source: chapter06/glibc.xml@ 7a28184

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Last change on this file since 7a28184 was 7a28184, checked in by Bruce Dubbs <bdubbs@…>, 15 years ago

Add optimization (-O3 and -pipe) to glibc in Chapter 6

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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>
47 <para>Some packages outside of LFS suggest installing GNU libiconv in
48 order to translate data from one encoding to another. The project's
49 home page (<ulink url="http://www.gnu.org/software/libiconv/"/>) says
50 <quote>This library provides an <function>iconv()</function>
51 implementation, for use on systems which don't have one, or whose
52 implementation cannot convert from/to Unicode.</quote> Glibc provides
53 an <function>iconv()</function> implementation and can convert from/to
54 Unicode, therefore libiconv is not required on an LFS system.</para>
55 </note>
56
57 <para>The Glibc build system is self-contained and will install
58 perfectly, even though the compiler specs file and linker are still
59 pointing at <filename class="directory">/tools</filename>. The specs
60 and linker cannot be adjusted before the Glibc install because the
61 Glibc autoconf tests would give false results and defeat the goal
62 of achieving a clean build.</para>
63
64 <para>The glibc-libidn tarball adds support for internationalized domain
65 names (IDN) to Glibc. Many programs that support IDN require the full
66 <filename class="libraryfile">libidn</filename> library, not this add-on (see
67 <ulink url="&blfs-root;view/svn/general/libidn.html"/>).
68 Unpack the tarball from within the Glibc source directory:</para>
69
70<screen><userinput remap="pre">tar -xvf ../glibc-libidn-&glibc-version;.tar.bz2
71mv glibc-libidn-&glibc-version; libidn</userinput></screen>
72
73 <para>In the vi_VN.TCVN locale, <command>bash</command> enters an infinite
74 loop at startup. It is unknown whether this is a <command>bash</command>
75 bug or a Glibc problem. Disable installation of this locale in order to
76 avoid the problem:</para>
77
78<screen><userinput remap="pre">sed -i '/vi_VN.TCVN/d' localedata/SUPPORTED</userinput></screen>
79
80 <para>When running <command>make install</command>, a script called
81 <filename>test-installation.pl</filename> performs a small sanity test on
82 our newly installed Glibc. However, because our toolchain still points to
83 the <filename class="directory">/tools</filename> directory, the sanity
84 test would be carried out against the wrong Glibc. We can force the script
85 to check the Glibc we have just installed with the following:</para>
86
87<screen><userinput remap="pre">DL=$(readelf -l /bin/sh | grep interpreter | \
88awk '{print $4}' | sed -e 's@/tools@@' -e 's@]$@@')
89sed -i &quot;s|libs -o|libs -L/usr/lib -Wl,-dynamic-linker=$DL -o|&quot; \
90 scripts/test-installation.pl
91unset DL</userinput></screen>
92
93 <para>First apply a patch which corrects a failure in the test suite:</para>
94
95<screen><userinput remap="pre">patch -Np1 -i ../&glibc-ildoubl-test-fix-patch;</userinput></screen>
96
97
98 <para>The <command>ldd</command> shell script contains Bash-specific
99 syntax. Change its default program interpreter to <command>/bin/bash</command>
100 in case another <command>/bin/sh</command> is installed as described in the
101 <ulink url="&blfs-root;view/svn/postlfs/shells.html">Shells</ulink>
102 chapter of the BLFS book:</para>
103
104<screen><userinput remap="pre">sed -i 's|@BASH@|/bin/bash|' elf/ldd.bash.in</userinput></screen>
105
106 <para>The Glibc documentation recommends building Glibc outside of the source
107 directory in a dedicated build directory:</para>
108
109<screen><userinput remap="pre">mkdir -v ../glibc-build
110cd ../glibc-build</userinput></screen>
111
112 <para>As in Chapter 5, add the needed compiler flags to CFLAGS for x86 machines.
113 Here, the optimization of the library is also set for the gcc compiler to
114 enhance compilation speed (-pipe) and package performance (-O3).</para>
115
116<screen><userinput remap="configure">case `uname -m` in
117 i?86) echo "CFLAGS += -march=i486 -mtune=native -O3 -pipe" &gt; configparms ;;
118esac</userinput></screen>
119
120 <para>Prepare Glibc for compilation:</para>
121
122<screen><userinput remap="configure">../glibc-&glibc-version;/configure --prefix=/usr \
123 --disable-profile --enable-add-ons \
124 --enable-kernel=2.6.0 --libexecdir=/usr/lib/glibc</userinput></screen>
125
126 <variablelist>
127 <title>The meaning of the new configure options:</title>
128
129 <varlistentry>
130 <term><parameter>--libexecdir=/usr/lib/glibc</parameter></term>
131 <listitem>
132 <para>This changes the location of the <command>pt_chown</command>
133 program from its default of <filename
134 class="directory">/usr/libexec</filename> to <filename
135 class="directory">/usr/lib/glibc</filename>.</para>
136 </listitem>
137 </varlistentry>
138
139 </variablelist>
140
141 <para>Compile the package:</para>
142
143<screen><userinput remap="make">make</userinput></screen>
144
145 <important>
146 <para>In this section, the test suite for Glibc is considered critical.
147 Do not skip it under any circumstance.</para>
148 </important>
149
150 <para>Before running the tests, copy a file from the source tree into our
151 build tree to prevent a couple of test failures, then test the
152 results:</para>
153
154<screen><userinput remap="test">cp -v ../glibc-&glibc-version;/iconvdata/gconv-modules iconvdata
155make -k check 2&gt;&amp;1 | tee glibc-check-log
156grep Error glibc-check-log</userinput></screen>
157
158 <para>You will probably see an expected (ignored) failure in the
159 <emphasis>posix/annexc</emphasis> test. In addition the Glibc test suite
160 is somewhat dependent on the host system. This is a list of the most
161 common issues:</para>
162
163 <itemizedlist>
164 <!-- Check again after updating from gcc-4.1.x -->
165 <listitem>
166 <para>The <emphasis>nptl/tst-cancel1</emphasis> test will fail when
167 using the 4.1 series of GCC.</para>
168 </listitem>
169 <!-- Was true in glibc-2.3.6 -->
170 <listitem>
171 <para>The <emphasis>nptl/tst-clock2</emphasis> and
172 <emphasis>tst-attr3</emphasis> tests sometimes
173 fail. The reason is not completely understood, but indications
174 are that a heavy system load can trigger these failures.</para>
175 </listitem>
176 <listitem>
177 <para>The math tests sometimes fail when running on
178 systems where the CPU is not a relatively new genuine Intel or
179 authentic AMD processor.</para>
180 </listitem>
181 <listitem>
182 <para>If you have mounted the LFS partition with the
183 <parameter>noatime</parameter> option, the <emphasis>atime</emphasis>
184 test will fail. As mentioned in <xref linkend="space-mounting"/>, do not
185 use the <parameter>noatime</parameter> option while building LFS.</para>
186 </listitem>
187 <listitem>
188 <para>When running on older and slower hardware or on systems under
189 load, some tests can fail because of test timeouts being exceeded.</para>
190 </listitem>
191 </itemizedlist>
192
193 <para>Though it is a harmless message, the install stage of Glibc will
194 complain about the absence of <filename>/etc/ld.so.conf</filename>.
195 Prevent this warning with:</para>
196
197<screen><userinput remap="install">touch /etc/ld.so.conf</userinput></screen>
198
199 <para>Install the package:</para>
200
201<screen><userinput remap="install">make install</userinput></screen>
202
203 <para>The locales that can make the system respond in a different language
204 were not installed by the above command. None of the locales are required,
205 but if some of them are missing, testsuites of the future packages would
206 skip important testcases.</para>
207
208 <para>Individual locales can be installed using the
209 <command>localedef</command> program. E.g., the first
210 <command>localedef</command> command below combines the
211 <filename>/usr/share/i18n/locales/cs_CZ</filename>
212 charset-independent locale definition with the
213 <filename>/usr/share/i18n/charmaps/UTF-8.gz</filename>
214 charmap definition and appends the result to the
215 <filename>/usr/lib/locale/locale-archive</filename> file.
216 The following instructions will install the minimum set of
217 locales necessary for the optimal coverage of tests:</para>
218
219<screen role="nodump"><userinput remap="locale-test">mkdir -pv /usr/lib/locale
220localedef -i cs_CZ -f UTF-8 cs_CZ.UTF-8
221localedef -i de_DE -f ISO-8859-1 de_DE
222localedef -i de_DE@euro -f ISO-8859-15 de_DE@euro
223localedef -i de_DE -f UTF-8 de_DE.UTF-8
224localedef -i en_HK -f ISO-8859-1 en_HK
225localedef -i en_PH -f ISO-8859-1 en_PH
226localedef -i en_US -f ISO-8859-1 en_US
227localedef -i en_US -f UTF-8 en_US.UTF-8
228localedef -i es_MX -f ISO-8859-1 es_MX
229localedef -i fa_IR -f UTF-8 fa_IR
230localedef -i fr_FR -f ISO-8859-1 fr_FR
231localedef -i fr_FR@euro -f ISO-8859-15 fr_FR@euro
232localedef -i fr_FR -f UTF-8 fr_FR.UTF-8
233localedef -i it_IT -f ISO-8859-1 it_IT
234localedef -i ja_JP -f EUC-JP ja_JP
235localedef -i tr_TR -f UTF-8 tr_TR.UTF-8
236localedef -i zh_CN -f GB18030 zh_CN.GB18030</userinput></screen>
237
238 <para>In addition, install the locale for your own country, language and
239 character set.</para>
240
241 <para>Alternatively, install all locales listed in the
242 <filename>glibc-&glibc-version;/localedata/SUPPORTED</filename> file
243 (it includes every locale listed above and many more) at once with the
244 following time-consuming command:</para>
245
246<screen><userinput remap="locale-full">make localedata/install-locales</userinput></screen>
247
248 <para>Then use the <command>localedef</command> command to create and
249 install locales not listed in the
250 <filename>glibc-&glibc-version;/localedata/SUPPORTED</filename> file
251 in the unlikely case you need them.</para>
252 <!-- The Live CD patches the localedata/SUPPORTED file instead of
253 running localedef, the results are equivalent -->
254
255 </sect2>
256
257 <sect2 id="conf-glibc" role="configuration">
258 <title>Configuring Glibc</title>
259
260 <indexterm zone="conf-glibc">
261 <primary sortas="e-/etc/nsswitch.conf">/etc/nsswitch.conf</primary>
262 </indexterm>
263
264 <indexterm zone="conf-glibc">
265 <primary sortas="e-/etc/localtime">/etc/localtime</primary>
266 </indexterm>
267
268 <para>The <filename>/etc/nsswitch.conf</filename> file needs to be created
269 because, although Glibc provides defaults when this file is missing or corrupt,
270 the Glibc defaults do not work well in a networked environment. The time zone
271 also needs to be configured.</para>
272
273 <para>Create a new file <filename>/etc/nsswitch.conf</filename> by running the
274 following:</para>
275
276<screen><userinput>cat &gt; /etc/nsswitch.conf &lt;&lt; "EOF"
277<literal># Begin /etc/nsswitch.conf
278
279passwd: files
280group: files
281shadow: files
282
283hosts: files dns
284networks: files
285
286protocols: files
287services: files
288ethers: files
289rpc: files
290
291# End /etc/nsswitch.conf</literal>
292EOF</userinput></screen>
293
294 <para>One way to determine the local time zone, run the following
295 script:</para>
296
297<screen role="nodump"><userinput>tzselect</userinput></screen>
298
299 <para>After answering a few questions about the location, the script will
300 output the name of the time zone (e.g.,
301 <emphasis>America/Edmonton</emphasis>). There are also some other possible
302 timezones listed in <filename
303 class='directory'>/usr/share/zoneinfo</filename> such as
304 <emphasis>Canada/Eastern</emphasis> or <emphasis>EST5EDT</emphasis> that
305 are not identified by the script but can be used.</para>
306
307 <para>Then create the <filename>/etc/localtime</filename> file by
308 running:</para>
309
310<screen><userinput>cp -v --remove-destination /usr/share/zoneinfo/<replaceable>&lt;xxx&gt;</replaceable> \
311 /etc/localtime</userinput></screen>
312
313 <para>Replace <replaceable>&lt;xxx&gt;</replaceable> with the name of the
314 time zone selected (e.g., Canada/Eastern).</para>
315
316 <variablelist>
317 <title>The meaning of the cp option:</title>
318
319 <varlistentry>
320 <term><parameter>--remove-destination</parameter></term>
321 <listitem>
322 <para>This is needed to force removal of the already existing symbolic
323 link. The reason for copying the file instead of using a symlink is to
324 cover the situation where <filename class="directory">/usr</filename>
325 is on a separate partition. This could be important when booted into
326 single user mode.</para>
327 </listitem>
328 </varlistentry>
329
330 </variablelist>
331
332 </sect2>
333
334 <sect2 id="conf-ld" role="configuration">
335 <title>Configuring the Dynamic Loader</title>
336
337 <indexterm zone="conf-ld">
338 <primary sortas="e-/etc/ld.so.conf">/etc/ld.so.conf</primary>
339 </indexterm>
340
341 <para>By default, the dynamic loader (<filename
342 class="libraryfile">/lib/ld-linux.so.2</filename>) searches through
343 <filename class="directory">/lib</filename> and <filename
344 class="directory">/usr/lib</filename> for dynamic libraries that are
345 needed by programs as they are run. However, if there are libraries in
346 directories other than <filename class="directory">/lib</filename> and
347 <filename class="directory">/usr/lib</filename>, these need to be added
348 to the <filename>/etc/ld.so.conf</filename> file in order for the
349 dynamic loader to find them. Two directories that are commonly known
350 to contain additional libraries are <filename
351 class="directory">/usr/local/lib</filename> and <filename
352 class="directory">/opt/lib</filename>, so add those directories to the
353 dynamic loader's search path.</para>
354
355 <para>Create a new file <filename>/etc/ld.so.conf</filename> by running the
356 following:</para>
357
358<screen><userinput>cat &gt; /etc/ld.so.conf &lt;&lt; "EOF"
359<literal># Begin /etc/ld.so.conf
360
361/usr/local/lib
362/opt/lib
363
364# End /etc/ld.so.conf</literal>
365EOF</userinput></screen>
366
367 </sect2>
368
369 <sect2 id="contents-glibc" role="content">
370 <title>Contents of Glibc</title>
371
372 <segmentedlist>
373 <segtitle>Installed programs</segtitle>
374 <segtitle>Installed libraries</segtitle>
375
376 <seglistitem>
377 <seg>catchsegv, gencat, getconf, getent, iconv, iconvconfig, ldconfig,
378 ldd, lddlibc4, locale, localedef, mtrace, nscd, pcprofiledump,
379 pt_chown, rpcgen, rpcinfo, sln, sprof, tzselect, xtrace,
380 zdump, and zic</seg>
381 <seg>ld.so, libBrokenLocale.{a,so}, libSegFault.so, libanl.{a,so},
382 libbsd-compat.a, libc.{a,so}, libc_nonshared.a, libcidn.so,
383 libcrypt.{a,so}, libdl.{a,so}, libg.a, libieee.a, libm.{a,so},
384 libmcheck.a, libmemusage.so, libnsl.{a,so}, libnss_compat.so,
385 libnss_dns.so, libnss_files.so, libnss_hesiod.so, libnss_nis.so,
386 libnss_nisplus.so, libpcprofile.so, libpthread.{a,so},
387 libpthread_nonshared.a, libresolv.{a,so}, librpcsvc.a, librt.{a,so},
388 libthread_db.so, and libutil.{a,so}</seg>
389 </seglistitem>
390 </segmentedlist>
391
392 <variablelist>
393 <bridgehead renderas="sect3">Short Descriptions</bridgehead>
394 <?dbfo list-presentation="list"?>
395 <?dbhtml list-presentation="table"?>
396
397 <varlistentry id="catchsegv">
398 <term><command>catchsegv</command></term>
399 <listitem>
400 <para>Can be used to create a stack trace when a program
401 terminates with a segmentation fault</para>
402 <indexterm zone="ch-system-glibc catchsegv">
403 <primary sortas="b-catchsegv">catchsegv</primary>
404 </indexterm>
405 </listitem>
406 </varlistentry>
407
408 <varlistentry id="gencat">
409 <term><command>gencat</command></term>
410 <listitem>
411 <para>Generates message catalogues</para>
412 <indexterm zone="ch-system-glibc gencat">
413 <primary sortas="b-gencat">gencat</primary>
414 </indexterm>
415 </listitem>
416 </varlistentry>
417
418 <varlistentry id="getconf">
419 <term><command>getconf</command></term>
420 <listitem>
421 <para>Displays the system configuration values for file system
422 specific variables</para>
423 <indexterm zone="ch-system-glibc getconf">
424 <primary sortas="b-getconf">getconf</primary>
425 </indexterm>
426 </listitem>
427 </varlistentry>
428
429 <varlistentry id="getent">
430 <term><command>getent</command></term>
431 <listitem>
432 <para>Gets entries from an administrative database</para>
433 <indexterm zone="ch-system-glibc getent">
434 <primary sortas="b-getent">getent</primary>
435 </indexterm>
436 </listitem>
437 </varlistentry>
438
439 <varlistentry id="iconv">
440 <term><command>iconv</command></term>
441 <listitem>
442 <para>Performs character set conversion</para>
443 <indexterm zone="ch-system-glibc iconv">
444 <primary sortas="b-iconv">iconv</primary>
445 </indexterm>
446 </listitem>
447 </varlistentry>
448
449 <varlistentry id="iconvconfig">
450 <term><command>iconvconfig</command></term>
451 <listitem>
452 <para>Creates fastloading <command>iconv</command> module configuration
453 files</para>
454 <indexterm zone="ch-system-glibc iconvconfig">
455 <primary sortas="b-iconvconfig">iconvconfig</primary>
456 </indexterm>
457 </listitem>
458 </varlistentry>
459
460 <varlistentry id="ldconfig">
461 <term><command>ldconfig</command></term>
462 <listitem>
463 <para>Configures the dynamic linker runtime bindings</para>
464 <indexterm zone="ch-system-glibc ldconfig">
465 <primary sortas="b-ldconfig">ldconfig</primary>
466 </indexterm>
467 </listitem>
468 </varlistentry>
469
470 <varlistentry id="ldd">
471 <term><command>ldd</command></term>
472 <listitem>
473 <para>Reports which shared libraries are required
474 by each given program or shared library</para>
475 <indexterm zone="ch-system-glibc ldd">
476 <primary sortas="b-ldd">ldd</primary>
477 </indexterm>
478 </listitem>
479 </varlistentry>
480
481 <varlistentry id="lddlibc4">
482 <term><command>lddlibc4</command></term>
483 <listitem>
484 <para>Assists <command>ldd</command> with object files</para>
485 <indexterm zone="ch-system-glibc lddlibc4">
486 <primary sortas="b-lddlibc4">lddlibc4</primary>
487 </indexterm>
488 </listitem>
489 </varlistentry>
490
491 <varlistentry id="locale">
492 <term><command>locale</command></term>
493 <listitem>
494 <para>Prints various information about the current locale</para>
495 <indexterm zone="ch-system-glibc locale">
496 <primary sortas="b-locale">locale</primary>
497 </indexterm>
498 </listitem>
499 </varlistentry>
500
501 <varlistentry id="localedef">
502 <term><command>localedef</command></term>
503 <listitem>
504 <para>Compiles locale specifications</para>
505 <indexterm zone="ch-system-glibc localedef">
506 <primary sortas="b-localedef">localedef</primary>
507 </indexterm>
508 </listitem>
509 </varlistentry>
510
511 <varlistentry id="mtrace">
512 <term><command>mtrace</command></term>
513 <listitem>
514 <para>Reads and interprets a memory trace file and displays a summary
515 in human-readable format</para>
516 <indexterm zone="ch-system-glibc mtrace">
517 <primary sortas="b-mtrace">mtrace</primary>
518 </indexterm>
519 </listitem>
520 </varlistentry>
521
522 <varlistentry id="nscd">
523 <term><command>nscd</command></term>
524 <listitem>
525 <para>A daemon that provides a cache for the most common name
526 service requests</para>
527 <indexterm zone="ch-system-glibc nscd">
528 <primary sortas="b-nscd">nscd</primary>
529 </indexterm>
530 </listitem>
531 </varlistentry>
532
533 <varlistentry id="pcprofiledump">
534 <term><command>pcprofiledump</command></term>
535 <listitem>
536 <para>Dumps information generated by PC profiling</para>
537 <indexterm zone="ch-system-glibc pcprofiledump">
538 <primary sortas="b-pcprofiledump">pcprofiledump</primary>
539 </indexterm>
540 </listitem>
541 </varlistentry>
542
543 <varlistentry id="pt_chown">
544 <term><command>pt_chown</command></term>
545 <listitem>
546 <para>A helper program for <command>grantpt</command> to set the owner,
547 group and access permissions of a slave pseudo terminal</para>
548 <indexterm zone="ch-system-glibc pt_chown">
549 <primary sortas="b-pt_chown">pt_chown</primary>
550 </indexterm>
551 </listitem>
552 </varlistentry>
553
554 <varlistentry id="rpcgen">
555 <term><command>rpcgen</command></term>
556 <listitem>
557 <para>Generates C code to implement the Remote Procedure Call (RPC)
558 protocol</para>
559 <indexterm zone="ch-system-glibc rpcgen">
560 <primary sortas="b-rpcgen">rpcgen</primary>
561 </indexterm>
562 </listitem>
563 </varlistentry>
564
565 <varlistentry id="rpcinfo">
566 <term><command>rpcinfo</command></term>
567 <listitem>
568 <para>Makes an RPC call to an RPC server</para>
569 <indexterm zone="ch-system-glibc rpcinfo">
570 <primary sortas="b-rpcinfo">rpcinfo</primary>
571 </indexterm>
572 </listitem>
573 </varlistentry>
574
575 <varlistentry id="sln">
576 <term><command>sln</command></term>
577 <listitem>
578 <para>A statically linked <command>ln</command> program</para>
579 <indexterm zone="ch-system-glibc sln">
580 <primary sortas="b-sln">sln</primary>
581 </indexterm>
582 </listitem>
583 </varlistentry>
584
585 <varlistentry id="sprof">
586 <term><command>sprof</command></term>
587 <listitem>
588 <para>Reads and displays shared object profiling data</para>
589 <indexterm zone="ch-system-glibc sprof">
590 <primary sortas="b-sprof">sprof</primary>
591 </indexterm>
592 </listitem>
593 </varlistentry>
594
595 <varlistentry id="tzselect">
596 <term><command>tzselect</command></term>
597 <listitem>
598 <para>Asks the user about the location of the system and reports
599 the corresponding time zone description</para>
600 <indexterm zone="ch-system-glibc tzselect">
601 <primary sortas="b-tzselect">tzselect</primary>
602 </indexterm>
603 </listitem>
604 </varlistentry>
605
606 <varlistentry id="xtrace">
607 <term><command>xtrace</command></term>
608 <listitem>
609 <para>Traces the execution of a program by printing the currently
610 executed function</para>
611 <indexterm zone="ch-system-glibc xtrace">
612 <primary sortas="b-xtrace">xtrace</primary>
613 </indexterm>
614 </listitem>
615 </varlistentry>
616
617 <varlistentry id="zdump">
618 <term><command>zdump</command></term>
619 <listitem>
620 <para>The time zone dumper</para>
621 <indexterm zone="ch-system-glibc zdump">
622 <primary sortas="b-zdump">zdump</primary>
623 </indexterm>
624 </listitem>
625 </varlistentry>
626
627 <varlistentry id="zic">
628 <term><command>zic</command></term>
629 <listitem>
630 <para>The time zone compiler</para>
631 <indexterm zone="ch-system-glibc zic">
632 <primary sortas="b-zic">zic</primary>
633 </indexterm>
634 </listitem>
635 </varlistentry>
636
637 <varlistentry id="ld.so">
638 <term><filename class="libraryfile">ld.so</filename></term>
639 <listitem>
640 <para>The helper program for shared library executables</para>
641 <indexterm zone="ch-system-glibc ld.so">
642 <primary sortas="c-ld.so">ld.so</primary>
643 </indexterm>
644 </listitem>
645 </varlistentry>
646
647 <varlistentry id="libBrokenLocale">
648 <term><filename class="libraryfile">libBrokenLocale</filename></term>
649 <listitem>
650 <para>Used internally by Glibc as a gross hack to get broken programs
651 (e.g., some Motif applications) running. See comments in
652 <filename>glibc-&glibc-version;/locale/broken_cur_max.c</filename>
653 for more information</para>
654 <indexterm zone="ch-system-glibc libBrokenLocale">
655 <primary sortas="c-libBrokenLocale">libBrokenLocale</primary>
656 </indexterm>
657 </listitem>
658 </varlistentry>
659
660 <varlistentry id="libSegFault">
661 <term><filename class="libraryfile">libSegFault</filename></term>
662 <listitem>
663 <para>The segmentation fault signal handler, used by
664 <command>catchsegv</command></para>
665 <indexterm zone="ch-system-glibc libSegFault">
666 <primary sortas="c-libSegFault">libSegFault</primary>
667 </indexterm>
668 </listitem>
669 </varlistentry>
670
671 <varlistentry id="libanl">
672 <term><filename class="libraryfile">libanl</filename></term>
673 <listitem>
674 <para>An asynchronous name lookup library</para>
675 <indexterm zone="ch-system-glibc libanl">
676 <primary sortas="c-libanl">libanl</primary>
677 </indexterm>
678 </listitem>
679 </varlistentry>
680
681 <varlistentry id="libbsd-compat">
682 <term><filename class="libraryfile">libbsd-compat</filename></term>
683 <listitem>
684 <para>Provides the portability needed in order to run certain
685 Berkeley Software Distribution (BSD) programs under Linux</para>
686 <indexterm zone="ch-system-glibc libbsd-compat">
687 <primary sortas="c-libbsd-compat">libbsd-compat</primary>
688 </indexterm>
689 </listitem>
690 </varlistentry>
691
692 <varlistentry id="libc">
693 <term><filename class="libraryfile">libc</filename></term>
694 <listitem>
695 <para>The main C library</para>
696 <indexterm zone="ch-system-glibc libc">
697 <primary sortas="c-libc">libc</primary>
698 </indexterm>
699 </listitem>
700 </varlistentry>
701
702 <varlistentry id="libcidn">
703 <term><filename class="libraryfile">libcidn</filename></term>
704 <listitem>
705 <para>Used internally by Glibc for handling internationalized domain
706 names in the <function>getaddrinfo()</function> function</para>
707 <indexterm zone="ch-system-glibc libcrypt">
708 <primary sortas="c-libcrypt">libcrypt</primary>
709 </indexterm>
710 </listitem>
711 </varlistentry>
712
713 <varlistentry id="libcrypt">
714 <term><filename class="libraryfile">libcrypt</filename></term>
715 <listitem>
716 <para>The cryptography library</para>
717 <indexterm zone="ch-system-glibc libcrypt">
718 <primary sortas="c-libcrypt">libcrypt</primary>
719 </indexterm>
720 </listitem>
721 </varlistentry>
722
723 <varlistentry id="libdl">
724 <term><filename class="libraryfile">libdl</filename></term>
725 <listitem>
726 <para>The dynamic linking interface library</para>
727 <indexterm zone="ch-system-glibc libdl">
728 <primary sortas="c-libdl">libdl</primary>
729 </indexterm>
730 </listitem>
731 </varlistentry>
732
733 <varlistentry id="libg">
734 <term><filename class="libraryfile">libg</filename></term>
735 <listitem>
736 <para>Dummy library containing no functions. Previously was a runtime
737 library for <command>g++</command></para>
738 <indexterm zone="ch-system-glibc libg">
739 <primary sortas="c-libg">libg</primary>
740 </indexterm>
741 </listitem>
742 </varlistentry>
743
744 <varlistentry id="libieee">
745 <term><filename class="libraryfile">libieee</filename></term>
746 <listitem>
747 <para>Linking in this module forces error handling rules for math
748 functions as defined by the Institute of Electrical and Electronic
749 Engineers (IEEE). The default is POSIX.1 error handling</para>
750 <indexterm zone="ch-system-glibc libieee">
751 <primary sortas="c-libieee">libieee</primary>
752 </indexterm>
753 </listitem>
754 </varlistentry>
755
756 <varlistentry id="libm">
757 <term><filename class="libraryfile">libm</filename></term>
758 <listitem>
759 <para>The mathematical library</para>
760 <indexterm zone="ch-system-glibc libm">
761 <primary sortas="c-libm">libm</primary>
762 </indexterm>
763 </listitem>
764 </varlistentry>
765
766 <varlistentry id="libmcheck">
767 <term><filename class="libraryfile">libmcheck</filename></term>
768 <listitem>
769 <para>Turns on memory allocation checking when linked to</para>
770 <indexterm zone="ch-system-glibc libmcheck">
771 <primary sortas="c-libmcheck">libmcheck</primary>
772 </indexterm>
773 </listitem>
774 </varlistentry>
775
776 <varlistentry id="libmemusage">
777 <term><filename class="libraryfile">libmemusage</filename></term>
778 <listitem>
779 <para>Used by <command>memusage</command> to help collect
780 information about the memory usage of a program</para>
781 <indexterm zone="ch-system-glibc libmemusage">
782 <primary sortas="c-libmemusage">libmemusage</primary>
783 </indexterm>
784 </listitem>
785 </varlistentry>
786
787 <varlistentry id="libnsl">
788 <term><filename class="libraryfile">libnsl</filename></term>
789 <listitem>
790 <para>The network services library</para>
791 <indexterm zone="ch-system-glibc libnsl">
792 <primary sortas="c-libnsl">libnsl</primary>
793 </indexterm>
794 </listitem>
795 </varlistentry>
796
797 <varlistentry id="libnss">
798 <term><filename class="libraryfile">libnss</filename></term>
799 <listitem>
800 <para>The Name Service Switch libraries, containing functions for
801 resolving host names, user names, group names, aliases, services,
802 protocols, etc.</para>
803 <indexterm zone="ch-system-glibc libnss">
804 <primary sortas="c-libnss">libnss</primary>
805 </indexterm>
806 </listitem>
807 </varlistentry>
808
809 <varlistentry id="libpcprofile">
810 <term><filename class="libraryfile">libpcprofile</filename></term>
811 <listitem>
812 <para>Contains profiling functions used to track the amount of CPU
813 time spent in specific source code lines</para>
814 <indexterm zone="ch-system-glibc libpcprofile">
815 <primary sortas="c-libpcprofile">libpcprofile</primary>
816 </indexterm>
817 </listitem>
818 </varlistentry>
819
820 <varlistentry id="libpthread">
821 <term><filename class="libraryfile">libpthread</filename></term>
822 <listitem>
823 <para>The POSIX threads library</para>
824 <indexterm zone="ch-system-glibc libpthread">
825 <primary sortas="c-libpthread">libpthread</primary>
826 </indexterm>
827 </listitem>
828 </varlistentry>
829
830 <varlistentry id="libresolv">
831 <term><filename class="libraryfile">libresolv</filename></term>
832 <listitem>
833 <para>Contains functions for creating, sending, and interpreting
834 packets to the Internet domain name servers</para>
835 <indexterm zone="ch-system-glibc libresolv">
836 <primary sortas="c-libresolv">libresolv</primary>
837 </indexterm>
838 </listitem>
839 </varlistentry>
840
841 <varlistentry id="librpcsvc">
842 <term><filename class="libraryfile">librpcsvc</filename></term>
843 <listitem>
844 <para>Contains functions providing miscellaneous RPC services</para>
845 <indexterm zone="ch-system-glibc librpcsvc">
846 <primary sortas="c-librpcsvc">librpcsvc</primary>
847 </indexterm>
848 </listitem>
849 </varlistentry>
850
851 <varlistentry id="librt">
852 <term><filename class="libraryfile">librt</filename></term>
853 <listitem>
854 <para>Contains functions providing most of the interfaces specified
855 by the POSIX.1b Realtime Extension</para>
856 <indexterm zone="ch-system-glibc librt">
857 <primary sortas="c-librt">librt</primary>
858 </indexterm>
859 </listitem>
860 </varlistentry>
861
862 <varlistentry id="libthread_db">
863 <term><filename class="libraryfile">libthread_db</filename></term>
864 <listitem>
865 <para>Contains functions useful for building debuggers for
866 multi-threaded programs</para>
867 <indexterm zone="ch-system-glibc libthread_db">
868 <primary sortas="c-libthread_db">libthread_db</primary>
869 </indexterm>
870 </listitem>
871 </varlistentry>
872
873 <varlistentry id="libutil">
874 <term><filename class="libraryfile">libutil</filename></term>
875 <listitem>
876 <para>Contains code for <quote>standard</quote> functions used in
877 many different Unix utilities</para>
878 <indexterm zone="ch-system-glibc libutil">
879 <primary sortas="c-libutil">libutil</primary>
880 </indexterm>
881 </listitem>
882 </varlistentry>
883
884 </variablelist>
885
886 </sect2>
887
888</sect1>
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