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 compliant
  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 <!-- No longer needed
  65     <para>Fix a problem introduced with the linux-5.2 kernel:</para>
  66
  67 <screen><userinput remap="pre">sed -i '/asm.socket.h/a# include &lt;linux/sockios.h&gt;' \
  68    sysdeps/unix/sysv/linux/bits/socket.h</userinput></screen>
  69 -->
  70     <para>Create a symlink for LSB
  71     compliance. Additionally, for x86_64, create a compatibility symlink
  72     required for the dynamic loader to function correctly:</para>
  73
  74 <screen><userinput remap="pre">case $(uname -m) in
  75     i?86)   ln -sfv ld-linux.so.2 /lib/ld-lsb.so.3
  76     ;;
  77     x86_64) ln -sfv ../lib/ld-linux-x86-64.so.2 /lib64
  78             ln -sfv ../lib/ld-linux-x86-64.so.2 /lib64/ld-lsb-x86-64.so.3
  79     ;;
  80 esac</userinput></screen>
  81 <!--
  82     <para>Remove a file that may be left over from a previous build attempt:
  83     </para>
  84
  85 <screen><userinput remap="pre">rm -f /usr/include/limits.h</userinput></screen>
  86 -->
  87     <para>The Glibc documentation recommends building Glibc
  88     in a dedicated build directory:</para>
  89
  90 <screen><userinput remap="pre">mkdir -v build
  91 cd       build</userinput></screen>
  92
  93     <para>Prepare Glibc for compilation:</para>
  94
  95 <screen><userinput remap="configure">CC="gcc -ffile-prefix-map=/tools=/usr" \
  96 ../configure --prefix=/usr                          \
  97              --disable-werror                       \
  98              --enable-kernel=&min-kernel;                    \
  99              --enable-stack-protector=strong        \
 100              --with-headers=/usr/include            \
 101              libc_cv_slibdir=/lib</userinput></screen>
 102
 103    <variablelist>
 104       <title>The meaning of the options and new configure parameters:</title>
 105
 106       <varlistentry>
 107         <term><parameter>CC="gcc -ffile-prefix-map=/tools=/usr"</parameter></term>
 108         <listitem>
 109           <para>Make GCC record any references to files in /tools in result
 110           of the compilation as if the files resided in /usr.  This avoids
 111           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>--with-headers=/usr/include</parameter></term>
 134         <listitem>
 135           <para>This option tells the build system where to find the
 136           kernel API headers. By default, those headers are sought in
 137           <filename class="directory">/tools/include</filename>.</para>
 138         </listitem>
 139       </varlistentry>
 140
 141       <varlistentry>
 142         <term><parameter>libc_cv_slibdir=/lib</parameter></term>
 143         <listitem>
 144           <para>This variable sets the correct library for all
 145           systems.  We do not want lib64 to be used.</para>
 146         </listitem>
 147       </varlistentry>
 148
 149     </variablelist>
 150
 151     <para>Compile the package:</para>
 152
 153 <screen><userinput remap="make">make</userinput></screen>
 154
 155     <important>
 156       <para>In this section, the test suite for Glibc is considered critical.
 157       Do not skip it under any circumstance.</para>
 158     </important>
 159
 160     <para>Generally a few tests do not pass. The test failures listed below
 161     are usually safe to ignore.</para>
 162
 163 <!-- Use remap="make" here to work around a jhalfs issue. -->
 164 <screen><userinput remap="make">case $(uname -m) in
 165   i?86)   ln -sfnv $PWD/elf/ld-linux.so.2        /lib ;;
 166   x86_64) ln -sfnv $PWD/elf/ld-linux-x86-64.so.2 /lib ;;
 167 esac</userinput></screen>
 168
 169     <note><para>The symbolic link above is needed to run the tests at this
 170     stage of building in the chroot environment.  It will be overwritten
 171     in the install phase below.</para></note>
 172
 173 <screen><userinput remap="test">make check</userinput></screen>
 174
 175     <para>You may see some test failures.  The Glibc test suite is
 176     somewhat dependent on the host system.  This is a list of the most common
 177     issues seen for some versions of LFS:</para>
 178
 179     <itemizedlist>
 180
 181       <listitem>
 182         <para><emphasis>misc/tst-ttyname</emphasis>
 183         is known to fail in the LFS chroot environment.</para>
 184       </listitem>
 185
 186       <listitem>
 187         <para><emphasis>inet/tst-idna_name_classify</emphasis>
 188         is known to fail in the LFS chroot environment.</para>
 189       </listitem>
 190
 191       <listitem>
 192         <para><emphasis>posix/tst-getaddrinfo4</emphasis> and
 193         <emphasis>posix/tst-getaddrinfo5</emphasis>
 194         may fail on some architectures.</para>
 195       </listitem>
 196
 197       <listitem>
 198         <para>The <emphasis>nss/tst-nss-files-hosts-multi</emphasis>
 199         test may fail for reasons that have not been determined.</para>
 200       </listitem>
 201
 202       <listitem>
 203         <para>The <emphasis>rt/tst-cputimer{1,2,3}</emphasis> tests depend on
 204         the host system kernel. Kernels 4.14.91&ndash;4.14.96,
 205         4.19.13&ndash;4.19.18, and 4.20.0&ndash;4.20.5 are known to
 206         cause these tests to fail.
 207         </para>
 208       </listitem>
 209
 210       <listitem>
 211         <para>The math tests sometimes fail when running on
 212         systems where the CPU is not a relatively new Intel or
 213         AMD processor.</para>
 214       </listitem>
 215 <!--
 216       <listitem>
 217         <para>The
 218         <emphasis>nptl/tst-thread-affinity-{pthread,pthread2,sched}</emphasis>
 219         tests may fail for reasons that have not been determined.  </para>
 220       </listitem>
 221
 222       <listitem>
 223         <para>Other tests known to fail on some architectures are
 224         malloc/tst-malloc-usable and nptl/tst-cleanupx4. </para>
 225       </listitem>
 226 -->
 227     </itemizedlist>
 228
 229     <para>Though it is a harmless message, the install stage of Glibc will
 230     complain about the absence of <filename>/etc/ld.so.conf</filename>.
 231     Prevent this warning with:</para>
 232
 233 <screen><userinput remap="install">touch /etc/ld.so.conf</userinput></screen>
 234
 235     <para>Fix the generated Makefile to skip an unneeded sanity check
 236     that fails in the LFS partial environment:
 237     </para>
 238
 239 <screen><userinput remap="install">sed '/test-installation/s@$(PERL)@echo not running@' -i ../Makefile</userinput></screen>
 240
 241     <para>Install the package:</para>
 242
 243 <screen><userinput remap="install">make install</userinput></screen>
 244
 245     <para>Install the configuration file and runtime directory for
 246     <command>nscd</command>:</para>
 247
 248 <screen><userinput remap="install">cp -v ../nscd/nscd.conf /etc/nscd.conf
 249 mkdir -pv /var/cache/nscd</userinput></screen>
 250
 251     <para revision="systemd">Install the systemd support files for
 252     <command>nscd</command>:</para>
 253
 254     <screen revision="systemd"><userinput remap="install">install -v -Dm644 ../nscd/nscd.tmpfiles /usr/lib/tmpfiles.d/nscd.conf
 255 install -v -Dm644 ../nscd/nscd.service /lib/systemd/system/nscd.service</userinput></screen>
 256
 257     <para>Next, install the locales that can make the system respond in a
 258     different language.  None of the locales are required, but if some of them
 259     are missing, the test suites of future packages would skip important
 260     testcases.</para>
 261
 262     <para>Individual locales can be installed using the
 263     <command>localedef</command> program. E.g., the first
 264     <command>localedef</command> command below combines the
 265     <filename>/usr/share/i18n/locales/cs_CZ</filename>
 266     charset-independent locale definition with the
 267     <filename>/usr/share/i18n/charmaps/UTF-8.gz</filename>
 268     charmap definition and appends the result to the
 269     <filename>/usr/lib/locale/locale-archive</filename> file.
 270     The following instructions will install the minimum set of
 271     locales necessary for the optimal coverage of tests:</para>
 272
 273 <screen role="nodump"><userinput remap="locale-test">mkdir -pv /usr/lib/locale
 274 localedef -i POSIX -f UTF-8 C.UTF-8 2> /dev/null || true
 275 localedef -i cs_CZ -f UTF-8 cs_CZ.UTF-8
 276 localedef -i de_DE -f ISO-8859-1 de_DE
 277 localedef -i de_DE@euro -f ISO-8859-15 de_DE@euro
 278 localedef -i de_DE -f UTF-8 de_DE.UTF-8
 279 localedef -i el_GR -f ISO-8859-7 el_GR
 280 localedef -i en_GB -f UTF-8 en_GB.UTF-8
 281 localedef -i en_HK -f ISO-8859-1 en_HK
 282 localedef -i en_PH -f ISO-8859-1 en_PH
 283 localedef -i en_US -f ISO-8859-1 en_US
 284 localedef -i en_US -f UTF-8 en_US.UTF-8
 285 localedef -i es_MX -f ISO-8859-1 es_MX
 286 localedef -i fa_IR -f UTF-8 fa_IR
 287 localedef -i fr_FR -f ISO-8859-1 fr_FR
 288 localedef -i fr_FR@euro -f ISO-8859-15 fr_FR@euro
 289 localedef -i fr_FR -f UTF-8 fr_FR.UTF-8
 290 localedef -i it_IT -f ISO-8859-1 it_IT
 291 localedef -i it_IT -f UTF-8 it_IT.UTF-8
 292 localedef -i ja_JP -f EUC-JP ja_JP
 293 localedef -i ja_JP -f SHIFT_JIS ja_JP.SIJS 2> /dev/null || true
 294 localedef -i ja_JP -f UTF-8 ja_JP.UTF-8
 295 localedef -i ru_RU -f KOI8-R ru_RU.KOI8-R
 296 localedef -i ru_RU -f UTF-8 ru_RU.UTF-8
 297 localedef -i tr_TR -f UTF-8 tr_TR.UTF-8
 298 localedef -i zh_CN -f GB18030 zh_CN.GB18030
 299 localedef -i zh_HK -f BIG5-HKSCS zh_HK.BIG5-HKSCS</userinput></screen>
 300
 301     <para>In addition, install the locale for your own country, language and
 302     character set.</para>
 303
 304     <para>Alternatively, install all locales listed in the
 305     <filename>glibc-&glibc-version;/localedata/SUPPORTED</filename> file
 306     (it includes every locale listed above and many more) at once with the
 307     following time-consuming command:</para>
 308
 309 <screen><userinput remap="locale-full">make localedata/install-locales</userinput></screen>
 310
 311     <para>Then use the <command>localedef</command> command to create and
 312     install locales not listed in the
 313     <filename>glibc-&glibc-version;/localedata/SUPPORTED</filename> file
 314     in the unlikely case you need them.</para>
 315
 316     <note><para>Glibc now uses libidn2 when resolving internationalized
 317     domain names.  This is a run time dependency.  If this capability
 318     is needed, the instructions for installing libidn2 are in the
 319     <ulink url="&blfs-book;general/libidn2.html">BLFS libidn2 page</ulink>.
 320     </para></note>
 321
 322   </sect2>
 323
 324   <sect2 id="conf-glibc" role="configuration">
 325     <title>Configuring Glibc</title>
 326
 327     <indexterm zone="conf-glibc">
 328       <primary sortas="e-/etc/nsswitch.conf">/etc/nsswitch.conf</primary>
 329     </indexterm>
 330
 331     <indexterm zone="conf-glibc">
 332       <primary sortas="e-/etc/localtime">/etc/localtime</primary>
 333     </indexterm>
 334
 335   <sect3>
 336   <title>Adding nsswitch.conf</title>
 337
 338     <para>The <filename>/etc/nsswitch.conf</filename> file needs to be created
 339     because the Glibc defaults do not work well in a networked environment.
 340     </para>
 341
 342     <para>Create a new file <filename>/etc/nsswitch.conf</filename> by running the
 343     following:</para>
 344
 345 <screen><userinput>cat &gt; /etc/nsswitch.conf &lt;&lt; "EOF"
 346 <literal># Begin /etc/nsswitch.conf
 347
 348 passwd: files
 349 group: files
 350 shadow: files
 351
 352 hosts: files dns
 353 networks: files
 354
 355 protocols: files
 356 services: files
 357 ethers: files
 358 rpc: files
 359
 360 # End /etc/nsswitch.conf</literal>
 361 EOF</userinput></screen>
 362
 363     </sect3>
 364
 365     <sect3>
 366     <title>Adding time zone data</title>
 367
 368     <para>Install and set up the time zone data with the following:</para>
 369 <screen><userinput>tar -xf ../../tzdata&tzdata-version;.tar.gz
 370
 371 ZONEINFO=/usr/share/zoneinfo
 372 mkdir -pv $ZONEINFO/{posix,right}
 373
 374 for tz in etcetera southamerica northamerica europe africa antarctica  \
 375           asia australasia backward pacificnew systemv; do
 376     zic -L /dev/null   -d $ZONEINFO       ${tz}
 377     zic -L /dev/null   -d $ZONEINFO/posix ${tz}
 378     zic -L leapseconds -d $ZONEINFO/right ${tz}
 379 done
 380
 381 cp -v zone.tab zone1970.tab iso3166.tab $ZONEINFO
 382 zic -d $ZONEINFO -p America/New_York
 383 unset ZONEINFO</userinput></screen>
 384
 385     <variablelist>
 386       <title>The meaning of the zic commands:</title>
 387
 388       <varlistentry>
 389         <term><parameter>zic -L /dev/null ...</parameter></term>
 390         <listitem>
 391           <para>This creates posix time zones, without any leap seconds.  It is
 392           conventional to put these in both
 393           <filename class="directory">zoneinfo</filename> and
 394           <filename class="directory">zoneinfo/posix</filename>. It is
 395           necessary to put the POSIX time zones in
 396           <filename class="directory">zoneinfo</filename>, otherwise various
 397           test-suites will report errors. On an embedded system, where space is
 398           tight and you do not intend to ever update the time zones, you could save
 399           1.9MB by not using the <filename class="directory">posix</filename>
 400           directory, but some applications or test-suites might produce some
 401           failures.</para>
 402         </listitem>
 403       </varlistentry>
 404       <varlistentry>
 405         <term><parameter>zic -L leapseconds ...</parameter></term>
 406         <listitem>
 407           <para>This creates right time zones, including leap seconds. On an
 408           embedded system, where space is tight and you do not intend to
 409           ever update the time zones, or care about the correct time, you could
 410           save 1.9MB by omitting the <filename class="directory">right</filename>
 411           directory.</para>
 412         </listitem>
 413       </varlistentry>
 414       <varlistentry>
 415         <term><parameter>zic ... -p ...</parameter></term>
 416         <listitem>
 417           <para>This creates the <filename>posixrules</filename> file. We use
 418           New York because POSIX requires the daylight savings time rules
 419           to be in accordance with US rules.</para>
 420         </listitem>
 421       </varlistentry>
 422     </variablelist>
 423
 424
 425     <para>One way to determine the local time zone is to run the following
 426     script:</para>
 427
 428 <screen role="nodump"><userinput>tzselect</userinput></screen>
 429
 430     <para>After answering a few questions about the location, the script will
 431     output the name of the time zone (e.g.,
 432     <emphasis>America/Edmonton</emphasis>). There are also some other possible
 433     time zones listed in <filename
 434     class='directory'>/usr/share/zoneinfo</filename> such as
 435     <emphasis>Canada/Eastern</emphasis> or <emphasis>EST5EDT</emphasis> that
 436     are not identified by the script but can be used.</para>
 437
 438     <para>Then create the <filename>/etc/localtime</filename> file by
 439     running:</para>
 440
 441 <screen><userinput>ln -sfv /usr/share/zoneinfo/<replaceable>&lt;xxx&gt;</replaceable> /etc/localtime</userinput></screen>
 442
 443     <para>Replace <replaceable>&lt;xxx&gt;</replaceable> with the name of the
 444     time zone selected (e.g., Canada/Eastern).</para>
 445
 446   </sect3>
 447
 448   <sect3 id="conf-ld" role="configuration">
 449     <title>Configuring the Dynamic Loader</title>
 450
 451     <indexterm zone="conf-ld">
 452       <primary sortas="e-/etc/ld.so.conf">/etc/ld.so.conf</primary>
 453     </indexterm>
 454
 455     <para>By default, the dynamic loader (<filename
 456     class="libraryfile">/lib/ld-linux.so.2</filename>) searches through
 457     <filename class="directory">/lib</filename> and <filename
 458     class="directory">/usr/lib</filename> for dynamic libraries that are
 459     needed by programs as they are run. However, if there are libraries in
 460     directories other than <filename class="directory">/lib</filename> and
 461     <filename class="directory">/usr/lib</filename>, these need to be added
 462     to the <filename>/etc/ld.so.conf</filename> file in order for the
 463     dynamic loader to find them. Two directories that are commonly known
 464     to contain additional libraries are <filename
 465     class="directory">/usr/local/lib</filename> and <filename
 466     class="directory">/opt/lib</filename>, so add those directories to the
 467     dynamic loader's search path.</para>
 468
 469     <para>Create a new file <filename>/etc/ld.so.conf</filename> by running the
 470     following:</para>
 471
 472 <screen><userinput>cat &gt; /etc/ld.so.conf &lt;&lt; "EOF"
 473 <literal># Begin /etc/ld.so.conf
 474 /usr/local/lib
 475 /opt/lib
 476 </literal>
 477 EOF</userinput></screen>
 478
 479   <para>If desired, the dynamic loader can also search a directory and
 480   include the contents of files found there.  Generally the files in
 481   this include directory are one line specifying the desired library path.
 482   To add this capability run the following commands:</para>
 483
 484 <screen role="nodump"><userinput>cat &gt;&gt; /etc/ld.so.conf &lt;&lt; "EOF"
 485 <literal># Add an include directory
 486 include /etc/ld.so.conf.d/*.conf
 487 </literal>
 488 EOF
 489 mkdir -pv /etc/ld.so.conf.d</userinput></screen>
 490
 491   </sect3>
 492   </sect2>
 493
 494   <sect2 id="contents-glibc" role="content">
 495     <title>Contents of Glibc</title>
 496
 497     <segmentedlist>
 498       <segtitle>Installed programs</segtitle>
 499       <segtitle>Installed libraries</segtitle>
 500       <segtitle>Installed directories</segtitle>
 501
 502       <seglistitem>
 503         <seg>catchsegv, gencat, getconf, getent, iconv, iconvconfig, ldconfig,
 504         ldd, lddlibc4, locale, localedef, makedb, mtrace, nscd,
 505         pcprofiledump, pldd, sln, sotruss, sprof, tzselect, xtrace,
 506         zdump, and zic</seg>
 507         <seg>ld-&glibc-version;.so, libBrokenLocale.{a,so}, libSegFault.so, libanl.{a,so},
 508         libc.{a,so}, libc_nonshared.a,
 509         libcrypt.{a,so}, libdl.{a,so}, libg.a, libm.{a,so},
 510         libmcheck.a, libmemusage.so, libmvec.{a,so}, libnsl.{a,so},
 511         libnss_compat.so, libnss_dns.so, libnss_files.so, libnss_hesiod.so,
 512         libpcprofile.so, libpthread.{a,so},
 513         libpthread_nonshared.a, libresolv.{a,so}, librt.{a,so},
 514         libthread_db.so, and libutil.{a,so}</seg>
 515         <seg>/usr/include/arpa, /usr/include/bits, /usr/include/gnu,
 516         /usr/include/net, /usr/include/netash, /usr/include/netatalk,
 517         /usr/include/netax25, /usr/include/neteconet, /usr/include/netinet,
 518         /usr/include/netipx, /usr/include/netiucv, /usr/include/netpacket,
 519         /usr/include/netrom, /usr/include/netrose, /usr/include/nfs,
 520         /usr/include/protocols, /usr/include/rpc,
 521         /usr/include/sys, /usr/lib/audit, /usr/lib/gconv, /usr/lib/locale,
 522         /usr/libexec/getconf, /usr/share/i18n, /usr/share/zoneinfo,
 523         /var/cache/nscd, and /var/lib/nss_db</seg>
 524       </seglistitem>
 525     </segmentedlist>
 526
 527     <variablelist>
 528       <bridgehead renderas="sect3">Short Descriptions</bridgehead>
 529       <?dbfo list-presentation="list"?>
 530       <?dbhtml list-presentation="table"?>
 531
 532       <varlistentry id="catchsegv">
 533         <term><command>catchsegv</command></term>
 534         <listitem>
 535           <para>Can be used to create a stack trace when a program
 536           terminates with a segmentation fault</para>
 537           <indexterm zone="ch-system-glibc catchsegv">
 538             <primary sortas="b-catchsegv">catchsegv</primary>
 539           </indexterm>
 540         </listitem>
 541       </varlistentry>
 542
 543       <varlistentry id="gencat">
 544         <term><command>gencat</command></term>
 545         <listitem>
 546           <para>Generates message catalogues</para>
 547           <indexterm zone="ch-system-glibc gencat">
 548             <primary sortas="b-gencat">gencat</primary>
 549           </indexterm>
 550         </listitem>
 551       </varlistentry>
 552
 553       <varlistentry id="getconf">
 554         <term><command>getconf</command></term>
 555         <listitem>
 556           <para>Displays the system configuration values for file system
 557           specific variables</para>
 558           <indexterm zone="ch-system-glibc getconf">
 559             <primary sortas="b-getconf">getconf</primary>
 560           </indexterm>
 561         </listitem>
 562       </varlistentry>
 563
 564       <varlistentry id="getent">
 565         <term><command>getent</command></term>
 566         <listitem>
 567           <para>Gets entries from an administrative database</para>
 568           <indexterm zone="ch-system-glibc getent">
 569             <primary sortas="b-getent">getent</primary>
 570           </indexterm>
 571         </listitem>
 572       </varlistentry>
 573
 574       <varlistentry id="iconv">
 575         <term><command>iconv</command></term>
 576         <listitem>
 577           <para>Performs character set conversion</para>
 578           <indexterm zone="ch-system-glibc iconv">
 579             <primary sortas="b-iconv">iconv</primary>
 580           </indexterm>
 581         </listitem>
 582       </varlistentry>
 583
 584       <varlistentry id="iconvconfig">
 585         <term><command>iconvconfig</command></term>
 586         <listitem>
 587           <para>Creates fastloading <command>iconv</command> module configuration
 588           files</para>
 589           <indexterm zone="ch-system-glibc iconvconfig">
 590             <primary sortas="b-iconvconfig">iconvconfig</primary>
 591           </indexterm>
 592         </listitem>
 593       </varlistentry>
 594
 595       <varlistentry id="ldconfig">
 596         <term><command>ldconfig</command></term>
 597         <listitem>
 598           <para>Configures the dynamic linker runtime bindings</para>
 599           <indexterm zone="ch-system-glibc ldconfig">
 600             <primary sortas="b-ldconfig">ldconfig</primary>
 601           </indexterm>
 602         </listitem>
 603       </varlistentry>
 604
 605       <varlistentry id="ldd">
 606         <term><command>ldd</command></term>
 607         <listitem>
 608           <para>Reports which shared libraries are required
 609           by each given program or shared library</para>
 610           <indexterm zone="ch-system-glibc ldd">
 611             <primary sortas="b-ldd">ldd</primary>
 612           </indexterm>
 613         </listitem>
 614       </varlistentry>
 615
 616       <varlistentry id="lddlibc4">
 617         <term><command>lddlibc4</command></term>
 618         <listitem>
 619           <para>Assists <command>ldd</command> with object files</para>
 620           <indexterm zone="ch-system-glibc lddlibc4">
 621             <primary sortas="b-lddlibc4">lddlibc4</primary>
 622           </indexterm>
 623         </listitem>
 624       </varlistentry>
 625
 626       <varlistentry id="locale">
 627         <term><command>locale</command></term>
 628         <listitem>
 629           <para>Prints various information about the current locale</para>
 630           <indexterm zone="ch-system-glibc locale">
 631             <primary sortas="b-locale">locale</primary>
 632           </indexterm>
 633         </listitem>
 634       </varlistentry>
 635
 636       <varlistentry id="localedef">
 637         <term><command>localedef</command></term>
 638         <listitem>
 639           <para>Compiles locale specifications</para>
 640           <indexterm zone="ch-system-glibc localedef">
 641             <primary sortas="b-localedef">localedef</primary>
 642           </indexterm>
 643         </listitem>
 644       </varlistentry>
 645
 646       <varlistentry id="makedb">
 647         <term><command>makedb</command></term>
 648         <listitem>
 649           <para>Creates a simple database from textual input</para>
 650           <indexterm zone="ch-system-glibc makedb">
 651             <primary sortas="b-makedb">makedb</primary>
 652           </indexterm>
 653         </listitem>
 654       </varlistentry>
 655
 656       <varlistentry id="mtrace">
 657         <term><command>mtrace</command></term>
 658         <listitem>
 659           <para>Reads and interprets a memory trace file and displays a summary
 660           in human-readable format</para>
 661           <indexterm zone="ch-system-glibc mtrace">
 662             <primary sortas="b-mtrace">mtrace</primary>
 663           </indexterm>
 664         </listitem>
 665       </varlistentry>
 666
 667       <varlistentry id="nscd">
 668         <term><command>nscd</command></term>
 669         <listitem>
 670           <para>A daemon that provides a cache for the most common name
 671           service requests</para>
 672           <indexterm zone="ch-system-glibc nscd">
 673             <primary sortas="b-nscd">nscd</primary>
 674           </indexterm>
 675         </listitem>
 676       </varlistentry>
 677
 678       <varlistentry id="pcprofiledump">
 679         <term><command>pcprofiledump</command></term>
 680         <listitem>
 681           <para>Dump information generated by PC profiling</para>
 682           <indexterm zone="ch-system-glibc pcprofiledump">
 683             <primary sortas="b-pcprofiledump">pcprofiledump</primary>
 684           </indexterm>
 685         </listitem>
 686       </varlistentry>
 687
 688       <varlistentry id="pldd">
 689         <term><command>pldd</command></term>
 690         <listitem>
 691           <para>Lists dynamic shared objects used by running processes</para>
 692           <indexterm zone="ch-system-glibc pldd">
 693             <primary sortas="b-pldd">pldd</primary>
 694           </indexterm>
 695         </listitem>
 696       </varlistentry>
 697
 698       <varlistentry id="sln">
 699         <term><command>sln</command></term>
 700         <listitem>
 701           <para>A statically linked <command>ln</command> program</para>
 702           <indexterm zone="ch-system-glibc sln">
 703             <primary sortas="b-sln">sln</primary>
 704           </indexterm>
 705         </listitem>
 706       </varlistentry>
 707
 708       <varlistentry id="sotruss">
 709         <term><command>sotruss</command></term>
 710         <listitem>
 711           <para>Traces shared library procedure calls of a specified command</para>
 712           <indexterm zone="ch-system-glibc sotruss">
 713             <primary sortas="b-sotruss">sotruss</primary>
 714           </indexterm>
 715         </listitem>
 716       </varlistentry>
 717
 718       <varlistentry id="sprof">
 719         <term><command>sprof</command></term>
 720         <listitem>
 721           <para>Reads and displays shared object profiling data</para>
 722           <indexterm zone="ch-system-glibc sprof">
 723             <primary sortas="b-sprof">sprof</primary>
 724           </indexterm>
 725         </listitem>
 726       </varlistentry>
 727
 728       <varlistentry id="tzselect">
 729         <term><command>tzselect</command></term>
 730         <listitem>
 731           <para>Asks the user about the location of the system and reports
 732           the corresponding time zone description</para>
 733           <indexterm zone="ch-system-glibc tzselect">
 734             <primary sortas="b-tzselect">tzselect</primary>
 735           </indexterm>
 736         </listitem>
 737       </varlistentry>
 738
 739       <varlistentry id="xtrace">
 740         <term><command>xtrace</command></term>
 741         <listitem>
 742           <para>Traces the execution of a program by printing the currently
 743           executed function</para>
 744           <indexterm zone="ch-system-glibc xtrace">
 745             <primary sortas="b-xtrace">xtrace</primary>
 746           </indexterm>
 747         </listitem>
 748       </varlistentry>
 749
 750       <varlistentry id="zdump">
 751         <term><command>zdump</command></term>
 752         <listitem>
 753           <para>The time zone dumper</para>
 754           <indexterm zone="ch-system-glibc zdump">
 755             <primary sortas="b-zdump">zdump</primary>
 756           </indexterm>
 757         </listitem>
 758       </varlistentry>
 759
 760       <varlistentry id="zic">
 761         <term><command>zic</command></term>
 762         <listitem>
 763           <para>The time zone compiler</para>
 764           <indexterm zone="ch-system-glibc zic">
 765             <primary sortas="b-zic">zic</primary>
 766           </indexterm>
 767         </listitem>
 768       </varlistentry>
 769
 770       <varlistentry id="ld.so">
 771         <term><filename class="libraryfile">ld-&glibc-version;.so</filename></term>
 772         <listitem>
 773           <para>The helper program for shared library executables</para>
 774           <indexterm zone="ch-system-glibc ld.so">
 775             <primary sortas="c-ld.so">ld-&glibc-version;.so</primary>
 776           </indexterm>
 777         </listitem>
 778       </varlistentry>
 779
 780       <varlistentry id="libBrokenLocale">
 781         <term><filename class="libraryfile">libBrokenLocale</filename></term>
 782         <listitem>
 783           <para>Used internally by Glibc as a gross hack to get broken programs
 784           (e.g., some Motif applications) running. See comments in
 785           <filename>glibc-&glibc-version;/locale/broken_cur_max.c</filename>
 786           for more information</para>
 787           <indexterm zone="ch-system-glibc libBrokenLocale">
 788             <primary sortas="c-libBrokenLocale">libBrokenLocale</primary>
 789           </indexterm>
 790         </listitem>
 791       </varlistentry>
 792
 793       <varlistentry id="libSegFault">
 794         <term><filename class="libraryfile">libSegFault</filename></term>
 795         <listitem>
 796           <para>The segmentation fault signal handler, used by
 797           <command>catchsegv</command></para>
 798           <indexterm zone="ch-system-glibc libSegFault">
 799             <primary sortas="c-libSegFault">libSegFault</primary>
 800           </indexterm>
 801         </listitem>
 802       </varlistentry>
 803
 804       <varlistentry id="libanl">
 805         <term><filename class="libraryfile">libanl</filename></term>
 806         <listitem>
 807           <para>An asynchronous name lookup library</para>
 808           <indexterm zone="ch-system-glibc libanl">
 809             <primary sortas="c-libanl">libanl</primary>
 810           </indexterm>
 811         </listitem>
 812       </varlistentry>
 813
 814       <varlistentry id="libc">
 815         <term><filename class="libraryfile">libc</filename></term>
 816         <listitem>
 817           <para>The main C library</para>
 818           <indexterm zone="ch-system-glibc libc">
 819             <primary sortas="c-libc">libc</primary>
 820           </indexterm>
 821         </listitem>
 822       </varlistentry>
 823
 824       <varlistentry id="libcrypt">
 825         <term><filename class="libraryfile">libcrypt</filename></term>
 826         <listitem>
 827           <para>The cryptography library</para>
 828           <indexterm zone="ch-system-glibc libcrypt">
 829             <primary sortas="c-libcrypt">libcrypt</primary>
 830           </indexterm>
 831         </listitem>
 832       </varlistentry>
 833
 834       <varlistentry id="libdl">
 835         <term><filename class="libraryfile">libdl</filename></term>
 836         <listitem>
 837           <para>The dynamic linking interface library</para>
 838           <indexterm zone="ch-system-glibc libdl">
 839             <primary sortas="c-libdl">libdl</primary>
 840           </indexterm>
 841         </listitem>
 842       </varlistentry>
 843
 844       <varlistentry id="libg">
 845         <term><filename class="libraryfile">libg</filename></term>
 846         <listitem>
 847           <para>Dummy library containing no functions. Previously was a runtime
 848           library for <command>g++</command></para>
 849           <indexterm zone="ch-system-glibc libg">
 850             <primary sortas="c-libg">libg</primary>
 851           </indexterm>
 852         </listitem>
 853       </varlistentry>
 854
 855       <varlistentry id="libm">
 856         <term><filename class="libraryfile">libm</filename></term>
 857         <listitem>
 858           <para>The mathematical library</para>
 859           <indexterm zone="ch-system-glibc libm">
 860             <primary sortas="c-libm">libm</primary>
 861           </indexterm>
 862         </listitem>
 863       </varlistentry>
 864
 865       <varlistentry id="libmcheck">
 866         <term><filename class="libraryfile">libmcheck</filename></term>
 867         <listitem>
 868           <para>Turns on memory allocation checking when linked to</para>
 869           <indexterm zone="ch-system-glibc libmcheck">
 870             <primary sortas="c-libmcheck">libmcheck</primary>
 871           </indexterm>
 872         </listitem>
 873       </varlistentry>
 874
 875       <varlistentry id="libmemusage">
 876         <term><filename class="libraryfile">libmemusage</filename></term>
 877         <listitem>
 878           <para>Used by <command>memusage</command> to help collect
 879           information about the memory usage of a program</para>
 880           <indexterm zone="ch-system-glibc libmemusage">
 881             <primary sortas="c-libmemusage">libmemusage</primary>
 882           </indexterm>
 883         </listitem>
 884       </varlistentry>
 885
 886       <varlistentry id="libnsl">
 887         <term><filename class="libraryfile">libnsl</filename></term>
 888         <listitem>
 889           <para>The network services library</para>
 890           <indexterm zone="ch-system-glibc libnsl">
 891             <primary sortas="c-libnsl">libnsl</primary>
 892           </indexterm>
 893         </listitem>
 894       </varlistentry>
 895
 896       <varlistentry id="libnss">
 897         <term><filename class="libraryfile">libnss</filename></term>
 898         <listitem>
 899           <para>The Name Service Switch libraries, containing functions for
 900           resolving host names, user names, group names, aliases, services,
 901           protocols, etc.</para>
 902           <indexterm zone="ch-system-glibc libnss">
 903             <primary sortas="c-libnss">libnss</primary>
 904           </indexterm>
 905         </listitem>
 906       </varlistentry>
 907
 908       <varlistentry id="libpcprofile">
 909         <term><filename class="libraryfile">libpcprofile</filename></term>
 910         <listitem>
 911           <para>Can be preloaded to PC profile an executable</para>
 912           <indexterm zone="ch-system-glibc libpcprofile">
 913             <primary sortas="c-libpcprofile">libpcprofile</primary>
 914           </indexterm>
 915         </listitem>
 916       </varlistentry>
 917
 918       <varlistentry id="libpthread">
 919         <term><filename class="libraryfile">libpthread</filename></term>
 920         <listitem>
 921           <para>The POSIX threads library</para>
 922           <indexterm zone="ch-system-glibc libpthread">
 923             <primary sortas="c-libpthread">libpthread</primary>
 924           </indexterm>
 925         </listitem>
 926       </varlistentry>
 927
 928       <varlistentry id="libresolv">
 929         <term><filename class="libraryfile">libresolv</filename></term>
 930         <listitem>
 931           <para>Contains functions for creating, sending, and interpreting
 932           packets to the Internet domain name servers</para>
 933           <indexterm zone="ch-system-glibc libresolv">
 934             <primary sortas="c-libresolv">libresolv</primary>
 935           </indexterm>
 936         </listitem>
 937       </varlistentry>
 938
 939       <varlistentry id="librt">
 940         <term><filename class="libraryfile">librt</filename></term>
 941         <listitem>
 942           <para>Contains functions providing most of the interfaces specified
 943           by the POSIX.1b Realtime Extension</para>
 944           <indexterm zone="ch-system-glibc librt">
 945             <primary sortas="c-librt">librt</primary>
 946           </indexterm>
 947         </listitem>
 948       </varlistentry>
 949
 950       <varlistentry id="libthread_db">
 951         <term><filename class="libraryfile">libthread_db</filename></term>
 952         <listitem>
 953           <para>Contains functions useful for building debuggers for
 954           multi-threaded programs</para>
 955           <indexterm zone="ch-system-glibc libthread_db">
 956             <primary sortas="c-libthread_db">libthread_db</primary>
 957           </indexterm>
 958         </listitem>
 959       </varlistentry>
 960
 961       <varlistentry id="libutil">
 962         <term><filename class="libraryfile">libutil</filename></term>
 963         <listitem>
 964           <para>Contains code for <quote>standard</quote> functions used in
 965           many different Unix utilities</para>
 966           <indexterm zone="ch-system-glibc libutil">
 967             <primary sortas="c-libutil">libutil</primary>
 968           </indexterm>
 969         </listitem>
 970       </varlistentry>
 971
 972     </variablelist>
 973
 974   </sect2>
 975
 976 </sect1>