108         <term><parameter>CC="gcc -isystem $GCC_INCDIR -isystem /usr/include"</parameter></term>
 109         <listitem>
 110           <para>Setting the location of both gcc and system include directories
 111           avoids introduction of invalid paths in debugging symbols.</para>
 112         </listitem>
 113       </varlistentry>
 114
 115       <varlistentry>
 116         <term><parameter>--disable-werror</parameter></term>
 117         <listitem>
 118           <para>This option disables the -Werror option passed to
 119           GCC.  This is necessary for running the test suite.</para>
 120         </listitem>
 121       </varlistentry>
 122
 123       <varlistentry>
 124         <term><parameter>--enable-stack-protector=strong</parameter></term>
 125         <listitem>
 126           <para>This option increases system security by adding
 127           extra code to check for buffer overflows, such as stack
 128           smashing attacks.</para>
 129         </listitem>
 130       </varlistentry>
 131
 132       <varlistentry>
 133         <term><parameter>libc_cv_slibdir=/lib</parameter></term>
 134         <listitem>
 135           <para>This variable sets the correct library for all
 136           systems.  We do not want lib64 to be used.</para>
 137         </listitem>
 138       </varlistentry>
 139
 140     </variablelist>
 141
 142     <para>Compile the package:</para>
 143
 144 <screen><userinput remap="make">make</userinput></screen>
 145
 146     <important>
 147       <para>In this section, the test suite for Glibc is considered critical.
 148       Do not skip it under any circumstance.</para>
 149     </important>
 150
 151     <para>Generally a few tests do not pass. The test failures listed below
 152     are usually safe to ignore.</para>
 153
 154 <screen><userinput remap="test">make check</userinput></screen>
 155
 156     <para>You may see some test failures.  The Glibc test suite is
 157     somewhat dependent on the host system.  This is a list of the most common
 158     issues seen for some versions of LFS:</para>
 159
 160     <itemizedlist>
 161
 162       <listitem>
 163         <para><emphasis>misc/tst-ttyname</emphasis>
 164         is known to fail in the LFS chroot environment.</para>
 165       </listitem>
 166
 167       <listitem>
 168         <para><emphasis>posix/tst-getaddrinfo4</emphasis> and
 169         <emphasis>posix/tst-getaddrinfo5</emphasis>
 170         may fail on some architectures.</para>
 171       </listitem>
 172 <!--
 173       <listitem>
 174         <para>The <emphasis>rt/tst-cputimer1</emphasis> and
 175         <emphasis>rt/tst-cpuclock2</emphasis> tests have been known to
 176         fail.  The reason is not completely understood, but indications are
 177         that minor timing issues can trigger these failures.</para>
 178       </listitem>
 179 -->
 180       <listitem>
 181         <para>The math tests sometimes fail when running on
 182         systems where the CPU is not a relatively new Intel or
 183         AMD processor.</para>
 184       </listitem>
 185 <!--
 186       <listitem>
 187         <para>The
 188         <emphasis>nptl/tst-thread-affinity-{pthread,pthread2,sched}</emphasis>
 189         tests may fail for reasons that have not been determined.  </para>
 190       </listitem>
 191
 192       <listitem>
 193         <para>Other tests known to fail on some architectures are
 194         malloc/tst-malloc-usable and nptl/tst-cleanupx4. </para>
 195       </listitem>
 196 -->
 197     </itemizedlist>
 198
 199     <para>Though it is a harmless message, the install stage of Glibc will
 200     complain about the absence of <filename>/etc/ld.so.conf</filename>.
 201     Prevent this warning with:</para>
 202
 203 <screen><userinput remap="install">touch /etc/ld.so.conf</userinput></screen>
 204
 205     <para>Fix the generated Makefile to skip an unneeded sanity check
 206     that fails in the LFS partial environment:
 207     </para>
 208
 209 <screen><userinput remap="install">sed '/test-installation/s@$(PERL)@echo not running@' -i ../Makefile</userinput></screen>
 210
 211     <para>Install the package:</para>
 212
 213 <screen><userinput remap="install">make install</userinput></screen>
 214
 215     <para>Install the configuration file and runtime directory for
 216     <command>nscd</command>:</para>
 217
 218 <screen><userinput remap="install">cp -v ../nscd/nscd.conf /etc/nscd.conf
 219 mkdir -pv /var/cache/nscd</userinput></screen>
 220
 221     <para revision="systemd">Install the systemd support files for
 222     <command>nscd</command>:</para>
 223
 224     <screen revision="systemd"><userinput remap="install">install -v -Dm644 ../nscd/nscd.tmpfiles /usr/lib/tmpfiles.d/nscd.conf
 225 install -v -Dm644 ../nscd/nscd.service /lib/systemd/system/nscd.service</userinput></screen>
 226
 227     <para>Next, install the locales that can make the system respond in a
 228     different language.  None of the locales are required, but if some of them
 229     are missing, the test suites of future packages would skip important
 230     testcases.</para>
 231
 232     <para>Individual locales can be installed using the
 233     <command>localedef</command> program. E.g., the first
 234     <command>localedef</command> command below combines the
 235     <filename>/usr/share/i18n/locales/cs_CZ</filename>
 236     charset-independent locale definition with the
 237     <filename>/usr/share/i18n/charmaps/UTF-8.gz</filename>
 238     charmap definition and appends the result to the
 239     <filename>/usr/lib/locale/locale-archive</filename> file.
 240     The following instructions will install the minimum set of
 241     locales necessary for the optimal coverage of tests:</para>
 242
 243 <screen role="nodump"><userinput remap="locale-test">mkdir -pv /usr/lib/locale
 244 localedef -i cs_CZ -f UTF-8 cs_CZ.UTF-8
 245 localedef -i de_DE -f ISO-8859-1 de_DE
 246 localedef -i de_DE@euro -f ISO-8859-15 de_DE@euro
 247 localedef -i de_DE -f UTF-8 de_DE.UTF-8
 248 localedef -i en_GB -f UTF-8 en_GB.UTF-8
 249 localedef -i en_HK -f ISO-8859-1 en_HK
 250 localedef -i en_PH -f ISO-8859-1 en_PH
 251 localedef -i en_US -f ISO-8859-1 en_US
 252 localedef -i en_US -f UTF-8 en_US.UTF-8
 253 localedef -i es_MX -f ISO-8859-1 es_MX
 254 localedef -i fa_IR -f UTF-8 fa_IR
 255 localedef -i fr_FR -f ISO-8859-1 fr_FR
 256 localedef -i fr_FR@euro -f ISO-8859-15 fr_FR@euro
 257 localedef -i fr_FR -f UTF-8 fr_FR.UTF-8
 258 localedef -i it_IT -f ISO-8859-1 it_IT
 259 localedef -i it_IT -f UTF-8 it_IT.UTF-8
 260 localedef -i ja_JP -f EUC-JP ja_JP
 261 localedef -i ru_RU -f KOI8-R ru_RU.KOI8-R
 262 localedef -i ru_RU -f UTF-8 ru_RU.UTF-8
 263 localedef -i tr_TR -f UTF-8 tr_TR.UTF-8
 264 localedef -i zh_CN -f GB18030 zh_CN.GB18030</userinput></screen>
 265
 266     <para>In addition, install the locale for your own country, language and
 267     character set.</para>
 268
 269     <para>Alternatively, install all locales listed in the
 270     <filename>glibc-&glibc-version;/localedata/SUPPORTED</filename> file
 271     (it includes every locale listed above and many more) at once with the
 272     following time-consuming command:</para>
 273
 274 <screen><userinput remap="locale-full">make localedata/install-locales</userinput></screen>
 275
 276     <para>Then use the <command>localedef</command> command to create and
 277     install locales not listed in the
 278     <filename>glibc-&glibc-version;/localedata/SUPPORTED</filename> file
 279     in the unlikely case you need them.</para>
 280
 281   </sect2>
 282
 283   <sect2 id="conf-glibc" role="configuration">
 284     <title>Configuring Glibc</title>
 285
 286     <indexterm zone="conf-glibc">
 287       <primary sortas="e-/etc/nsswitch.conf">/etc/nsswitch.conf</primary>
 288     </indexterm>
 289
 290     <indexterm zone="conf-glibc">
 291       <primary sortas="e-/etc/localtime">/etc/localtime</primary>
 292     </indexterm>
 293
 294   <sect3>
 295   <title>Adding nsswitch.conf</title>
 296
 297     <para>The <filename>/etc/nsswitch.conf</filename> file needs to be created
 298     because the Glibc defaults do not work well in a networked environment.
 299     </para>
 300
 301     <para>Create a new file <filename>/etc/nsswitch.conf</filename> by running the
 302     following:</para>
 303
 304 <screen><userinput>cat &gt; /etc/nsswitch.conf &lt;&lt; "EOF"
 305 <literal># Begin /etc/nsswitch.conf
 306
 307 passwd: files
 308 group: files
 309 shadow: files
 310
 311 hosts: files dns
 312 networks: files
 313
 314 protocols: files
 315 services: files
 316 ethers: files
 317 rpc: files
 318
 319 # End /etc/nsswitch.conf</literal>
 320 EOF</userinput></screen>
 321
 322     </sect3>
 323
 324     <sect3>
 325     <title>Adding time zone data</title>
 326
 327     <para>Install and set up the time zone data with the following:</para>
 328 <screen><userinput>tar -xf ../../tzdata&tzdata-version;.tar.gz
 329
 330 ZONEINFO=/usr/share/zoneinfo
 331 mkdir -pv $ZONEINFO/{posix,right}
 332
 333 for tz in etcetera southamerica northamerica europe africa antarctica  \
 334           asia australasia backward pacificnew systemv; do
 335     zic -L /dev/null   -d $ZONEINFO       -y "sh yearistype.sh" ${tz}
 336     zic -L /dev/null   -d $ZONEINFO/posix -y "sh yearistype.sh" ${tz}
 337     zic -L leapseconds -d $ZONEINFO/right -y "sh yearistype.sh" ${tz}
 338 done
 339
 340 cp -v zone.tab zone1970.tab iso3166.tab $ZONEINFO
 341 zic -d $ZONEINFO -p America/New_York
 342 unset ZONEINFO</userinput></screen>
 343
 344     <variablelist>
 345       <title>The meaning of the zic commands:</title>
 346
 347       <varlistentry>
 348         <term><parameter>zic -L /dev/null ...</parameter></term>
 349         <listitem>
 350           <para>This creates posix time zones, without any leap seconds.  It is
 351           conventional to put these in both
 352           <filename class="directory">zoneinfo</filename> and
 353           <filename class="directory">zoneinfo/posix</filename>. It is
 354           necessary to put the POSIX time zones in
 355           <filename class="directory">zoneinfo</filename>, otherwise various
 356           test-suites will report errors. On an embedded system, where space is
 357           tight and you do not intend to ever update the time zones, you could save
 358           1.9MB by not using the <filename class="directory">posix</filename>
 359           directory, but some applications or test-suites might produce some
 360           failures.</para>
 361         </listitem>
 362       </varlistentry>
 363       <varlistentry>
 364         <term><parameter>zic -L leapseconds ...</parameter></term>
 365         <listitem>
 366           <para>This creates right time zones, including leap seconds. On an
 367           embedded system, where space is tight and you do not intend to
 368           ever update the time zones, or care about the correct time, you could
 369           save 1.9MB by omitting the <filename class="directory">right</filename>
 370           directory.</para>
 371         </listitem>
 372       </varlistentry>
 373       <varlistentry>
 374         <term><parameter>zic ... -p ...</parameter></term>
 375         <listitem>
 376           <para>This creates the <filename>posixrules</filename> file. We use
 377           New York because POSIX requires the daylight savings time rules
 378           to be in accordance with US rules.</para>
 379         </listitem>
 380       </varlistentry>
 381     </variablelist>
 382
 383
 384     <para>One way to determine the local time zone is to run the following
 385     script:</para>
 386
 387 <screen role="nodump"><userinput>tzselect</userinput></screen>
 388
 389     <para>After answering a few questions about the location, the script will
 390     output the name of the time zone (e.g.,
 391     <emphasis>America/Edmonton</emphasis>). There are also some other possible
 392     time zones listed in <filename
 393     class='directory'>/usr/share/zoneinfo</filename> such as
 394     <emphasis>Canada/Eastern</emphasis> or <emphasis>EST5EDT</emphasis> that
 395     are not identified by the script but can be used.</para>
 396
 397     <para>Then create the <filename>/etc/localtime</filename> file by
 398     running:</para>
 399
 400 <screen revision="sysv"><userinput>cp -v /usr/share/zoneinfo/<replaceable>&lt;xxx&gt;</replaceable> /etc/localtime</userinput></screen>
 401
 402 <screen revision="systemd"><userinput>ln -sfv /usr/share/zoneinfo/<replaceable>&lt;xxx&gt;</replaceable> /etc/localtime</userinput></screen>
 403
 404     <para>Replace <replaceable>&lt;xxx&gt;</replaceable> with the name of the
 405     time zone selected (e.g., Canada/Eastern).</para>
 406
 407   </sect3>
 408
 409   <sect3 id="conf-ld" role="configuration">
 410     <title>Configuring the Dynamic Loader</title>
 411
 412     <indexterm zone="conf-ld">
 413       <primary sortas="e-/etc/ld.so.conf">/etc/ld.so.conf</primary>
 414     </indexterm>
 415
 416     <para>By default, the dynamic loader (<filename
 417     class="libraryfile">/lib/ld-linux.so.2</filename>) searches through
 418     <filename class="directory">/lib</filename> and <filename
 419     class="directory">/usr/lib</filename> for dynamic libraries that are
 420     needed by programs as they are run. However, if there are libraries in
 421     directories other than <filename class="directory">/lib</filename> and
 422     <filename class="directory">/usr/lib</filename>, these need to be added
 423     to the <filename>/etc/ld.so.conf</filename> file in order for the
 424     dynamic loader to find them. Two directories that are commonly known
 425     to contain additional libraries are <filename
 426     class="directory">/usr/local/lib</filename> and <filename
 427     class="directory">/opt/lib</filename>, so add those directories to the
 428     dynamic loader's search path.</para>
 429
 430     <para>Create a new file <filename>/etc/ld.so.conf</filename> by running the
 431     following:</para>
 432
 433 <screen><userinput>cat &gt; /etc/ld.so.conf &lt;&lt; "EOF"
 434 <literal># Begin /etc/ld.so.conf
 435 /usr/local/lib
 436 /opt/lib
 437 </literal>
 438 EOF</userinput></screen>
 439
 440   <para>If desired, the dynamic loader can also search a directory and
 441   include the contents of files found there.  Generally the files in
 442   this include directory are one line specifying the desired library path.
 443   To add this capability run the following commands:</para>
 444
 445 <screen role="nodump"><userinput>cat &gt;&gt; /etc/ld.so.conf &lt;&lt; "EOF"
 446 <literal># Add an include directory
 447 include /etc/ld.so.conf.d/*.conf
 448 </literal>
 449 EOF
 450 mkdir -pv /etc/ld.so.conf.d</userinput></screen>
 451
 452   </sect3>
 453   </sect2>
 454
 455   <sect2 id="contents-glibc" role="content">
 456     <title>Contents of Glibc</title>
 457
 458     <segmentedlist>
 459       <segtitle>Installed programs</segtitle>
 460       <segtitle>Installed libraries</segtitle>
 461       <segtitle>Installed directories</segtitle>
 462
 463       <seglistitem>
 464         <seg>catchsegv, gencat, getconf, getent, iconv, iconvconfig, ldconfig,
 465         ldd, lddlibc4, locale, localedef, makedb, mtrace, nscd,
 466         pldd, sln, sotruss, sprof, tzselect, xtrace,
 467         zdump, and zic</seg>
 468         <seg>ld-&glibc-version;.so, libBrokenLocale.{a,so}, libSegFault.so, libanl.{a,so},
 469         libc.{a,so}, libc_nonshared.a, libcidn.so,
 470         libcrypt.{a,so}, libdl.{a,so}, libg.a, libieee.a, libm.{a,so},
 471         libmcheck.a, libmemusage.so, libnsl.{a,so}, libnss_compat.so,
 472         libnss_dns.so, libnss_files.so, libnss_hesiod.so, libnss_nis.so,
 473         libnss_nisplus.so, libpthread.{a,so},
 474         libpthread_nonshared.a, libresolv.{a,so}, librpcsvc.a, librt.{a,so},
 475         libthread_db.so, and libutil.{a,so}</seg>
 476         <seg>/usr/include/arpa, /usr/include/bits, /usr/include/gnu,
 477         /usr/include/net, /usr/include/netash, /usr/include/netatalk,
 478         /usr/include/netax25, /usr/include/neteconet, /usr/include/netinet,
 479         /usr/include/netipx, /usr/include/netiucv, /usr/include/netpacket,
 480         /usr/include/netrom, /usr/include/netrose, /usr/include/nfs,
 481         /usr/include/protocols, /usr/include/rpc, /usr/include/rpcsvc,
 482         /usr/include/sys, /usr/lib/audit, /usr/lib/gconv, /usr/lib/locale,
 483         /usr/libexec/getconf, /usr/share/i18n, /usr/share/zoneinfo,
 484         /var/cache/nscd, and /var/lib/nss_db</seg>
 485       </seglistitem>
 486     </segmentedlist>
 487
 488     <variablelist>
 489       <bridgehead renderas="sect3">Short Descriptions</bridgehead>
 490       <?dbfo list-presentation="list"?>
 491       <?dbhtml list-presentation="table"?>
 492
 493       <varlistentry id="catchsegv">
 494         <term><command>catchsegv</command></term>
 495         <listitem>
 496           <para>Can be used to create a stack trace when a program
 497           terminates with a segmentation fault</para>
 498           <indexterm zone="ch-system-glibc catchsegv">
 499             <primary sortas="b-catchsegv">catchsegv</primary>
 500           </indexterm>
 501         </listitem>
 502       </varlistentry>
 503
 504       <varlistentry id="gencat">
 505         <term><command>gencat</command></term>
 506         <listitem>
 507           <para>Generates message catalogues</para>
 508           <indexterm zone="ch-system-glibc gencat">
 509             <primary sortas="b-gencat">gencat</primary>
 510           </indexterm>
 511         </listitem>
 512       </varlistentry>
 513
 514       <varlistentry id="getconf">
 515         <term><command>getconf</command></term>
 516         <listitem>
 517           <para>Displays the system configuration values for file system
 518           specific variables</para>
 519           <indexterm zone="ch-system-glibc getconf">
 520             <primary sortas="b-getconf">getconf</primary>
 521           </indexterm>
 522         </listitem>
 523       </varlistentry>
 524
 525       <varlistentry id="getent">
 526         <term><command>getent</command></term>
 527         <listitem>
 528           <para>Gets entries from an administrative database</para>
 529           <indexterm zone="ch-system-glibc getent">
 530             <primary sortas="b-getent">getent</primary>
 531           </indexterm>
 532         </listitem>
 533       </varlistentry>
 534
 535       <varlistentry id="iconv">
 536         <term><command>iconv</command></term>
 537         <listitem>
 538           <para>Performs character set conversion</para>
 539           <indexterm zone="ch-system-glibc iconv">
 540             <primary sortas="b-iconv">iconv</primary>
 541           </indexterm>
 542         </listitem>
 543       </varlistentry>
 544
 545       <varlistentry id="iconvconfig">
 546         <term><command>iconvconfig</command></term>
 547         <listitem>
 548           <para>Creates fastloading <command>iconv</command> module configuration
 549           files</para>
 550           <indexterm zone="ch-system-glibc iconvconfig">
 551             <primary sortas="b-iconvconfig">iconvconfig</primary>
 552           </indexterm>
 553         </listitem>
 554       </varlistentry>
 555
 556       <varlistentry id="ldconfig">
 557         <term><command>ldconfig</command></term>
 558         <listitem>
 559           <para>Configures the dynamic linker runtime bindings</para>
 560           <indexterm zone="ch-system-glibc ldconfig">
 561             <primary sortas="b-ldconfig">ldconfig</primary>
 562           </indexterm>
 563         </listitem>
 564       </varlistentry>
 565
 566       <varlistentry id="ldd">
 567         <term><command>ldd</command></term>
 568         <listitem>
 569           <para>Reports which shared libraries are required
 570           by each given program or shared library</para>
 571           <indexterm zone="ch-system-glibc ldd">
 572             <primary sortas="b-ldd">ldd</primary>
 573           </indexterm>
 574         </listitem>
 575       </varlistentry>
 576
 577       <varlistentry id="lddlibc4">
 578         <term><command>lddlibc4</command></term>
 579         <listitem>
 580           <para>Assists <command>ldd</command> with object files</para>
 581           <indexterm zone="ch-system-glibc lddlibc4">
 582             <primary sortas="b-lddlibc4">lddlibc4</primary>
 583           </indexterm>
 584         </listitem>
 585       </varlistentry>
 586
 587       <varlistentry id="locale">
 588         <term><command>locale</command></term>
 589         <listitem>
 590           <para>Prints various information about the current locale</para>
 591           <indexterm zone="ch-system-glibc locale">
 592             <primary sortas="b-locale">locale</primary>
 593           </indexterm>
 594         </listitem>
 595       </varlistentry>
 596
 597       <varlistentry id="localedef">
 598         <term><command>localedef</command></term>
 599         <listitem>
 600           <para>Compiles locale specifications</para>
 601           <indexterm zone="ch-system-glibc localedef">
 602             <primary sortas="b-localedef">localedef</primary>
 603           </indexterm>
 604         </listitem>
 605       </varlistentry>
 606
 607       <varlistentry id="makedb">
 608         <term><command>makedb</command></term>
 609         <listitem>
 610           <para>Creates a simple database from textual input</para>
 611           <indexterm zone="ch-system-glibc makedb">
 612             <primary sortas="b-makedb">makedb</primary>
 613           </indexterm>
 614         </listitem>
 615       </varlistentry>
 616
 617       <varlistentry id="mtrace">
 618         <term><command>mtrace</command></term>
 619         <listitem>
 620           <para>Reads and interprets a memory trace file and displays a summary
 621           in human-readable format</para>
 622           <indexterm zone="ch-system-glibc mtrace">
 623             <primary sortas="b-mtrace">mtrace</primary>
 624           </indexterm>
 625         </listitem>
 626       </varlistentry>
 627
 628       <varlistentry id="nscd">
 629         <term><command>nscd</command></term>
 630         <listitem>
 631           <para>A daemon that provides a cache for the most common name
 632           service requests</para>
 633           <indexterm zone="ch-system-glibc nscd">
 634             <primary sortas="b-nscd">nscd</primary>
 635           </indexterm>
 636         </listitem>
 637       </varlistentry>
 638
 639       <varlistentry id="pldd">
 640         <term><command>pldd</command></term>
 641         <listitem>
 642           <para>Lists dynamic shared objects used by running processes</para>
 643           <indexterm zone="ch-system-glibc pldd">
 644             <primary sortas="b-pldd">pldd</primary>
 645           </indexterm>
 646         </listitem>
 647       </varlistentry>
 648
 649       <varlistentry id="sln">
 650         <term><command>sln</command></term>
 651         <listitem>
 652           <para>A statically linked <command>ln</command> program</para>
 653           <indexterm zone="ch-system-glibc sln">
 654             <primary sortas="b-sln">sln</primary>
 655           </indexterm>
 656         </listitem>
 657       </varlistentry>
 658
 659       <varlistentry id="sotruss">
 660         <term><command>sotruss</command></term>
 661         <listitem>
 662           <para>Traces shared library procedure calls of a specified command</para>
 663           <indexterm zone="ch-system-glibc sotruss">
 664             <primary sortas="b-sotruss">sotruss</primary>
 665           </indexterm>
 666         </listitem>
 667       </varlistentry>
 668
 669       <varlistentry id="sprof">
 670         <term><command>sprof</command></term>
 671         <listitem>
 672           <para>Reads and displays shared object profiling data</para>
 673           <indexterm zone="ch-system-glibc sprof">
 674             <primary sortas="b-sprof">sprof</primary>
 675           </indexterm>
 676         </listitem>
 677       </varlistentry>
 678
 679       <varlistentry id="tzselect">
 680         <term><command>tzselect</command></term>
 681         <listitem>
 682           <para>Asks the user about the location of the system and reports
 683           the corresponding time zone description</para>
 684           <indexterm zone="ch-system-glibc tzselect">
 685             <primary sortas="b-tzselect">tzselect</primary>
 686           </indexterm>
 687         </listitem>
 688       </varlistentry>
 689
 690       <varlistentry id="xtrace">
 691         <term><command>xtrace</command></term>
 692         <listitem>
 693           <para>Traces the execution of a program by printing the currently
 694           executed function</para>
 695           <indexterm zone="ch-system-glibc xtrace">
 696             <primary sortas="b-xtrace">xtrace</primary>
 697           </indexterm>
 698         </listitem>
 699       </varlistentry>
 700
 701       <varlistentry id="zdump">
 702         <term><command>zdump</command></term>
 703         <listitem>
 704           <para>The time zone dumper</para>
 705           <indexterm zone="ch-system-glibc zdump">
 706             <primary sortas="b-zdump">zdump</primary>
 707           </indexterm>
 708         </listitem>
 709       </varlistentry>
 710
 711       <varlistentry id="zic">
 712         <term><command>zic</command></term>
 713         <listitem>
 714           <para>The time zone compiler</para>
 715           <indexterm zone="ch-system-glibc zic">
 716             <primary sortas="b-zic">zic</primary>
 717           </indexterm>
 718         </listitem>
 719       </varlistentry>
 720
 721       <varlistentry id="ld.so">
 722         <term><filename class="libraryfile">ld-&glibc-version;.so</filename></term>
 723         <listitem>
 724           <para>The helper program for shared library executables</para>
 725           <indexterm zone="ch-system-glibc ld.so">
 726             <primary sortas="c-ld.so">ld-&glibc-version;.so</primary>
 727           </indexterm>
 728         </listitem>
 729       </varlistentry>
 730
 731       <varlistentry id="libBrokenLocale">
 732         <term><filename class="libraryfile">libBrokenLocale</filename></term>
 733         <listitem>
 734           <para>Used internally by Glibc as a gross hack to get broken programs
 735           (e.g., some Motif applications) running. See comments in
 736           <filename>glibc-&glibc-version;/locale/broken_cur_max.c</filename>
 737           for more information</para>
 738           <indexterm zone="ch-system-glibc libBrokenLocale">
 739             <primary sortas="c-libBrokenLocale">libBrokenLocale</primary>
 740           </indexterm>
 741         </listitem>
 742       </varlistentry>
 743
 744       <varlistentry id="libSegFault">
 745         <term><filename class="libraryfile">libSegFault</filename></term>
 746         <listitem>
 747           <para>The segmentation fault signal handler, used by
 748           <command>catchsegv</command></para>
 749           <indexterm zone="ch-system-glibc libSegFault">
 750             <primary sortas="c-libSegFault">libSegFault</primary>
 751           </indexterm>
 752         </listitem>
 753       </varlistentry>
 754
 755       <varlistentry id="libanl">
 756         <term><filename class="libraryfile">libanl</filename></term>
 757         <listitem>
 758           <para>An asynchronous name lookup library</para>
 759           <indexterm zone="ch-system-glibc libanl">
 760             <primary sortas="c-libanl">libanl</primary>
 761           </indexterm>
 762         </listitem>
 763       </varlistentry>
 764
 765       <varlistentry id="libc">
 766         <term><filename class="libraryfile">libc</filename></term>
 767         <listitem>
 768           <para>The main C library</para>
 769           <indexterm zone="ch-system-glibc libc">
 770             <primary sortas="c-libc">libc</primary>
 771           </indexterm>
 772         </listitem>
 773       </varlistentry>
 774
 775       <varlistentry id="libcidn">
 776         <term><filename class="libraryfile">libcidn</filename></term>
 777         <listitem>
 778           <para>Used internally by Glibc for handling internationalized domain
 779           names in the <function>getaddrinfo()</function> function</para>
 780           <indexterm zone="ch-system-glibc libcidn">
 781             <primary sortas="c-libcidn">libcidn</primary>
 782           </indexterm>
 783         </listitem>
 784       </varlistentry>
 785
 786       <varlistentry id="libcrypt">
 787         <term><filename class="libraryfile">libcrypt</filename></term>
 788         <listitem>
 789           <para>The cryptography library</para>
 790           <indexterm zone="ch-system-glibc libcrypt">
 791             <primary sortas="c-libcrypt">libcrypt</primary>
 792           </indexterm>
 793         </listitem>
 794       </varlistentry>
 795
 796       <varlistentry id="libdl">
 797         <term><filename class="libraryfile">libdl</filename></term>
 798         <listitem>
 799           <para>The dynamic linking interface library</para>
 800           <indexterm zone="ch-system-glibc libdl">
 801             <primary sortas="c-libdl">libdl</primary>
 802           </indexterm>
 803         </listitem>
 804       </varlistentry>
 805
 806       <varlistentry id="libg">
 807         <term><filename class="libraryfile">libg</filename></term>
 808         <listitem>
 809           <para>Dummy library containing no functions. Previously was a runtime
 810           library for <command>g++</command></para>
 811           <indexterm zone="ch-system-glibc libg">
 812             <primary sortas="c-libg">libg</primary>
 813           </indexterm>
 814         </listitem>
 815       </varlistentry>
 816
 817       <varlistentry id="libieee">
 818         <term><filename class="libraryfile">libieee</filename></term>
 819         <listitem>
 820           <para>Linking in this module forces error handling rules for math
 821           functions as defined by the Institute of Electrical and Electronic
 822           Engineers (IEEE). The default is POSIX.1 error handling</para>
 823           <indexterm zone="ch-system-glibc libieee">
 824             <primary sortas="c-libieee">libieee</primary>
 825           </indexterm>
 826         </listitem>
 827       </varlistentry>
 828
 829       <varlistentry id="libm">
 830         <term><filename class="libraryfile">libm</filename></term>
 831         <listitem>
 832           <para>The mathematical library</para>
 833           <indexterm zone="ch-system-glibc libm">
 834             <primary sortas="c-libm">libm</primary>
 835           </indexterm>
 836         </listitem>
 837       </varlistentry>
 838
 839       <varlistentry id="libmcheck">
 840         <term><filename class="libraryfile">libmcheck</filename></term>
 841         <listitem>
 842           <para>Turns on memory allocation checking when linked to</para>
 843           <indexterm zone="ch-system-glibc libmcheck">
 844             <primary sortas="c-libmcheck">libmcheck</primary>
 845           </indexterm>
 846         </listitem>
 847       </varlistentry>
 848
 849       <varlistentry id="libmemusage">
 850         <term><filename class="libraryfile">libmemusage</filename></term>
 851         <listitem>
 852           <para>Used by <command>memusage</command> to help collect
 853           information about the memory usage of a program</para>
 854           <indexterm zone="ch-system-glibc libmemusage">
 855             <primary sortas="c-libmemusage">libmemusage</primary>
 856           </indexterm>
 857         </listitem>
 858       </varlistentry>
 859
 860       <varlistentry id="libnsl">
 861         <term><filename class="libraryfile">libnsl</filename></term>
 862         <listitem>
 863           <para>The network services library</para>
 864           <indexterm zone="ch-system-glibc libnsl">
 865             <primary sortas="c-libnsl">libnsl</primary>
 866           </indexterm>
 867         </listitem>
 868       </varlistentry>
 869
 870       <varlistentry id="libnss">
 871         <term><filename class="libraryfile">libnss</filename></term>
 872         <listitem>
 873           <para>The Name Service Switch libraries, containing functions for
 874           resolving host names, user names, group names, aliases, services,
 875           protocols, etc.</para>
 876           <indexterm zone="ch-system-glibc libnss">
 877             <primary sortas="c-libnss">libnss</primary>
 878           </indexterm>
 879         </listitem>
 880       </varlistentry>
 881
 882       <varlistentry id="libpthread">
 883         <term><filename class="libraryfile">libpthread</filename></term>
 884         <listitem>
 885           <para>The POSIX threads library</para>
 886           <indexterm zone="ch-system-glibc libpthread">
 887             <primary sortas="c-libpthread">libpthread</primary>
 888           </indexterm>
 889         </listitem>
 890       </varlistentry>
 891
 892       <varlistentry id="libresolv">
 893         <term><filename class="libraryfile">libresolv</filename></term>
 894         <listitem>
 895           <para>Contains functions for creating, sending, and interpreting
 896           packets to the Internet domain name servers</para>
 897           <indexterm zone="ch-system-glibc libresolv">
 898             <primary sortas="c-libresolv">libresolv</primary>
 899           </indexterm>
 900         </listitem>
 901       </varlistentry>
 902
 903       <varlistentry id="librpcsvc">
 904         <term><filename class="libraryfile">librpcsvc</filename></term>
 905         <listitem>
 906           <para>Contains functions providing miscellaneous RPC services</para>
 907           <indexterm zone="ch-system-glibc librpcsvc">
 908             <primary sortas="c-librpcsvc">librpcsvc</primary>
 909           </indexterm>
 910         </listitem>
 911       </varlistentry>
 912
 913       <varlistentry id="librt">
 914         <term><filename class="libraryfile">librt</filename></term>
 915         <listitem>
 916           <para>Contains functions providing most of the interfaces specified
 917           by the POSIX.1b Realtime Extension</para>
 918           <indexterm zone="ch-system-glibc librt">
 919             <primary sortas="c-librt">librt</primary>
 920           </indexterm>
 921         </listitem>
 922       </varlistentry>
 923
 924       <varlistentry id="libthread_db">
 925         <term><filename class="libraryfile">libthread_db</filename></term>
 926         <listitem>
 927           <para>Contains functions useful for building debuggers for
 928           multi-threaded programs</para>
 929           <indexterm zone="ch-system-glibc libthread_db">
 930             <primary sortas="c-libthread_db">libthread_db</primary>
 931           </indexterm>
 932         </listitem>
 933       </varlistentry>
 934
 935       <varlistentry id="libutil">
 936         <term><filename class="libraryfile">libutil</filename></term>
 937         <listitem>
 938           <para>Contains code for <quote>standard</quote> functions used in
 939           many different Unix utilities</para>
 940           <indexterm zone="ch-system-glibc libutil">
 941             <primary sortas="c-libutil">libutil</primary>
 942           </indexterm>
 943         </listitem>
 944       </varlistentry>
 945
 946     </variablelist>
 947
 948   </sect2>
 949
 950 </sect1>