perl/INSTALL
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   1If you read this file _as_is_, just ignore the funny characters you see.
   2It is written in the POD format (see pod/perlpod.pod) which is specially
   3designed to be readable as is.
   4
   5=head1 NAME
   6
   7Install - Build and Installation guide for perl 5.
   8
   9=head1 SYNOPSIS
  10
  11First, make sure you have an up-to-date version of Perl.  If you
  12didn't get your Perl source from CPAN, check the latest version at
  13http://www.cpan.org/src/.  Perl uses a version scheme where even-numbered
  14subreleases (like 5.8.x and 5.10.x) are stable maintenance releases and
  15odd-numbered subreleases (like 5.7.x and 5.9.x) are unstable
  16development releases.  Development releases should not be used in
  17production environments.  Fixes and new features are first carefully
  18tested in development releases and only if they prove themselves to be
  19worthy will they be migrated to the maintenance releases.
  20
  21The basic steps to build and install perl 5 on a Unix system with all
  22the defaults are to run, from a freshly unpacked source tree:
  23
  24        sh Configure -de
  25        make
  26        make test
  27        make install
  28
  29Each of these is explained in further detail below.
  30
  31The above commands will install Perl to /usr/local (or some other
  32platform-specific directory -- see the appropriate file in hints/.)
  33If that's not okay with you, you can run Configure interactively, by
  34just typing "sh Configure" (without the -de args). You can also specify
  35any prefix location by adding "-Dprefix='/some/dir'" to Configure's args.
  36To explicitly name the perl binary, use the command
  37"make install PERLNAME=myperl".
  38
  39These options, and many more, are explained in further detail below.
  40
  41If you have problems, corrections, or questions, please see
  42L<"Reporting Problems"> below.
  43
  44For information on what's new in this release, see the
  45pod/perl5101delta.pod file.  For more information about how to find more
  46specific detail about changes, see the Changes file.
  47
  48=head1 DESCRIPTION
  49
  50This document is written in pod format as an easy way to indicate its
  51structure.  The pod format is described in pod/perlpod.pod, but you can
  52read it as is with any pager or editor.  Headings and items are marked
  53by lines beginning with '='.  The other mark-up used is
  54
  55    B<text>     embolden text, used for switches, programs or commands
  56    C<code>     literal code
  57    L<name>     A link (cross reference) to name
  58    F<file>     A filename
  59
  60Although most of the defaults are probably fine for most users,
  61you should probably at least skim through this document before
  62proceeding.
  63
  64In addition to this file, check if there is a README file specific to
  65your operating system, since it may provide additional or different
  66instructions for building Perl.  If there is a hint file for your
  67system (in the hints/ directory) you might also want to read it
  68for even more information.
  69
  70For additional information about porting Perl, see the section on
  71L<"Porting information"> below, and look at the files in the Porting/
  72directory.
  73
  74=head1 PRELIMINARIES
  75
  76=head2 Changes and Incompatibilities
  77
  78Please see pod/perl5101delta.pod for a description of the changes and
  79potential incompatibilities introduced with this release.  A few of
  80the most important issues are listed below, but you should refer
  81to pod/perl5101delta.pod for more detailed information.
  82
  83B<WARNING:> This version is not binary compatible with releases of
  84Perl prior to 5.10.0.
  85If you have built extensions (i.e. modules that include C code)
  86using an earlier version of Perl, you will need to rebuild and reinstall
  87those extensions.
  88
  89Pure perl modules without XS or C code should continue to work fine
  90without reinstallation.  See the discussion below on
  91L<"Coexistence with earlier versions of perl 5"> for more details.
  92
  93The standard extensions supplied with Perl will be handled automatically.
  94
  95On a related issue, old modules may possibly be affected by the changes
  96in the Perl language in the current release.  Please see
  97pod/perl5101delta.pod for a description of what's changed.  See your
  98installed copy of the perllocal.pod file for a (possibly incomplete)
  99list of locally installed modules.  Also see CPAN::autobundle for one
 100way to make a "bundle" of your currently installed modules.
 101
 102=head1 Run Configure
 103
 104Configure will figure out various things about your system.  Some
 105things Configure will figure out for itself, other things it will ask
 106you about.  To accept the default, just press RETURN.   The default is
 107almost always okay.  It is normal for some things to be "NOT found",
 108since Configure often searches for many different ways of performing
 109the same function.
 110
 111At any Configure prompt, you can type  &-d  and Configure will use the
 112defaults from then on.
 113
 114After it runs, Configure will perform variable substitution on all the
 115*.SH files and offer to run make depend.
 116
 117The results of a Configure run are stored in the config.sh and Policy.sh
 118files.
 119
 120=head2 Common Configure options
 121
 122Configure supports a number of useful options.  Run
 123
 124        Configure -h
 125
 126to get a listing.  See the Porting/Glossary file for a complete list of
 127Configure variables you can set and their definitions.
 128
 129=over 4
 130
 131=item C compiler
 132
 133To compile with gcc, if it's not the default compiler on your
 134system, you should run
 135
 136        sh Configure -Dcc=gcc
 137
 138This is the preferred way to specify gcc (or any another alternative
 139compiler) so that the hints files can set appropriate defaults.
 140
 141=item Installation prefix
 142
 143By default, for most systems, perl will be installed in
 144/usr/local/{bin, lib, man}.  (See L<"Installation Directories">
 145and L<"Coexistence with earlier versions of perl 5"> below for
 146further details.)
 147
 148You can specify a different 'prefix' for the default installation
 149directory when Configure prompts you, or by using the Configure command
 150line option -Dprefix='/some/directory', e.g.
 151
 152        sh Configure -Dprefix=/opt/perl
 153
 154If your prefix contains the string "perl", then the suggested
 155directory structure is simplified.  For example, if you use
 156prefix=/opt/perl, then Configure will suggest /opt/perl/lib instead of
 157/opt/perl/lib/perl5/.  Again, see L<"Installation Directories"> below
 158for more details.  Do not include a trailing slash, (i.e. /opt/perl/)
 159or you may experience odd test failures.
 160
 161NOTE:  You must not specify an installation directory that is the same
 162as or below your perl source directory.  If you do, installperl will
 163attempt infinite recursion.
 164
 165=item /usr/bin/perl
 166
 167It may seem obvious, but Perl is useful only when users can easily
 168find it.  It's often a good idea to have both /usr/bin/perl and
 169/usr/local/bin/perl be symlinks to the actual binary.  Be especially
 170careful, however, not to overwrite a version of perl supplied by your
 171vendor unless you are sure you know what you are doing.  If you insist
 172on replacing your vendor's perl, useful information on how it was
 173configured may be found with
 174
 175        perl -V:config_args
 176
 177(Check the output carefully, however, since this doesn't preserve
 178spaces in arguments to Configure.  For that, you have to look carefully
 179at config_arg1, config_arg2, etc.)
 180
 181By default, Configure will not try to link /usr/bin/perl to the current
 182version of perl.  You can turn on that behavior by running
 183
 184        Configure -Dinstallusrbinperl
 185
 186or by answering 'yes' to the appropriate Configure prompt.
 187
 188In any case, system administrators are strongly encouraged to put
 189(symlinks to) perl and its accompanying utilities, such as perldoc,
 190into a directory typically found along a user's PATH, or in another
 191obvious and convenient place.
 192
 193=item Building a development release
 194
 195For development releases (odd subreleases, like 5.9.x) if you want to
 196use Configure -d, you will also need to supply -Dusedevel to Configure,
 197because the default answer to the question "do you really want to
 198Configure a development version?" is "no".  The -Dusedevel skips that
 199sanity check.
 200
 201=back
 202
 203If you are willing to accept all the defaults, and you want terse
 204output, you can run
 205
 206        sh Configure -des
 207
 208=head2 Altering Configure variables for C compiler switches etc.
 209
 210For most users, most of the Configure defaults are fine, or can easily
 211be set on the Configure command line.  However, if Configure doesn't
 212have an option to do what you want, you can change Configure variables
 213after the platform hints have been run by using Configure's -A switch.
 214For example, here's how to add a couple of extra flags to C compiler
 215invocations:
 216
 217        sh Configure -Accflags="-DPERL_EXTERNAL_GLOB -DNO_HASH_SEED"
 218
 219To clarify, those ccflags values are not Configure options; if passed to
 220Configure directly, they won't do anything useful (they will define a
 221variable in config.sh, but without taking any action based upon it).
 222But when passed to the compiler, those flags will activate #ifdefd code.
 223
 224For more help on Configure switches, run
 225
 226        sh Configure -h
 227
 228=head2 Major Configure-time Build Options
 229
 230There are several different ways to Configure and build perl for your
 231system.  For most users, the defaults are sensible and will work.
 232Some users, however, may wish to further customize perl.  Here are
 233some of the main things you can change.
 234
 235=head3 Threads
 236
 237On some platforms, perl can be compiled with support for threads.  To
 238enable this, run
 239
 240        sh Configure -Dusethreads
 241
 242The default is to compile without thread support.
 243
 244Perl used to have two different internal threads implementations.  The current
 245model (available internally since 5.6, and as a user-level module since 5.8) is
 246called interpreter-based implementation (ithreads), with one interpreter per
 247thread, and explicit sharing of data.  The (deprecated) 5.005 version
 248(5005threads) has been removed for release 5.10.
 249
 250The 'threads' module is for use with the ithreads implementation.  The
 251'Thread' module emulates the old 5005threads interface on top of the current
 252ithreads model.
 253
 254When using threads, perl uses a dynamically-sized buffer for some of
 255the thread-safe library calls, such as those in the getpw*() family.
 256This buffer starts small, but it will keep growing until the result
 257fits.  To get a fixed upper limit, you should compile Perl with
 258PERL_REENTRANT_MAXSIZE defined to be the number of bytes you want.  One
 259way to do this is to run Configure with
 260C<-Accflags=-DPERL_REENTRANT_MAXSIZE=65536>.
 261
 262=head3 Large file support
 263
 264Since Perl 5.6.0, Perl has supported large files (files larger than
 2652 gigabytes), and in many common platforms like Linux or Solaris this
 266support is on by default.
 267
 268This is both good and bad. It is good in that you can use large files,
 269seek(), stat(), and -s them.  It is bad in that if you are interfacing Perl
 270using some extension, the components you are connecting to must also
 271be large file aware: if Perl thinks files can be large but the other
 272parts of the software puzzle do not understand the concept, bad things
 273will happen.
 274
 275There's also one known limitation with the current large files
 276implementation: unless you also have 64-bit integers (see the next
 277section), you cannot use the printf/sprintf non-decimal integer formats
 278like C<%x> to print filesizes.  You can use C<%d>, though.
 279
 280If you want to compile perl without large file support, use
 281
 282    sh Configure -Uuselargefiles
 283
 284=head3 64 bit support
 285
 286If your platform does not run natively at 64 bits, but can simulate
 287them with compiler flags and/or C<long long> or C<int64_t>,
 288you can build a perl that uses 64 bits.
 289
 290There are actually two modes of 64-bitness: the first one is achieved
 291using Configure -Duse64bitint and the second one using Configure
 292-Duse64bitall.  The difference is that the first one is minimal and
 293the second one maximal.  The first works in more places than the second.
 294
 295The C<use64bitint> option does only as much as is required to get
 29664-bit integers into Perl (this may mean, for example, using "long
 297longs") while your memory may still be limited to 2 gigabytes (because
 298your pointers could still be 32-bit).  Note that the name C<64bitint>
 299does not imply that your C compiler will be using 64-bit C<int>s (it
 300might, but it doesn't have to).  The C<use64bitint> simply means that
 301you will be able to have 64 bit-wide scalar values.
 302
 303The C<use64bitall> option goes all the way by attempting to switch
 304integers (if it can), longs (and pointers) to being 64-bit.  This may
 305create an even more binary incompatible Perl than -Duse64bitint: the
 306resulting executable may not run at all in a 32-bit box, or you may
 307have to reboot/reconfigure/rebuild your operating system to be 64-bit
 308aware.
 309
 310Natively 64-bit systems need neither -Duse64bitint nor -Duse64bitall.
 311On these systems, it might be the default compilation mode, and there
 312is currently no guarantee that passing no use64bitall option to the
 313Configure process will build a 32bit perl. Implementing -Duse32bit*
 314options is planned for perl 5.12.
 315
 316=head3 Long doubles
 317
 318In some systems you may be able to use long doubles to enhance the
 319range and precision of your double precision floating point numbers
 320(that is, Perl's numbers).  Use Configure -Duselongdouble to enable
 321this support (if it is available).
 322
 323=head3 "more bits"
 324
 325You can "Configure -Dusemorebits" to turn on both the 64-bit support
 326and the long double support.
 327
 328=head3 Algorithmic Complexity Attacks on Hashes
 329
 330In Perls 5.8.0 and earlier it was easy to create degenerate hashes.
 331Processing such hashes would consume large amounts of CPU time,
 332enabling a "Denial of Service" attack against Perl.  Such hashes may be
 333a problem for example for mod_perl sites, sites with Perl CGI scripts
 334and web services, that process data originating from external sources.
 335
 336In Perl 5.8.1 a security feature was introduced to make it harder to
 337create such degenerate hashes. A visible side effect of this was that
 338the keys(), values(), and each() functions may return the hash elements
 339in different order between different runs of Perl even with the same
 340data.  It also had unintended binary incompatibility issues with
 341certain modules compiled against Perl 5.8.0.
 342
 343In Perl 5.8.2 an improved scheme was introduced.  Hashes will return
 344elements in the same order as Perl 5.8.0 by default.  On a hash by hash
 345basis, if pathological data is detected during a hash key insertion,
 346then that hash will switch to an alternative random hash seed.  As
 347adding keys can always dramatically change returned hash element order,
 348existing programs will not be affected by this, unless they
 349specifically test for pre-recorded hash return order for contrived
 350data. (eg the list of keys generated by C<map {"\0"x$_} 0..15> trigger
 351randomisation) In effect the new implementation means that 5.8.1 scheme
 352is only being used on hashes which are under attack.
 353
 354One can still revert to the old guaranteed repeatable order (and be
 355vulnerable to attack by wily crackers) by setting the environment
 356variable PERL_HASH_SEED, see L<perlrun/PERL_HASH_SEED>.  Another option
 357is to add -DUSE_HASH_SEED_EXPLICIT to the compilation flags (for
 358example by using C<Configure -Accflags=-DUSE_HASH_SEED_EXPLICIT>), in
 359which case one has to explicitly set the PERL_HASH_SEED environment
 360variable to enable the security feature, or by adding -DNO_HASH_SEED to
 361the compilation flags to completely disable the randomisation feature.
 362
 363B<Perl has never guaranteed any ordering of the hash keys>, and the
 364ordering has already changed several times during the lifetime of Perl
 3655.  Also, the ordering of hash keys has always been, and continues to
 366be, affected by the insertion order.  Note that because of this
 367randomisation for example the Data::Dumper results will be different
 368between different runs of Perl, since Data::Dumper by default dumps
 369hashes "unordered".  The use of the Data::Dumper C<Sortkeys> option is
 370recommended.
 371
 372=head3 SOCKS
 373
 374Perl can be configured to be 'socksified', that is, to use the SOCKS
 375TCP/IP proxy protocol library.  SOCKS is used to give applications
 376access to transport layer network proxies.  Perl supports only SOCKS
 377Version 5.  The corresponding Configure option is -Dusesocks.
 378You can find more about SOCKS from wikipedia at
 379L<http://en.wikipedia.org/wiki/SOCKS>.
 380
 381=head3 Dynamic Loading
 382
 383By default, Configure will compile perl to use dynamic loading.
 384If you want to force perl to be compiled completely
 385statically, you can either choose this when Configure prompts you or
 386you can use the Configure command line option -Uusedl.
 387With this option, you won't be able to use any new extension
 388(XS) module without recompiling perl itself.
 389
 390=head3 Building a shared Perl library
 391
 392Currently, for most systems, the main perl executable is built by
 393linking the "perl library" libperl.a with perlmain.o, your static
 394extensions, and various extra libraries, such as -lm.
 395
 396On systems that support dynamic loading, it may be possible to
 397replace libperl.a with a shared libperl.so.  If you anticipate building
 398several different perl binaries (e.g. by embedding libperl into
 399different programs, or by using the optional compiler extension), then
 400you might wish to build a shared libperl.so so that all your binaries
 401can share the same library.
 402
 403The disadvantages are that there may be a significant performance
 404penalty associated with the shared libperl.so, and that the overall
 405mechanism is still rather fragile with respect to different versions
 406and upgrades.
 407
 408In terms of performance, on my test system (Solaris 2.5_x86) the perl
 409test suite took roughly 15% longer to run with the shared libperl.so.
 410Your system and typical applications may well give quite different
 411results.
 412
 413The default name for the shared library is typically something like
 414libperl.so.5.8.8 (for Perl 5.8.8), or libperl.so.588, or simply
 415libperl.so.  Configure tries to guess a sensible naming convention
 416based on your C library name.  Since the library gets installed in a
 417version-specific architecture-dependent directory, the exact name
 418isn't very important anyway, as long as your linker is happy.
 419
 420You can elect to build a shared libperl by
 421
 422        sh Configure -Duseshrplib
 423
 424To build a shared libperl, the environment variable controlling shared
 425library search (LD_LIBRARY_PATH in most systems, DYLD_LIBRARY_PATH for
 426NeXTSTEP/OPENSTEP/Darwin, LIBRARY_PATH for BeOS, LD_LIBRARY_PATH/SHLIB_PATH
 427for HP-UX, LIBPATH for AIX, PATH for Cygwin) must be set up to include
 428the Perl build directory because that's where the shared libperl will
 429be created.  Configure arranges makefile to have the correct shared
 430library search settings.  You can find the name of the environment
 431variable Perl thinks works in your your system by
 432
 433        grep ldlibpthname config.sh
 434
 435However, there are some special cases where manually setting the
 436shared library path might be required.  For example, if you want to run
 437something like the following with the newly-built but not-yet-installed
 438./perl:
 439
 440        cd t; ./perl -MTestInit misc/failing_test.t
 441
 442or
 443
 444        ./perl -Ilib ~/my_mission_critical_test
 445
 446then you need to set up the shared library path explicitly.
 447You can do this with
 448
 449   LD_LIBRARY_PATH=`pwd`:$LD_LIBRARY_PATH; export LD_LIBRARY_PATH
 450
 451for Bourne-style shells, or
 452
 453   setenv LD_LIBRARY_PATH `pwd`
 454
 455for Csh-style shells.  (This procedure may also be needed if for some
 456unexpected reason Configure fails to set up makefile correctly.) (And
 457again, it may be something other than LD_LIBRARY_PATH for you, see above.)
 458
 459You can often recognize failures to build/use a shared libperl from error
 460messages complaining about a missing libperl.so (or libperl.sl in HP-UX),
 461for example:
 462
 463    18126:./miniperl: /sbin/loader: Fatal Error: cannot map libperl.so
 464
 465There is also an potential problem with the shared perl library if you
 466want to have more than one "flavor" of the same version of perl (e.g.
 467with and without -DDEBUGGING).  For example, suppose you build and
 468install a standard Perl 5.10.1 with a shared library.  Then, suppose you
 469try to build Perl 5.10.1 with -DDEBUGGING enabled, but everything else
 470the same, including all the installation directories.  How can you
 471ensure that your newly built perl will link with your newly built
 472libperl.so.8 rather with the installed libperl.so.8?  The answer is
 473that you might not be able to.  The installation directory is encoded
 474in the perl binary with the LD_RUN_PATH environment variable (or
 475equivalent ld command-line option).  On Solaris, you can override that
 476with LD_LIBRARY_PATH; on Linux, you can only override at runtime via
 477LD_PRELOAD, specifying the exact filename you wish to be used; and on
 478Digital Unix, you can override LD_LIBRARY_PATH by setting the
 479_RLD_ROOT environment variable to point to the perl build directory.
 480
 481In other words, it is generally not a good idea to try to build a perl
 482with a shared library if $archlib/CORE/$libperl already exists from a
 483previous build.
 484
 485A good workaround is to specify a different directory for the
 486architecture-dependent library for your -DDEBUGGING version of perl.
 487You can do this by changing all the *archlib* variables in config.sh to
 488point to your new architecture-dependent library.
 489
 490=head3 Environment access
 491
 492Perl often needs to write to the program's environment, such as when C<%ENV>
 493is assigned to. Many implementations of the C library function C<putenv()>
 494leak memory, so where possible perl will manipulate the environment directly
 495to avoid these leaks. The default is now to perform direct manipulation
 496whenever perl is running as a stand alone interpreter, and to call the safe
 497but potentially leaky C<putenv()> function when the perl interpreter is
 498embedded in another application. You can force perl to always use C<putenv()>
 499by compiling with -DPERL_USE_SAFE_PUTENV. You can force an embedded perl to
 500use direct manipulation by setting C<PL_use_safe_putenv = 0;> after the
 501C<perl_construct()> call.
 502
 503=head2 Installation Directories
 504
 505The installation directories can all be changed by answering the
 506appropriate questions in Configure.  For convenience, all the installation
 507questions are near the beginning of Configure.  Do not include trailing
 508slashes on directory names.  At any point during the Configure process,
 509you can answer a question with  &-d  and Configure will use the defaults
 510from then on.  Alternatively, you can
 511
 512        grep '^install' config.sh
 513
 514after Configure has run to verify the installation paths.
 515
 516The defaults are intended to be reasonable and sensible for most
 517people building from sources.  Those who build and distribute binary
 518distributions or who export perl to a range of systems will probably
 519need to alter them.  If you are content to just accept the defaults,
 520you can safely skip the next section.
 521
 522The directories set up by Configure fall into three broad categories.
 523
 524=over 4
 525
 526=item Directories for the perl distribution
 527
 528By default, Configure will use the following directories for 5.10.1.
 529$version is the full perl version number, including subversion, e.g.
 5305.10.1 or 5.9.5, and $archname is a string like sun4-sunos,
 531determined by Configure.  The full definitions of all Configure
 532variables are in the file Porting/Glossary.
 533
 534    Configure variable  Default value
 535    $prefixexp          /usr/local
 536    $binexp             $prefixexp/bin
 537    $scriptdirexp       $prefixexp/bin
 538    $privlibexp         $prefixexp/lib/perl5/$version
 539    $archlibexp         $prefixexp/lib/perl5/$version/$archname
 540    $man1direxp         $prefixexp/man/man1
 541    $man3direxp         $prefixexp/man/man3
 542    $html1direxp        (none)
 543    $html3direxp        (none)
 544
 545$prefixexp is generated from $prefix, with ~ expansion done to convert home
 546directories into absolute paths. Similarly for the other variables listed. As
 547file system calls do not do this, you should always reference the ...exp
 548variables, to support users who build perl in their home directory.
 549
 550Actually, Configure recognizes the SVR3-style
 551/usr/local/man/l_man/man1 directories, if present, and uses those
 552instead.  Also, if $prefix contains the string "perl", the library
 553directories are simplified as described below.  For simplicity, only
 554the common style is shown here.
 555
 556=item Directories for site-specific add-on files
 557
 558After perl is installed, you may later wish to add modules (e.g. from
 559CPAN) or scripts.  Configure will set up the following directories to
 560be used for installing those add-on modules and scripts.
 561
 562    Configure variable  Default value
 563    $siteprefixexp      $prefixexp
 564    $sitebinexp         $siteprefixexp/bin
 565    $sitescriptexp      $siteprefixexp/bin
 566    $sitelibexp         $siteprefixexp/lib/perl5/site_perl/$version
 567    $sitearchexp        $siteprefixexp/lib/perl5/site_perl/$version/$archname
 568    $siteman1direxp     $siteprefixexp/man/man1
 569    $siteman3direxp     $siteprefixexp/man/man3
 570    $sitehtml1direxp    (none)
 571    $sitehtml3direxp    (none)
 572
 573By default, ExtUtils::MakeMaker will install architecture-independent
 574modules into $sitelib and architecture-dependent modules into $sitearch.
 575
 576=item Directories for vendor-supplied add-on files
 577
 578Lastly, if you are building a binary distribution of perl for
 579distribution, Configure can optionally set up the following directories
 580for you to use to distribute add-on modules.
 581
 582    Configure variable  Default value
 583    $vendorprefixexp    (none)
 584    (The next ones are set only if vendorprefix is set.)
 585    $vendorbinexp       $vendorprefixexp/bin
 586    $vendorscriptexp    $vendorprefixexp/bin
 587    $vendorlibexp
 588        $vendorprefixexp/lib/perl5/vendor_perl/$version
 589    $vendorarchexp
 590        $vendorprefixexp/lib/perl5/vendor_perl/$version/$archname
 591    $vendorman1direxp   $vendorprefixexp/man/man1
 592    $vendorman3direxp   $vendorprefixexp/man/man3
 593    $vendorhtml1direxp  (none)
 594    $vendorhtml3direxp  (none)
 595
 596These are normally empty, but may be set as needed.  For example,
 597a vendor might choose the following settings:
 598
 599    $prefix             /usr
 600    $siteprefix         /usr/local
 601    $vendorprefix       /usr
 602
 603This would have the effect of setting the following:
 604
 605    $binexp             /usr/bin
 606    $scriptdirexp       /usr/bin
 607    $privlibexp         /usr/lib/perl5/$version
 608    $archlibexp         /usr/lib/perl5/$version/$archname
 609    $man1direxp         /usr/man/man1
 610    $man3direxp         /usr/man/man3
 611
 612    $sitebinexp         /usr/local/bin
 613    $sitescriptexp      /usr/local/bin
 614    $sitelibexp         /usr/local/lib/perl5/site_perl/$version
 615    $sitearchexp        /usr/local/lib/perl5/site_perl/$version/$archname
 616    $siteman1direxp     /usr/local/man/man1
 617    $siteman3direxp     /usr/local/man/man3
 618
 619    $vendorbinexp       /usr/bin
 620    $vendorscriptexp    /usr/bin
 621    $vendorlibexp       /usr/lib/perl5/vendor_perl/$version
 622    $vendorarchexp      /usr/lib/perl5/vendor_perl/$version/$archname
 623    $vendorman1direxp   /usr/man/man1
 624    $vendorman3direxp   /usr/man/man3
 625
 626Note how in this example, the vendor-supplied directories are in the
 627/usr hierarchy, while the directories reserved for the end-user are in
 628the /usr/local hierarchy.
 629
 630The entire installed library hierarchy is installed in locations with
 631version numbers, keeping the installations of different versions distinct.
 632However, later installations of Perl can still be configured to search the
 633installed libraries corresponding to compatible earlier versions.
 634See L<"Coexistence with earlier versions of perl 5"> below for more details
 635on how Perl can be made to search older version directories.
 636
 637Of course you may use these directories however you see fit.  For
 638example, you may wish to use $siteprefix for site-specific files that
 639are stored locally on your own disk and use $vendorprefix for
 640site-specific files that are stored elsewhere on your organization's
 641network.  One way to do that would be something like
 642
 643        sh Configure -Dsiteprefix=/usr/local -Dvendorprefix=/usr/share/perl
 644
 645=item otherlibdirs
 646
 647As a final catch-all, Configure also offers an $otherlibdirs
 648variable.  This variable contains a colon-separated list of additional
 649directories to add to @INC.  By default, it will be empty.
 650Perl will search these directories (including architecture and
 651version-specific subdirectories) for add-on modules and extensions.
 652
 653For example, if you have a bundle of perl libraries from a previous
 654installation, perhaps in a strange place:
 655
 656        Configure -Dotherlibdirs=/usr/lib/perl5/site_perl/5.8.1
 657
 658=item APPLLIB_EXP
 659
 660There is one other way of adding paths to @INC at perl build time, and
 661that is by setting the APPLLIB_EXP C pre-processor token to a colon-
 662separated list of directories, like this
 663
 664       sh Configure -Accflags='-DAPPLLIB_EXP=\"/usr/libperl\"'
 665
 666The directories defined by APPLLIB_EXP get added to @INC I<first>,
 667ahead of any others, and so provide a way to override the standard perl
 668modules should you, for example, want to distribute fixes without
 669touching the perl distribution proper.  And, like otherlib dirs,
 670version and architecture specific subdirectories are also searched, if
 671present, at run time.  Of course, you can still search other @INC
 672directories ahead of those in APPLLIB_EXP by using any of the standard
 673run-time methods: $PERLLIB, $PERL5LIB, -I, use lib, etc.
 674
 675=item usesitecustomize
 676
 677Run-time customization of @INC can be enabled with:
 678
 679        sh Configure -Dusesitecustomize
 680
 681which will define USE_SITECUSTOMIZE and $Config{usesitecustomize}.
 682When enabled, this makes perl run F<$sitelibexp/sitecustomize.pl> before
 683anything else.  This script can then be set up to add additional
 684entries to @INC.
 685
 686=item Man Pages
 687
 688By default, man pages will be installed in $man1dir and $man3dir, which
 689are normally /usr/local/man/man1 and /usr/local/man/man3.  If you
 690want to use a .3pm suffix for perl man pages, you can do that with
 691
 692        sh Configure -Dman3ext=3pm
 693
 694=item HTML pages
 695
 696Currently, the standard perl installation does not do anything with
 697HTML documentation, but that may change in the future.  Further, some
 698add-on modules may wish to install HTML documents.  The html Configure
 699variables listed above are provided if you wish to specify where such
 700documents should be placed.  The default is "none", but will likely
 701eventually change to something useful based on user feedback.
 702
 703=back
 704
 705Some users prefer to append a "/share" to $privlib and $sitelib
 706to emphasize that those directories can be shared among different
 707architectures.
 708
 709Note that these are just the defaults.  You can actually structure the
 710directories any way you like.  They don't even have to be on the same
 711filesystem.
 712
 713Further details about the installation directories, maintenance and
 714development subversions, and about supporting multiple versions are
 715discussed in L<"Coexistence with earlier versions of perl 5"> below.
 716
 717If you specify a prefix that contains the string "perl", then the
 718library directory structure is slightly simplified.  Instead of
 719suggesting $prefix/lib/perl5/, Configure will suggest $prefix/lib.
 720
 721Thus, for example, if you Configure with
 722-Dprefix=/opt/perl, then the default library directories for 5.9.0 are
 723
 724    Configure variable  Default value
 725        $privlib        /opt/perl/lib/5.9.0
 726        $archlib        /opt/perl/lib/5.9.0/$archname
 727        $sitelib        /opt/perl/lib/site_perl/5.9.0
 728        $sitearch       /opt/perl/lib/site_perl/5.9.0/$archname
 729
 730=head2 Changing the installation directory
 731
 732Configure distinguishes between the directory in which perl (and its
 733associated files) should be installed, and the directory in which it
 734will eventually reside.  For most sites, these two are the same; for
 735sites that use AFS, this distinction is handled automatically.
 736However, sites that use package management software such as rpm or
 737dpkg, or users building binary packages for distribution may also
 738wish to install perl into a different directory before moving perl
 739to its final destination.  There are two ways to do that:
 740
 741=over 4
 742
 743=item installprefix
 744
 745To install perl under the /tmp/perl5 directory, use the following
 746command line:
 747
 748    sh Configure -Dinstallprefix=/tmp/perl5
 749
 750(replace /tmp/perl5 by a directory of your choice).
 751
 752Beware, though, that if you go to try to install new add-on
 753modules, they too will get installed in under '/tmp/perl5' if you
 754follow this example.  That's why it's usually better to use DESTDIR,
 755as shown in the next section.
 756
 757=item DESTDIR
 758
 759If you need to install perl on many identical systems, it is convenient
 760to compile it once and create an archive that can be installed on
 761multiple systems.  Suppose, for example, that you want to create an
 762archive that can be installed in /opt/perl.  One way to do that is by
 763using the DESTDIR variable during C<make install>.  The DESTDIR is
 764automatically prepended to all the installation paths.  Thus you
 765simply do:
 766
 767    sh Configure -Dprefix=/opt/perl -des
 768    make
 769    make test
 770    make install DESTDIR=/tmp/perl5
 771    cd /tmp/perl5/opt/perl
 772    tar cvf /tmp/perl5-archive.tar .
 773
 774=back
 775
 776=head2 Relocatable @INC
 777
 778To create a relocatable perl tree, use the following command line:
 779
 780    sh Configure -Duserelocatableinc
 781
 782Then the paths in @INC (and everything else in %Config) can be
 783optionally located via the path of the perl executable.
 784
 785That means that, if the string ".../" is found at the start of any
 786path, it's substituted with the directory of $^X. So, the relocation
 787can be configured on a per-directory basis, although the default with
 788"-Duserelocatableinc" is that everything is relocated. The initial
 789install is done to the original configured prefix.
 790
 791=head2 Site-wide Policy settings
 792
 793After Configure runs, it stores a number of common site-wide "policy"
 794answers (such as installation directories) in the Policy.sh file.
 795If you want to build perl on another system using the same policy
 796defaults, simply copy the Policy.sh file to the new system's perl build
 797directory, and Configure will use it. This will work even if Policy.sh was
 798generated for another version of Perl, or on a system with a
 799different architecture and/or operating system. However, in such cases,
 800you should review the contents of the file before using it: for
 801example, your new target may not keep its man pages in the same place
 802as the system on which the file was generated.
 803
 804Alternatively, if you wish to change some or all of those policy
 805answers, you should
 806
 807        rm -f Policy.sh
 808
 809to ensure that Configure doesn't re-use them.
 810
 811Further information is in the Policy_sh.SH file itself.
 812
 813If the generated Policy.sh file is unsuitable, you may freely edit it
 814to contain any valid shell commands.  It will be run just after the
 815platform-specific hints files.
 816
 817=head2 Disabling older versions of Perl
 818
 819Configure will search for binary compatible versions of previously
 820installed perl binaries in the tree that is specified as target tree,
 821and these will be used as locations to search for modules by the perl
 822being built. The list of perl versions found will be put in the Configure
 823variable inc_version_list.
 824
 825To disable this use of older perl modules, even completely valid pure perl
 826modules, you can specify to not include the paths found:
 827
 828       sh Configure -Dinc_version_list=none ...
 829
 830When using the newer perl, you can add these paths again in the
 831$PERL5LIB environment variable or with perl's -I runtime option.
 832
 833=head2 Building Perl outside of the source directory
 834
 835Sometimes it is desirable to build Perl in a directory different from
 836where the sources are, for example if you want to keep your sources
 837read-only, or if you want to share the sources between different binary
 838architectures.  You can do this (if your file system supports symbolic
 839links) by
 840
 841        mkdir /tmp/perl/build/directory
 842        cd /tmp/perl/build/directory
 843        sh /path/to/perl/source/Configure -Dmksymlinks ...
 844
 845This will create in /tmp/perl/build/directory a tree of symbolic links
 846pointing to files in /path/to/perl/source.  The original files are left
 847unaffected.  After Configure has finished you can just say
 848
 849        make
 850        make test
 851        make install
 852
 853as usual, and Perl will be built in /tmp/perl/build/directory.
 854
 855=head2 Building a debugging perl
 856
 857You can run perl scripts under the perl debugger at any time with
 858B<perl -d your_script>.  If, however, you want to debug perl itself,
 859you probably want to have support for perl internal debugging code
 860(activated by adding -DDEBUGGING to ccflags), and/or support for the
 861system debugger by adding -g to the optimisation flags. For that,
 862use the parameter:
 863
 864        sh Configure -DDEBUGGING
 865
 866or
 867
 868        sh Configure -DDEBUGGING=<mode>
 869
 870For a more eye appealing call, -DEBUGGING is defined to be an alias
 871for -DDEBUGGING. For both, the -U calls are also supported, in order
 872to be able to overrule the hints or Policy.sh settings.
 873
 874Here are the DEBUGGING modes:
 875
 876=over 4
 877
 878=item -DDEBUGGING
 879
 880=item -DEBUGGING
 881
 882=item -DEBUGGING=both
 883
 884Sets both -DDEBUGGING in the ccflags, and adds -g to optimize.
 885
 886You can actually specify -g and -DDEBUGGING independently (see below),
 887but usually it's convenient to have both.
 888
 889=item -DEBUGGING=-g
 890
 891=item -Doptimize=-g
 892
 893Adds -g to optimize, but does not set -DDEBUGGING.
 894
 895(Note:  Your system may actually require something like cc -g2.
 896Check your man pages for cc(1) and also any hint file for your system.)
 897
 898=item -DEBUGGING=none
 899
 900=item -UDEBUGGING
 901
 902Removes -g from optimize, and -DDEBUGGING from ccflags.
 903
 904=back
 905
 906If you are using a shared libperl, see the warnings about multiple
 907versions of perl under L<Building a shared Perl library>.
 908
 909Note that a perl built with -DDEBUGGING will be bigger and will run more
 910slowly than a standard perl.
 911
 912=head2 DTrace support
 913
 914On platforms where DTrace is available, it may be enabled by 
 915using the -Dusedtrace option to Configure. DTrace probes are available for
 916subroutine entry (sub-entry) and subroutine exit (sub-exit). Here's a
 917simple D script that uses them:
 918
 919  perl$target:::sub-entry, perl$target:::sub-return {
 920    printf("%s %s (%s:%d)\n", probename == "sub-entry" ? "->" : "<-",
 921              copyinstr(arg0), copyinstr(arg1), arg2);
 922  }
 923
 924
 925=head2 Extensions
 926
 927Perl ships with a number of standard extensions.  These are contained
 928in the ext/ subdirectory.
 929
 930By default, Configure will offer to build every extension which appears
 931to be supported.  For example, Configure will offer to build GDBM_File
 932only if it is able to find the gdbm library.
 933
 934To disable certain extensions so that they are not built, use the
 935-Dnoextensions=... and -Donlyextensions=... options.  They both accept
 936a space-separated list of extensions.  The extensions listed in
 937C<noextensions> are removed from the list of extensions to build, while
 938the C<onlyextensions> is rather more severe and builds only the listed
 939extensions.  The latter should be used with extreme caution since
 940certain extensions are used by many other extensions and modules:
 941examples of such modules include Fcntl and IO.  The order of processing
 942these options is first C<only> (if present), then C<no> (if present).
 943
 944Of course, you may always run Configure interactively and select only
 945the extensions you want.
 946
 947If you unpack any additional extensions in the ext/ directory before
 948running Configure, then Configure will offer to build those additional
 949extensions as well.  Most users probably shouldn't have to do this --
 950it is usually easier to build additional extensions later after perl
 951has been installed.  However, if you wish to have those additional
 952extensions statically linked into the perl binary, then this offers a
 953convenient way to do that in one step.  (It is not necessary, however;
 954you can build and install extensions just fine even if you don't have
 955dynamic loading.  See lib/ExtUtils/MakeMaker.pm for more details.)
 956Another way of specifying extra modules is described in
 957L<"Adding extra modules to the build"> below.
 958
 959If you re-use an old config.sh but change your system (e.g. by
 960adding libgdbm) Configure will still offer your old choices of extensions
 961for the default answer, but it will also point out the discrepancy to
 962you.
 963
 964=head2 Including locally-installed libraries
 965
 966Perl comes with interfaces to number of libraries, including threads,
 967dbm, ndbm, gdbm, and Berkeley db.  For the *db* extension, if
 968Configure can find the appropriate header files and libraries, it will
 969automatically include that extension.  The threading extension needs
 970to be specified explicitely (see L<Threads>).
 971
 972Those libraries are not distributed with perl. If your header (.h) files
 973for those libraries are not in a directory normally searched by your C
 974compiler, then you will need to include the appropriate -I/your/directory
 975option when prompted by Configure.  If your libraries are not in a
 976directory normally searched by your C compiler and linker, then you will
 977need to include the appropriate -L/your/directory option when prompted
 978by Configure. See the examples below.
 979
 980=head3 Examples
 981
 982=over 4
 983
 984=item gdbm in /usr/local
 985
 986Suppose you have gdbm and want Configure to find it and build the
 987GDBM_File extension.  This example assumes you have gdbm.h
 988installed in /usr/local/include/gdbm.h and libgdbm.a installed in
 989/usr/local/lib/libgdbm.a.  Configure should figure all the
 990necessary steps out automatically.
 991
 992Specifically, when Configure prompts you for flags for
 993your C compiler, you should include -I/usr/local/include, if it's
 994not here yet. Similarly, when Configure prompts you for linker flags,
 995you should include -L/usr/local/lib.
 996
 997If you are using dynamic loading, then when Configure prompts you for
 998linker flags for dynamic loading, you should again include
 999-L/usr/local/lib.
1000
1001Again, this should all happen automatically.  This should also work if
1002you have gdbm installed in any of (/usr/local, /opt/local, /usr/gnu,
1003/opt/gnu, /usr/GNU, or /opt/GNU).
1004
1005=item BerkeleyDB in /usr/local/BerkeleyDB
1006
1007The version of BerkeleyDB distributed by sleepycat.com installs in a
1008version-specific directory by default, typically something like
1009/usr/local/BerkeleyDB.4.7.  To have Configure find that, you need to add
1010-I/usr/local/BerkeleyDB.4.7/include to cc flags, as in the previous example,
1011and you will also have to take extra steps to help Configure find -ldb.
1012Specifically, when Configure prompts you for library directories,
1013add /usr/local/BerkeleyDB.4.7/lib to the list.  Also, you will need to
1014add appropriate linker flags to tell the runtime linker where to find the
1015BerkeleyDB shared libraries.
1016
1017It is possible to specify this from the command line (all on one
1018line):
1019
1020    sh Configure -de \
1021        -Dlocincpth='/usr/local/BerkeleyDB.4.7/include /usr/local/include' \
1022        -Dloclibpth='/usr/local/BerkeleyDB.4.7/lib /usr/local/lib' \
1023        -Aldflags='-R/usr/local/BerkeleyDB.4.7/lib'
1024
1025locincpth is a space-separated list of include directories to search.
1026Configure will automatically add the appropriate -I directives.
1027
1028loclibpth is a space-separated list of library directories to search.
1029Configure will automatically add the appropriate -L directives.
1030
1031The addition to ldflags is so that the dynamic linker knows where to find
1032the BerkeleyDB libraries.  For Linux and Solaris, the -R option does that.
1033Other systems may use different flags.  Use the appropriate flag for your
1034system.
1035
1036=back
1037
1038=head2 Overriding an old config.sh
1039
1040If you want to use an old config.sh produced by a previous run of
1041Configure, but override some of the items with command line options, you
1042need to use B<Configure -O>.
1043
1044=head2 GNU-style configure
1045
1046If you prefer the GNU-style configure command line interface, you can
1047use the supplied configure.gnu command, e.g.
1048
1049        CC=gcc ./configure.gnu
1050
1051The configure.gnu script emulates a few of the more common configure
1052options.  Try
1053
1054        ./configure.gnu --help
1055
1056for a listing.
1057
1058(The file is called configure.gnu to avoid problems on systems
1059that would not distinguish the files "Configure" and "configure".)
1060
1061=head2 Malloc Issues
1062
1063Perl relies heavily on malloc(3) to grow data structures as needed,
1064so perl's performance can be noticeably affected by the performance of
1065the malloc function on your system.  The perl source is shipped with a
1066version of malloc that has been optimized for the typical requests from
1067perl, so there's a chance that it may be both faster and use less memory
1068than your system malloc.
1069
1070However, if your system already has an excellent malloc, or if you are
1071experiencing difficulties with extensions that use third-party libraries
1072that call malloc, then you should probably use your system's malloc.
1073(Or, you might wish to explore the malloc flags discussed below.)
1074
1075=over 4
1076
1077=item Using the system malloc
1078
1079To build without perl's malloc, you can use the Configure command
1080
1081        sh Configure -Uusemymalloc
1082
1083or you can answer 'n' at the appropriate interactive Configure prompt.
1084
1085Note that Perl's malloc isn't always used by default; that actually
1086depends on your system. For example, on Linux and FreeBSD (and many more
1087systems), Configure chooses to use the system's malloc by default.
1088See the appropriate file in the F<hints/> directory to see how the
1089default is set.
1090
1091=item -DPERL_POLLUTE_MALLOC
1092
1093NOTE: This flag is enabled automatically on some platforms if you just
1094run Configure to accept all the defaults.
1095
1096Perl's malloc family of functions are normally called Perl_malloc(),
1097Perl_realloc(), Perl_calloc() and Perl_mfree().
1098These names do not clash with the system versions of these functions.
1099
1100If this flag is enabled, however, Perl's malloc family of functions
1101will have the same names as the system versions.  This may be required
1102sometimes if you have libraries that like to free() data that may have
1103been allocated by Perl_malloc() and vice versa.
1104
1105Note that enabling this option may sometimes lead to duplicate symbols
1106from the linker for malloc et al.  In such cases, the system probably
1107does not allow its malloc functions to be fully replaced with custom
1108versions.
1109
1110=item -DPERL_DEBUGGING_MSTATS
1111
1112This flag enables debugging mstats, which is required to use the
1113Devel::Peek::mstat() function. You cannot enable this unless you are
1114using Perl's malloc, so a typical Configure command would be
1115
1116       sh Configure -Accflags=-DPERL_DEBUGGING_MSTATS -Dusemymalloc
1117
1118to enable this option.
1119
1120=back
1121
1122=head2 What if it doesn't work?
1123
1124If you run into problems, try some of the following ideas.
1125If none of them help, then see L<"Reporting Problems"> below.
1126
1127=over 4
1128
1129=item Running Configure Interactively
1130
1131If Configure runs into trouble, remember that you can always run
1132Configure interactively so that you can check (and correct) its
1133guesses.
1134
1135All the installation questions have been moved to the top, so you don't
1136have to wait for them.  Once you've handled them (and your C compiler and
1137flags) you can type  &-d  at the next Configure prompt and Configure
1138will use the defaults from then on.
1139
1140If you find yourself trying obscure command line incantations and
1141config.over tricks, I recommend you run Configure interactively
1142instead.  You'll probably save yourself time in the long run.
1143
1144=item Hint files
1145
1146Hint files tell Configure about a number of things:
1147
1148=over 4
1149
1150=item o
1151
1152The peculiarities or conventions of particular platforms -- non-standard
1153library locations and names, default installation locations for binaries,
1154and so on.
1155
1156=item o
1157
1158The deficiencies of the platform -- for example, library functions that,
1159although present, are too badly broken to be usable; or limits on
1160resources that are generously available on most platforms.
1161
1162=item o
1163
1164How best to optimize for the platform, both in terms of binary size and/or
1165speed, and for Perl feature support. Because of wide variations in the
1166implementation of shared libraries and of threading, for example, Configure
1167often needs hints in order to be able to use these features.
1168
1169=back
1170
1171The perl distribution includes many system-specific hints files
1172in the hints/ directory. If one of them matches your system, Configure
1173will offer to use that hint file. Unless you have a very good reason
1174not to, you should accept its offer.
1175
1176Several of the hint files contain additional important information.
1177If you have any problems, it is a good idea to read the relevant hint file
1178for further information.  See hints/solaris_2.sh for an extensive example.
1179More information about writing good hints is in the hints/README.hints
1180file, which also explains hint files known as callback-units.
1181
1182Note that any hint file is read before any Policy file, meaning that
1183Policy overrides hints -- see L</Site-wide Policy settings>.
1184
1185=item WHOA THERE!!!
1186
1187If you are re-using an old config.sh, it's possible that Configure detects
1188different values from the ones specified in this file.  You will almost
1189always want to keep the previous value, unless you have changed something
1190on your system.
1191
1192For example, suppose you have added libgdbm.a to your system
1193and you decide to reconfigure perl to use GDBM_File.  When you run
1194Configure again, you will need to add -lgdbm to the list of libraries.
1195Now, Configure will find your gdbm include file and library and will
1196issue a message:
1197
1198    *** WHOA THERE!!! ***
1199        The previous value for $i_gdbm on this machine was "undef"!
1200        Keep the previous value? [y]
1201
1202In this case, you do not want to keep the previous value, so you
1203should answer 'n'.  (You'll also have to manually add GDBM_File to
1204the list of dynamic extensions to build.)
1205
1206=item Changing Compilers
1207
1208If you change compilers or make other significant changes, you should
1209probably not re-use your old config.sh.  Simply remove it or
1210rename it, then rerun Configure with the options you want to use.
1211
1212=item Propagating your changes to config.sh
1213
1214If you make any changes to config.sh, you should propagate
1215them to all the .SH files by running
1216
1217        sh Configure -S
1218
1219You will then have to rebuild by running
1220
1221        make depend
1222        make
1223
1224=item config.over and config.arch
1225
1226You can also supply a shell script config.over to over-ride
1227Configure's guesses.  It will get loaded up at the very end, just
1228before config.sh is created.  You have to be careful with this,
1229however, as Configure does no checking that your changes make sense.
1230This file is usually good for site-specific customizations.
1231
1232There is also another file that, if it exists, is loaded before the
1233config.over, called config.arch.  This file is intended to be per
1234architecture, not per site, and usually it's the architecture-specific
1235hints file that creates the config.arch.
1236
1237=item config.h
1238
1239Many of the system dependencies are contained in config.h.
1240Configure builds config.h by running the config_h.SH script.
1241The values for the variables are taken from config.sh.
1242
1243If there are any problems, you can edit config.h directly.  Beware,
1244though, that the next time you run Configure, your changes will be
1245lost.
1246
1247=item cflags
1248
1249If you have any additional changes to make to the C compiler command
1250line, they can be made in cflags.SH.  For instance, to turn off the
1251optimizer on toke.c, find the line in the switch structure for
1252toke.c and put the command optimize='-g' before the ;; .  You
1253can also edit cflags directly, but beware that your changes will be
1254lost the next time you run Configure.
1255
1256To explore various ways of changing ccflags from within a hint file,
1257see the file hints/README.hints.
1258
1259To change the C flags for all the files, edit config.sh and change either
1260$ccflags or $optimize, and then re-run
1261
1262        sh Configure -S
1263        make depend
1264
1265=item No sh
1266
1267If you don't have sh, you'll have to copy the sample file
1268Porting/config.sh to config.sh and edit your config.sh to reflect your
1269system's peculiarities.  See Porting/pumpkin.pod for more information.
1270You'll probably also have to extensively modify the extension building
1271mechanism.
1272
1273=item Porting information
1274
1275Specific information for the OS/2, Plan 9, VMS and Win32 ports is in the
1276corresponding README files and subdirectories.  Additional information,
1277including a glossary of all those config.sh variables, is in the Porting
1278subdirectory.  Porting/Glossary should especially come in handy.
1279
1280Ports for other systems may also be available.  You should check out
1281http://www.cpan.org/ports for current information on ports to
1282various other operating systems.
1283
1284If you plan to port Perl to a new architecture, study carefully the
1285section titled "Philosophical Issues in Patching and Porting Perl"
1286in the file Porting/pumpkin.pod and the file Porting/patching.pod.
1287Study also how other non-UNIX ports have solved problems.
1288
1289=back
1290
1291=head2 Adding extra modules to the build
1292
1293You can specify extra modules or module bundles to be fetched from the
1294CPAN and installed as part of the Perl build.  Either use the -Dextras=...
1295command line parameter to Configure, for example like this:
1296
1297        Configure -Dextras="Bundle::LWP DBI"
1298
1299or answer first 'y' to the question 'Install any extra modules?' and
1300then answer "Bundle::LWP DBI" to the 'Extras?' question.
1301The module or the bundle names are as for the CPAN module 'install' command.
1302This will only work if those modules are to be built as dynamic
1303extensions.  If you wish to include those extra modules as static
1304extensions, see L<"Extensions"> above.
1305
1306Notice that because the CPAN module will be used to fetch the extra
1307modules, you will need access to the CPAN, either via the Internet,
1308or via a local copy such as a CD-ROM or a local CPAN mirror.  If you
1309do not, using the extra modules option will die horribly.
1310
1311Also notice that you yourself are responsible for satisfying any extra
1312dependencies such as external headers or libraries BEFORE trying the build.
1313For example: you will need to have the Foo database specific
1314headers and libraries installed for the DBD::Foo module.  The Configure
1315process or the Perl build process will not help you with these.
1316
1317=head2 suidperl
1318
1319suidperl is an optional component, which is normally neither built
1320nor installed by default.  From perlfaq1:
1321
1322        On some systems, setuid and setgid scripts (scripts written
1323        in the C shell, Bourne shell, or Perl, for example, with the
1324        set user or group ID permissions enabled) are insecure due to
1325        a race condition in the kernel. For those systems, Perl versions
1326        5 and 4 attempt to work around this vulnerability with an optional
1327        component, a special program named suidperl, also known as sperl.
1328        This program attempts to emulate the set-user-ID and set-group-ID
1329        features of the kernel.
1330
1331Because of the buggy history of suidperl, and the difficulty
1332of properly security auditing as large and complex piece of
1333software as Perl, we cannot recommend using suidperl and the feature
1334should be considered deprecated.
1335
1336Instead, use a tool specifically designed to handle changes in
1337privileges, such as B<sudo>.
1338
1339=head1 make depend
1340
1341This will look for all the includes.  The output is stored in makefile.
1342The only difference between Makefile and makefile is the dependencies at
1343the bottom of makefile.  If you have to make any changes, you should edit
1344makefile, not Makefile, since the Unix make command reads makefile first.
1345(On non-Unix systems, the output may be stored in a different file.
1346Check the value of $firstmakefile in your config.sh if in doubt.)
1347
1348Configure will offer to do this step for you, so it isn't listed
1349explicitly above.
1350
1351=head1 make
1352
1353This will attempt to make perl in the current directory.
1354
1355=head2 Expected errors
1356
1357These error reports are normal, and can be ignored:
1358
1359  ...
1360  make: [extra.pods] Error 1 (ignored)
1361  ...
1362  make: [extras.make] Error 1 (ignored)
1363
1364=head2 What if it doesn't work?
1365
1366If you can't compile successfully, try some of the following ideas.
1367If none of them help, and careful reading of the error message and
1368the relevant manual pages on your system doesn't help,
1369then see L<"Reporting Problems"> below.
1370
1371=over 4
1372
1373=item hints
1374
1375If you used a hint file, try reading the comments in the hint file
1376for further tips and information.
1377
1378=item extensions
1379
1380If you can successfully build miniperl, but the process crashes
1381during the building of extensions, run
1382
1383        make minitest
1384
1385to test your version of miniperl.
1386
1387=item locale
1388
1389If you have any locale-related environment variables set, try unsetting
1390them.  I have some reports that some versions of IRIX hang while
1391running B<./miniperl configpm> with locales other than the C locale.
1392See the discussion under L<"make test"> below about locales and the
1393whole L<perllocale/"LOCALE PROBLEMS"> section in the file pod/perllocale.pod.
1394The latter is especially useful if you see something like this
1395
1396        perl: warning: Setting locale failed.
1397        perl: warning: Please check that your locale settings:
1398                LC_ALL = "En_US",
1399                LANG = (unset)
1400            are supported and installed on your system.
1401        perl: warning: Falling back to the standard locale ("C").
1402
1403at Perl startup.
1404
1405=item other environment variables
1406
1407Configure does not check for environment variables that can sometimes
1408have a major influence on how perl is built or tested. For example,
1409OBJECT_MODE on AIX determines the way the compiler and linker deal with
1410their objects, but this is a variable that only influences build-time
1411behaviour, and should not affect the perl scripts that are eventually
1412executed by the perl binary. Other variables, like PERL_UNICODE,
1413PERL5LIB, and PERL5OPT will influence the behaviour of the test suite.
1414So if you are getting strange test failures, you may want to try
1415retesting with the various PERL variables unset.
1416
1417=item varargs
1418
1419If you get varargs problems with gcc, be sure that gcc is installed
1420correctly and that you are not passing -I/usr/include to gcc.  When using
1421gcc, you should probably have i_stdarg='define' and i_varargs='undef'
1422in config.sh.  The problem is usually solved by installing gcc
1423correctly.  If you do change config.sh, don't forget to propagate
1424your changes (see L<"Propagating your changes to config.sh"> below).
1425See also the L<"vsprintf"> item below.
1426
1427=item util.c
1428
1429If you get error messages such as the following (the exact line
1430numbers and function name may vary in different versions of perl):
1431
1432    util.c: In function `Perl_form':
1433    util.c:1107: number of arguments doesn't match prototype
1434    proto.h:125: prototype declaration
1435
1436it might well be a symptom of the gcc "varargs problem".  See the
1437previous L<"varargs"> item.
1438
1439=item LD_LIBRARY_PATH
1440
1441If you run into dynamic loading problems, check your setting of
1442the LD_LIBRARY_PATH environment variable.  If you're creating a static
1443Perl library (libperl.a rather than libperl.so) it should build
1444fine with LD_LIBRARY_PATH unset, though that may depend on details
1445of your local set-up.
1446
1447=item nm extraction
1448
1449If Configure seems to be having trouble finding library functions,
1450try not using nm extraction.  You can do this from the command line
1451with
1452
1453        sh Configure -Uusenm
1454
1455or by answering the nm extraction question interactively.
1456If you have previously run Configure, you should not reuse your old
1457config.sh.
1458
1459=item umask not found
1460
1461If the build processes encounters errors relating to umask(), the problem
1462is probably that Configure couldn't find your umask() system call.
1463Check your config.sh.  You should have d_umask='define'.  If you don't,
1464this is probably the L<"nm extraction"> problem discussed above.  Also,
1465try reading the hints file for your system for further information.
1466
1467=item vsprintf
1468
1469If you run into problems with vsprintf in compiling util.c, the
1470problem is probably that Configure failed to detect your system's
1471version of vsprintf().  Check whether your system has vprintf().
1472(Virtually all modern Unix systems do.)  Then, check the variable
1473d_vprintf in config.sh.  If your system has vprintf, it should be:
1474
1475        d_vprintf='define'
1476
1477If Configure guessed wrong, it is likely that Configure guessed wrong
1478on a number of other common functions too.  This is probably
1479the L<"nm extraction"> problem discussed above.
1480
1481=item do_aspawn
1482
1483If you run into problems relating to do_aspawn or do_spawn, the
1484problem is probably that Configure failed to detect your system's
1485fork() function.  Follow the procedure in the previous item
1486on L<"nm extraction">.
1487
1488=item __inet_* errors
1489
1490If you receive unresolved symbol errors during Perl build and/or test
1491referring to __inet_* symbols, check to see whether BIND 8.1 is
1492installed.  It installs a /usr/local/include/arpa/inet.h that refers to
1493these symbols.  Versions of BIND later than 8.1 do not install inet.h
1494in that location and avoid the errors.  You should probably update to a
1495newer version of BIND (and remove the files the old one left behind).
1496If you can't, you can either link with the updated resolver library provided
1497with BIND 8.1 or rename /usr/local/bin/arpa/inet.h during the Perl build and
1498test process to avoid the problem.
1499
1500=item .*_r() prototype NOT found
1501
1502On a related note, if you see a bunch of complaints like the above about
1503reentrant functions - specifically networking-related ones - being present
1504but without prototypes available, check to see if BIND 8.1 (or possibly
1505other BIND 8 versions) is (or has been) installed. They install
1506header files such as netdb.h into places such as /usr/local/include (or into
1507another directory as specified at build/install time), at least optionally.
1508Remove them or put them in someplace that isn't in the C preprocessor's
1509header file include search path (determined by -I options plus defaults,
1510normally /usr/include).
1511
1512=item #error "No DATAMODEL_NATIVE specified"
1513
1514This is a common error when trying to build perl on Solaris 2.6 with a
1515gcc installation from Solaris 2.5 or 2.5.1.  The Solaris header files
1516changed, so you need to update your gcc installation.  You can either
1517rerun the fixincludes script from gcc or take the opportunity to
1518update your gcc installation.
1519
1520=item Optimizer
1521
1522If you can't compile successfully, try turning off your compiler's
1523optimizer.  Edit config.sh and change the line
1524
1525        optimize='-O'
1526
1527to
1528
1529        optimize=' '
1530
1531then propagate your changes with B<sh Configure -S> and rebuild
1532with B<make depend; make>.
1533
1534=item Missing functions and Undefined symbols
1535
1536If the build of miniperl fails with a long list of missing functions or
1537undefined symbols, check the libs variable in the config.sh file.  It
1538should look something like
1539
1540        libs='-lsocket -lnsl -ldl -lm -lc'
1541
1542The exact libraries will vary from system to system, but you typically
1543need to include at least the math library -lm.  Normally, Configure
1544will suggest the correct defaults.  If the libs variable is empty, you
1545need to start all over again.  Run
1546
1547        make distclean
1548
1549and start from the very beginning.  This time, unless you are sure of
1550what you are doing, accept the default list of libraries suggested by
1551Configure.
1552
1553If the libs variable looks correct, you might have the
1554L<"nm extraction"> problem discussed above.
1555
1556If you stil have missing routines or undefined symbols, you probably
1557need to add some library or other, or you need to undefine some feature
1558that Configure thought was there but is defective or incomplete.  If
1559you used a hint file, see if it has any relevant advice.  You can also
1560look through through config.h for likely suspects.
1561
1562=item toke.c
1563
1564Some compilers will not compile or optimize the larger files (such as
1565toke.c) without some extra switches to use larger jump offsets or
1566allocate larger internal tables.  You can customize the switches for
1567each file in cflags.  It's okay to insert rules for specific files into
1568makefile since a default rule only takes effect in the absence of a
1569specific rule.
1570
1571=item Missing dbmclose
1572
1573SCO prior to 3.2.4 may be missing dbmclose().  An upgrade to 3.2.4
1574that includes libdbm.nfs (which includes dbmclose()) may be available.
1575
1576=item Note (probably harmless): No library found for -lsomething
1577
1578If you see such a message during the building of an extension, but
1579the extension passes its tests anyway (see L<"make test"> below),
1580then don't worry about the warning message.  The extension
1581Makefile.PL goes looking for various libraries needed on various
1582systems; few systems will need all the possible libraries listed.
1583Most users will see warnings for the ones they don't have.  The
1584phrase 'probably harmless' is intended to reassure you that nothing
1585unusual is happening, and the build process is continuing.
1586
1587On the other hand, if you are building GDBM_File and you get the
1588message
1589
1590    Note (probably harmless): No library found for -lgdbm
1591
1592then it's likely you're going to run into trouble somewhere along
1593the line, since it's hard to see how you can use the GDBM_File
1594extension without the -lgdbm library.
1595
1596It is true that, in principle, Configure could have figured all of
1597this out, but Configure and the extension building process are not
1598quite that tightly coordinated.
1599
1600=item sh: ar: not found
1601
1602This is a message from your shell telling you that the command 'ar'
1603was not found.  You need to check your PATH environment variable to
1604make sure that it includes the directory with the 'ar' command.  This
1605is a common problem on Solaris, where 'ar' is in the /usr/ccs/bin
1606directory.
1607
1608=item db-recno failure on tests 51, 53 and 55
1609
1610Old versions of the DB library (including the DB library which comes
1611with FreeBSD 2.1) had broken handling of recno databases with modified
1612bval settings.  Upgrade your DB library or OS.
1613
1614=item Bad arg length for semctl, is XX, should be ZZZ
1615
1616If you get this error message from the ext/IPC/SysV/t/sem test, your System
1617V IPC may be broken.  The XX typically is 20, and that is what ZZZ
1618also should be.  Consider upgrading your OS, or reconfiguring your OS
1619to include the System V semaphores.
1620
1621=item ext/IPC/SysV/t/sem........semget: No space left on device
1622
1623Either your account or the whole system has run out of semaphores.  Or
1624both.  Either list the semaphores with "ipcs" and remove the unneeded
1625ones (which ones these are depends on your system and applications)
1626with "ipcrm -s SEMAPHORE_ID_HERE" or configure more semaphores to your
1627system.
1628
1629=item GNU binutils
1630
1631If you mix GNU binutils (nm, ld, ar) with equivalent vendor-supplied
1632tools you may be in for some trouble.  For example creating archives
1633with an old GNU 'ar' and then using a new current vendor-supplied 'ld'
1634may lead into linking problems.  Either recompile your GNU binutils
1635under your current operating system release, or modify your PATH not
1636to include the GNU utils before running Configure, or specify the
1637vendor-supplied utilities explicitly to Configure, for example by
1638Configure -Dar=/bin/ar.
1639
1640=item THIS PACKAGE SEEMS TO BE INCOMPLETE
1641
1642The F<Configure> program has not been able to find all the files which
1643make up the complete Perl distribution.  You may have a damaged source
1644archive file (in which case you may also have seen messages such as
1645C<gzip: stdin: unexpected end of file> and C<tar: Unexpected EOF on
1646archive file>), or you may have obtained a structurally-sound but
1647incomplete archive.  In either case, try downloading again from the
1648official site named at the start of this document.  If you do find
1649that any site is carrying a corrupted or incomplete source code
1650archive, please report it to the site's maintainer.
1651
1652=item invalid token: ##
1653
1654You are using a non-ANSI-compliant C compiler.  To compile Perl, you
1655need to use a compiler that supports ANSI C.  If there is a README
1656file for your system, it may have further details on your compiler
1657options.
1658
1659=item Miscellaneous
1660
1661Some additional things that have been reported:
1662
1663Genix may need to use libc rather than libc_s, or #undef VARARGS.
1664
1665NCR Tower 32 (OS 2.01.01) may need -W2,-Sl,2000 and #undef MKDIR.
1666
1667UTS may need one or more of -K or -g, and undef LSTAT.
1668
1669FreeBSD can fail the ext/IPC/SysV/t/sem.t test if SysV IPC has not been
1670configured in the kernel.  Perl tries to detect this, though, and
1671you will get a message telling you what to do.
1672
1673Building Perl on a system that has also BIND (headers and libraries)
1674installed may run into troubles because BIND installs its own netdb.h
1675and socket.h, which may not agree with the operating system's ideas of
1676the same files.  Similarly, including -lbind may conflict with libc's
1677view of the world.  You may have to tweak -Dlocincpth and -Dloclibpth
1678to avoid the BIND.
1679
1680=back
1681
1682=head2 Cross-compilation
1683
1684Perl can be cross-compiled.  It is just not trivial, cross-compilation
1685rarely is.  Perl is routinely cross-compiled for many platforms (as of
1686June 2005 at least PocketPC aka WinCE, Open Zaurus, EPOC, Symbian, and
1687the IBM OS/400).  These platforms are known as the B<target> platforms,
1688while the systems where the compilation takes place are the B<host>
1689platforms.
1690
1691What makes the situation difficult is that first of all,
1692cross-compilation environments vary significantly in how they are set
1693up and used, and secondly because the primary way of configuring Perl
1694(using the rather large Unix-tool-dependent Configure script) is not
1695awfully well suited for cross-compilation.  However, starting from
1696version 5.8.0, the Configure script also knows one way of supporting
1697cross-compilation support, please keep reading.
1698
1699See the following files for more information about compiling Perl for
1700the particular platforms:
1701
1702=over 4
1703
1704=item WinCE/PocketPC
1705
1706README.ce
1707
1708=item Open Zaurus
1709
1710Cross/README
1711
1712=item EPOC
1713
1714README.epoc
1715
1716=item Symbian
1717
1718README.symbian
1719
1720=item OS/400
1721
1722README.os400
1723
1724=back
1725
1726Packaging and transferring either the core Perl modules or CPAN
1727modules to the target platform is also left up to the each
1728cross-compilation environment.  Often the cross-compilation target
1729platforms are somewhat limited in diskspace: see the section
1730L<Minimizing the Perl installation> to learn more of the minimal set
1731of files required for a functional Perl installation.
1732
1733For some cross-compilation environments the Configure option
1734C<-Dinstallprefix=...> might be handy, see L<Changing the installation
1735directory>.
1736
1737About the cross-compilation support of Configure: what is known to
1738work is running Configure in a cross-compilation environment and
1739building the miniperl executable.  What is known not to work is
1740building the perl executable because that would require building
1741extensions: Dynaloader statically and File::Glob dynamically, for
1742extensions one needs MakeMaker and MakeMaker is not yet
1743cross-compilation aware, and neither is the main Makefile.
1744
1745The cross-compilation setup of Configure has successfully been used in
1746at least two Linux cross-compilation environments.  The setups were
1747both such that the host system was Intel Linux with a gcc built for
1748cross-compiling into ARM Linux, and there was a SSH connection to the
1749target system.
1750
1751To run Configure in cross-compilation mode the basic switch that
1752has to be used is C<-Dusecrosscompile>.
1753
1754   sh ./Configure -des -Dusecrosscompile -D...
1755
1756This will make the cpp symbol USE_CROSS_COMPILE and the %Config
1757symbol C<usecrosscompile> available, and C<xconfig.h> will be used
1758for cross-compilation.
1759
1760During the Configure and build, certain helper scripts will be created
1761into the Cross/ subdirectory.  The scripts are used to execute a
1762cross-compiled executable, and to transfer files to and from the
1763target host.  The execution scripts are named F<run-*> and the
1764transfer scripts F<to-*> and F<from-*>.  The part after the dash is
1765the method to use for remote execution and transfer: by default the
1766methods are B<ssh> and B<scp>, thus making the scripts F<run-ssh>,
1767F<to-scp>, and F<from-scp>.
1768
1769To configure the scripts for a target host and a directory (in which
1770the execution will happen and which is to and from where the transfer
1771happens), supply Configure with
1772
1773    -Dtargethost=so.me.ho.st -Dtargetdir=/tar/get/dir
1774
1775The targethost is what e.g. ssh will use as the hostname, the targetdir
1776must exist (the scripts won't create it), the targetdir defaults to /tmp.
1777You can also specify a username to use for ssh/rsh logins
1778
1779    -Dtargetuser=luser
1780
1781but in case you don't, "root" will be used.
1782
1783Because this is a cross-compilation effort, you will also need to specify
1784which target environment and which compilation environment to use.
1785This includes the compiler, the header files, and the libraries.
1786In the below we use the usual settings for the iPAQ cross-compilation
1787environment:
1788
1789    -Dtargetarch=arm-linux
1790    -Dcc=arm-linux-gcc
1791    -Dusrinc=/skiff/local/arm-linux/include
1792    -Dincpth=/skiff/local/arm-linux/include
1793    -Dlibpth=/skiff/local/arm-linux/lib
1794
1795If the name of the C<cc> has the usual GNU C semantics for cross
1796compilers, that is, CPU-OS-gcc, the names of the C<ar>, C<nm>, and
1797C<ranlib> will also be automatically chosen to be CPU-OS-ar and so on.
1798(The C<ld> requires more thought and will be chosen later by Configure
1799as appropriate.)  Also, in this case the incpth, libpth, and usrinc
1800will be guessed by Configure (unless explicitly set to something else,
1801in which case Configure's guesses with be appended).
1802
1803In addition to the default execution/transfer methods you can also
1804choose B<rsh> for execution, and B<rcp> or B<cp> for transfer,
1805for example:
1806
1807    -Dtargetrun=rsh -Dtargetto=rcp -Dtargetfrom=cp
1808
1809Putting it all together:
1810
1811    sh ./Configure -des -Dusecrosscompile \
1812        -Dtargethost=so.me.ho.st \
1813        -Dtargetdir=/tar/get/dir \
1814        -Dtargetuser=root \
1815        -Dtargetarch=arm-linux \
1816        -Dcc=arm-linux-gcc \
1817        -Dusrinc=/skiff/local/arm-linux/include \
1818        -Dincpth=/skiff/local/arm-linux/include \
1819        -Dlibpth=/skiff/local/arm-linux/lib \
1820        -D...
1821
1822or if you are happy with the defaults:
1823
1824    sh ./Configure -des -Dusecrosscompile \
1825        -Dtargethost=so.me.ho.st \
1826        -Dcc=arm-linux-gcc \
1827        -D...
1828
1829Another example where the cross-compiler has been installed under
1830F</usr/local/arm/2.95.5>:
1831
1832    sh ./Configure -des -Dusecrosscompile \
1833        -Dtargethost=so.me.ho.st \
1834        -Dcc=/usr/local/arm/2.95.5/bin/arm-linux-gcc \
1835        -Dincpth=/usr/local/arm/2.95.5/include \
1836        -Dusrinc=/usr/local/arm/2.95.5/include \
1837        -Dlibpth=/usr/local/arm/2.95.5/lib
1838
1839=head1 make test
1840
1841This will run the regression tests on the perl you just made.  If
1842'make test' doesn't say "All tests successful" then something went
1843wrong.  See the file t/README in the t subdirectory.
1844
1845Note that you can't run the tests in background if this disables
1846opening of /dev/tty. You can use 'make test-notty' in that case but
1847a few tty tests will be skipped.
1848
1849=head2 What if make test doesn't work?
1850
1851If make test bombs out, just cd to the t directory and run ./TEST
1852by hand to see if it makes any difference.  If individual tests
1853bomb, you can run them by hand, e.g.,
1854
1855        cd t ; ./perl -MTestInit op/groups.t
1856
1857Another way to get more detailed information about failed tests and
1858individual subtests is to cd to the t directory and run
1859
1860        cd t ; ./perl harness <list of tests>
1861
1862(this assumes that most basic tests succeed, since harness uses
1863complicated constructs). If no list of tests is provided, harness
1864will run all tests.
1865
1866You should also read the individual tests to see if there are any helpful
1867comments that apply to your system.  You may also need to setup your
1868shared library path if you get errors like:
1869
1870        /sbin/loader: Fatal Error: cannot map libperl.so
1871
1872See L</"Building a shared Perl library"> earlier in this document.
1873
1874=over 4
1875
1876=item locale
1877
1878Note:  One possible reason for errors is that some external programs
1879may be broken due to the combination of your environment and the way
1880'make test' exercises them.  For example, this may happen if you have
1881one or more of these environment variables set:  LC_ALL LC_CTYPE
1882LC_COLLATE LANG.  In some versions of UNIX, the non-English locales
1883are known to cause programs to exhibit mysterious errors.
1884
1885If you have any of the above environment variables set, please try
1886
1887        setenv LC_ALL C
1888
1889(for C shell) or
1890
1891        LC_ALL=C;export LC_ALL
1892
1893for Bourne or Korn shell) from the command line and then retry
1894make test.  If the tests then succeed, you may have a broken program that
1895is confusing the testing.  Please run the troublesome test by hand as
1896shown above and see whether you can locate the program.  Look for
1897things like:  exec, `backquoted command`, system, open("|...") or
1898open("...|").  All these mean that Perl is trying to run some
1899external program.
1900
1901=item Timing problems
1902
1903Several tests in the test suite check timing functions, such as
1904sleep(), and see if they return in a reasonable amount of time.
1905If your system is quite busy and doesn't respond quickly enough,
1906these tests might fail.  If possible, try running the tests again
1907with the system under a lighter load.  These timing-sensitive
1908and load-sensitive tests include F<t/op/alarm.t>,
1909F<ext/Time-HiRes/t/HiRes.t>, F<ext/threads-shared/t/waithires.t>,
1910F<ext/threads-shared/t/stress.t>, F<lib/Benchmark.t>,
1911F<lib/Memoize/t/expmod_t.t>, and F<lib/Memoize/t/speed.t>.
1912
1913You might also experience some failures in F<t/op/stat.t> if you build
1914perl on an NFS filesystem, if the remote clock and the system clock are
1915different.
1916
1917=item Out of memory
1918
1919On some systems, particularly those with smaller amounts of RAM, some
1920of the tests in t/op/pat.t may fail with an "Out of memory" message.
1921For example, on my SparcStation IPC with 12 MB of RAM, in perl5.5.670,
1922test 85 will fail if run under either t/TEST or t/harness.
1923
1924Try stopping other jobs on the system and then running the test by itself:
1925
1926        cd t; ./perl -MTestInit op/pat.t
1927
1928to see if you have any better luck.  If your perl still fails this
1929test, it does not necessarily mean you have a broken perl.  This test
1930tries to exercise the regular expression subsystem quite thoroughly,
1931and may well be far more demanding than your normal usage.
1932
1933=item libgcc_s.so.1: cannot open shared object file
1934
1935This message has been reported on gcc-3.2.3 and earlier installed with
1936a non-standard prefix.  Setting the LD_LIBRARY_PATH environment variable
1937(or equivalent) to include gcc's lib/ directory with the libgcc_s.so.1
1938shared library should fix the problem.
1939
1940=item Failures from lib/File/Temp/t/security saying "system possibly insecure"
1941
1942First, such warnings are not necessarily serious or indicative of a
1943real security threat.  That being said, they bear investigating.
1944
1945Note that each of the tests is run twice.  The first time is in the
1946directory returned by File::Spec->tmpdir() (often /tmp on Unix
1947systems), and the second time in the directory from which the test was
1948run (usually the 't' directory, if the test was run as part of 'make
1949test').
1950
1951The tests may fail for the following reasons:
1952
1953(1) If the directory the tests are being run in is owned by somebody
1954other than the user running the tests, or by root (uid 0).
1955
1956This failure can happen if the Perl source code distribution is
1957unpacked in such a way that the user ids in the distribution package
1958are used as-is.  Some tar programs do this.
1959
1960(2) If the directory the tests are being run in is writable by group or
1961by others, and there is no sticky bit set for the directory.  (With
1962UNIX/POSIX semantics, write access to a directory means the right to
1963add or remove files in that directory.  The 'sticky bit' is a feature
1964used in some UNIXes to give extra protection to files: if the bit is
1965set for a directory, no one but the owner (or root) can remove that
1966file even if the permissions would otherwise allow file removal by
1967others.)
1968
1969This failure may or may not be a real problem: it depends on the
1970permissions policy used on this particular system.  This failure can
1971also happen if the system either doesn't support the sticky bit (this
1972is the case with many non-UNIX platforms: in principle File::Temp
1973should know about these platforms and skip the tests), or if the system
1974supports the sticky bit but for some reason or reasons it is not being
1975used.  This is, for example, the case with HP-UX: as of HP-UX release
197611.00, the sticky bit is very much supported, but HP-UX doesn't use it
1977on its /tmp directory as shipped.  Also, as with the permissions, some
1978local policy might dictate that the stickiness is not used.
1979
1980(3) If the system supports the POSIX 'chown giveaway' feature and if
1981any of the parent directories of the temporary file back to the root
1982directory are 'unsafe', using the definitions given above in (1) and
1983(2).  For Unix systems, this is usually not an issue if you are
1984building on a local disk.  See the documentation for the File::Temp
1985module for more information about 'chown giveaway'.
1986
1987See the documentation for the File::Temp module for more information
1988about the various security aspects of temporary files.
1989
1990=back
1991
1992The core distribution can now run its regression tests in parallel on
1993Unix-like platforms. Instead of running C<make test>, set C<TEST_JOBS> in
1994your environment to the number of tests to run in parallel, and run
1995C<make test_harness>. On a Bourne-like shell, this can be done as
1996
1997    TEST_JOBS=3 make test_harness  # Run 3 tests in parallel
1998
1999An environment variable is used, rather than parallel make itself, because
2000L<TAP::Harness> needs to be able to schedule individual non-conflicting test
2001scripts itself, and there is no standard interface to C<make> utilities to
2002interact with their job schedulers.
2003
2004=head1 make install
2005
2006This will put perl into the public directory you specified to
2007Configure; by default this is /usr/local/bin.  It will also try
2008to put the man pages in a reasonable place.  It will not nroff the man
2009pages, however.  You may need to be root to run B<make install>.  If you
2010are not root, you must still have permission to install into the directories
2011in question and you should ignore any messages about chown not working.
2012
2013If "make install" just says "`install' is up to date" or something
2014similar, you may be on a case-insensitive filesystems such as Mac's HFS+,
2015and you should say "make install-all".  (This confusion is brought to you
2016by the Perl distribution having a file called INSTALL.)
2017
2018=head2 Installing perl under different names
2019
2020If you want to install perl under a name other than "perl" (for example,
2021when installing perl with special features enabled, such as debugging),
2022indicate the alternate name on the "make install" line, such as:
2023
2024    make install PERLNAME=myperl
2025
2026You can separately change the base used for versioned names (like
2027"perl5.8.9") by setting PERLNAME_VERBASE, like
2028
2029    make install PERLNAME=perl5 PERLNAME_VERBASE=perl
2030
2031This can be useful if you have to install perl as "perl5" (e.g. to
2032avoid conflicts with an ancient version in /usr/bin supplied by your vendor).
2033Without this the versioned binary would be called "perl55.8.8".
2034
2035=head2 Installing perl under a different directory
2036
2037You can install perl under a different destination directory by using
2038the DESTDIR variable during C<make install>, with a command like
2039
2040        make install DESTDIR=/tmp/perl5
2041
2042DESTDIR is automatically prepended to all the installation paths.  See
2043the example in L<"DESTDIR"> above.
2044
2045=head2 Installed files
2046
2047If you want to see exactly what will happen without installing
2048anything, you can run
2049
2050        ./perl installperl -n
2051        ./perl installman -n
2052
2053make install will install the following:
2054
2055    binaries
2056
2057        perl,
2058            perl5.n.n   where 5.n.n is the current release number.  This
2059                        will be a link to perl.
2060        suidperl,
2061            sperl5.n.n  If you requested setuid emulation.
2062        a2p             awk-to-perl translator
2063
2064    scripts
2065
2066        cppstdin        This is used by the deprecated switch perl -P, if
2067                        your cc -E can't read from stdin.
2068        c2ph, pstruct   Scripts for handling C structures in header files.
2069        config_data     Manage Module::Build-like module configuration
2070        corelist        Shows versions of modules that come with different
2071                        versions of perl
2072        cpan            The CPAN shell
2073        cpan2dist       The CPANPLUS distribution creator
2074        cpanp           The CPANPLUS shell
2075        cpanp-run-perl  An helper for cpanp
2076        dprofpp         Perl code profiler post-processor
2077        enc2xs          Encoding module generator
2078        find2perl       find-to-perl translator
2079        h2ph            Extract constants and simple macros from C headers
2080        h2xs            Converts C .h header files to Perl extensions.
2081        instmodsh       A shell to examine installed modules.
2082        libnetcfg       Configure libnet.
2083        perlbug         Tool to report bugs in Perl.
2084        perldoc         Tool to read perl's pod documentation.
2085        perlivp         Perl Installation Verification Procedure
2086        piconv          A Perl implementation of the encoding conversion
2087                        utility iconv
2088        pl2pm           Convert Perl 4 .pl files to Perl 5 .pm modules
2089        pod2html,       Converters from perl's pod documentation format
2090        pod2latex,      to other useful formats.
2091        pod2man,
2092        pod2text,
2093        pod2usage
2094        podchecker      POD syntax checker
2095        podselect       Prints sections of POD documentation
2096        prove           A command-line tool for running tests
2097        psed            A Perl implementation of sed
2098        ptar            A Perl implementation of tar
2099        ptardiff        A diff for tar archives
2100        s2p             sed-to-perl translator
2101        shasum          A tool to print or check SHA checksums
2102        splain          Describe Perl warnings and errors
2103        xsubpp          Compiler to convert Perl XS code into C code
2104
2105    library files
2106
2107                        in $privlib and $archlib specified to
2108                        Configure, usually under /usr/local/lib/perl5/.
2109
2110    documentation
2111
2112        man pages       in $man1dir, usually /usr/local/man/man1.
2113        module man
2114        pages           in $man3dir, usually /usr/local/man/man3.
2115        pod/*.pod       in $privlib/pod/.
2116
2117installperl will also create the directories listed above
2118in L<"Installation Directories">.
2119
2120Perl's *.h header files and the libperl library are also installed
2121under $archlib so that any user may later build new modules, run the
2122optional Perl compiler, or embed the perl interpreter into another
2123program even if the Perl source is no longer available.
2124
2125=head2 Installing only version-specific parts
2126
2127Sometimes you only want to install the version-specific parts of the perl
2128installation.  For example, you may wish to install a newer version of
2129perl alongside an already installed production version without
2130disabling installation of new modules for the production version.
2131To only install the version-specific parts of the perl installation, run
2132
2133        Configure -Dversiononly
2134
2135or answer 'y' to the appropriate Configure prompt.  Alternatively,
2136you can just manually run
2137
2138        ./perl installperl -v
2139
2140and skip installman altogether.
2141
2142See also L<"Maintaining completely separate versions"> for another
2143approach.
2144
2145=head1 cd /usr/include; h2ph *.h sys/*.h
2146
2147Some perl scripts need to be able to obtain information from the
2148system header files.  This command will convert the most commonly used
2149header files in /usr/include into files that can be easily interpreted
2150by perl.  These files will be placed in the architecture-dependent
2151library ($archlib) directory you specified to Configure.
2152
2153Note:  Due to differences in the C and perl languages, the conversion
2154of the header files is not perfect.  You will probably have to
2155hand-edit some of the converted files to get them to parse correctly.
2156For example, h2ph breaks spectacularly on type casting and certain
2157structures.
2158
2159=head1 installhtml --help
2160
2161Some sites may wish to make perl documentation available in HTML
2162format.  The installhtml utility can be used to convert pod
2163documentation into linked HTML files and install them.
2164
2165Currently, the supplied ./installhtml script does not make use of the
2166html Configure variables.  This should be fixed in a future release.
2167
2168The following command-line is an example of one used to convert
2169perl documentation:
2170
2171  ./installhtml                   \
2172      --podroot=.                 \
2173      --podpath=lib:ext:pod:vms   \
2174      --recurse                   \
2175      --htmldir=/perl/nmanual     \
2176      --htmlroot=/perl/nmanual    \
2177      --splithead=pod/perlipc     \
2178      --splititem=pod/perlfunc    \
2179      --libpods=perlfunc:perlguts:perlvar:perlrun:perlop \
2180      --verbose
2181
2182See the documentation in installhtml for more details.  It can take
2183many minutes to execute a large installation and you should expect to
2184see warnings like "no title", "unexpected directive" and "cannot
2185resolve" as the files are processed. We are aware of these problems
2186(and would welcome patches for them).
2187
2188You may find it helpful to run installhtml twice. That should reduce
2189the number of "cannot resolve" warnings.
2190
2191=head1 cd pod && make tex && (process the latex files)
2192
2193Some sites may also wish to make the documentation in the pod/ directory
2194available in TeX format.  Type
2195
2196        (cd pod && make tex && <process the latex files>)
2197
2198=head1 Starting all over again
2199
2200If you wish to re-build perl from the same build directory, you should
2201clean it out with the command
2202
2203        make distclean
2204
2205or
2206
2207        make realclean
2208
2209The only difference between the two is that make distclean also removes
2210your old config.sh and Policy.sh files.
2211
2212If you are upgrading from a previous version of perl, or if you
2213change systems or compilers or make other significant changes, or if
2214you are experiencing difficulties building perl, you should not re-use
2215your old config.sh.
2216
2217If your reason to reuse your old config.sh is to save your particular
2218installation choices, then you can probably achieve the same effect by
2219using the Policy.sh file.  See the section on L<"Site-wide Policy
2220settings"> above.
2221
2222=head1 Reporting Problems
2223
2224Wherever possible please use the perlbug tool supplied with this Perl
2225to report problems, as it automatically includes summary configuration
2226information about your perl, which may help us track down problems far
2227more quickly. But first you should read the advice in this file,
2228carefully re-read the error message and check the relevant manual pages
2229on your system, as these may help you find an immediate solution.  If
2230you are not sure whether what you are seeing is a bug, you can send a
2231message describing the problem to the comp.lang.perl.misc newsgroup to
2232get advice.
2233
2234The perlbug tool is installed along with perl, so after you have
2235completed C<make install> it should be possible to run it with plain
2236C<perlbug>.  If the install fails, or you want to report problems with
2237C<make test> without installing perl, then you can use C<make nok> to
2238run perlbug to report the problem, or run it by hand from this source
2239directory with C<./perl -Ilib utils/perlbug>
2240
2241If the build fails too early to run perlbug uninstalled, then please
2242B<run> the C<./myconfig> shell script, and mail its output along with
2243an accurate description of your problem to perlbug@perl.org
2244
2245If Configure itself fails, and does not generate a config.sh file
2246(needed to run C<./myconfig>), then please mail perlbug@perl.org the
2247description of how Configure fails along with details of your system
2248- for example the output from running C<uname -a>
2249
2250Please try to make your message brief but clear.  Brief, clear bug
2251reports tend to get answered more quickly.  Please don't worry if your
2252written English is not great - what matters is how well you describe
2253the important technical details of the problem you have encountered,
2254not whether your grammar and spelling is flawless.
2255
2256Trim out unnecessary information.  Do not include large files (such as
2257config.sh or a complete Configure or make log) unless absolutely
2258necessary.  Do not include a complete transcript of your build
2259session.  Just include the failing commands, the relevant error
2260messages, and whatever preceding commands are necessary to give the
2261appropriate context.  Plain text should usually be sufficient--fancy
2262attachments or encodings may actually reduce the number of people who
2263read your message.  Your message will get relayed to over 400
2264subscribers around the world so please try to keep it brief but clear.
2265
2266If the bug you are reporting has security implications, which make it
2267inappropriate to send to a publicly archived mailing list, then please send
2268it to perl5-security-report@perl.org. This points to a closed subscription
2269unarchived mailing list, which includes all the core committers, who be able
2270to help assess the impact of issues, figure out a resolution, and help
2271co-ordinate the release of patches to mitigate or fix the problem across all
2272platforms on which Perl is supported. Please only use this address for security
2273issues in the Perl core, not for modules independently distributed on CPAN.
2274
2275If you are unsure what makes a good bug report please read "How to
2276report Bugs Effectively" by Simon Tatham:
2277http://www.chiark.greenend.org.uk/~sgtatham/bugs.html
2278
2279=head1 Coexistence with earlier versions of perl 5
2280
2281This version is not binary compatible with releases of Perl prior
2282to 5.10.0.  In other words, you will have to recompile any XS modules
2283installed under version 5.8.9 (or earlier).
2284
2285In general, you can usually safely upgrade from one version of Perl (e.g.
22865.X.Y) to another similar minor version (e.g. 5.X.(Y+1))) without
2287re-compiling all of your extensions.  You can also safely leave the old
2288version around in case the new version causes you problems for some reason.
2289
2290Usually, most extensions will probably not need to be recompiled to be
2291used with a newer version of Perl.  Here is how it is supposed to work.
2292(These examples assume you accept all the Configure defaults.)
2293
2294Suppose you already have versions 5.8.9 and 5.10.0 installed, and you
2295are now installing 5.10.1.  The directories searched by version 5.10.1
2296will be:
2297
2298    /usr/local/lib/perl5/5.10.1/$archname
2299    /usr/local/lib/perl5/5.10.1
2300    /usr/local/lib/perl5/site_perl/5.10.1/$archname
2301    /usr/local/lib/perl5/site_perl/5.10.1
2302
2303    /usr/local/lib/perl5/site_perl/5.10.0/$archname
2304    /usr/local/lib/perl5/site_perl/5.10.0
2305    /usr/local/lib/perl5/site_perl/5.8.9
2306    /usr/local/lib/perl5/site_perl
2307
2308Notice the last four entries -- Perl understands the default structure
2309of the $sitelib directories and will look back in older, compatible
2310directories.  It will load up architecture-dependent modules from your
23115.10.0 installation, and pure perl modules from either your 5.10.0 or
23125.8.9 installations.  The last entry, /usr/local/lib/perl5/site_perl/,
2313is there for 5.004-era pure perl modules.
2314
2315Next, suppose that you now upgrade a module to one which requires
2316features present only in 5.10.1.  That new module will get installed into
2317/usr/local/lib/perl5/site_perl/5.10.1 and will be available to 5.10.1,
2318but will not interfere with the 5.10.0 version.
2319
2320This way, you can choose to share compatible extensions, but also upgrade
2321to a newer version of an extension that may be incompatible with earlier
2322versions, without breaking the earlier versions' installations.
2323
2324This search order is scheduled for revision starting in version 5.11.0.
2325
2326=head2 Maintaining completely separate versions
2327
2328Many users prefer to keep all versions of perl in completely
2329separate directories.  This guarantees that an update to one version
2330won't interfere with another version.  (The defaults guarantee this for
2331libraries after 5.6.0, but not for executables. TODO?)  One convenient
2332way to do this is by using a separate prefix for each version, such as
2333
2334        sh Configure -Dprefix=/opt/perl5.10.1
2335
2336and adding /opt/perl5.10.1/bin to the shell PATH variable.  Such users
2337may also wish to add a symbolic link /usr/local/bin/perl so that
2338scripts can still start with #!/usr/local/bin/perl.
2339
2340Others might share a common directory for maintenance sub-versions
2341(e.g. 5.10 for all 5.10.x versions), but change directory with
2342each major version.
2343
2344If you are installing a development subversion, you probably ought to
2345seriously consider using a separate directory, since development
2346subversions may not have all the compatibility wrinkles ironed out
2347yet.
2348
2349=head2 Upgrading from 5.8.x or earlier
2350
2351B<Perl 5.10.1 is binary incompatible with Perl 5.8.x and any earlier
2352Perl release.>  Perl modules having binary parts
2353(meaning that a C compiler is used) will have to be recompiled to be
2354used with 5.10.1.  If you find you do need to rebuild an extension with
23555.10.1, you may safely do so without disturbing the older
2356installations.  (See L<"Coexistence with earlier versions of perl 5">
2357above.)
2358
2359See your installed copy of the perllocal.pod file for a (possibly
2360incomplete) list of locally installed modules.  Note that you want
2361perllocal.pod, not perllocale.pod, for installed module information.
2362
2363=head1 Minimizing the Perl installation
2364
2365The following section is meant for people worrying about squeezing the
2366Perl installation into minimal systems (for example when installing
2367operating systems, or in really small filesystems).
2368
2369Leaving out as many extensions as possible is an obvious way:
2370Encode, with its big conversion tables, consumes a lot of
2371space.  On the other hand, you cannot throw away everything.  The
2372Fcntl module is pretty essential.  If you need to do network
2373programming, you'll appreciate the Socket module, and so forth: it all
2374depends on what do you need to do.
2375
2376In the following we offer two different slimmed down installation
2377recipes.  They are informative, not normative: the choice of files
2378depends on what you need.
2379
2380Firstly, the bare minimum to run this script
2381
2382  use strict;
2383  use warnings;
2384  foreach my $f (</*>) {
2385     print("$f\n");
2386  }
2387
2388in Linux is as follows (under $Config{prefix}):
2389
2390  ./bin/perl
2391  ./lib/perl5/5.9.3/strict.pm
2392  ./lib/perl5/5.9.3/warnings.pm
2393  ./lib/perl5/5.9.3/i686-linux/File/Glob.pm
2394  ./lib/perl5/5.9.3/i686-linux/XSLoader.pm
2395  ./lib/perl5/5.9.3/i686-linux/auto/File/Glob/Glob.so
2396
2397Secondly, Debian perl-base package contains the following files,
2398size about 1.9MB in its i386 version:
2399
2400  /usr/bin/perl
2401  /usr/bin/perl5.8.4
2402  /usr/lib/perl/5.8
2403  /usr/lib/perl/5.8.4/B.pm
2404  /usr/lib/perl/5.8.4/B/Deparse.pm
2405  /usr/lib/perl/5.8.4/Config.pm
2406  /usr/lib/perl/5.8.4/Cwd.pm
2407  /usr/lib/perl/5.8.4/Data/Dumper.pm
2408  /usr/lib/perl/5.8.4/DynaLoader.pm
2409  /usr/lib/perl/5.8.4/Errno.pm
2410  /usr/lib/perl/5.8.4/Fcntl.pm
2411  /usr/lib/perl/5.8.4/File/Glob.pm
2412  /usr/lib/perl/5.8.4/IO.pm
2413  /usr/lib/perl/5.8.4/IO/File.pm
2414  /usr/lib/perl/5.8.4/IO/Handle.pm
2415  /usr/lib/perl/5.8.4/IO/Pipe.pm
2416  /usr/lib/perl/5.8.4/IO/Seekable.pm
2417  /usr/lib/perl/5.8.4/IO/Select.pm
2418  /usr/lib/perl/5.8.4/IO/Socket.pm
2419  /usr/lib/perl/5.8.4/POSIX.pm
2420  /usr/lib/perl/5.8.4/Socket.pm
2421  /usr/lib/perl/5.8.4/XSLoader.pm
2422  /usr/lib/perl/5.8.4/auto/Cwd/Cwd.bs
2423  /usr/lib/perl/5.8.4/auto/Cwd/Cwd.so
2424  /usr/lib/perl/5.8.4/auto/Data/Dumper/Dumper.bs
2425  /usr/lib/perl/5.8.4/auto/Data/Dumper/Dumper.so
2426  /usr/lib/perl/5.8.4/auto/DynaLoader/DynaLoader.a
2427  /usr/lib/perl/5.8.4/auto/DynaLoader/autosplit.ix
2428  /usr/lib/perl/5.8.4/auto/DynaLoader/dl_expandspec.al
2429  /usr/lib/perl/5.8.4/auto/DynaLoader/dl_find_symbol_anywhere.al
2430  /usr/lib/perl/5.8.4/auto/DynaLoader/dl_findfile.al
2431  /usr/lib/perl/5.8.4/auto/DynaLoader/extralibs.ld
2432  /usr/lib/perl/5.8.4/auto/Fcntl/Fcntl.bs
2433  /usr/lib/perl/5.8.4/auto/Fcntl/Fcntl.so
2434  /usr/lib/perl/5.8.4/auto/File/Glob/Glob.bs
2435  /usr/lib/perl/5.8.4/auto/File/Glob/Glob.so
2436  /usr/lib/perl/5.8.4/auto/IO/IO.bs
2437  /usr/lib/perl/5.8.4/auto/IO/IO.so
2438  /usr/lib/perl/5.8.4/auto/POSIX/POSIX.bs
2439  /usr/lib/perl/5.8.4/auto/POSIX/POSIX.so
2440  /usr/lib/perl/5.8.4/auto/POSIX/autosplit.ix
2441  /usr/lib/perl/5.8.4/auto/POSIX/load_imports.al
2442  /usr/lib/perl/5.8.4/auto/Socket/Socket.bs
2443  /usr/lib/perl/5.8.4/auto/Socket/Socket.so
2444  /usr/lib/perl/5.8.4/lib.pm
2445  /usr/lib/perl/5.8.4/re.pm
2446  /usr/share/doc/perl-base
2447  /usr/share/doc/perl/AUTHORS.gz
2448  /usr/share/doc/perl/Documentation
2449  /usr/share/doc/perl/README.Debian.gz
2450  /usr/share/doc/perl/changelog.Debian.gz
2451  /usr/share/doc/perl/copyright
2452  /usr/share/man/man1/perl.1.gz
2453  /usr/share/perl/5.8
2454  /usr/share/perl/5.8.4/AutoLoader.pm
2455  /usr/share/perl/5.8.4/Carp.pm
2456  /usr/share/perl/5.8.4/Carp/Heavy.pm
2457  /usr/share/perl/5.8.4/Exporter.pm
2458  /usr/share/perl/5.8.4/Exporter/Heavy.pm
2459  /usr/share/perl/5.8.4/File/Spec.pm
2460  /usr/share/perl/5.8.4/File/Spec/Unix.pm
2461  /usr/share/perl/5.8.4/FileHandle.pm
2462  /usr/share/perl/5.8.4/Getopt/Long.pm
2463  /usr/share/perl/5.8.4/IO/Socket/INET.pm
2464  /usr/share/perl/5.8.4/IO/Socket/UNIX.pm
2465  /usr/share/perl/5.8.4/IPC/Open2.pm
2466  /usr/share/perl/5.8.4/IPC/Open3.pm
2467  /usr/share/perl/5.8.4/List/Util.pm
2468  /usr/share/perl/5.8.4/Scalar/Util.pm
2469  /usr/share/perl/5.8.4/SelectSaver.pm
2470  /usr/share/perl/5.8.4/Symbol.pm
2471  /usr/share/perl/5.8.4/Text/ParseWords.pm
2472  /usr/share/perl/5.8.4/Text/Tabs.pm
2473  /usr/share/perl/5.8.4/Text/Wrap.pm
2474  /usr/share/perl/5.8.4/attributes.pm
2475  /usr/share/perl/5.8.4/base.pm
2476  /usr/share/perl/5.8.4/bytes.pm
2477  /usr/share/perl/5.8.4/bytes_heavy.pl
2478  /usr/share/perl/5.8.4/constant.pm
2479  /usr/share/perl/5.8.4/fields.pm
2480  /usr/share/perl/5.8.4/integer.pm
2481  /usr/share/perl/5.8.4/locale.pm
2482  /usr/share/perl/5.8.4/overload.pm
2483  /usr/share/perl/5.8.4/strict.pm
2484  /usr/share/perl/5.8.4/utf8.pm
2485  /usr/share/perl/5.8.4/utf8_heavy.pl
2486  /usr/share/perl/5.8.4/vars.pm
2487  /usr/share/perl/5.8.4/warnings.pm
2488  /usr/share/perl/5.8.4/warnings/register.pm
2489
2490A nice trick to find out the minimal set of Perl library files you will
2491need to run a Perl program is
2492
2493   perl -e 'do "prog.pl"; END { print "$_\n" for sort keys %INC }'
2494
2495(this will not find libraries required in runtime, unfortunately, but
2496it's a minimal set) and if you want to find out all the files you can
2497use something like the below
2498
2499   strace perl -le 'do "x.pl"' 2>&1 | perl -nle '/^open\(\"(.+?)"/ && print $1'
2500
2501(The 'strace' is Linux-specific, other similar utilities include 'truss'
2502and 'ktrace'.)
2503
2504=head2 C<-DNO_MATHOMS>
2505
2506If you configure perl with C<-Accflags=-DNO_MATHOMS>, the functions from
2507F<mathoms.c> will not be compiled in. Those functions are no longer used
2508by perl itself; for source compatibility reasons, though, they weren't
2509completely removed.
2510
2511=head1 DOCUMENTATION
2512
2513Read the manual entries before running perl.  The main documentation
2514is in the pod/ subdirectory and should have been installed during the
2515build process.  Type B<man perl> to get started.  Alternatively, you
2516can type B<perldoc perl> to use the supplied perldoc script.  This is
2517sometimes useful for finding things in the library modules.
2518
2519=head1 AUTHOR
2520
2521Original author:  Andy Dougherty doughera@lafayette.edu , borrowing very
2522heavily from the original README by Larry Wall, with lots of helpful
2523feedback and additions from the perl5-porters@perl.org folks.
2524
2525If you have problems, corrections, or questions, please see
2526L<"Reporting Problems"> above.
2527
2528=head1 REDISTRIBUTION
2529
2530This document is part of the Perl package and may be distributed under
2531the same terms as perl itself, with the following additional request:
2532If you are distributing a modified version of perl (perhaps as part of
2533a larger package) please B<do> modify these installation instructions
2534and the contact information to match your distribution.
2535
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