perl-policy.xml

   1 <?xml version='1.0' encoding='utf-8'?>
   2 <!-- -*- DocBook -*- -->
   3 <!DOCTYPE book PUBLIC "-//OASIS//DTD DocBook XML V4.5//EN"
   4     "http://www.oasis-open.org/docbook/xml/4.5/docbookx.dtd" [
   5 <!ENTITY % versiondata SYSTEM "version.xml"> %versiondata;
   6 ]>
   7
   8 <book lang="en">
   9   <title>Debian Perl Policy</title>
  10
  11   <bookinfo>
  12     <authorgroup>
  13       <author>
  14         <personname>
  15           <firstname>Rapha&euml;l</firstname><surname>Hertzog</surname>
  16         </personname>
  17       </author>
  18       <author>
  19         <personname>
  20           <firstname>Brendan</firstname><surname>O'Dea</surname>
  21         </personname>
  22       </author>
  23       <author>
  24         <othername>The Debian Policy Mailing List</othername>
  25         <email>debian-policy@lists.debian.org</email>
  26       </author>
  27     </authorgroup>
  28
  29     <releaseinfo>version &version;</releaseinfo>
  30     <pubdate>&date;</pubdate>
  31
  32     <abstract>
  33       <para>
  34         This document describes the packaging of Perl within the Debian
  35         distribution and the policy requirements for packaged Perl
  36         programs and modules.
  37       </para>
  38     </abstract>
  39
  40     <copyright>
  41       <year>1999</year>
  42       <year>2001</year>
  43       <holder>Rapha&euml;l Hertzog</holder>
  44       <holder>Brendan O'Dea</holder>
  45     </copyright>
  46     <legalnotice>
  47       <para>
  48         These are the copyright dates of the original Debian Perl Policy.
  49         Since then, this document has been updated by many others.  No
  50         comprehensive collection of copyright notices for subsequent work
  51         exists.
  52       </para>
  53       <para>
  54         This manual is free software; you may redistribute it and/or
  55         modify it under the terms of the GNU General Public License as
  56         published by the Free Software Foundation; either version 2 of the
  57         License, or (at your option) any later version.
  58       </para>
  59       <para>
  60         This is distributed in the hope that it will be useful, but
  61         WITHOUT ANY WARRANTY; without even the implied warranty of
  62         MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  63         General Public License for more details.
  64       </para>
  65       <para>
  66         A copy of the GNU General Public License is available as
  67         <filename>/usr/share/common-licenses/GPL</filename> in the Debian
  68         distribution or on the World Wide Web at <ulink
  69         url="https://www.gnu.org/licenses/">https://www.gnu.org/licenses/</ulink>.
  70       </para>
  71     </legalnotice>
  72   </bookinfo>
  73
  74   <chapter id="ch1">
  75     <title>About this document</title>
  76     <para>
  77       This document is distributed as the <literal>perl-policy</literal>
  78       files in the Debian package <systemitem role="package"><ulink
  79       url="https://packages.debian.org/debian-policy">debian-policy</ulink></systemitem>.
  80       It is also available from the Debian web mirrors at <ulink
  81       url="https://www.debian.org/doc/packaging-manuals/perl-policy/">https://www.debian.org/doc/packaging-manuals/perl-policy/</ulink>.
  82     </para>
  83   </chapter>
  84
  85   <chapter id="ch-perl">
  86     <title>Perl Packaging</title>
  87
  88     <section id="s-versions">
  89       <title>Versions</title>
  90
  91       <para>
  92         At any given time, the package <systemitem
  93         role="package">perl</systemitem> should represent the current
  94         stable upstream version of Perl revision 5 (see <xref
  95         linkend="ap-perl6"/>).
  96       </para>
  97       <para>
  98         Only one package may contain the
  99         <filename>/usr/bin/perl</filename> binary and that package must
 100         either be <systemitem role="package">perl</systemitem> or a
 101         dependency of that package (see <xref linkend="s-base"/>).
 102       </para>
 103       <para>
 104         Where possible, Perl should be compiled to provide binary
 105         compatibility to at least the last released package version to
 106         allow a grace period over which binary module packages may be
 107         re-built against the new package (see <xref
 108         linkend="s-binary-modules"/>).
 109       </para>
 110       <para>
 111         The <systemitem role="package">perl-base</systemitem> package must
 112         provide <systemitem
 113         role="package">perlapi-<replaceable>abiname</replaceable></systemitem>
 114         for all released package versions it is compatible with.  The
 115         choice of <replaceable>abiname</replaceable> is arbitrary, but if
 116         it differs from
 117         <literal>$Config{version}</literal><footnote><para> see the
 118         <literal>Config</literal> module </para> </footnote>, it must be
 119         specified in <literal>$Config{debian_abi}</literal>.
 120       </para>
 121     </section>
 122
 123     <section id="s-base">
 124       <title>Base Package</title>
 125
 126       <para>
 127         In order to provide a minimal installation of Perl for use by
 128         applications without requiring the whole of Perl to be installed,
 129         the <systemitem role="package">perl-base</systemitem> package
 130         contains the binary and a basic set of modules.
 131       </para>
 132       <para>
 133         As Perl has been part of the essential set for some time and is
 134         used without dependencies by such things as package maintainer
 135         scripts, <systemitem role="package">perl-base</systemitem> must be
 136         priority <emphasis>required</emphasis> and marked as
 137         <emphasis>essential</emphasis>.
 138       </para>
 139       <para>
 140         Note that the <systemitem role="package">perl-base</systemitem>
 141         package is intended only to provide for exceptional circumstances
 142         and the contents may change.  In general, only packages which form
 143         part of the base system should use only the facilities of
 144         <systemitem role="package">perl-base</systemitem> rather than
 145         declaring a dependency on <systemitem
 146         role="package">perl</systemitem>.
 147       </para>
 148     </section>
 149
 150     <section id="s-paths">
 151       <title>Module Path</title>
 152
 153       <para>
 154         Perl searches several different locations for modules, referred to
 155         in this document as <replaceable>core</replaceable> in which
 156         modules distributed with Perl are installed,
 157         <replaceable>vendor</replaceable> for packaged modules and
 158         <replaceable>site</replaceable> for modules installed by the local
 159         administrator.
 160       </para>
 161       <para>
 162         The module search path (<literal>@INC</literal>) in the current
 163         Debian packages has been ordered to include these locations in the
 164         following order<footnote><para>@INC contains other paths which
 165         should be considered internal to the implementation of the perl
 166         packaging</para></footnote>
 167       </para>
 168       <variablelist>
 169         <varlistentry>
 170           <term><replaceable>site</replaceable> (current)</term>
 171           <listitem>
 172             <para>
 173               Modules installed by the local administrator for the current
 174               version of Perl (see <xref linkend="ch-site"/>).
 175             </para>
 176             <screen>
 177 $Config{sitearch}  (currently /usr/local/lib/<replaceable>arch-triplet</replaceable>/perl/<replaceable>version</replaceable>)
 178 $Config{sitelib}   (currently /usr/local/share/perl/<replaceable>version</replaceable>)</screen>
 179             <para>
 180               Where <replaceable>version</replaceable> indicates the
 181               current Perl version (<literal>$Config{version}</literal>).
 182             </para>
 183             <para>
 184               These locations, particularly
 185               <literal>$Config{sitearch}</literal>, may change if the
 186               binary interface between the Perl interpreter and compiled
 187               modules has to be changed in an incompatible way without a
 188               change in <replaceable>version</replaceable>.  While this
 189               will only be done as a last resort, packages should use
 190               <literal>$Config{sitelib}</literal> and
 191               <literal>$Config{sitearch}</literal>, not hardcode the
 192               current locations.<footnote><para> Build systems based on
 193               <literal>ExtUtils::MakeMaker</literal> and
 194               <literal>Module::Build</literal> do this
 195               automatically.</para></footnote>
 196             </para>
 197           </listitem>
 198         </varlistentry>
 199         <varlistentry>
 200           <term><replaceable>vendor</replaceable></term>
 201           <listitem>
 202             <para>
 203               Packaged modules (see <xref linkend="ch-module_packages"/>).
 204             </para>
 205             <screen>
 206 $Config{vendorarch} (currently /usr/lib/<replaceable>arch-triplet</replaceable>/perl5/<replaceable>shortversion</replaceable>)
 207 $Config{vendorlib}  (currently /usr/share/perl5)</screen>
 208             <para>
 209               Where <replaceable>shortversion</replaceable> indicates the
 210               current Perl major version (for example
 211               <literal>5.22</literal>).
 212             </para>
 213             <para>
 214               These locations, particularly
 215               <literal>$Config{vendorarch}</literal>, may change if
 216               necessary<footnote><para> For example, to include the
 217               multiarch triplet </para> </footnote>.  Packages should use
 218               <literal>$Config{vendorlib}</literal> and
 219               <literal>$Config{vendorarch}</literal>, not hardcode the
 220               current locations.<footnote><para> Build systems based on
 221               <literal>ExtUtils::MakeMaker</literal> and
 222               <literal>Module::Build</literal> do this automatically.
 223               </para> </footnote>
 224             </para>
 225           </listitem>
 226         </varlistentry>
 227         <varlistentry>
 228           <term><replaceable>core</replaceable></term>
 229           <listitem>
 230             <para>
 231               Modules included in the core Perl distribution.
 232             </para>
 233             <screen>
 234 $Config{archlib} (currently /usr/lib/<replaceable>arch-triplet</replaceable>/perl/<replaceable>shortversion</replaceable>)
 235 $Config{privlib} (currently /usr/share/perl/<replaceable>shortversion</replaceable>)</screen>
 236             <para>
 237               Where <replaceable>shortversion</replaceable> indicates the
 238               current Perl major version (for example
 239               <literal>5.22</literal>).
 240             </para>
 241             <para>
 242               These locations should be considered internal to the
 243               <systemitem role="package">perl</systemitem> source package.
 244               If necessary, packages should use
 245               <literal>$Config{archlib}</literal> and
 246               <literal>$Config{privlib}</literal> instead of hardcoding
 247               the current locations.<footnote><para> Build systems based
 248               on <literal>ExtUtils::MakeMaker</literal> and
 249               <literal>Module::Build</literal> do this automatically.
 250               </para> </footnote>
 251             </para>
 252           </listitem>
 253         </varlistentry>
 254         <varlistentry>
 255           <term><replaceable>site</replaceable> (old)</term>
 256           <listitem>
 257             <para>
 258               <replaceable>site</replaceable> directories (as above) for
 259               modules installed with previously released <systemitem
 260               role="package">perl</systemitem> packages for which the
 261               current package is binary compatible are included if
 262               present.
 263             </para>
 264           </listitem>
 265         </varlistentry>
 266       </variablelist>
 267       <para>
 268         In each of the directory pairs above, the <filename>lib</filename>
 269         component is for binary (XS) modules, and
 270         <filename>share</filename> for architecture-independent
 271         (pure-perl) modules.
 272       </para>
 273     </section>
 274
 275     <section id="s-docs">
 276       <title>Documentation</title>
 277
 278       <para>
 279         The POD files and manual pages which do not refer to programs may
 280         be split out into a separate <systemitem
 281         role="package">perl-doc</systemitem> package.
 282       </para>
 283       <para>
 284         Manual pages distributed with packages built from the perl source
 285         package must be installed into the standard directories:
 286       </para>
 287       <variablelist>
 288         <varlistentry>
 289           <term>Programs</term>
 290           <listitem>
 291             <para>
 292               Manual pages for programs and scripts are installed into
 293               <filename>/usr/share/man/man1</filename> with the extension
 294               <literal>.1</literal>.
 295             </para>
 296           </listitem>
 297         </varlistentry>
 298         <varlistentry>
 299           <term>Modules</term>
 300           <listitem>
 301             <para>
 302               Manual pages for modules are installed into
 303               <filename>/usr/share/man/man3</filename> with the extension
 304               <literal>.3perl</literal>.
 305             </para>
 306           </listitem>
 307         </varlistentry>
 308       </variablelist>
 309       <para>
 310         The extensions used for manual pages distributed with module
 311         packages are different.  See <xref linkend="s-vendor-dirs"/>.
 312       </para>
 313     </section>
 314
 315   </chapter>
 316
 317   <chapter id="ch-site">
 318     <title>Locally Installed Modules</title>
 319
 320     <section id="s-site-dirs">
 321       <title>Site Directories</title>
 322
 323       <para>
 324         The Perl packages must provide a mechanism for the local
 325         administrator to install modules under
 326         <filename>/usr/local</filename> but must not create or remove
 327         those directories.
 328       </para>
 329       <para>
 330         Modules should be installed to the directories described above in
 331         <xref linkend="s-paths"/> as <replaceable>site</replaceable>
 332         (current), programs to <filename>/usr/local/bin</filename> and
 333         manual pages under <filename>/usr/local/man</filename>.
 334       </para>
 335     </section>
 336
 337     <section id="s-site-install">
 338       <title>Site Installation</title>
 339
 340       <para>
 341         The following commands should be sufficient in the majority of
 342         cases for the local administrator to install modules and must
 343         create directories as required:
 344       </para>
 345       <screen>
 346 perl Makefile.PL
 347 make install</screen>
 348     </section>
 349
 350   </chapter>
 351
 352   <chapter id="ch-module_packages">
 353     <title>Packaged Modules</title>
 354
 355     <section id="s-vendor-dirs">
 356       <title>Vendor Directories</title>
 357
 358       <para>
 359         The installation directory for Debian modules must be different
 360         from that for <replaceable>core</replaceable> and
 361         <replaceable>site</replaceable> modules.
 362       </para>
 363       <para>
 364         The current Perl packaging uses the
 365         <replaceable>vendor</replaceable> directories for this purpose,
 366         which are at present as described in <xref linkend="s-paths"/> as
 367         <replaceable>vendor</replaceable>.
 368       </para>
 369       <para>
 370         The Perl distribution includes many modules available separately
 371         from <ulink url="https://www.cpan.org/">CPAN</ulink> which may
 372         have a newer version.  The intent of the <literal>@INC</literal>
 373         ordering (described in <xref linkend="s-paths"/>) is to allow such
 374         modules to be packaged to <replaceable>vendor</replaceable> which
 375         take precedence over the version in
 376         <replaceable>core</replaceable>.  A packaged module which shadows
 377         a <replaceable>core</replaceable> module in this way must be a
 378         newer version.
 379       </para>
 380       <para>
 381         Module packages must install manual pages into the standard
 382         directories (see <xref linkend="s-docs"/>) using the extensions
 383         <literal>.1p</literal> and <literal>.3pm</literal> to ensure that
 384         no conflict arises where a packaged module duplicates a
 385         <replaceable>core</replaceable> module.
 386       </para>
 387       <para>
 388         <filename>.packlist</filename> files should not be installed.
 389       </para>
 390     </section>
 391
 392     <section id="s-package-names">
 393       <title>Module Package Names</title>
 394       <para>
 395         Perl module packages should be named for the primary module
 396         provided.  The naming convention is to lowercase the Perl module
 397         name, prepend, <literal>lib</literal>, change all occurrences of
 398         <literal>::</literal> to <literal>-</literal>, and append
 399         <literal>-perl</literal>.  For example:
 400       </para>
 401       <table frame="all">
 402         <title>Module to package mappings</title>
 403         <tgroup cols="2">
 404           <thead>
 405             <row>
 406               <entry>Module</entry>
 407               <entry>Package</entry>
 408             </row>
 409           </thead>
 410           <tbody>
 411             <row>
 412               <entry>Foo::Bar</entry>
 413               <entry>libfoo-bar-perl</entry>
 414             </row>
 415             <row>
 416               <entry>Foo::Bar::Baz</entry>
 417               <entry>libfoo-bar-baz-perl</entry>
 418             </row>
 419             <row>
 420               <entry>Foo::BarBaz</entry>
 421               <entry>libfoo-barbaz-perl</entry>
 422             </row>
 423           </tbody>
 424         </tgroup>
 425       </table>
 426       <para>
 427         Packages which include multiple modules may additionally include
 428         provides for the additional modules using the same convention.
 429       </para>
 430     </section>
 431
 432     <section id="s-vendor-install">
 433       <title>Vendor Installation</title>
 434       <para>
 435         A module should use the following lines in the
 436         <filename>debian/rules</filename> <literal>build</literal>
 437         target:
 438         <footnote>
 439           <para>
 440             The environment variable <literal>PERL_MM_OPT</literal> may be
 441             used to pass the <literal>INSTALLDIRS=vendor</literal> option
 442             in cases where <filename>Makefile.PL</filename> is not invoked
 443             directly from
 444             <filename>debian/rules</filename>
 445           </para>
 446         </footnote>
 447       </para>
 448       <screen>
 449 perl Makefile.PL INSTALLDIRS=vendor
 450 $(MAKE) OPTIMIZE="-O2 -g -Wall"</screen>
 451       <para>
 452         and this one to install the results into the temporary tree:
 453       </para>
 454       <screen>$(MAKE) install DESTDIR=$(CURDIR)/debian/&lt;tmp&gt;</screen>
 455       <para>
 456         <footnote><para>Replace &lt;tmp&gt; with the appropriate directory
 457         (nominally just tmp)</para></footnote>
 458       </para>
 459     </section>
 460
 461     <section id="s-module-deps">
 462       <title>Module Dependencies</title>
 463
 464       <section id="s-indep-modules">
 465         <title>Architecture-Independent Modules</title>
 466
 467         <para>
 468           Architecture-independent modules which require
 469           <replaceable>core</replaceable> modules from the <systemitem
 470           role="package">perl</systemitem> package must specify a
 471           dependency on that package.
 472         </para>
 473         <para>
 474           Modules which contain explicit <literal>require
 475           <replaceable>version</replaceable></literal> or <literal>use
 476           <replaceable>version</replaceable></literal> statements must
 477           specify a dependency on <systemitem
 478           role="package">perl</systemitem> or <systemitem
 479           role="package">perl-base</systemitem> with the minimum required
 480           version, or more simply the current version.
 481         </para>
 482       </section>
 483
 484       <section id="s-binary-modules">
 485         <title>Binary and Other Architecture Dependent Modules</title>
 486
 487         <para>
 488           Binary modules must specify a dependency on either <systemitem
 489           role="package">perl</systemitem> or <systemitem
 490           role="package">perl-base</systemitem> with a minimum version of
 491           the <systemitem role="package">perl</systemitem> package used to
 492           build the module.  Additionally, all binary modules (regardless
 493           of their installation directory) and any other modules installed
 494           into <literal>$Config{vendorarch}</literal> must depend on the
 495           expansion of <systemitem
 496           role="package">perlapi-$Config{debian_abi}</systemitem> using
 497           the <literal>Config</literal> module.  If
 498           <literal>$Config{debian_abi}</literal> is empty or not set,
 499           <literal>$Config{version}</literal> must be used.
 500         </para>
 501       </section>
 502
 503       <section id="s-dh-perl">
 504         <title>Automating Perl Dependencies</title>
 505
 506         <para>
 507           Rather than hard-coding the dependencies into the control file,
 508           using a substitution such as <literal>${perl:Depends}</literal>
 509           is suggested.  This allows the dependencies to be determined at
 510           build time and written to the <filename>substvars</filename>
 511           file in the form
 512           <literal>perl:Depends=<replaceable>deps</replaceable></literal>.<footnote><para>
 513           Please note that dependencies caused by versioned uses and on
 514           separately packaged modules are not included in this variable
 515           and must be explicitly included.  </para> </footnote>
 516         </para>
 517         <para>
 518           Packages built with <command>debhelper</command> may use
 519           <citerefentry><refentrytitle>dh_perl</refentrytitle><manvolnum>1</manvolnum></citerefentry>
 520           to generate this substitution automatically.  This additionally
 521           requires a versioned <literal>Build-Depends</literal> (or
 522           <literal>Build-Depends-Indep</literal>) on <literal>debhelper
 523           (>= 3.0.18)</literal>.
 524         </para>
 525       </section>
 526     </section>
 527   </chapter>
 528
 529   <chapter id="ch-programs">
 530     <title>Perl Programs</title>
 531
 532     <section id="s-hash-bang">
 533       <title>Script Magic</title>
 534
 535       <para>
 536         All packaged perl programs must start with
 537         <literal>#!/usr/bin/perl</literal> and may append such flags as
 538         are required.
 539       </para>
 540     </section>
 541
 542     <section id="s-program-deps">
 543       <title>Program Dependencies</title>
 544
 545       <para>
 546         Programs which require <replaceable>core</replaceable> modules
 547         from the <systemitem role="package">perl</systemitem> package must
 548         specify a dependency on that package.
 549       </para>
 550       <para>
 551         Programs which contain explicit <literal>require
 552         <replaceable>version</replaceable></literal> or <literal>use
 553         <replaceable>version</replaceable></literal> statements must
 554         specify a dependency on <systemitem
 555         role="package">perl</systemitem> or <systemitem
 556         role="package">perl-base</systemitem> with the minimum required
 557         version, or more simply the current version.
 558       </para>
 559       <para>
 560         As with modules, packages using <command>debhelper</command> may
 561         use
 562         <citerefentry><refentrytitle>dh_perl</refentrytitle><manvolnum>1</manvolnum></citerefentry>
 563         to automatically generate dependences (see <xref
 564         linkend="s-dh-perl"/>).
 565       </para>
 566     </section>
 567
 568   </chapter>
 569
 570   <chapter id="ch-embed">
 571     <title>Programs Embedding Perl</title>
 572
 573     <section id="s-build-embedded">
 574       <title>Building Embedded Programs</title>
 575
 576       <para>
 577         Programs which embed a perl interpreter must declare a
 578         <literal>Build-Depends</literal> on <systemitem
 579         role="package">libperl-dev</systemitem>.
 580       </para>
 581       <para>
 582         The default linker options produced by
 583       </para>
 584       <screen>perl -MExtUtils::Embed -e ldopts</screen>
 585       <para>
 586         will link against the dynamic <literal>libperl</literal>.  If
 587         programs wish to link to the static library, then
 588         <literal>-lperl</literal> should be changed to
 589         <filename>/usr/lib/libperl.a</filename> in those options.
 590       </para>
 591     </section>
 592
 593     <section id="s-embedded-deps">
 594       <title>Embedded Perl Dependencies</title>
 595
 596       <para>
 597         Dependencies for programs linking against the shared Perl library
 598         will be automatically created by
 599         <command>dpkg-shlibdeps</command>.  Note however that the shared
 600         perl library package only suggests <systemitem
 601         role="package">perl-base</systemitem> and packages requiring any
 602         <replaceable>core</replaceable> modules from the <systemitem
 603         role="package">perl</systemitem> package must depend upon it
 604         explicitly.
 605       </para>
 606     </section>
 607
 608     <section id="s-perl-upgrades">
 609       <title>Perl Package Upgrades</title>
 610
 611       <para>
 612         Starting from <systemitem role="package">perl</systemitem>
 613         5.12.3-2, a dpkg trigger named
 614         <replaceable>perl-major-upgrade</replaceable> will be triggered by
 615         the postinst of the <systemitem role="package">perl</systemitem>
 616         package during major upgrades.  Some examples of things which
 617         constitute a major upgrade are an upgrade which would change the
 618         value of versioned directories in <literal>@INC</literal>, or one
 619         which changes <literal>abiname</literal>.  Any package may declare
 620         an interest in the trigger, especially packages including
 621         long-running daemons which would stop working until restart.
 622       </para>
 623       <para>
 624         It is suggested that such packages include an appropriate section
 625         in their postinst to handle the trigger by restarting relevant
 626         daemons or notifying users of further action.
 627       </para>
 628     </section>
 629
 630   </chapter>
 631
 632   <appendix id="ap-perl6">
 633     <title>Perl 6</title>
 634
 635     <para>
 636       The current stable upstream version at the time of this writing is
 637       5.6.0.  There is currently work in progress on the next major
 638       revision, although the specifications have yet to be finalised.
 639     </para>
 640     <para>
 641       It is anticipated that when Perl 6 is released it will initially be
 642       packaged as <systemitem role="package">perl6</systemitem>, install
 643       the binary as <filename>/usr/bin/perl6</filename> and use different
 644       directories for packaged modules to <systemitem
 645       role="package">perl</systemitem>:
 646     </para>
 647     <screen>
 648 /usr/lib/perl6
 649 /usr/share/perl6</screen>
 650     <para>
 651       This will allow Perl 5 and 6 packages and modules (which should be
 652       packaged as <systemitem
 653       role="package">libfoo-bar-perl6</systemitem>), to co-exist for as
 654       long as required.
 655     </para>
 656     <para>
 657       At some stage in the future when Perl 6 is sufficiently mature, the
 658       package naming may be reversed such that the <systemitem
 659       role="package">perl</systemitem> package contains Perl 6 and the
 660       current package becomes <systemitem
 661       role="package">perl5</systemitem>.
 662     </para>
 663   </appendix>
 664 </book>