source: chapter08/glibc.xml@ ba40e32

12.1 12.1-rc1 multilib trunk xry111/arm64 xry111/clfs-ng xry111/loongarch xry111/loongarch-12.1 xry111/mips64el xry111/update-glibc
Last change on this file since ba40e32 was ba40e32, checked in by Xi Ruoyao <xry111@…>, 9 months ago

systemd: Use NSS modules provided by systemd in nsswitch.conf

It allows a simplification to /etc/hosts. Also correct some info about
FQDN in both sysv and systemd.
  • Property mode set to 100644
File size: 35.9 KB
Line 
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>Now fix two security vulnerabilities and a regression causing the
54 posix_memalign() function very slow in some conditions:</para>
55
56<screen><userinput remap="pre">patch -Np1 -i ../&glibc-upstream-fixes-patch;</userinput></screen>
57
58 <para>The Glibc documentation recommends building Glibc
59 in a dedicated build directory:</para>
60
61<screen><userinput remap="pre">mkdir -v build
62cd build</userinput></screen>
63
64 <para>Ensure that the <command>ldconfig</command> and <command>sln</command>
65 utilities will be installed into
66 <filename class="directory">/usr/sbin</filename>:</para>
67
68<screen><userinput remap="pre">echo "rootsbindir=/usr/sbin" &gt; configparms</userinput></screen>
69
70 <para>Prepare Glibc for compilation:</para>
71
72<screen><userinput remap="configure">../configure --prefix=/usr \
73 --disable-werror \
74 --enable-kernel=&min-kernel; \
75 --enable-stack-protector=strong \
76 --with-headers=/usr/include \
77 libc_cv_slibdir=/usr/lib</userinput></screen>
78
79 <variablelist>
80 <title>The meaning of the configure options:</title>
81
82 <varlistentry>
83 <term><parameter>--disable-werror</parameter></term>
84 <listitem>
85 <para>This option disables the -Werror option passed to
86 GCC. This is necessary for running the test suite.</para>
87 </listitem>
88 </varlistentry>
89
90 <varlistentry>
91 <term><parameter>--enable-kernel=&min-kernel;</parameter></term>
92 <listitem>
93 <para>This option tells the build system that this Glibc may
94 be used with kernels as old as &min-kernel;. This means generating
95 workarounds in case a system call introduced in a later version
96 cannot be used.</para>
97 </listitem>
98 </varlistentry>
99
100 <varlistentry>
101 <term><parameter>--enable-stack-protector=strong</parameter></term>
102 <listitem>
103 <para>This option increases system security by adding
104 extra code to check for buffer overflows, such as stack
105 smashing attacks.</para>
106 </listitem>
107 </varlistentry>
108<!-- do we need this one? -->
109 <varlistentry>
110 <term><parameter>--with-headers=/usr/include</parameter></term>
111 <listitem>
112 <para>This option tells the build system where to find the
113 kernel API headers.</para>
114 </listitem>
115 </varlistentry>
116
117 <varlistentry>
118 <term><parameter>libc_cv_slibdir=/usr/lib</parameter></term>
119 <listitem>
120 <para>This variable sets the correct library for all
121 systems. We do not want lib64 to be used.</para>
122 </listitem>
123 </varlistentry>
124
125 </variablelist>
126
127 <para>Compile the package:</para>
128
129<screen><userinput remap="make">make</userinput></screen>
130
131 <important>
132 <para>In this section, the test suite for Glibc is considered critical.
133 Do not skip it under any circumstance.</para>
134 </important>
135
136 <para>Generally a few tests do not pass. The test failures listed below
137 are usually safe to ignore.</para>
138
139<!-- Use remap="make" here to work around a jhalfs issue. -->
140<!--<screen><userinput remap="make">case $(uname -m) in
141 i?86) ln -sfnv $PWD/elf/ld-linux.so.2 /lib ;;
142 x86_64) ln -sfnv $PWD/elf/ld-linux-x86-64.so.2 /lib ;;
143esac</userinput></screen>
144
145 <note><para>The symbolic link above is needed to run the tests at this
146 stage of building in the chroot environment. It will be overwritten
147 in the install phase below.</para></note>
148-->
149<screen><userinput remap="test">make check</userinput></screen>
150
151 <para>You may see some test failures. The Glibc test suite is
152 somewhat dependent on the host system. A few failures out of
153 over 5000 tests can generally be ignored. This is a list of the
154 most common issues seen for recent versions of LFS:</para>
155
156 <itemizedlist>
157
158 <listitem>
159 <para><emphasis>io/tst-lchmod</emphasis>
160 is known to fail in the LFS chroot environment.</para>
161 </listitem>
162
163<!-- Did not fail with glibc-2.38
164 <listitem>
165 <para><emphasis>misc/tst-ttyname</emphasis>
166 is known to fail in the LFS chroot environment.</para>
167 </listitem>
168-->
169
170 <!-- https://sourceware.org/pipermail/libc-alpha/2022-August/141567.html -->
171 <listitem>
172 <para>The <emphasis>stdlib/tst-arc4random-thread</emphasis>
173 test is known to fail if the host kernel is relatively old.</para>
174 </listitem>
175
176 <listitem>
177 <para>Some tests, for example
178 <emphasis>nss/tst-nss-files-hosts-multi</emphasis>,
179 are known to fail on relatively slow systems due to an internal
180 timeout.</para>
181 </listitem>
182
183 <listitem>
184 <para>Additionally, some tests may fail with a relatively old CPU
185 model or host kernel version.</para>
186 </listitem>
187 </itemizedlist>
188
189 <para>Though it is a harmless message, the install stage of Glibc will
190 complain about the absence of <filename>/etc/ld.so.conf</filename>.
191 Prevent this warning with:</para>
192
193<screen><userinput remap="install">touch /etc/ld.so.conf</userinput></screen>
194
195 <!-- https://sourceware.org/bugzilla/show_bug.cgi?id=21911 -->
196 <para>Fix the Makefile to skip an outdated sanity check
197 that fails with a modern Glibc configuration:</para>
198
199<screen><userinput remap="install">sed '/test-installation/s@$(PERL)@echo not running@' -i ../Makefile</userinput></screen>
200
201 <para>Install the package:</para>
202
203<screen><userinput remap="install">make install</userinput></screen>
204
205 <para>Fix a hardcoded path to the executable loader in the
206 <command>ldd</command> script:</para>
207
208<screen><userinput remap="install">sed '/RTLDLIST=/s@/usr@@g' -i /usr/bin/ldd</userinput></screen>
209
210 <para>Install the configuration file and runtime directory for
211 <command>nscd</command>:</para>
212
213<screen><userinput remap="install">cp -v ../nscd/nscd.conf /etc/nscd.conf
214mkdir -pv /var/cache/nscd</userinput></screen>
215
216 <para revision="systemd">Install the systemd support files for
217 <command>nscd</command>:</para>
218
219 <screen revision="systemd"><userinput remap="install">install -v -Dm644 ../nscd/nscd.tmpfiles /usr/lib/tmpfiles.d/nscd.conf
220install -v -Dm644 ../nscd/nscd.service /usr/lib/systemd/system/nscd.service</userinput></screen>
221
222 <para>Next, install the locales that can make the system respond in a
223 different language. None of these locales are required, but if some of them
224 are missing, the test suites of some packages will skip important
225 test cases.</para>
226
227 <para>Individual locales can be installed using the
228 <command>localedef</command> program. E.g., the second
229 <command>localedef</command> command below combines the
230 <filename>/usr/share/i18n/locales/cs_CZ</filename>
231 charset-independent locale definition with the
232 <filename>/usr/share/i18n/charmaps/UTF-8.gz</filename>
233 charmap definition and appends the result to the
234 <filename>/usr/lib/locale/locale-archive</filename> file.
235 The following instructions will install the minimum set of
236 locales necessary for the optimal coverage of tests:</para>
237
238<screen role="nodump"><userinput remap="locale-test">mkdir -pv /usr/lib/locale
239localedef -i POSIX -f UTF-8 C.UTF-8 2> /dev/null || true
240localedef -i cs_CZ -f UTF-8 cs_CZ.UTF-8
241localedef -i de_DE -f ISO-8859-1 de_DE
242localedef -i de_DE@euro -f ISO-8859-15 de_DE@euro
243localedef -i de_DE -f UTF-8 de_DE.UTF-8
244localedef -i el_GR -f ISO-8859-7 el_GR
245localedef -i en_GB -f ISO-8859-1 en_GB
246localedef -i en_GB -f UTF-8 en_GB.UTF-8
247localedef -i en_HK -f ISO-8859-1 en_HK
248localedef -i en_PH -f ISO-8859-1 en_PH
249localedef -i en_US -f ISO-8859-1 en_US
250localedef -i en_US -f UTF-8 en_US.UTF-8
251localedef -i es_ES -f ISO-8859-15 es_ES@euro
252localedef -i es_MX -f ISO-8859-1 es_MX
253localedef -i fa_IR -f UTF-8 fa_IR
254localedef -i fr_FR -f ISO-8859-1 fr_FR
255localedef -i fr_FR@euro -f ISO-8859-15 fr_FR@euro
256localedef -i fr_FR -f UTF-8 fr_FR.UTF-8
257localedef -i is_IS -f ISO-8859-1 is_IS
258localedef -i is_IS -f UTF-8 is_IS.UTF-8
259localedef -i it_IT -f ISO-8859-1 it_IT
260localedef -i it_IT -f ISO-8859-15 it_IT@euro
261localedef -i it_IT -f UTF-8 it_IT.UTF-8
262localedef -i ja_JP -f EUC-JP ja_JP
263localedef -i ja_JP -f SHIFT_JIS ja_JP.SJIS 2> /dev/null || true
264localedef -i ja_JP -f UTF-8 ja_JP.UTF-8
265localedef -i nl_NL@euro -f ISO-8859-15 nl_NL@euro
266localedef -i ru_RU -f KOI8-R ru_RU.KOI8-R
267localedef -i ru_RU -f UTF-8 ru_RU.UTF-8
268localedef -i se_NO -f UTF-8 se_NO.UTF-8
269localedef -i ta_IN -f UTF-8 ta_IN.UTF-8
270localedef -i tr_TR -f UTF-8 tr_TR.UTF-8
271localedef -i zh_CN -f GB18030 zh_CN.GB18030
272localedef -i zh_HK -f BIG5-HKSCS zh_HK.BIG5-HKSCS
273localedef -i zh_TW -f UTF-8 zh_TW.UTF-8</userinput></screen>
274
275 <para>In addition, install the locale for your own country, language and
276 character set.</para>
277
278 <para>Alternatively, install all the locales listed in the
279 <filename>glibc-&glibc-version;/localedata/SUPPORTED</filename> file
280 (it includes every locale listed above and many more) at once with the
281 following time-consuming command:</para>
282
283<screen><userinput remap="locale-full">make localedata/install-locales</userinput></screen>
284
285 <para>Then use the <command>localedef</command> command to create and
286 install locales not listed in the
287 <filename>glibc-&glibc-version;/localedata/SUPPORTED</filename> file
288 when you need them. For instance, the following two locales are
289 needed for some tests later in this chapter:</para>
290
291<screen role="nodump"><userinput remap="locale-full">localedef -i POSIX -f UTF-8 C.UTF-8 2> /dev/null || true
292localedef -i ja_JP -f SHIFT_JIS ja_JP.SJIS 2> /dev/null || true</userinput></screen>
293
294 <note><para>Glibc now uses libidn2 when resolving internationalized
295 domain names. This is a run time dependency. If this capability
296 is needed, the instructions for installing libidn2 are in the
297 <ulink url="&blfs-book;general/libidn2.html">BLFS libidn2 page</ulink>.
298 </para></note>
299
300 </sect2>
301
302 <sect2 id="conf-glibc" role="configuration">
303 <title>Configuring Glibc</title>
304
305 <indexterm zone="conf-glibc">
306 <primary sortas="e-/etc/nsswitch.conf">/etc/nsswitch.conf</primary>
307 </indexterm>
308
309 <indexterm zone="conf-glibc">
310 <primary sortas="e-/etc/localtime">/etc/localtime</primary>
311 </indexterm>
312
313 <sect3>
314 <title>Adding nsswitch.conf</title>
315
316 <para>The <filename>/etc/nsswitch.conf</filename> file needs to be created
317 because the Glibc defaults do not work well in a networked environment.
318 </para>
319
320 <para>Create a new file <filename>/etc/nsswitch.conf</filename> by running the
321 following:</para>
322
323<screen revision='sysv'><userinput>cat &gt; /etc/nsswitch.conf &lt;&lt; "EOF"
324<literal># Begin /etc/nsswitch.conf
325
326passwd: files
327group: files
328shadow: files
329
330hosts: files dns
331networks: files
332
333protocols: files
334services: files
335ethers: files
336rpc: files
337
338# End /etc/nsswitch.conf</literal>
339EOF</userinput></screen>
340
341<screen revision='systemd'><userinput>cat &gt; /etc/nsswitch.conf &lt;&lt; "EOF"
342<literal># Begin /etc/nsswitch.conf
343
344passwd: files systemd
345group: files systemd
346shadow: files systemd
347
348hosts: mymachines resolve [!UNAVAIL=return] files myhostname dns
349networks: files
350
351protocols: files
352services: files
353ethers: files
354rpc: files
355
356# End /etc/nsswitch.conf</literal>
357EOF</userinput></screen>
358
359 </sect3>
360
361 <sect3>
362 <title>Adding Time Zone Data</title>
363
364 <para>Install and set up the time zone data with the following:</para>
365<screen><userinput>tar -xf ../../tzdata&tzdata-version;.tar.gz
366
367ZONEINFO=/usr/share/zoneinfo
368mkdir -pv $ZONEINFO/{posix,right}
369
370for tz in etcetera southamerica northamerica europe africa antarctica \
371 asia australasia backward; do
372 zic -L /dev/null -d $ZONEINFO ${tz}
373 zic -L /dev/null -d $ZONEINFO/posix ${tz}
374 zic -L leapseconds -d $ZONEINFO/right ${tz}
375done
376
377cp -v zone.tab zone1970.tab iso3166.tab $ZONEINFO
378zic -d $ZONEINFO -p America/New_York
379unset ZONEINFO</userinput></screen>
380
381 <variablelist>
382 <title>The meaning of the zic commands:</title>
383
384 <varlistentry>
385 <term><parameter>zic -L /dev/null ...</parameter></term>
386 <listitem>
387 <para>This creates posix time zones without any leap seconds. It is
388 conventional to put these in both
389 <filename class="directory">zoneinfo</filename> and
390 <filename class="directory">zoneinfo/posix</filename>. It is
391 necessary to put the POSIX time zones in
392 <filename class="directory">zoneinfo</filename>, otherwise various
393 test suites will report errors. On an embedded system, where space is
394 tight and you do not intend to ever update the time zones, you could save
395 1.9 MB by not using the <filename class="directory">posix</filename>
396 directory, but some applications or test suites might produce some
397 failures.</para>
398 </listitem>
399 </varlistentry>
400 <varlistentry>
401 <term><parameter>zic -L leapseconds ...</parameter></term>
402 <listitem>
403 <para>This creates right time zones, including leap seconds. On an
404 embedded system, where space is tight and you do not intend to
405 ever update the time zones, or care about the correct time, you could
406 save 1.9MB by omitting the <filename class="directory">right</filename>
407 directory.</para>
408 </listitem>
409 </varlistentry>
410 <varlistentry>
411 <term><parameter>zic ... -p ...</parameter></term>
412 <listitem>
413 <para>This creates the <filename>posixrules</filename> file. We use
414 New York because POSIX requires the daylight savings time rules
415 to be in accordance with US rules.</para>
416 </listitem>
417 </varlistentry>
418 </variablelist>
419
420
421 <para>One way to determine the local time zone is to run the following
422 script:</para>
423
424<screen role="nodump"><userinput>tzselect</userinput></screen>
425
426 <para>After answering a few questions about the location, the script will
427 output the name of the time zone (e.g.,
428 <emphasis>America/Edmonton</emphasis>). There are also some other possible
429 time zones listed in <filename
430 class='directory'>/usr/share/zoneinfo</filename> such as
431 <emphasis>Canada/Eastern</emphasis> or <emphasis>EST5EDT</emphasis> that
432 are not identified by the script but can be used.</para>
433
434 <para>Then create the <filename>/etc/localtime</filename> file by
435 running:</para>
436
437<screen><userinput>ln -sfv /usr/share/zoneinfo/<replaceable>&lt;xxx&gt;</replaceable> /etc/localtime</userinput></screen>
438
439 <para>Replace <replaceable>&lt;xxx&gt;</replaceable> with the name of the
440 time zone selected (e.g., Canada/Eastern).</para>
441
442 </sect3>
443
444 <sect3 id="conf-ld" role="configuration">
445 <title>Configuring the Dynamic Loader</title>
446
447 <indexterm zone="conf-ld">
448 <primary sortas="e-/etc/ld.so.conf">/etc/ld.so.conf</primary>
449 </indexterm>
450
451 <para>By default, the dynamic loader (<filename
452 class="libraryfile">/lib/ld-linux.so.2</filename>) searches through
453 <filename class="directory">/usr/lib</filename> for dynamic libraries
454 that are needed by programs as they are run. However, if there are
455 libraries in directories other than
456 <filename class="directory">/usr/lib</filename>, these need to be added
457 to the <filename>/etc/ld.so.conf</filename> file in order for the
458 dynamic loader to find them. Two directories that are commonly known
459 to contain additional libraries are <filename
460 class="directory">/usr/local/lib</filename> and <filename
461 class="directory">/opt/lib</filename>, so add those directories to the
462 dynamic loader's search path.</para>
463
464 <para>Create a new file <filename>/etc/ld.so.conf</filename> by running the
465 following:</para>
466
467<screen><userinput>cat &gt; /etc/ld.so.conf &lt;&lt; "EOF"
468<literal># Begin /etc/ld.so.conf
469/usr/local/lib
470/opt/lib
471</literal>
472EOF</userinput></screen>
473
474 <para>If desired, the dynamic loader can also search a directory and
475 include the contents of files found there. Generally the files in
476 this include directory are one line specifying the desired library path.
477 To add this capability run the following commands:</para>
478
479<screen role="nodump"><userinput>cat &gt;&gt; /etc/ld.so.conf &lt;&lt; "EOF"
480<literal># Add an include directory
481include /etc/ld.so.conf.d/*.conf
482</literal>
483EOF
484mkdir -pv /etc/ld.so.conf.d</userinput></screen>
485
486 </sect3>
487 </sect2>
488
489 <sect2 id="contents-glibc" role="content">
490 <title>Contents of Glibc</title>
491
492 <segmentedlist>
493 <segtitle>Installed programs</segtitle>
494 <segtitle>Installed libraries</segtitle>
495 <segtitle>Installed directories</segtitle>
496
497 <seglistitem>
498 <seg>gencat, getconf, getent, iconv, iconvconfig, ldconfig,
499 ldd, lddlibc4,
500 ld.so (symlink to ld-linux-x86-64.so.2 or ld-linux.so.2),
501 locale, localedef, makedb, mtrace, nscd,
502 pcprofiledump, pldd, sln, sotruss, sprof, tzselect, xtrace,
503 zdump, and zic</seg>
504 <seg>ld-linux-x86-64.so.2, ld-linux.so.2,
505 libBrokenLocale.{a,so}, libanl.{a,so},
506 libc.{a,so}, libc_nonshared.a, libc_malloc_debug.so,
507 libdl.{a,so.2}, libg.a, libm.{a,so},
508 libmcheck.a, libmemusage.so, libmvec.{a,so}, libnsl.so.1,
509 libnss_compat.so, libnss_dns.so, libnss_files.so, libnss_hesiod.so,
510 libpcprofile.so, libpthread.{a,so.0},
511 libresolv.{a,so}, librt.{a,so.1},
512 libthread_db.so, and libutil.{a,so.1}</seg>
513 <seg>/usr/include/arpa, /usr/include/bits, /usr/include/gnu,
514 /usr/include/net, /usr/include/netash, /usr/include/netatalk,
515 /usr/include/netax25, /usr/include/neteconet, /usr/include/netinet,
516 /usr/include/netipx, /usr/include/netiucv, /usr/include/netpacket,
517 /usr/include/netrom, /usr/include/netrose, /usr/include/nfs,
518 /usr/include/protocols, /usr/include/rpc,
519 /usr/include/sys, /usr/lib/audit, /usr/lib/gconv, /usr/lib/locale,
520 /usr/libexec/getconf, /usr/share/i18n, /usr/share/zoneinfo,
521 /var/cache/nscd, and /var/lib/nss_db</seg>
522 </seglistitem>
523 </segmentedlist>
524
525 <variablelist>
526 <bridgehead renderas="sect3">Short Descriptions</bridgehead>
527 <?dbfo list-presentation="list"?>
528 <?dbhtml list-presentation="table"?>
529
530 <varlistentry id="gencat">
531 <term><command>gencat</command></term>
532 <listitem>
533 <para>Generates message catalogues</para>
534 <indexterm zone="ch-system-glibc gencat">
535 <primary sortas="b-gencat">gencat</primary>
536 </indexterm>
537 </listitem>
538 </varlistentry>
539
540 <varlistentry id="getconf">
541 <term><command>getconf</command></term>
542 <listitem>
543 <para>Displays the system configuration values for file system
544 specific variables</para>
545 <indexterm zone="ch-system-glibc getconf">
546 <primary sortas="b-getconf">getconf</primary>
547 </indexterm>
548 </listitem>
549 </varlistentry>
550
551 <varlistentry id="getent">
552 <term><command>getent</command></term>
553 <listitem>
554 <para>Gets entries from an administrative database</para>
555 <indexterm zone="ch-system-glibc getent">
556 <primary sortas="b-getent">getent</primary>
557 </indexterm>
558 </listitem>
559 </varlistentry>
560
561 <varlistentry id="iconv">
562 <term><command>iconv</command></term>
563 <listitem>
564 <para>Performs character set conversion</para>
565 <indexterm zone="ch-system-glibc iconv">
566 <primary sortas="b-iconv">iconv</primary>
567 </indexterm>
568 </listitem>
569 </varlistentry>
570
571 <varlistentry id="iconvconfig">
572 <term><command>iconvconfig</command></term>
573 <listitem>
574 <para>Creates fastloading <command>iconv</command> module configuration
575 files</para>
576 <indexterm zone="ch-system-glibc iconvconfig">
577 <primary sortas="b-iconvconfig">iconvconfig</primary>
578 </indexterm>
579 </listitem>
580 </varlistentry>
581
582 <varlistentry id="ldconfig">
583 <term><command>ldconfig</command></term>
584 <listitem>
585 <para>Configures the dynamic linker runtime bindings</para>
586 <indexterm zone="ch-system-glibc ldconfig">
587 <primary sortas="b-ldconfig">ldconfig</primary>
588 </indexterm>
589 </listitem>
590 </varlistentry>
591
592 <varlistentry id="ldd">
593 <term><command>ldd</command></term>
594 <listitem>
595 <para>Reports which shared libraries are required
596 by each given program or shared library</para>
597 <indexterm zone="ch-system-glibc ldd">
598 <primary sortas="b-ldd">ldd</primary>
599 </indexterm>
600 </listitem>
601 </varlistentry>
602
603 <varlistentry id="lddlibc4">
604 <term><command>lddlibc4</command></term>
605 <listitem>
606 <para>Assists <command>ldd</command> with object files.
607 It does not exist on newer architectures like x86_64</para>
608 <indexterm zone="ch-system-glibc lddlibc4">
609 <primary sortas="b-lddlibc4">lddlibc4</primary>
610 </indexterm>
611 </listitem>
612 </varlistentry>
613
614 <varlistentry id="locale">
615 <term><command>locale</command></term>
616 <listitem>
617 <para>Prints various information about the current locale</para>
618 <indexterm zone="ch-system-glibc locale">
619 <primary sortas="b-locale">locale</primary>
620 </indexterm>
621 </listitem>
622 </varlistentry>
623
624 <varlistentry id="localedef">
625 <term><command>localedef</command></term>
626 <listitem>
627 <para>Compiles locale specifications</para>
628 <indexterm zone="ch-system-glibc localedef">
629 <primary sortas="b-localedef">localedef</primary>
630 </indexterm>
631 </listitem>
632 </varlistentry>
633
634 <varlistentry id="makedb">
635 <term><command>makedb</command></term>
636 <listitem>
637 <para>Creates a simple database from textual input</para>
638 <indexterm zone="ch-system-glibc makedb">
639 <primary sortas="b-makedb">makedb</primary>
640 </indexterm>
641 </listitem>
642 </varlistentry>
643
644 <varlistentry id="mtrace">
645 <term><command>mtrace</command></term>
646 <listitem>
647 <para>Reads and interprets a memory trace file and displays a summary
648 in human-readable format</para>
649 <indexterm zone="ch-system-glibc mtrace">
650 <primary sortas="b-mtrace">mtrace</primary>
651 </indexterm>
652 </listitem>
653 </varlistentry>
654
655 <varlistentry id="nscd">
656 <term><command>nscd</command></term>
657 <listitem>
658 <para>A daemon that provides a cache for the most common name
659 service requests</para>
660 <indexterm zone="ch-system-glibc nscd">
661 <primary sortas="b-nscd">nscd</primary>
662 </indexterm>
663 </listitem>
664 </varlistentry>
665
666 <varlistentry id="pcprofiledump">
667 <term><command>pcprofiledump</command></term>
668 <listitem>
669 <para>Dump information generated by PC profiling</para>
670 <indexterm zone="ch-system-glibc pcprofiledump">
671 <primary sortas="b-pcprofiledump">pcprofiledump</primary>
672 </indexterm>
673 </listitem>
674 </varlistentry>
675
676 <varlistentry id="pldd">
677 <term><command>pldd</command></term>
678 <listitem>
679 <para>Lists dynamic shared objects used by running processes</para>
680 <indexterm zone="ch-system-glibc pldd">
681 <primary sortas="b-pldd">pldd</primary>
682 </indexterm>
683 </listitem>
684 </varlistentry>
685
686 <varlistentry id="sln">
687 <term><command>sln</command></term>
688 <listitem>
689 <para>A statically linked <command>ln</command> program</para>
690 <indexterm zone="ch-system-glibc sln">
691 <primary sortas="b-sln">sln</primary>
692 </indexterm>
693 </listitem>
694 </varlistentry>
695
696 <varlistentry id="sotruss">
697 <term><command>sotruss</command></term>
698 <listitem>
699 <para>Traces shared library procedure calls of a specified command</para>
700 <indexterm zone="ch-system-glibc sotruss">
701 <primary sortas="b-sotruss">sotruss</primary>
702 </indexterm>
703 </listitem>
704 </varlistentry>
705
706 <varlistentry id="sprof">
707 <term><command>sprof</command></term>
708 <listitem>
709 <para>Reads and displays shared object profiling data</para>
710 <indexterm zone="ch-system-glibc sprof">
711 <primary sortas="b-sprof">sprof</primary>
712 </indexterm>
713 </listitem>
714 </varlistentry>
715
716 <varlistentry id="tzselect">
717 <term><command>tzselect</command></term>
718 <listitem>
719 <para>Asks the user about the location of the system and reports
720 the corresponding time zone description</para>
721 <indexterm zone="ch-system-glibc tzselect">
722 <primary sortas="b-tzselect">tzselect</primary>
723 </indexterm>
724 </listitem>
725 </varlistentry>
726
727 <varlistentry id="xtrace">
728 <term><command>xtrace</command></term>
729 <listitem>
730 <para>Traces the execution of a program by printing the currently
731 executed function</para>
732 <indexterm zone="ch-system-glibc xtrace">
733 <primary sortas="b-xtrace">xtrace</primary>
734 </indexterm>
735 </listitem>
736 </varlistentry>
737
738 <varlistentry id="zdump">
739 <term><command>zdump</command></term>
740 <listitem>
741 <para>The time zone dumper</para>
742 <indexterm zone="ch-system-glibc zdump">
743 <primary sortas="b-zdump">zdump</primary>
744 </indexterm>
745 </listitem>
746 </varlistentry>
747
748 <varlistentry id="zic">
749 <term><command>zic</command></term>
750 <listitem>
751 <para>The time zone compiler</para>
752 <indexterm zone="ch-system-glibc zic">
753 <primary sortas="b-zic">zic</primary>
754 </indexterm>
755 </listitem>
756 </varlistentry>
757
758 <varlistentry id="ld.so">
759 <term><filename class="libraryfile">ld-*.so</filename></term>
760 <listitem>
761 <para>The helper program for shared library executables</para>
762 <indexterm zone="ch-system-glibc ld.so">
763 <primary sortas="c-ld.so">ld-&glibc-version;.so</primary>
764 </indexterm>
765 </listitem>
766 </varlistentry>
767
768 <varlistentry id="libBrokenLocale">
769 <term><filename class="libraryfile">libBrokenLocale</filename></term>
770 <listitem>
771 <para>Used internally by Glibc as a gross hack to get broken programs
772 (e.g., some Motif applications) running. See comments in
773 <filename>glibc-&glibc-version;/locale/broken_cur_max.c</filename>
774 for more information</para>
775 <indexterm zone="ch-system-glibc libBrokenLocale">
776 <primary sortas="c-libBrokenLocale">libBrokenLocale</primary>
777 </indexterm>
778 </listitem>
779 </varlistentry>
780
781 <varlistentry id="libanl">
782 <term><filename class="libraryfile">libanl</filename></term>
783 <listitem>
784 <para>Dummy library containing no functions. Previously was the
785 asynchronous name lookup library, whose functions are now in
786 <filename class='libraryfile'>libc</filename></para>
787 <indexterm zone="ch-system-glibc libanl">
788 <primary sortas="c-libanl">libanl</primary>
789 </indexterm>
790 </listitem>
791 </varlistentry>
792
793 <varlistentry id="libc">
794 <term><filename class="libraryfile">libc</filename></term>
795 <listitem>
796 <para>The main C library</para>
797 <indexterm zone="ch-system-glibc libc">
798 <primary sortas="c-libc">libc</primary>
799 </indexterm>
800 </listitem>
801 </varlistentry>
802
803 <varlistentry id="libc_malloc_debug">
804 <term><filename class="libraryfile">libc_malloc_debug</filename></term>
805 <listitem>
806 <para>Turns on memory allocation checking when preloaded</para>
807 <indexterm zone="ch-system-glibc libc_malloc_debug">
808 <primary sortas="c-libc_malloc_debug">libc_malloc_debug</primary>
809 </indexterm>
810 </listitem>
811 </varlistentry>
812
813 <varlistentry id="libdl">
814 <term><filename class="libraryfile">libdl</filename></term>
815 <listitem>
816 <para>Dummy library containing no functions. Previously was the
817 dynamic linking interface library, whose functions are now in
818 <filename class="libraryfile">libc</filename></para>
819 <indexterm zone="ch-system-glibc libdl">
820 <primary sortas="c-libdl">libdl</primary>
821 </indexterm>
822 </listitem>
823 </varlistentry>
824
825 <varlistentry id="libg">
826 <term><filename class="libraryfile">libg</filename></term>
827 <listitem>
828 <para>Dummy library containing no functions. Previously was a runtime
829 library for <command>g++</command></para>
830 <indexterm zone="ch-system-glibc libg">
831 <primary sortas="c-libg">libg</primary>
832 </indexterm>
833 </listitem>
834 </varlistentry>
835
836 <varlistentry id="libm">
837 <term><filename class="libraryfile">libm</filename></term>
838 <listitem>
839 <para>The mathematical library</para>
840 <indexterm zone="ch-system-glibc libm">
841 <primary sortas="c-libm">libm</primary>
842 </indexterm>
843 </listitem>
844 </varlistentry>
845
846 <varlistentry id="libmvec">
847 <term><filename class="libraryfile">libmvec</filename></term>
848 <listitem>
849 <para>The vector math library, linked in as needed
850 when <filename class='libraryfile'>libm</filename> is used</para>
851 <indexterm zone="ch-system-glibc libmvec">
852 <primary sortas="c-libmvec">libmvec</primary>
853 </indexterm>
854 </listitem>
855 </varlistentry>
856
857 <varlistentry id="libmcheck">
858 <term><filename class="libraryfile">libmcheck</filename></term>
859 <listitem>
860 <para>Turns on memory allocation checking when linked to</para>
861 <indexterm zone="ch-system-glibc libmcheck">
862 <primary sortas="c-libmcheck">libmcheck</primary>
863 </indexterm>
864 </listitem>
865 </varlistentry>
866
867 <varlistentry id="libmemusage">
868 <term><filename class="libraryfile">libmemusage</filename></term>
869 <listitem>
870 <para>Used by <command>memusage</command> to help collect
871 information about the memory usage of a program</para>
872 <indexterm zone="ch-system-glibc libmemusage">
873 <primary sortas="c-libmemusage">libmemusage</primary>
874 </indexterm>
875 </listitem>
876 </varlistentry>
877
878 <varlistentry id="libnsl">
879 <term><filename class="libraryfile">libnsl</filename></term>
880 <listitem>
881 <para>The network services library, now deprecated</para>
882 <indexterm zone="ch-system-glibc libnsl">
883 <primary sortas="c-libnsl">libnsl</primary>
884 </indexterm>
885 </listitem>
886 </varlistentry>
887
888 <varlistentry id="libnss">
889 <term><filename class="libraryfile">libnss_*</filename></term>
890 <listitem>
891 <para>The Name Service Switch modules, containing functions for
892 resolving host names, user names, group names, aliases, services,
893 protocols, etc. Loaded by
894 <filename class='libraryfile'>libc</filename> according to the
895 configuration in <filename>/etc/nsswitch.conf</filename></para>
896 <indexterm zone="ch-system-glibc libnss">
897 <primary sortas="c-libnss">libnss_*</primary>
898 </indexterm>
899 </listitem>
900 </varlistentry>
901
902 <varlistentry id="libpcprofile">
903 <term><filename class="libraryfile">libpcprofile</filename></term>
904 <listitem>
905 <para>Can be preloaded to PC profile an executable</para>
906 <indexterm zone="ch-system-glibc libpcprofile">
907 <primary sortas="c-libpcprofile">libpcprofile</primary>
908 </indexterm>
909 </listitem>
910 </varlistentry>
911
912 <varlistentry id="libpthread">
913 <term><filename class="libraryfile">libpthread</filename></term>
914 <listitem>
915 <para>Dummy library containing no functions. Previously contained
916 functions providing most of the interfaces specified
917 by the POSIX.1c Threads Extensions and the semaphore interfaces
918 specified by the POSIX.1b Real-time Extensions, now the functions
919 are in <filename class="libraryfile">libc</filename></para>
920 <indexterm zone="ch-system-glibc libpthread">
921 <primary sortas="c-libpthread">libpthread</primary>
922 </indexterm>
923 </listitem>
924 </varlistentry>
925
926 <varlistentry id="libresolv">
927 <term><filename class="libraryfile">libresolv</filename></term>
928 <listitem>
929 <para>Contains functions for creating, sending, and interpreting
930 packets to the Internet domain name servers</para>
931 <indexterm zone="ch-system-glibc libresolv">
932 <primary sortas="c-libresolv">libresolv</primary>
933 </indexterm>
934 </listitem>
935 </varlistentry>
936
937 <varlistentry id="librt">
938 <term><filename class="libraryfile">librt</filename></term>
939 <listitem>
940 <para>Contains functions providing most of the interfaces specified
941 by the POSIX.1b Real-time Extensions</para>
942 <indexterm zone="ch-system-glibc librt">
943 <primary sortas="c-librt">librt</primary>
944 </indexterm>
945 </listitem>
946 </varlistentry>
947
948 <varlistentry id="libthread_db">
949 <term><filename class="libraryfile">libthread_db</filename></term>
950 <listitem>
951 <para>Contains functions useful for building debuggers for
952 multi-threaded programs</para>
953 <indexterm zone="ch-system-glibc libthread_db">
954 <primary sortas="c-libthread_db">libthread_db</primary>
955 </indexterm>
956 </listitem>
957 </varlistentry>
958
959 <varlistentry id="libutil">
960 <term><filename class="libraryfile">libutil</filename></term>
961 <listitem>
962 <para>Dummy library containing no functions. Previously contained
963 code for <quote>standard</quote> functions used in
964 many different Unix utilities. These functions are now in
965 <filename class="libraryfile">libc</filename></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>
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