BOOK/chapter08/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-fin-sbu;</seg>
  37         <seg>&glibc-fin-du;</seg>
  38       </seglistitem>
  39     </segmentedlist>
  40
  41   </sect2>
  42
  43   <sect2 role="installation">
  44     <title>Installation of Glibc</title>
  45
  46     <para>Some of the Glibc programs use the non-FHS compliant
  47     <filename class="directory">/var/db</filename> directory to store
  48     their runtime data. Apply the following patch to make such programs
  49     store their runtime data in the FHS-compliant locations:</para>
  50
  51 <screen><userinput remap="pre">patch -Np1 -i ../&glibc-fhs-patch;</userinput></screen>
  52
  53     <para>The Glibc documentation recommends building Glibc
  54     in a dedicated build directory:</para>
  55
  56 <screen><userinput remap="pre">mkdir -v build
  57 cd       build</userinput></screen>
  58
  59     <para>Prepare Glibc for compilation:</para>
  60
  61 <screen><userinput remap="configure">../configure --prefix=/usr                            \
  62              --disable-werror                         \
  63              --enable-kernel=&min-kernel;                      \
  64              --enable-stack-protector=strong          \
  65              --with-headers=/usr/include              \
  66              libc_cv_slibdir=/lib</userinput></screen>
  67
  68     <variablelist>
  69       <title>The meaning of the configure options:</title>
  70
  71       <varlistentry>
  72         <term><parameter>--disable-werror</parameter></term>
  73         <listitem>
  74           <para>This option disables the -Werror option passed to
  75           GCC.  This is necessary for running the test suite.</para>
  76         </listitem>
  77       </varlistentry>
  78
  79       <varlistentry>
  80         <term><parameter>--enable-kernel=&min-kernel;</parameter></term>
  81         <listitem>
  82           <para>This option tells the build system that this glibc may
  83           be used with kernels as old as &min-kernel;. This means generating
  84           workarounds in case a system call introduced in a later version
  85           cannot be used.</para>
  86         </listitem>
  87       </varlistentry>
  88
  89       <varlistentry>
  90         <term><parameter>--enable-stack-protector=strong</parameter></term>
  91         <listitem>
  92           <para>This option increases system security by adding
  93           extra code to check for buffer overflows, such as stack
  94           smashing attacks.</para>
  95         </listitem>
  96       </varlistentry>
  97 <!-- do we need this one? -->
  98       <varlistentry>
  99         <term><parameter>--with-headers=/usr/include</parameter></term>
 100         <listitem>
 101           <para>This option tells the build system where to find the
 102           kernel API headers.</para>
 103         </listitem>
 104       </varlistentry>
 105
 106       <varlistentry>
 107         <term><parameter>libc_cv_slibdir=/lib</parameter></term>
 108         <listitem>
 109           <para>This variable sets the correct library for all
 110           systems.  We do not want lib64 to be used.</para>
 111         </listitem>
 112       </varlistentry>
 113
 114     </variablelist>
 115
 116     <para>Compile the package:</para>
 117
 118 <screen><userinput remap="make">make</userinput></screen>
 119
 120     <important>
 121       <para>In this section, the test suite for Glibc is considered critical.
 122       Do not skip it under any circumstance.</para>
 123     </important>
 124
 125     <para>Generally a few tests do not pass. The test failures listed below
 126     are usually safe to ignore.</para>
 127
 128 <!-- Use remap="make" here to work around a jhalfs issue. -->
 129 <screen><userinput remap="make">case $(uname -m) in
 130   i?86)   ln -sfnv $PWD/elf/ld-linux.so.2        /lib ;;
 131   x86_64) ln -sfnv $PWD/elf/ld-linux-x86-64.so.2 /lib ;;
 132 esac</userinput></screen>
 133
 134     <note><para>The symbolic link above is needed to run the tests at this
 135     stage of building in the chroot environment.  It will be overwritten
 136     in the install phase below.</para></note>
 137
 138 <screen><userinput remap="test">make check</userinput></screen>
 139
 140     <para>You may see some test failures.  The Glibc test suite is
 141     somewhat dependent on the host system.  This is a list of the most common
 142     issues seen for some versions of LFS:</para>
 143
 144     <itemizedlist>
 145
 146       <listitem>
 147         <para><emphasis>io/tst-lchmod</emphasis>
 148         is known to fail in the LFS chroot environment.</para>
 149       </listitem>
 150
 151       <listitem>
 152         <para><emphasis>misc/tst-ttyname</emphasis>
 153         is known to fail in the LFS chroot environment.</para>
 154       </listitem>
 155 <!--
 156       <listitem>
 157         <para><emphasis>inet/tst-idna_name_classify</emphasis>
 158         is known to fail in the LFS chroot environment.</para>
 159       </listitem>
 160
 161       <listitem>
 162         <para><emphasis>posix/tst-getaddrinfo4</emphasis> and
 163         <emphasis>posix/tst-getaddrinfo5</emphasis>
 164         may fail on some architectures.</para>
 165       </listitem>
 166 -->
 167       <listitem>
 168         <para>The <emphasis>nss/tst-nss-files-hosts-multi</emphasis>
 169         test may fail for reasons that have not been determined.</para>
 170       </listitem>
 171
 172       <listitem>
 173         <para>The <emphasis>rt/tst-cputimer{1,2,3}</emphasis> tests depend on
 174         the host system kernel. Kernels 4.14.91&ndash;4.14.96,
 175         4.19.13&ndash;4.19.18, and 4.20.0&ndash;4.20.5 are known to
 176         cause these tests to fail.
 177         </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     </itemizedlist>
 187
 188     <para>Though it is a harmless message, the install stage of Glibc will
 189     complain about the absence of <filename>/etc/ld.so.conf</filename>.
 190     Prevent this warning with:</para>
 191
 192 <screen><userinput remap="install">touch /etc/ld.so.conf</userinput></screen>
 193
 194     <para>Fix the generated Makefile to skip an unneeded sanity check
 195     that fails in the LFS partial environment:
 196     </para>
 197
 198 <screen><userinput remap="install">sed '/test-installation/s@$(PERL)@echo not running@' -i ../Makefile</userinput></screen>
 199
 200     <para>Install the package:</para>
 201
 202 <screen><userinput remap="install">make install</userinput></screen>
 203
 204     <para>Install the configuration file and runtime directory for
 205     <command>nscd</command>:</para>
 206
 207 <screen><userinput remap="install">cp -v ../nscd/nscd.conf /etc/nscd.conf
 208 mkdir -pv /var/cache/nscd</userinput></screen>
 209
 210     <para revision="systemd">Install the systemd support files for
 211     <command>nscd</command>:</para>
 212
 213     <screen revision="systemd"><userinput remap="install">install -v -Dm644 ../nscd/nscd.tmpfiles /usr/lib/tmpfiles.d/nscd.conf
 214 install -v -Dm644 ../nscd/nscd.service /lib/systemd/system/nscd.service</userinput></screen>
 215
 216     <para>Next, install the locales that can make the system respond in a
 217     different language.  None of the locales are required, but if some of them
 218     are missing, the test suites of future packages would skip important
 219     testcases.</para>
 220
 221     <para>Individual locales can be installed using the
 222     <command>localedef</command> program. E.g., the first
 223     <command>localedef</command> command below combines the
 224     <filename>/usr/share/i18n/locales/cs_CZ</filename>
 225     charset-independent locale definition with the
 226     <filename>/usr/share/i18n/charmaps/UTF-8.gz</filename>
 227     charmap definition and appends the result to the
 228     <filename>/usr/lib/locale/locale-archive</filename> file.
 229     The following instructions will install the minimum set of
 230     locales necessary for the optimal coverage of tests:</para>
 231
 232 <screen role="nodump"><userinput remap="locale-test">mkdir -pv /usr/lib/locale
 233 localedef -i POSIX -f UTF-8 C.UTF-8 2> /dev/null || true
 234 localedef -i cs_CZ -f UTF-8 cs_CZ.UTF-8
 235 localedef -i de_DE -f ISO-8859-1 de_DE
 236 localedef -i de_DE@euro -f ISO-8859-15 de_DE@euro
 237 localedef -i de_DE -f UTF-8 de_DE.UTF-8
 238 localedef -i el_GR -f ISO-8859-7 el_GR
 239 localedef -i en_GB -f UTF-8 en_GB.UTF-8
 240 localedef -i en_HK -f ISO-8859-1 en_HK
 241 localedef -i en_PH -f ISO-8859-1 en_PH
 242 localedef -i en_US -f ISO-8859-1 en_US
 243 localedef -i en_US -f UTF-8 en_US.UTF-8
 244 localedef -i es_MX -f ISO-8859-1 es_MX
 245 localedef -i fa_IR -f UTF-8 fa_IR
 246 localedef -i fr_FR -f ISO-8859-1 fr_FR
 247 localedef -i fr_FR@euro -f ISO-8859-15 fr_FR@euro
 248 localedef -i fr_FR -f UTF-8 fr_FR.UTF-8
 249 localedef -i it_IT -f ISO-8859-1 it_IT
 250 localedef -i it_IT -f UTF-8 it_IT.UTF-8
 251 localedef -i ja_JP -f EUC-JP ja_JP
 252 localedef -i ja_JP -f SHIFT_JIS ja_JP.SIJS 2> /dev/null || true
 253 localedef -i ja_JP -f UTF-8 ja_JP.UTF-8
 254 localedef -i ru_RU -f KOI8-R ru_RU.KOI8-R
 255 localedef -i ru_RU -f UTF-8 ru_RU.UTF-8
 256 localedef -i tr_TR -f UTF-8 tr_TR.UTF-8
 257 localedef -i zh_CN -f GB18030 zh_CN.GB18030
 258 localedef -i zh_HK -f BIG5-HKSCS zh_HK.BIG5-HKSCS</userinput></screen>
 259
 260     <para>In addition, install the locale for your own country, language and
 261     character set.</para>
 262
 263     <para>Alternatively, install all locales listed in the
 264     <filename>glibc-&glibc-version;/localedata/SUPPORTED</filename> file
 265     (it includes every locale listed above and many more) at once with the
 266     following time-consuming command:</para>
 267
 268 <screen><userinput remap="locale-full">make localedata/install-locales</userinput></screen>
 269
 270     <para>Then use the <command>localedef</command> command to create and
 271     install locales not listed in the
 272     <filename>glibc-&glibc-version;/localedata/SUPPORTED</filename> file
 273     in the unlikely case you need them.</para>
 274
 275     <note><para>Glibc now uses libidn2 when resolving internationalized
 276     domain names.  This is a run time dependency.  If this capability
 277     is needed, the instructions for installing libidn2 are in the
 278     <ulink url="&blfs-book;general/libidn2.html">BLFS libidn2 page</ulink>.
 279     </para></note>
 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; do
 335     zic -L /dev/null   -d $ZONEINFO       ${tz}
 336     zic -L /dev/null   -d $ZONEINFO/posix ${tz}
 337     zic -L leapseconds -d $ZONEINFO/right ${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           1.9 MB 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><userinput>ln -sfv /usr/share/zoneinfo/<replaceable>&lt;xxx&gt;</replaceable> /etc/localtime</userinput></screen>
 401
 402     <para>Replace <replaceable>&lt;xxx&gt;</replaceable> with the name of the
 403     time zone selected (e.g., Canada/Eastern).</para>
 404
 405   </sect3>
 406
 407   <sect3 id="conf-ld" role="configuration">
 408     <title>Configuring the Dynamic Loader</title>
 409
 410     <indexterm zone="conf-ld">
 411       <primary sortas="e-/etc/ld.so.conf">/etc/ld.so.conf</primary>
 412     </indexterm>
 413
 414     <para>By default, the dynamic loader (<filename
 415     class="libraryfile">/lib/ld-linux.so.2</filename>) searches through
 416     <filename class="directory">/lib</filename> and <filename
 417     class="directory">/usr/lib</filename> for dynamic libraries that are
 418     needed by programs as they are run. However, if there are libraries in
 419     directories other than <filename class="directory">/lib</filename> and
 420     <filename class="directory">/usr/lib</filename>, these need to be added
 421     to the <filename>/etc/ld.so.conf</filename> file in order for the
 422     dynamic loader to find them. Two directories that are commonly known
 423     to contain additional libraries are <filename
 424     class="directory">/usr/local/lib</filename> and <filename
 425     class="directory">/opt/lib</filename>, so add those directories to the
 426     dynamic loader's search path.</para>
 427
 428     <para>Create a new file <filename>/etc/ld.so.conf</filename> by running the
 429     following:</para>
 430
 431 <screen><userinput>cat &gt; /etc/ld.so.conf &lt;&lt; "EOF"
 432 <literal># Begin /etc/ld.so.conf
 433 /usr/local/lib
 434 /opt/lib
 435 </literal>
 436 EOF</userinput></screen>
 437
 438   <para>If desired, the dynamic loader can also search a directory and
 439   include the contents of files found there.  Generally the files in
 440   this include directory are one line specifying the desired library path.
 441   To add this capability run the following commands:</para>
 442
 443 <screen role="nodump"><userinput>cat &gt;&gt; /etc/ld.so.conf &lt;&lt; "EOF"
 444 <literal># Add an include directory
 445 include /etc/ld.so.conf.d/*.conf
 446 </literal>
 447 EOF
 448 mkdir -pv /etc/ld.so.conf.d</userinput></screen>
 449
 450   </sect3>
 451   </sect2>
 452
 453   <sect2 id="contents-glibc" role="content">
 454     <title>Contents of Glibc</title>
 455
 456     <segmentedlist>
 457       <segtitle>Installed programs</segtitle>
 458       <segtitle>Installed libraries</segtitle>
 459       <segtitle>Installed directories</segtitle>
 460
 461       <seglistitem>
 462         <seg>catchsegv, gencat, getconf, getent, iconv, iconvconfig, ldconfig,
 463         ldd, lddlibc4, locale, localedef, makedb, mtrace, nscd,
 464         pcprofiledump, pldd, sln, sotruss, sprof, tzselect, xtrace,
 465         zdump, and zic</seg>
 466         <seg>ld-&glibc-version;.so, libBrokenLocale.{a,so}, libSegFault.so, libanl.{a,so},
 467         libc.{a,so}, libc_nonshared.a,
 468         libcrypt.{a,so}, libdl.{a,so}, libg.a, libm.{a,so},
 469         libmcheck.a, libmemusage.so, libmvec.{a,so}, libnsl.{a,so},
 470         libnss_compat.so, libnss_dns.so, libnss_files.so, libnss_hesiod.so,
 471         libpcprofile.so, libpthread.{a,so},
 472         libpthread_nonshared.a, libresolv.{a,so}, librt.{a,so},
 473         libthread_db.so, and libutil.{a,so}</seg>
 474         <seg>/usr/include/arpa, /usr/include/bits, /usr/include/gnu,
 475         /usr/include/net, /usr/include/netash, /usr/include/netatalk,
 476         /usr/include/netax25, /usr/include/neteconet, /usr/include/netinet,
 477         /usr/include/netipx, /usr/include/netiucv, /usr/include/netpacket,
 478         /usr/include/netrom, /usr/include/netrose, /usr/include/nfs,
 479         /usr/include/protocols, /usr/include/rpc,
 480         /usr/include/sys, /usr/lib/audit, /usr/lib/gconv, /usr/lib/locale,
 481         /usr/libexec/getconf, /usr/share/i18n, /usr/share/zoneinfo,
 482         /var/cache/nscd, and /var/lib/nss_db</seg>
 483       </seglistitem>
 484     </segmentedlist>
 485
 486     <variablelist>
 487       <bridgehead renderas="sect3">Short Descriptions</bridgehead>
 488       <?dbfo list-presentation="list"?>
 489       <?dbhtml list-presentation="table"?>
 490
 491       <varlistentry id="catchsegv">
 492         <term><command>catchsegv</command></term>
 493         <listitem>
 494           <para>Can be used to create a stack trace when a program
 495           terminates with a segmentation fault</para>
 496           <indexterm zone="ch-system-glibc catchsegv">
 497             <primary sortas="b-catchsegv">catchsegv</primary>
 498           </indexterm>
 499         </listitem>
 500       </varlistentry>
 501
 502       <varlistentry id="gencat">
 503         <term><command>gencat</command></term>
 504         <listitem>
 505           <para>Generates message catalogues</para>
 506           <indexterm zone="ch-system-glibc gencat">
 507             <primary sortas="b-gencat">gencat</primary>
 508           </indexterm>
 509         </listitem>
 510       </varlistentry>
 511
 512       <varlistentry id="getconf">
 513         <term><command>getconf</command></term>
 514         <listitem>
 515           <para>Displays the system configuration values for file system
 516           specific variables</para>
 517           <indexterm zone="ch-system-glibc getconf">
 518             <primary sortas="b-getconf">getconf</primary>
 519           </indexterm>
 520         </listitem>
 521       </varlistentry>
 522
 523       <varlistentry id="getent">
 524         <term><command>getent</command></term>
 525         <listitem>
 526           <para>Gets entries from an administrative database</para>
 527           <indexterm zone="ch-system-glibc getent">
 528             <primary sortas="b-getent">getent</primary>
 529           </indexterm>
 530         </listitem>
 531       </varlistentry>
 532
 533       <varlistentry id="iconv">
 534         <term><command>iconv</command></term>
 535         <listitem>
 536           <para>Performs character set conversion</para>
 537           <indexterm zone="ch-system-glibc iconv">
 538             <primary sortas="b-iconv">iconv</primary>
 539           </indexterm>
 540         </listitem>
 541       </varlistentry>
 542
 543       <varlistentry id="iconvconfig">
 544         <term><command>iconvconfig</command></term>
 545         <listitem>
 546           <para>Creates fastloading <command>iconv</command> module configuration
 547           files</para>
 548           <indexterm zone="ch-system-glibc iconvconfig">
 549             <primary sortas="b-iconvconfig">iconvconfig</primary>
 550           </indexterm>
 551         </listitem>
 552       </varlistentry>
 553
 554       <varlistentry id="ldconfig">
 555         <term><command>ldconfig</command></term>
 556         <listitem>
 557           <para>Configures the dynamic linker runtime bindings</para>
 558           <indexterm zone="ch-system-glibc ldconfig">
 559             <primary sortas="b-ldconfig">ldconfig</primary>
 560           </indexterm>
 561         </listitem>
 562       </varlistentry>
 563
 564       <varlistentry id="ldd">
 565         <term><command>ldd</command></term>
 566         <listitem>
 567           <para>Reports which shared libraries are required
 568           by each given program or shared library</para>
 569           <indexterm zone="ch-system-glibc ldd">
 570             <primary sortas="b-ldd">ldd</primary>
 571           </indexterm>
 572         </listitem>
 573       </varlistentry>
 574
 575       <varlistentry id="lddlibc4">
 576         <term><command>lddlibc4</command></term>
 577         <listitem>
 578           <para>Assists <command>ldd</command> with object files</para>
 579           <indexterm zone="ch-system-glibc lddlibc4">
 580             <primary sortas="b-lddlibc4">lddlibc4</primary>
 581           </indexterm>
 582         </listitem>
 583       </varlistentry>
 584
 585       <varlistentry id="locale">
 586         <term><command>locale</command></term>
 587         <listitem>
 588           <para>Prints various information about the current locale</para>
 589           <indexterm zone="ch-system-glibc locale">
 590             <primary sortas="b-locale">locale</primary>
 591           </indexterm>
 592         </listitem>
 593       </varlistentry>
 594
 595       <varlistentry id="localedef">
 596         <term><command>localedef</command></term>
 597         <listitem>
 598           <para>Compiles locale specifications</para>
 599           <indexterm zone="ch-system-glibc localedef">
 600             <primary sortas="b-localedef">localedef</primary>
 601           </indexterm>
 602         </listitem>
 603       </varlistentry>
 604
 605       <varlistentry id="makedb">
 606         <term><command>makedb</command></term>
 607         <listitem>
 608           <para>Creates a simple database from textual input</para>
 609           <indexterm zone="ch-system-glibc makedb">
 610             <primary sortas="b-makedb">makedb</primary>
 611           </indexterm>
 612         </listitem>
 613       </varlistentry>
 614
 615       <varlistentry id="mtrace">
 616         <term><command>mtrace</command></term>
 617         <listitem>
 618           <para>Reads and interprets a memory trace file and displays a summary
 619           in human-readable format</para>
 620           <indexterm zone="ch-system-glibc mtrace">
 621             <primary sortas="b-mtrace">mtrace</primary>
 622           </indexterm>
 623         </listitem>
 624       </varlistentry>
 625
 626       <varlistentry id="nscd">
 627         <term><command>nscd</command></term>
 628         <listitem>
 629           <para>A daemon that provides a cache for the most common name
 630           service requests</para>
 631           <indexterm zone="ch-system-glibc nscd">
 632             <primary sortas="b-nscd">nscd</primary>
 633           </indexterm>
 634         </listitem>
 635       </varlistentry>
 636
 637       <varlistentry id="pcprofiledump">
 638         <term><command>pcprofiledump</command></term>
 639         <listitem>
 640           <para>Dump information generated by PC profiling</para>
 641           <indexterm zone="ch-system-glibc pcprofiledump">
 642             <primary sortas="b-pcprofiledump">pcprofiledump</primary>
 643           </indexterm>
 644         </listitem>
 645       </varlistentry>
 646
 647       <varlistentry id="pldd">
 648         <term><command>pldd</command></term>
 649         <listitem>
 650           <para>Lists dynamic shared objects used by running processes</para>
 651           <indexterm zone="ch-system-glibc pldd">
 652             <primary sortas="b-pldd">pldd</primary>
 653           </indexterm>
 654         </listitem>
 655       </varlistentry>
 656
 657       <varlistentry id="sln">
 658         <term><command>sln</command></term>
 659         <listitem>
 660           <para>A statically linked <command>ln</command> program</para>
 661           <indexterm zone="ch-system-glibc sln">
 662             <primary sortas="b-sln">sln</primary>
 663           </indexterm>
 664         </listitem>
 665       </varlistentry>
 666
 667       <varlistentry id="sotruss">
 668         <term><command>sotruss</command></term>
 669         <listitem>
 670           <para>Traces shared library procedure calls of a specified command</para>
 671           <indexterm zone="ch-system-glibc sotruss">
 672             <primary sortas="b-sotruss">sotruss</primary>
 673           </indexterm>
 674         </listitem>
 675       </varlistentry>
 676
 677       <varlistentry id="sprof">
 678         <term><command>sprof</command></term>
 679         <listitem>
 680           <para>Reads and displays shared object profiling data</para>
 681           <indexterm zone="ch-system-glibc sprof">
 682             <primary sortas="b-sprof">sprof</primary>
 683           </indexterm>
 684         </listitem>
 685       </varlistentry>
 686
 687       <varlistentry id="tzselect">
 688         <term><command>tzselect</command></term>
 689         <listitem>
 690           <para>Asks the user about the location of the system and reports
 691           the corresponding time zone description</para>
 692           <indexterm zone="ch-system-glibc tzselect">
 693             <primary sortas="b-tzselect">tzselect</primary>
 694           </indexterm>
 695         </listitem>
 696       </varlistentry>
 697
 698       <varlistentry id="xtrace">
 699         <term><command>xtrace</command></term>
 700         <listitem>
 701           <para>Traces the execution of a program by printing the currently
 702           executed function</para>
 703           <indexterm zone="ch-system-glibc xtrace">
 704             <primary sortas="b-xtrace">xtrace</primary>
 705           </indexterm>
 706         </listitem>
 707       </varlistentry>
 708
 709       <varlistentry id="zdump">
 710         <term><command>zdump</command></term>
 711         <listitem>
 712           <para>The time zone dumper</para>
 713           <indexterm zone="ch-system-glibc zdump">
 714             <primary sortas="b-zdump">zdump</primary>
 715           </indexterm>
 716         </listitem>
 717       </varlistentry>
 718
 719       <varlistentry id="zic">
 720         <term><command>zic</command></term>
 721         <listitem>
 722           <para>The time zone compiler</para>
 723           <indexterm zone="ch-system-glibc zic">
 724             <primary sortas="b-zic">zic</primary>
 725           </indexterm>
 726         </listitem>
 727       </varlistentry>
 728
 729       <varlistentry id="ld.so">
 730         <term><filename class="libraryfile">ld-&glibc-version;.so</filename></term>
 731         <listitem>
 732           <para>The helper program for shared library executables</para>
 733           <indexterm zone="ch-system-glibc ld.so">
 734             <primary sortas="c-ld.so">ld-&glibc-version;.so</primary>
 735           </indexterm>
 736         </listitem>
 737       </varlistentry>
 738
 739       <varlistentry id="libBrokenLocale">
 740         <term><filename class="libraryfile">libBrokenLocale</filename></term>
 741         <listitem>
 742           <para>Used internally by Glibc as a gross hack to get broken programs
 743           (e.g., some Motif applications) running. See comments in
 744           <filename>glibc-&glibc-version;/locale/broken_cur_max.c</filename>
 745           for more information</para>
 746           <indexterm zone="ch-system-glibc libBrokenLocale">
 747             <primary sortas="c-libBrokenLocale">libBrokenLocale</primary>
 748           </indexterm>
 749         </listitem>
 750       </varlistentry>
 751
 752       <varlistentry id="libSegFault">
 753         <term><filename class="libraryfile">libSegFault</filename></term>
 754         <listitem>
 755           <para>The segmentation fault signal handler, used by
 756           <command>catchsegv</command></para>
 757           <indexterm zone="ch-system-glibc libSegFault">
 758             <primary sortas="c-libSegFault">libSegFault</primary>
 759           </indexterm>
 760         </listitem>
 761       </varlistentry>
 762
 763       <varlistentry id="libanl">
 764         <term><filename class="libraryfile">libanl</filename></term>
 765         <listitem>
 766           <para>An asynchronous name lookup library</para>
 767           <indexterm zone="ch-system-glibc libanl">
 768             <primary sortas="c-libanl">libanl</primary>
 769           </indexterm>
 770         </listitem>
 771       </varlistentry>
 772
 773       <varlistentry id="libc">
 774         <term><filename class="libraryfile">libc</filename></term>
 775         <listitem>
 776           <para>The main C library</para>
 777           <indexterm zone="ch-system-glibc libc">
 778             <primary sortas="c-libc">libc</primary>
 779           </indexterm>
 780         </listitem>
 781       </varlistentry>
 782
 783       <varlistentry id="libcrypt">
 784         <term><filename class="libraryfile">libcrypt</filename></term>
 785         <listitem>
 786           <para>The cryptography library</para>
 787           <indexterm zone="ch-system-glibc libcrypt">
 788             <primary sortas="c-libcrypt">libcrypt</primary>
 789           </indexterm>
 790         </listitem>
 791       </varlistentry>
 792
 793       <varlistentry id="libdl">
 794         <term><filename class="libraryfile">libdl</filename></term>
 795         <listitem>
 796           <para>The dynamic linking interface library</para>
 797           <indexterm zone="ch-system-glibc libdl">
 798             <primary sortas="c-libdl">libdl</primary>
 799           </indexterm>
 800         </listitem>
 801       </varlistentry>
 802
 803       <varlistentry id="libg">
 804         <term><filename class="libraryfile">libg</filename></term>
 805         <listitem>
 806           <para>Dummy library containing no functions. Previously was a runtime
 807           library for <command>g++</command></para>
 808           <indexterm zone="ch-system-glibc libg">
 809             <primary sortas="c-libg">libg</primary>
 810           </indexterm>
 811         </listitem>
 812       </varlistentry>
 813
 814       <varlistentry id="libm">
 815         <term><filename class="libraryfile">libm</filename></term>
 816         <listitem>
 817           <para>The mathematical library</para>
 818           <indexterm zone="ch-system-glibc libm">
 819             <primary sortas="c-libm">libm</primary>
 820           </indexterm>
 821         </listitem>
 822       </varlistentry>
 823
 824       <varlistentry id="libmcheck">
 825         <term><filename class="libraryfile">libmcheck</filename></term>
 826         <listitem>
 827           <para>Turns on memory allocation checking when linked to</para>
 828           <indexterm zone="ch-system-glibc libmcheck">
 829             <primary sortas="c-libmcheck">libmcheck</primary>
 830           </indexterm>
 831         </listitem>
 832       </varlistentry>
 833
 834       <varlistentry id="libmemusage">
 835         <term><filename class="libraryfile">libmemusage</filename></term>
 836         <listitem>
 837           <para>Used by <command>memusage</command> to help collect
 838           information about the memory usage of a program</para>
 839           <indexterm zone="ch-system-glibc libmemusage">
 840             <primary sortas="c-libmemusage">libmemusage</primary>
 841           </indexterm>
 842         </listitem>
 843       </varlistentry>
 844
 845       <varlistentry id="libnsl">
 846         <term><filename class="libraryfile">libnsl</filename></term>
 847         <listitem>
 848           <para>The network services library</para>
 849           <indexterm zone="ch-system-glibc libnsl">
 850             <primary sortas="c-libnsl">libnsl</primary>
 851           </indexterm>
 852         </listitem>
 853       </varlistentry>
 854
 855       <varlistentry id="libnss">
 856         <term><filename class="libraryfile">libnss</filename></term>
 857         <listitem>
 858           <para>The Name Service Switch libraries, containing functions for
 859           resolving host names, user names, group names, aliases, services,
 860           protocols, etc.</para>
 861           <indexterm zone="ch-system-glibc libnss">
 862             <primary sortas="c-libnss">libnss</primary>
 863           </indexterm>
 864         </listitem>
 865       </varlistentry>
 866
 867       <varlistentry id="libpcprofile">
 868         <term><filename class="libraryfile">libpcprofile</filename></term>
 869         <listitem>
 870           <para>Can be preloaded to PC profile an executable</para>
 871           <indexterm zone="ch-system-glibc libpcprofile">
 872             <primary sortas="c-libpcprofile">libpcprofile</primary>
 873           </indexterm>
 874         </listitem>
 875       </varlistentry>
 876
 877       <varlistentry id="libpthread">
 878         <term><filename class="libraryfile">libpthread</filename></term>
 879         <listitem>
 880           <para>The POSIX threads library</para>
 881           <indexterm zone="ch-system-glibc libpthread">
 882             <primary sortas="c-libpthread">libpthread</primary>
 883           </indexterm>
 884         </listitem>
 885       </varlistentry>
 886
 887       <varlistentry id="libresolv">
 888         <term><filename class="libraryfile">libresolv</filename></term>
 889         <listitem>
 890           <para>Contains functions for creating, sending, and interpreting
 891           packets to the Internet domain name servers</para>
 892           <indexterm zone="ch-system-glibc libresolv">
 893             <primary sortas="c-libresolv">libresolv</primary>
 894           </indexterm>
 895         </listitem>
 896       </varlistentry>
 897
 898       <varlistentry id="librt">
 899         <term><filename class="libraryfile">librt</filename></term>
 900         <listitem>
 901           <para>Contains functions providing most of the interfaces specified
 902           by the POSIX.1b Realtime Extension</para>
 903           <indexterm zone="ch-system-glibc librt">
 904             <primary sortas="c-librt">librt</primary>
 905           </indexterm>
 906         </listitem>
 907       </varlistentry>
 908
 909       <varlistentry id="libthread_db">
 910         <term><filename class="libraryfile">libthread_db</filename></term>
 911         <listitem>
 912           <para>Contains functions useful for building debuggers for
 913           multi-threaded programs</para>
 914           <indexterm zone="ch-system-glibc libthread_db">
 915             <primary sortas="c-libthread_db">libthread_db</primary>
 916           </indexterm>
 917         </listitem>
 918       </varlistentry>
 919
 920       <varlistentry id="libutil">
 921         <term><filename class="libraryfile">libutil</filename></term>
 922         <listitem>
 923           <para>Contains code for <quote>standard</quote> functions used in
 924           many different Unix utilities</para>
 925           <indexterm zone="ch-system-glibc libutil">
 926             <primary sortas="c-libutil">libutil</primary>
 927           </indexterm>
 928         </listitem>
 929       </varlistentry>
 930
 931     </variablelist>
 932
 933   </sect2>
 934
 935 </sect1>