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    1 If you read this file _as_is_, just ignore the funny characters you see.
    2 It is written in the POD format (see pod/perlpod.pod) which is specially
    3 designed to be readable as is.
    5 =head1 NAME
    7 INSTALL - Build and Installation guide for perl 5.
    9 =head1 SYNOPSIS
   11 First, make sure you have an up-to-date version of Perl.  If you
   12 didn't get your Perl source from CPAN, check the latest version at
   13 http://www.cpan.org/src/.  Perl uses a version scheme where even-numbered
   14 subreleases (like 5.8.x and 5.10.x) are stable maintenance releases and
   15 odd-numbered subreleases (like 5.7.x and 5.9.x) are unstable
   16 development releases.  Development releases should not be used in
   17 production environments.  Fixes and new features are first carefully
   18 tested in development releases and only if they prove themselves to be
   19 worthy will they be migrated to the maintenance releases.
   21 The basic steps to build and install perl 5 on a Unix system with all
   22 the defaults are to run, from a freshly unpacked source tree:
   24 	sh Configure -de
   25 	make
   26 	make test
   27 	make install
   29 Each of these is explained in further detail below.
   31 The above commands will install Perl to /usr/local (or some other
   32 platform-specific directory -- see the appropriate file in hints/.)
   33 If that's not okay with you, you can run Configure interactively, by
   34 just typing "sh Configure" (without the -de args). You can also specify
   35 any prefix location by adding "-Dprefix='/some/dir'" to Configure's args.
   36 To explicitly name the perl binary, use the command
   37 "make install PERLNAME=myperl".
   39 Building perl from source requires an ANSI compliant C compiler.
   40 A minimum of C89 is required. Some features available in C99 will
   41 be probed for and used when found. The perl build process does not
   42 rely on anything more than C89.
   44 These options, and many more, are explained in further detail below.
   46 If you're building perl from a git repository, you should also consult
   47 the documentation in pod/perlgit.pod for information on that special
   48 circumstance.
   50 If you have problems, corrections, or questions, please see
   51 L<"Reporting Problems"> below.
   53 For information on what's new in this release, see the
   54 pod/perldelta.pod file.  For more information about how to find more
   55 specific detail about changes, see the Changes file.
   57 =head1 DESCRIPTION
   59 This document is written in pod format as an easy way to indicate its
   60 structure.  The pod format is described in pod/perlpod.pod, but you can
   61 read it as is with any pager or editor.  Headings and items are marked
   62 by lines beginning with '='.  The other mark-up used is
   64     B<text>     embolden text, used for switches, programs or commands
   65     C<code>	literal code
   66     L<name>     A link (cross reference) to name
   67     F<file>     A filename
   69 Although most of the defaults are probably fine for most users,
   70 you should probably at least skim through this document before
   71 proceeding.
   73 In addition to this file, check if there is a README file specific to
   74 your operating system, since it may provide additional or different
   75 instructions for building Perl.  If there is a hint file for your
   76 system (in the hints/ directory) you might also want to read it
   77 for even more information.
   79 For additional information about porting Perl, see the section on
   80 L<"Porting information"> below, and look at the files in the Porting/
   81 directory.
   83 =head1 PRELIMINARIES
   85 =head2 Changes and Incompatibilities
   87 Please see pod/perldelta.pod for a description of the changes and
   88 potential incompatibilities introduced with this release.  A few of
   89 the most important issues are listed below, but you should refer
   90 to pod/perldelta.pod for more detailed information.
   92 B<WARNING:> This version is not binary compatible with versions of Perl
   93 earlier than 5.30.0.  If you have built extensions (i.e. modules that
   94 include C code) using an earlier version of Perl, you will need to
   95 rebuild and reinstall those extensions.
   97 Pure perl modules without XS or C code should continue to work fine
   98 without reinstallation.  See the discussion below on
   99 L<"Coexistence with earlier versions of perl 5"> for more details.
  101 The standard extensions supplied with Perl will be handled automatically.
  103 On a related issue, old modules may possibly be affected by the changes
  104 in the Perl language in the current release.  Please see
  105 pod/perldelta.pod for a description of what's changed.  See your
  106 installed copy of the perllocal.pod file for a (possibly incomplete)
  107 list of locally installed modules.  Also see the L<CPAN> module's
  108 C<autobundle> function for one way to make a "bundle" of your currently
  109 installed modules.
  111 =head1 Run Configure
  113 Configure will figure out various things about your system.  Some
  114 things Configure will figure out for itself, other things it will ask
  115 you about.  To accept the default, just press RETURN.   The default is
  116 almost always okay.  It is normal for some things to be "NOT found",
  117 since Configure often searches for many different ways of performing
  118 the same function.
  120 At any Configure prompt, you can type  &-d  and Configure will use the
  121 defaults from then on.
  123 After it runs, Configure will perform variable substitution on all the
  124 *.SH files and offer to run make depend.
  126 The results of a Configure run are stored in the config.sh and Policy.sh
  127 files.
  129 =head2 Common Configure options
  131 Configure supports a number of useful options.  Run
  133 	Configure -h
  135 to get a listing.  See the Porting/Glossary file for a complete list of
  136 Configure variables you can set and their definitions.
  138 =over 4
  140 =item C compiler
  142 To compile with gcc, if it's not the default compiler on your
  143 system, you should run
  145 	sh Configure -Dcc=gcc
  147 This is the preferred way to specify gcc (or any another alternative
  148 compiler) so that the hints files can set appropriate defaults.
  150 =item Installation prefix
  152 By default, for most systems, perl will be installed in
  153 /usr/local/{bin, lib, man}.  (See L<"Installation Directories">
  154 and L<"Coexistence with earlier versions of perl 5"> below for
  155 further details.)
  157 You can specify a different 'prefix' for the default installation
  158 directory when Configure prompts you, or by using the Configure command
  159 line option -Dprefix='/some/directory', e.g.
  161 	sh Configure -Dprefix=/opt/perl
  163 If your prefix contains the string "perl", then the suggested
  164 directory structure is simplified.  For example, if you use
  165 prefix=/opt/perl, then Configure will suggest /opt/perl/lib instead of
  166 /opt/perl/lib/perl5/.  Again, see L<"Installation Directories"> below
  167 for more details.  Do not include a trailing slash, (i.e. /opt/perl/)
  168 or you may experience odd test failures.
  170 NOTE:  You must not specify an installation directory that is the same
  171 as or below your perl source directory.  If you do, installperl will
  172 attempt infinite recursion.
  174 =item /usr/bin/perl
  176 It may seem obvious, but Perl is useful only when users can easily
  177 find it.  It's often a good idea to have both /usr/bin/perl and
  178 /usr/local/bin/perl be symlinks to the actual binary.  Be especially
  179 careful, however, not to overwrite a version of perl supplied by your
  180 vendor unless you are sure you know what you are doing.  If you insist
  181 on replacing your vendor's perl, useful information on how it was
  182 configured may be found with
  184 	perl -V:config_args
  186 (Check the output carefully, however, since this doesn't preserve
  187 spaces in arguments to Configure.  For that, you have to look carefully
  188 at config_arg1, config_arg2, etc.)
  190 By default, Configure will not try to link /usr/bin/perl to the current
  191 version of perl.  You can turn on that behavior by running
  193 	Configure -Dinstallusrbinperl
  195 or by answering 'yes' to the appropriate Configure prompt.
  197 In any case, system administrators are strongly encouraged to put
  198 (symlinks to) perl and its accompanying utilities, such as perldoc,
  199 into a directory typically found along a user's PATH, or in another
  200 obvious and convenient place.
  202 =item Building a development release
  204 For development releases (odd subreleases, like 5.9.x) if you want to
  205 use Configure -d, you will also need to supply -Dusedevel to Configure,
  206 because the default answer to the question "do you really want to
  207 Configure a development version?" is "no".  The -Dusedevel skips that
  208 sanity check.
  210 =back
  212 If you are willing to accept all the defaults, and you want terse
  213 output, you can run
  215 	sh Configure -des
  217 =head2 Altering Configure variables for C compiler switches etc.
  219 For most users, most of the Configure defaults are fine, or can easily
  220 be set on the Configure command line.  However, if Configure doesn't
  221 have an option to do what you want, you can change Configure variables
  222 after the platform hints have been run by using Configure's -A switch.
  223 For example, here's how to add a couple of extra flags to C compiler
  224 invocations:
  226 	sh Configure -Accflags="-DPERL_EXTERNAL_GLOB -DNO_HASH_SEED"
  228 To clarify, those ccflags values are not Configure options; if passed to
  229 Configure directly, they won't do anything useful (they will define a
  230 variable in config.sh, but without taking any action based upon it).
  231 But when passed to the compiler, those flags will activate #ifdefd code.
  233 For more help on Configure switches, run
  235 	sh Configure -h
  237 =head2 Major Configure-time Build Options
  239 There are several different ways to Configure and build perl for your
  240 system.  For most users, the defaults are sensible and will work.
  241 Some users, however, may wish to further customize perl.  Here are
  242 some of the main things you can change.
  244 =head3 Threads
  246 On some platforms, perl can be compiled with support for threads.  To
  247 enable this, run
  249 	sh Configure -Dusethreads
  251 The default is to compile without thread support.
  253 Perl used to have two different internal threads implementations.  The
  254 current model (available internally since 5.6, and as a user-level module
  255 since 5.8) is called interpreter-based implementation (ithreads), with
  256 one interpreter per thread, and explicit sharing of data. The (deprecated)
  257 5.005 version (5005threads) was removed for release 5.10.
  259 The 'threads' module is for use with the ithreads implementation.  The
  260 'Thread' module emulates the old 5005threads interface on top of the
  261 current ithreads model.
  263 When using threads, perl uses a dynamically-sized buffer for some of
  264 the thread-safe library calls, such as those in the getpw*() family.
  265 This buffer starts small, but it will keep growing until the result
  266 fits.  To get a fixed upper limit, you should compile Perl with
  267 PERL_REENTRANT_MAXSIZE defined to be the number of bytes you want.  One
  268 way to do this is to run Configure with
  269 C<-Accflags=-DPERL_REENTRANT_MAXSIZE=65536>.
  271 =head3 Large file support
  273 Since Perl 5.6.0, Perl has supported large files (files larger than
  274 2 gigabytes), and in many common platforms like Linux or Solaris this
  275 support is on by default.
  277 This is both good and bad. It is good in that you can use large files,
  278 seek(), stat(), and -s them.  It is bad in that if you are interfacing
  279 Perl using some extension, the components you are connecting to must also
  280 be large file aware: if Perl thinks files can be large but the other
  281 parts of the software puzzle do not understand the concept, bad things
  282 will happen.
  284 There's also one known limitation with the current large files
  285 implementation: unless you also have 64-bit integers (see the next
  286 section), you cannot use the printf/sprintf non-decimal integer formats
  287 like C<%x> to print filesizes.  You can use C<%d>, though.
  289 If you want to compile perl without large file support, use
  291     sh Configure -Uuselargefiles
  293 =head3 64 bit support
  295 If your platform does not run natively at 64 bits, but can simulate
  296 them with compiler flags and/or C<long long> or C<int64_t>,
  297 you can build a perl that uses 64 bits.
  299 There are actually two modes of 64-bitness: the first one is achieved
  300 using Configure -Duse64bitint and the second one using Configure
  301 -Duse64bitall.  The difference is that the first one is minimal and
  302 the second one maximal.  The first works in more places than the second.
  304 The C<use64bitint> option does only as much as is required to get
  305 64-bit integers into Perl (this may mean, for example, using "long
  306 longs") while your memory may still be limited to 2 gigabytes (because
  307 your pointers could still be 32-bit).  Note that the name C<64bitint>
  308 does not imply that your C compiler will be using 64-bit C<int>s (it
  309 might, but it doesn't have to).  The C<use64bitint> simply means that
  310 you will be able to have 64 bit-wide scalar values.
  312 The C<use64bitall> option goes all the way by attempting to switch
  313 integers (if it can), longs (and pointers) to being 64-bit.  This may
  314 create an even more binary incompatible Perl than -Duse64bitint: the
  315 resulting executable may not run at all in a 32-bit box, or you may
  316 have to reboot/reconfigure/rebuild your operating system to be 64-bit
  317 aware.
  319 Natively 64-bit systems need neither -Duse64bitint nor -Duse64bitall.
  320 On these systems, it might be the default compilation mode, and there
  321 is currently no guarantee that passing no use64bitall option to the
  322 Configure process will build a 32bit perl. Implementing -Duse32bit*
  323 options is planned for a future release of perl.
  325 =head3 Long doubles
  327 In some systems you may be able to use long doubles to enhance the
  328 range and precision of your double precision floating point numbers
  329 (that is, Perl's numbers).  Use Configure -Duselongdouble to enable
  330 this support (if it is available).
  332 Note that the exact format and range of long doubles varies:
  333 the most common is the x86 80-bit (64 bits of mantissa) format,
  334 but there are others, with different mantissa and exponent ranges.
  336 =head3 "more bits"
  338 You can "Configure -Dusemorebits" to turn on both the 64-bit support
  339 and the long double support.
  341 =head3 quadmath
  343 One option for more precision is that gcc 4.6 and later have a library
  344 called quadmath, which implements the IEEE 754 quadruple precision
  345 (128-bit, 113 bits of mantissa) floating point numbers.  The library
  346 works at least on x86 and ia64 platforms.  It may be part of your gcc
  347 installation, or you may need to install it separately.
  349 With "Configure -Dusequadmath" you can try enabling its use, but note
  350 the compiler dependency, you may need to also add "-Dcc=...".
  351 At C level the type is called C<__float128> (note, not "long double"),
  352 but Perl source knows it as NV.  (This is not "long doubles".)
  354 =head3 Algorithmic Complexity Attacks on Hashes
  356 Perl 5.18 reworked the measures used to secure its hash function
  357 from algorithmic complexity attacks.  By default it will build with
  358 all of these measures enabled along with support for controlling and
  359 disabling them via environment variables.
  361 You can override various aspects of this feature by defining various
  362 symbols during configure. An example might be:
  364     sh Configure -Accflags=-DPERL_HASH_FUNC_SIPHASH
  366 B<Unless stated otherwise these options are considered experimental or
  367 insecure and are not recommended for production use.>
  369 Since Perl 5.18 we have included support for multiple hash functions,
  370 although from time to time we change which functions we support,
  371 and which function is default (currently SBOX+STADTX on 64 bit builds
  372 and SBOX+ZAPHOD32 for 32 bit builds). You can choose a different
  373 algorithm by defining one of the following symbols during configure.
  374 Note that there security implications of which hash function you choose
  375 to use. The functions are listed roughly by how secure they are believed
  376 to be, with the one believed to be most secure at release time being PERL_HASH_FUNC_SIPHASH.
  383 In addition, these, (or custom hash functions), may be "fronted" by the
  384 SBOX32 hash function for keys under a chosen size. This hash function is
  385 special in that it has proven theoretical security properties, and is very
  386 fast to hash, but which by nature is restricted to a maximum key length,
  387 and which has rather expensive setup costs (relatively speaking), both in
  388 terms of performance and more importantly in terms of memory. SBOX32
  389 requires 1k of storage per character it can hash, and it must populate that
  390 storage with 256 32-bit random values as well. In practice the RNG we use
  391 for seeding the SBOX32 storage is very efficient and populating the table
  392 required for hashing even fairly long keys is negligible as we only do it
  393 during startup. By default we build with SBOX32 enabled, but you change that
  394 by setting
  398 to zero in configure. By default Perl will use SBOX32 to hash strings 24 bytes
  399 or shorter, you can change this length by setting
  401     SBOX32_MAX_LEN
  403 to the desired length, with the maximum length being 256.
  405 As of Perl 5.18 the order returned by keys(), values(), and each() is
  406 non-deterministic and distinct per hash, and the insert order for
  407 colliding keys is randomized as well, and perl allows for controlling this
  408 by the PERL_PERTURB_KEYS environment setting. You can disable this behavior
  409 entirely with the define
  413 You can disable the environment variable checks and compile time specify
  414 the type of key traversal randomization to be used by defining one of these:
  419 Since Perl 5.18 the seed used for the hash function is randomly selected
  420 at process start, which can be overridden by specifying a seed by setting
  421 the PERL_HASH_SEED environment variable.
  423 You can change this behavior so that your perl is built with a hard coded
  424 seed with the define
  426     NO_HASH_SEED
  428 Note that if you do this you should modify the code in hv_func.h to specify
  429 your own key. In the future this define may be renamed and replaced with one
  430 that requires you to specify the key to use.
  432 B<NOTE WELL: Perl has never guaranteed any ordering of the hash keys>, and the
  433 ordering has already changed several times during the lifetime of Perl
  434 5.  Also, the ordering of hash keys has always been, and continues to
  435 be, affected by the insertion order regardless of whether you build with
  436 or without the randomization features.  Note that because of this
  437 and especially with randomization that the key order of a hash is *undefined*
  438 and that things like Data::Dumper, for example, may produce different output
  439 between different runs of Perl, since Data::Dumper serializes the key in the
  440 native order for the hash.  The use of the Data::Dumper C<Sortkeys> option is
  441 recommended if you are comparing dumps between different invocations of perl.
  443 See L<perlrun/PERL_HASH_SEED> and L<perlrun/PERL_PERTURB_KEYS> for
  444 details on the environment variables, and L<perlsec/Algorithmic
  445 Complexity Attacks> for further security details.
  447 The C<PERL_HASH_SEED> and PERL_PERTURB_KEYS> environment variables can
  448 be disabled by building configuring perl with
  449 C<-Accflags=-DNO_PERL_HASH_ENV>.
  451 The C<PERL_HASH_SEED_DEBUG> environment variable can be disabled by
  452 configuring perl with C<-Accflags=-DNO_PERL_HASH_SEED_DEBUG>.
  454 =head3 SOCKS
  456 Perl can be configured to be 'socksified', that is, to use the SOCKS
  457 TCP/IP proxy protocol library.  SOCKS is used to give applications
  458 access to transport layer network proxies.  Perl supports only SOCKS
  459 Version 5.  The corresponding Configure option is -Dusesocks.
  460 You can find more about SOCKS from wikipedia at
  461 L<http://en.wikipedia.org/wiki/SOCKS>.
  463 =head3 Dynamic Loading
  465 By default, Configure will compile perl to use dynamic loading.
  466 If you want to force perl to be compiled completely
  467 statically, you can either choose this when Configure prompts you or
  468 you can use the Configure command line option -Uusedl.
  469 With this option, you won't be able to use any new extension
  470 (XS) module without recompiling perl itself.
  472 =head3 Building a shared Perl library
  474 Currently, for most systems, the main perl executable is built by
  475 linking the "perl library" libperl.a with perlmain.o, your static
  476 extensions, and various extra libraries, such as -lm.
  478 On systems that support dynamic loading, it may be possible to
  479 replace libperl.a with a shared libperl.so.  If you anticipate building
  480 several different perl binaries (e.g. by embedding libperl into
  481 different programs, or by using the optional compiler extension), then
  482 you might wish to build a shared libperl.so so that all your binaries
  483 can share the same library.
  485 The disadvantages are that there may be a significant performance
  486 penalty associated with the shared libperl.so, and that the overall
  487 mechanism is still rather fragile with respect to different versions
  488 and upgrades.
  490 In terms of performance, on my test system (Solaris 2.5_x86) the perl
  491 test suite took roughly 15% longer to run with the shared libperl.so.
  492 Your system and typical applications may well give quite different
  493 results.
  495 The default name for the shared library is typically something like
  496 libperl.so.5.8.8 (for Perl 5.8.8), or libperl.so.588, or simply
  497 libperl.so.  Configure tries to guess a sensible naming convention
  498 based on your C library name.  Since the library gets installed in a
  499 version-specific architecture-dependent directory, the exact name
  500 isn't very important anyway, as long as your linker is happy.
  502 You can elect to build a shared libperl by
  504 	sh Configure -Duseshrplib
  506 To build a shared libperl, the environment variable controlling shared
  507 library search (LD_LIBRARY_PATH in most systems, DYLD_LIBRARY_PATH for
  509 for HP-UX, LIBPATH for AIX, PATH for Cygwin) must be set up to include
  510 the Perl build directory because that's where the shared libperl will
  511 be created.  Configure arranges makefile to have the correct shared
  512 library search settings.  You can find the name of the environment
  513 variable Perl thinks works in your your system by
  515 	grep ldlibpthname config.sh
  517 However, there are some special cases where manually setting the
  518 shared library path might be required.  For example, if you want to run
  519 something like the following with the newly-built but not-yet-installed
  520 ./perl:
  522         ./perl -I. -MTestInit t/misc/failing_test.t
  524 or
  526         ./perl -Ilib ~/my_mission_critical_test
  528 then you need to set up the shared library path explicitly.
  529 You can do this with
  533 for Bourne-style shells, or
  535    setenv LD_LIBRARY_PATH `pwd`
  537 for Csh-style shells.  (This procedure may also be needed if for some
  538 unexpected reason Configure fails to set up makefile correctly.) (And
  539 again, it may be something other than LD_LIBRARY_PATH for you, see above.)
  541 You can often recognize failures to build/use a shared libperl from error
  542 messages complaining about a missing libperl.so (or libperl.sl in HP-UX),
  543 for example:
  545     18126:./miniperl: /sbin/loader: Fatal Error: cannot map libperl.so
  547 There is also an potential problem with the shared perl library if you
  548 want to have more than one "flavor" of the same version of perl (e.g.
  549 with and without -DDEBUGGING).  For example, suppose you build and
  550 install a standard Perl 5.10.0 with a shared library.  Then, suppose you
  551 try to build Perl 5.10.0 with -DDEBUGGING enabled, but everything else
  552 the same, including all the installation directories.  How can you
  553 ensure that your newly built perl will link with your newly built
  554 libperl.so.8 rather with the installed libperl.so.8?  The answer is
  555 that you might not be able to.  The installation directory is encoded
  556 in the perl binary with the LD_RUN_PATH environment variable (or
  557 equivalent ld command-line option).  On Solaris, you can override that
  558 with LD_LIBRARY_PATH; on Linux, you can only override at runtime via
  559 LD_PRELOAD, specifying the exact filename you wish to be used; and on
  560 Digital Unix, you can override LD_LIBRARY_PATH by setting the
  561 _RLD_ROOT environment variable to point to the perl build directory.
  563 In other words, it is generally not a good idea to try to build a perl
  564 with a shared library if $archlib/CORE/$libperl already exists from a
  565 previous build.
  567 A good workaround is to specify a different directory for the
  568 architecture-dependent library for your -DDEBUGGING version of perl.
  569 You can do this by changing all the *archlib* variables in config.sh to
  570 point to your new architecture-dependent library.
  572 =head3 Environment access
  574 Perl often needs to write to the program's environment, such as when
  575 C<%ENV> is assigned to. Many implementations of the C library function
  576 C<putenv()> leak memory, so where possible perl will manipulate the
  577 environment directly to avoid these leaks. The default is now to perform
  578 direct manipulation whenever perl is running as a stand alone interpreter,
  579 and to call the safe but potentially leaky C<putenv()> function when the
  580 perl interpreter is embedded in another application. You can force perl
  581 to always use C<putenv()> by compiling with
  582 C<-Accflags="-DPERL_USE_SAFE_PUTENV">, see section L</"Altering Configure
  583 variables for C compiler switches etc.">.  You can force an embedded perl
  584 to use direct manipulation by setting C<PL_use_safe_putenv = 0;> after
  585 the C<perl_construct()> call.
  587 =head2 Installation Directories
  589 The installation directories can all be changed by answering the
  590 appropriate questions in Configure.  For convenience, all the installation
  591 questions are near the beginning of Configure.  Do not include trailing
  592 slashes on directory names.  At any point during the Configure process,
  593 you can answer a question with  &-d  and Configure will use the defaults
  594 from then on.  Alternatively, you can
  596 	grep '^install' config.sh
  598 after Configure has run to verify the installation paths.
  600 The defaults are intended to be reasonable and sensible for most
  601 people building from sources.  Those who build and distribute binary
  602 distributions or who export perl to a range of systems will probably
  603 need to alter them.  If you are content to just accept the defaults,
  604 you can safely skip the next section.
  606 The directories set up by Configure fall into three broad categories.
  608 =over 4
  610 =item Directories for the perl distribution
  612 By default, Configure will use the following directories for 5.30.3.
  613 $version is the full perl version number, including subversion, e.g.
  614 5.12.3, and $archname is a string like sun4-sunos,
  615 determined by Configure.  The full definitions of all Configure
  616 variables are in the file Porting/Glossary.
  618     Configure variable	Default value
  619     $prefixexp		/usr/local
  620     $binexp		$prefixexp/bin
  621     $scriptdirexp	$prefixexp/bin
  622     $privlibexp		$prefixexp/lib/perl5/$version
  623     $archlibexp		$prefixexp/lib/perl5/$version/$archname
  624     $man1direxp		$prefixexp/man/man1
  625     $man3direxp		$prefixexp/man/man3
  626     $html1direxp	(none)
  627     $html3direxp	(none)
  629 $prefixexp is generated from $prefix, with ~ expansion done to convert
  630 home directories into absolute paths. Similarly for the other variables
  631 listed. As file system calls do not do this, you should always reference
  632 the ...exp variables, to support users who build perl in their home
  633 directory.
  635 Actually, Configure recognizes the SVR3-style
  636 /usr/local/man/l_man/man1 directories, if present, and uses those
  637 instead.  Also, if $prefix contains the string "perl", the library
  638 directories are simplified as described below.  For simplicity, only
  639 the common style is shown here.
  641 =item Directories for site-specific add-on files
  643 After perl is installed, you may later wish to add modules (e.g. from
  644 CPAN) or scripts.  Configure will set up the following directories to
  645 be used for installing those add-on modules and scripts.
  647    Configure        Default
  648    variable          value
  649  $siteprefixexp    $prefixexp
  650  $sitebinexp       $siteprefixexp/bin
  651  $sitescriptexp    $siteprefixexp/bin
  652  $sitelibexp       $siteprefixexp/lib/perl5/site_perl/$version
  653  $sitearchexp
  654                $siteprefixexp/lib/perl5/site_perl/$version/$archname
  655  $siteman1direxp   $siteprefixexp/man/man1
  656  $siteman3direxp   $siteprefixexp/man/man3
  657  $sitehtml1direxp  (none)
  658  $sitehtml3direxp  (none)
  660 By default, ExtUtils::MakeMaker will install architecture-independent
  661 modules into $sitelib and architecture-dependent modules into $sitearch.
  663 =item Directories for vendor-supplied add-on files
  665 Lastly, if you are building a binary distribution of perl for
  666 distribution, Configure can optionally set up the following directories
  667 for you to use to distribute add-on modules.
  669    Configure          Default
  670    variable            value
  671  $vendorprefixexp    (none)
  673  (The next ones are set only if vendorprefix is set.)
  675  $vendorbinexp       $vendorprefixexp/bin
  676  $vendorscriptexp    $vendorprefixexp/bin
  677  $vendorlibexp       $vendorprefixexp/lib/perl5/vendor_perl/$version
  678  $vendorarchexp
  679            $vendorprefixexp/lib/perl5/vendor_perl/$version/$archname
  680  $vendorman1direxp   $vendorprefixexp/man/man1
  681  $vendorman3direxp   $vendorprefixexp/man/man3
  682  $vendorhtml1direxp  (none)
  683  $vendorhtml3direxp  (none)
  685 These are normally empty, but may be set as needed.  For example,
  686 a vendor might choose the following settings:
  688  $prefix           /usr
  689  $siteprefix       /usr/local
  690  $vendorprefix     /usr
  692 This would have the effect of setting the following:
  694  $binexp           /usr/bin
  695  $scriptdirexp     /usr/bin
  696  $privlibexp       /usr/lib/perl5/$version
  697  $archlibexp       /usr/lib/perl5/$version/$archname
  698  $man1direxp       /usr/man/man1
  699  $man3direxp       /usr/man/man3
  701  $sitebinexp       /usr/local/bin
  702  $sitescriptexp    /usr/local/bin
  703  $sitelibexp       /usr/local/lib/perl5/site_perl/$version
  704  $sitearchexp      /usr/local/lib/perl5/site_perl/$version/$archname
  705  $siteman1direxp   /usr/local/man/man1
  706  $siteman3direxp   /usr/local/man/man3
  708  $vendorbinexp     /usr/bin
  709  $vendorscriptexp  /usr/bin
  710  $vendorlibexp     /usr/lib/perl5/vendor_perl/$version
  711  $vendorarchexp    /usr/lib/perl5/vendor_perl/$version/$archname
  712  $vendorman1direxp /usr/man/man1
  713  $vendorman3direxp /usr/man/man3
  715 Note how in this example, the vendor-supplied directories are in the
  716 /usr hierarchy, while the directories reserved for the end user are in
  717 the /usr/local hierarchy.
  719 The entire installed library hierarchy is installed in locations with
  720 version numbers, keeping the installations of different versions distinct.
  721 However, later installations of Perl can still be configured to search
  722 the installed libraries corresponding to compatible earlier versions.
  723 See L<"Coexistence with earlier versions of perl 5"> below for more
  724 details on how Perl can be made to search older version directories.
  726 Of course you may use these directories however you see fit.  For
  727 example, you may wish to use $siteprefix for site-specific files that
  728 are stored locally on your own disk and use $vendorprefix for
  729 site-specific files that are stored elsewhere on your organization's
  730 network.  One way to do that would be something like
  732  sh Configure -Dsiteprefix=/usr/local -Dvendorprefix=/usr/share/perl
  734 =item otherlibdirs
  736 As a final catch-all, Configure also offers an $otherlibdirs
  737 variable.  This variable contains a colon-separated list of additional
  738 directories to add to @INC.  By default, it will be empty.
  739 Perl will search these directories (including architecture and
  740 version-specific subdirectories) for add-on modules and extensions.
  742 For example, if you have a bundle of perl libraries from a previous
  743 installation, perhaps in a strange place:
  745 	sh Configure -Dotherlibdirs=/usr/lib/perl5/site_perl/5.8.1
  747 =item APPLLIB_EXP
  749 There is one other way of adding paths to @INC at perl build time, and
  750 that is by setting the APPLLIB_EXP C pre-processor token to a colon-
  751 separated list of directories, like this
  753        sh Configure -Accflags='-DAPPLLIB_EXP=\"/usr/libperl\"'
  755 The directories defined by APPLLIB_EXP get added to @INC I<first>,
  756 ahead of any others, and so provide a way to override the standard perl
  757 modules should you, for example, want to distribute fixes without
  758 touching the perl distribution proper.  And, like otherlib dirs,
  759 version and architecture specific subdirectories are also searched, if
  760 present, at run time.  Of course, you can still search other @INC
  761 directories ahead of those in APPLLIB_EXP by using any of the standard
  762 run-time methods: $PERLLIB, $PERL5LIB, -I, use lib, etc.
  764 =item default_inc_excludes_dot
  766 Since version 5.26.0, default perl builds no longer includes C<'.'> as the
  767 last element of @INC. The old behaviour can restored using 
  769 	sh Configure -Udefault_inc_excludes_dot
  771 Note that this is likely to make programs run under such a perl
  772 interpreter less secure.
  774 =item usesitecustomize
  776 Run-time customization of @INC can be enabled with:
  778 	sh Configure -Dusesitecustomize
  780 which will define USE_SITECUSTOMIZE and $Config{usesitecustomize}.
  781 When enabled, this makes perl run F<$sitelibexp/sitecustomize.pl> before
  782 anything else.  This script can then be set up to add additional
  783 entries to @INC.
  785 =item Man Pages
  787 By default, man pages will be installed in $man1dir and $man3dir, which
  788 are normally /usr/local/man/man1 and /usr/local/man/man3.  If you
  789 want to use a .3pm suffix for perl man pages, you can do that with
  791 	sh Configure -Dman3ext=3pm
  793 You can disable installation of man pages completely using
  795 	sh Configure -Dman1dir=none -Dman3dir=none
  797 =item HTML pages
  799 Currently, the standard perl installation does not do anything with
  800 HTML documentation, but that may change in the future.  Further, some
  801 add-on modules may wish to install HTML documents.  The html Configure
  802 variables listed above are provided if you wish to specify where such
  803 documents should be placed.  The default is "none", but will likely
  804 eventually change to something useful based on user feedback.
  806 =back
  808 Some users prefer to append a "/share" to $privlib and $sitelib
  809 to emphasize that those directories can be shared among different
  810 architectures.
  812 Note that these are just the defaults.  You can actually structure the
  813 directories any way you like.  They don't even have to be on the same
  814 filesystem.
  816 Further details about the installation directories, maintenance and
  817 development subversions, and about supporting multiple versions are
  818 discussed in L<"Coexistence with earlier versions of perl 5"> below.
  820 If you specify a prefix that contains the string "perl", then the
  821 library directory structure is slightly simplified.  Instead of
  822 suggesting $prefix/lib/perl5/, Configure will suggest $prefix/lib.
  824 Thus, for example, if you Configure with
  825 -Dprefix=/opt/perl, then the default library directories for 5.9.0 are
  827     Configure variable	Default value
  828 	$privlib	/opt/perl/lib/5.9.0
  829 	$archlib	/opt/perl/lib/5.9.0/$archname
  830 	$sitelib	/opt/perl/lib/site_perl/5.9.0
  831 	$sitearch	/opt/perl/lib/site_perl/5.9.0/$archname
  833 =head2 Changing the installation directory
  835 Configure distinguishes between the directory in which perl (and its
  836 associated files) should be installed, and the directory in which it
  837 will eventually reside.  For most sites, these two are the same; for
  838 sites that use AFS, this distinction is handled automatically.
  839 However, sites that use package management software such as rpm or
  840 dpkg, or users building binary packages for distribution may also
  841 wish to install perl into a different directory before moving perl
  842 to its final destination.  There are two ways to do that:
  844 =over 4
  846 =item installprefix
  848 To install perl under the /tmp/perl5 directory, use the following
  849 command line:
  851     sh Configure -Dinstallprefix=/tmp/perl5
  853 (replace /tmp/perl5 by a directory of your choice).
  855 Beware, though, that if you go to try to install new add-on
  856 modules, they too will get installed in under '/tmp/perl5' if you
  857 follow this example.  That's why it's usually better to use DESTDIR,
  858 as shown in the next section.
  860 =item DESTDIR
  862 If you need to install perl on many identical systems, it is convenient
  863 to compile it once and create an archive that can be installed on
  864 multiple systems.  Suppose, for example, that you want to create an
  865 archive that can be installed in /opt/perl.  One way to do that is by
  866 using the DESTDIR variable during C<make install>.  The DESTDIR is
  867 automatically prepended to all the installation paths.  Thus you
  868 simply do:
  870     sh Configure -Dprefix=/opt/perl -des
  871     make
  872     make test
  873     make install DESTDIR=/tmp/perl5
  874     cd /tmp/perl5/opt/perl
  875     tar cvf /tmp/perl5-archive.tar .
  877 =back
  879 =head2 Relocatable @INC
  881 To create a relocatable perl tree, use the following command line:
  883     sh Configure -Duserelocatableinc
  885 Then the paths in @INC (and everything else in %Config) can be
  886 optionally located via the path of the perl executable.
  888 That means that, if the string ".../" is found at the start of any
  889 path, it's substituted with the directory of $^X. So, the relocation
  890 can be configured on a per-directory basis, although the default with
  891 "-Duserelocatableinc" is that everything is relocated. The initial
  892 install is done to the original configured prefix.
  894 This option is not compatible with the building of a shared libperl
  895 ("-Duseshrplib"), because in that case perl is linked with an hard-coded
  896 rpath that points at the libperl.so, that cannot be relocated.
  898 =head2 Site-wide Policy settings
  900 After Configure runs, it stores a number of common site-wide "policy"
  901 answers (such as installation directories) in the Policy.sh file.
  902 If you want to build perl on another system using the same policy
  903 defaults, simply copy the Policy.sh file to the new system's perl build
  904 directory, and Configure will use it. This will work even if Policy.sh was
  905 generated for another version of Perl, or on a system with a
  906 different architecture and/or operating system. However, in such cases,
  907 you should review the contents of the file before using it: for
  908 example, your new target may not keep its man pages in the same place
  909 as the system on which the file was generated.
  911 Alternatively, if you wish to change some or all of those policy
  912 answers, you should
  914 	rm -f Policy.sh
  916 to ensure that Configure doesn't re-use them.
  918 Further information is in the Policy_sh.SH file itself.
  920 If the generated Policy.sh file is unsuitable, you may freely edit it
  921 to contain any valid shell commands.  It will be run just after the
  922 platform-specific hints files.
  924 =head2 Disabling older versions of Perl
  926 Configure will search for binary compatible versions of previously
  927 installed perl binaries in the tree that is specified as target tree,
  928 and these will be used as locations to search for modules by the perl
  929 being built. The list of perl versions found will be put in the Configure
  930 variable inc_version_list.
  932 To disable this use of older perl modules, even completely valid pure
  933 perl modules, you can specify to not include the paths found:
  935        sh Configure -Dinc_version_list=none ...
  937 If you do want to use modules from some previous perl versions, the
  938 variable must contain a space separated list of directories under the
  939 site_perl directory, and has to include architecture-dependent
  940 directories separately, eg.
  942        sh Configure -Dinc_version_list="5.16.0/x86_64-linux 5.16.0" ...
  944 When using the newer perl, you can add these paths again in the
  945 PERL5LIB environment variable or with perl's -I runtime option.
  947 =head2 Building Perl outside of the source directory
  949 Sometimes it is desirable to build Perl in a directory different from
  950 where the sources are, for example if you want to keep your sources
  951 read-only, or if you want to share the sources between different binary
  952 architectures.  You can do this (if your file system supports symbolic
  953 links) by
  955 	mkdir /tmp/perl/build/directory
  956 	cd /tmp/perl/build/directory
  957 	sh /path/to/perl/source/Configure -Dmksymlinks ...
  959 This will create in /tmp/perl/build/directory a tree of symbolic links
  960 pointing to files in /path/to/perl/source.  The original files are left
  961 unaffected.  After Configure has finished you can just say
  963 	make
  964 	make test
  965 	make install
  967 as usual, and Perl will be built in /tmp/perl/build/directory.
  969 =head2 Building a debugging perl
  971 You can run perl scripts under the perl debugger at any time with
  972 B<perl -d your_script>.  If, however, you want to debug perl itself,
  973 you probably want to have support for perl internal debugging code
  974 (activated by adding -DDEBUGGING to ccflags), and/or support for the
  975 system debugger by adding -g to the optimisation flags.
  977 A perl compiled with the DEBUGGING C preprocessor macro will support the
  978 C<-D> perl command-line switch, have assertions enabled, and have many
  979 extra checks compiled into the code; but will execute much more slowly
  980 (typically 2-3x) and the binary will be much larger (typically 2-3x).
  982 As a convenience, debugging code (-DDEBUGGING) and debugging symbols (-g)
  983 can be enabled jointly or separately using a Configure switch, also
  984 (somewhat confusingly) named -DDEBUGGING.  For a more eye appealing call,
  985 -DEBUGGING is defined to be an alias for -DDEBUGGING. For both, the -U
  986 calls are also supported, in order to be able to overrule the hints or
  987 Policy.sh settings.
  989 Here are the DEBUGGING modes:
  991 =over 4
  993 =item Configure -DDEBUGGING
  995 =item Configure -DEBUGGING
  997 =item Configure -DEBUGGING=both
  999 Sets both -DDEBUGGING in the ccflags, and adds -g to optimize.
 1001 You can actually specify -g and -DDEBUGGING independently (see below),
 1002 but usually it's convenient to have both.
 1004 =item Configure -DEBUGGING=-g
 1006 =item Configure -Doptimize=-g
 1008 Adds -g to optimize, but does not set -DDEBUGGING.
 1010 (Note:  Your system may actually require something like cc -g2.
 1011 Check your man pages for cc(1) and also any hint file for your system.)
 1013 =item Configure -DEBUGGING=none
 1015 =item Configure -UDEBUGGING
 1017 Removes -g from optimize, and -DDEBUGGING from ccflags.
 1019 =back
 1021 If you are using a shared libperl, see the warnings about multiple
 1022 versions of perl under L<Building a shared Perl library>.
 1024 Note that a perl built with -DDEBUGGING will be much bigger and will run
 1025 much, much more slowly than a standard perl.
 1027 =head2 DTrace support
 1029 On platforms where DTrace is available, it may be enabled by
 1030 using the -Dusedtrace option to Configure. DTrace probes are available
 1031 for subroutine entry (sub-entry) and subroutine exit (sub-exit). Here's a
 1032 simple D script that uses them:
 1034   perl$target:::sub-entry, perl$target:::sub-return {
 1035     printf("%s %s (%s:%d)\n", probename == "sub-entry" ? "->" : "<-",
 1036               copyinstr(arg0), copyinstr(arg1), arg2);
 1037   }
 1040 =head2 Extensions
 1042 Perl ships with a number of standard extensions.  These are contained
 1043 in the ext/ subdirectory.
 1045 By default, Configure will offer to build every extension which appears
 1046 to be supported.  For example, Configure will offer to build GDBM_File
 1047 only if it is able to find the gdbm library.
 1049 To disable certain extensions so that they are not built, use the
 1050 -Dnoextensions=... and -Donlyextensions=... options.  They both accept
 1051 a space-separated list of extensions, such as C<IPC/SysV>. The extensions
 1052 listed in
 1053 C<noextensions> are removed from the list of extensions to build, while
 1054 the C<onlyextensions> is rather more severe and builds only the listed
 1055 extensions.  The latter should be used with extreme caution since
 1056 certain extensions are used by many other extensions and modules:
 1057 examples of such modules include Fcntl and IO.  The order of processing
 1058 these options is first C<only> (if present), then C<no> (if present).
 1060 Of course, you may always run Configure interactively and select only
 1061 the extensions you want.
 1063 If you unpack any additional extensions in the ext/ directory before
 1064 running Configure, then Configure will offer to build those additional
 1065 extensions as well.  Most users probably shouldn't have to do this --
 1066 it is usually easier to build additional extensions later after perl
 1067 has been installed.  However, if you wish to have those additional
 1068 extensions statically linked into the perl binary, then this offers a
 1069 convenient way to do that in one step.  (It is not necessary, however;
 1070 you can build and install extensions just fine even if you don't have
 1071 dynamic loading.  See lib/ExtUtils/MakeMaker.pm for more details.)
 1072 Another way of specifying extra modules is described in
 1073 L<"Adding extra modules to the build"> below.
 1075 If you re-use an old config.sh but change your system (e.g. by
 1076 adding libgdbm) Configure will still offer your old choices of extensions
 1077 for the default answer, but it will also point out the discrepancy to
 1078 you.
 1080 =head2 Including locally-installed libraries
 1082 Perl comes with interfaces to number of libraries, including threads,
 1083 dbm, ndbm, gdbm, and Berkeley db.  For the *db* extension, if
 1084 Configure can find the appropriate header files and libraries, it will
 1085 automatically include that extension.  The threading extension needs
 1086 to be specified explicitly (see L</Threads>).
 1088 Those libraries are not distributed with perl. If your header (.h) files
 1089 for those libraries are not in a directory normally searched by your C
 1090 compiler, then you will need to include the appropriate -I/your/directory
 1091 option when prompted by Configure.  If your libraries are not in a
 1092 directory normally searched by your C compiler and linker, then you will
 1093 need to include the appropriate -L/your/directory option when prompted
 1094 by Configure. See the examples below.
 1096 =head3 Examples
 1098 =over 4
 1100 =item gdbm in /usr/local
 1102 Suppose you have gdbm and want Configure to find it and build the
 1103 GDBM_File extension.  This example assumes you have gdbm.h
 1104 installed in /usr/local/include/gdbm.h and libgdbm.a installed in
 1105 /usr/local/lib/libgdbm.a.  Configure should figure all the
 1106 necessary steps out automatically.
 1108 Specifically, when Configure prompts you for flags for
 1109 your C compiler, you should include -I/usr/local/include, if it's
 1110 not here yet. Similarly, when Configure prompts you for linker flags,
 1111 you should include -L/usr/local/lib.
 1113 If you are using dynamic loading, then when Configure prompts you for
 1114 linker flags for dynamic loading, you should again include
 1115 -L/usr/local/lib.
 1117 Again, this should all happen automatically.  This should also work if
 1118 you have gdbm installed in any of (/usr/local, /opt/local, /usr/gnu,
 1119 /opt/gnu, /usr/GNU, or /opt/GNU).
 1121 =item BerkeleyDB in /usr/local/BerkeleyDB
 1123 The version of BerkeleyDB distributed by Oracle installs in a
 1124 version-specific directory by default, typically something like
 1125 /usr/local/BerkeleyDB.4.7.  To have Configure find that, you need to add
 1126 -I/usr/local/BerkeleyDB.4.7/include to cc flags, as in the previous
 1127 example, and you will also have to take extra steps to help Configure
 1128 find -ldb.  Specifically, when Configure prompts you for library
 1129 directories, add /usr/local/BerkeleyDB.4.7/lib to the list.  Also, you
 1130 will need to add appropriate linker flags to tell the runtime linker
 1131 where to find the BerkeleyDB shared libraries.
 1133 It is possible to specify this from the command line (all on one
 1134 line):
 1136  sh Configure -de \
 1137     -Dlocincpth='/usr/local/BerkeleyDB.4.7/include             \
 1138                                            /usr/local/include' \
 1139     -Dloclibpth='/usr/local/BerkeleyDB.4.7/lib /usr/local/lib' \
 1140     -Aldflags='-R/usr/local/BerkeleyDB.4.7/lib'
 1142 locincpth is a space-separated list of include directories to search.
 1143 Configure will automatically add the appropriate -I directives.
 1145 loclibpth is a space-separated list of library directories to search.
 1146 Configure will automatically add the appropriate -L directives.
 1148 The addition to ldflags is so that the dynamic linker knows where to find
 1149 the BerkeleyDB libraries.  For Linux and Solaris, the -R option does that.
 1150 Other systems may use different flags.  Use the appropriate flag for your
 1151 system.
 1153 =back
 1155 =head2 Specifying a logical root directory
 1157 If you are cross-compiling, or are using a compiler which has it's own
 1158 headers and libraries in a nonstandard location, and your compiler
 1159 understands the C<--sysroot> option, you can use the C<-Dsysroot> option
 1160 to specify the logical root directory under which all libraries and
 1161 headers are searched for. This patch adjusts Configure to search under
 1162 $sysroot, instead of /.
 1164 --sysroot is added to ccflags and friends so that make in
 1165 ExtUtils::MakeMaker, and other extensions, will use it.
 1167 =head2 Overriding an old config.sh
 1169 If you want to use an old config.sh produced by a previous run of
 1170 Configure, but override some of the items with command line options, you
 1171 need to use B<Configure -O>.
 1173 =head2 GNU-style configure
 1175 If you prefer the GNU-style configure command line interface, you can
 1176 use the supplied configure.gnu command, e.g.
 1178 	CC=gcc ./configure.gnu
 1180 The configure.gnu script emulates a few of the more common configure
 1181 options.  Try
 1183 	./configure.gnu --help
 1185 for a listing.
 1187 (The file is called configure.gnu to avoid problems on systems
 1188 that would not distinguish the files "Configure" and "configure".)
 1190 =head2 Malloc Issues
 1192 Perl relies heavily on malloc(3) to grow data structures as needed,
 1193 so perl's performance can be noticeably affected by the performance of
 1194 the malloc function on your system.  The perl source is shipped with a
 1195 version of malloc that has been optimized for the typical requests from
 1196 perl, so there's a chance that it may be both faster and use less memory
 1197 than your system malloc.
 1199 However, if your system already has an excellent malloc, or if you are
 1200 experiencing difficulties with extensions that use third-party libraries
 1201 that call malloc, then you should probably use your system's malloc.
 1202 (Or, you might wish to explore the malloc flags discussed below.)
 1204 =over 4
 1206 =item Using the system malloc
 1208 To build without perl's malloc, you can use the Configure command
 1210 	sh Configure -Uusemymalloc
 1212 or you can answer 'n' at the appropriate interactive Configure prompt.
 1214 Note that Perl's malloc isn't always used by default; that actually
 1215 depends on your system. For example, on Linux and FreeBSD (and many more
 1216 systems), Configure chooses to use the system's malloc by default.
 1217 See the appropriate file in the F<hints/> directory to see how the
 1218 default is set.
 1222 NOTE: This flag is enabled automatically on some platforms if you just
 1223 run Configure to accept all the defaults.
 1225 Perl's malloc family of functions are normally called Perl_malloc(),
 1226 Perl_realloc(), Perl_calloc() and Perl_mfree().
 1227 These names do not clash with the system versions of these functions.
 1229 If this flag is enabled, however, Perl's malloc family of functions
 1230 will have the same names as the system versions.  This may be required
 1231 sometimes if you have libraries that like to free() data that may have
 1232 been allocated by Perl_malloc() and vice versa.
 1234 Note that enabling this option may sometimes lead to duplicate symbols
 1235 from the linker for malloc et al.  In such cases, the system probably
 1236 does not allow its malloc functions to be fully replaced with custom
 1237 versions.
 1241 This flag enables debugging mstats, which is required to use the
 1242 Devel::Peek::mstat() function. You cannot enable this unless you are
 1243 using Perl's malloc, so a typical Configure command would be
 1245        sh Configure -Accflags=-DPERL_DEBUGGING_MSTATS -Dusemymalloc
 1247 to enable this option.
 1249 =back
 1251 =head2 What if it doesn't work?
 1253 If you run into problems, try some of the following ideas.
 1254 If none of them help, then see L<"Reporting Problems"> below.
 1256 =over 4
 1258 =item Running Configure Interactively
 1260 If Configure runs into trouble, remember that you can always run
 1261 Configure interactively so that you can check (and correct) its
 1262 guesses.
 1264 All the installation questions have been moved to the top, so you don't
 1265 have to wait for them.  Once you've handled them (and your C compiler and
 1266 flags) you can type  &-d  at the next Configure prompt and Configure
 1267 will use the defaults from then on.
 1269 If you find yourself trying obscure command line incantations and
 1270 config.over tricks, I recommend you run Configure interactively
 1271 instead.  You'll probably save yourself time in the long run.
 1273 =item Hint files
 1275 Hint files tell Configure about a number of things:
 1277 =over 4
 1279 =item o
 1281 The peculiarities or conventions of particular platforms -- non-standard
 1282 library locations and names, default installation locations for binaries,
 1283 and so on.
 1285 =item o
 1287 The deficiencies of the platform -- for example, library functions that,
 1288 although present, are too badly broken to be usable; or limits on
 1289 resources that are generously available on most platforms.
 1291 =item o
 1293 How best to optimize for the platform, both in terms of binary size
 1294 and/or speed, and for Perl feature support. Because of wide variations in
 1295 the implementation of shared libraries and of threading, for example,
 1296 Configure often needs hints in order to be able to use these features.
 1298 =back
 1300 The perl distribution includes many system-specific hints files
 1301 in the hints/ directory. If one of them matches your system, Configure
 1302 will offer to use that hint file. Unless you have a very good reason
 1303 not to, you should accept its offer.
 1305 Several of the hint files contain additional important information.
 1306 If you have any problems, it is a good idea to read the relevant hint
 1307 file for further information.  See hints/solaris_2.sh for an extensive
 1308 example.  More information about writing good hints is in the
 1309 hints/README.hints file, which also explains hint files known as
 1310 callback-units.
 1312 Note that any hint file is read before any Policy file, meaning that
 1313 Policy overrides hints -- see L</Site-wide Policy settings>.
 1315 =item WHOA THERE!!!
 1317 If you are re-using an old config.sh, it's possible that Configure
 1318 detects different values from the ones specified in this file.  You will
 1319 almost always want to keep the previous value, unless you have changed
 1320 something on your system.
 1322 For example, suppose you have added libgdbm.a to your system
 1323 and you decide to reconfigure perl to use GDBM_File.  When you run
 1324 Configure again, you will need to add -lgdbm to the list of libraries.
 1325 Now, Configure will find your gdbm include file and library and will
 1326 issue a message:
 1328     *** WHOA THERE!!! ***
 1329 	The previous value for $i_gdbm on this machine was "undef"!
 1330 	Keep the previous value? [y]
 1332 In this case, you do not want to keep the previous value, so you
 1333 should answer 'n'.  (You'll also have to manually add GDBM_File to
 1334 the list of dynamic extensions to build.)
 1336 =item Changing Compilers
 1338 If you change compilers or make other significant changes, you should
 1339 probably not re-use your old config.sh.  Simply remove it or
 1340 rename it, then rerun Configure with the options you want to use.
 1342 =item Propagating your changes to config.sh
 1344 If you make any changes to config.sh, you should propagate
 1345 them to all the .SH files by running
 1347 	sh Configure -S
 1349 You will then have to rebuild by running
 1351 	make depend
 1352 	make
 1354 =item config.over and config.arch
 1356 You can also supply a shell script config.over to override
 1357 Configure's guesses.  It will get loaded up at the very end, just
 1358 before config.sh is created.  You have to be careful with this,
 1359 however, as Configure does no checking that your changes make sense.
 1360 This file is usually good for site-specific customizations.
 1362 There is also another file that, if it exists, is loaded before the
 1363 config.over, called config.arch.  This file is intended to be per
 1364 architecture, not per site, and usually it's the architecture-specific
 1365 hints file that creates the config.arch.
 1367 =item config.h
 1369 Many of the system dependencies are contained in config.h.
 1370 Configure builds config.h by running the config_h.SH script.
 1371 The values for the variables are taken from config.sh.
 1373 If there are any problems, you can edit config.h directly.  Beware,
 1374 though, that the next time you run Configure, your changes will be
 1375 lost.
 1377 =item cflags
 1379 If you have any additional changes to make to the C compiler command
 1380 line, they can be made in cflags.SH.  For instance, to turn off the
 1381 optimizer on toke.c, find the switch structure marked 'or customize here',
 1382 and add a line for toke.c ahead of the catch-all *) so that it now reads:
 1384     : or customize here
 1386     case "$file" in
 1387     toke) optimize='-g' ;;
 1388     *) ;;
 1390 You should not edit the generated file cflags directly, as your changes
 1391 will be lost the next time you run Configure, or if you edit config.sh.
 1393 To explore various ways of changing ccflags from within a hint file,
 1394 see the file hints/README.hints.
 1396 To change the C flags for all the files, edit config.sh and change either
 1397 $ccflags or $optimize, and then re-run
 1399 	sh Configure -S
 1400 	make depend
 1402 =item No sh
 1404 If you don't have sh, you'll have to copy the sample file
 1405 Porting/config.sh to config.sh and edit your config.sh to reflect your
 1406 system's peculiarities.  See Porting/pumpkin.pod for more information.
 1407 You'll probably also have to extensively modify the extension building
 1408 mechanism.
 1410 =item Porting information
 1412 Specific information for the OS/2, Plan 9, VMS and Win32 ports is in the
 1413 corresponding README files and subdirectories.  Additional information,
 1414 including a glossary of all those config.sh variables, is in the Porting
 1415 subdirectory.  Porting/Glossary should especially come in handy.
 1417 Ports for other systems may also be available.  You should check out
 1418 http://www.cpan.org/ports for current information on ports to
 1419 various other operating systems.
 1421 If you plan to port Perl to a new architecture, study carefully the
 1422 section titled "Philosophical Issues in Patching and Porting Perl"
 1423 in the file Porting/pumpkin.pod and the file pod/perlgit.pod.
 1424 Study also how other non-UNIX ports have solved problems.
 1426 =back
 1428 =head2 Adding extra modules to the build
 1430 You can specify extra modules or module bundles to be fetched from the
 1431 CPAN and installed as part of the Perl build.  Either use the -Dextras=...
 1432 command line parameter to Configure, for example like this:
 1434 	Configure -Dextras="Bundle::LWP DBI"
 1436 or answer first 'y' to the question 'Install any extra modules?' and
 1437 then answer "Bundle::LWP DBI" to the 'Extras?' question.
 1438 The module or the bundle names are as for the CPAN module 'install'
 1439 command.  This will only work if those modules are to be built as dynamic
 1440 extensions.  If you wish to include those extra modules as static
 1441 extensions, see L<"Extensions"> above.
 1443 Notice that because the CPAN module will be used to fetch the extra
 1444 modules, you will need access to the CPAN, either via the Internet,
 1445 or via a local copy such as a CD-ROM or a local CPAN mirror.  If you
 1446 do not, using the extra modules option will die horribly.
 1448 Also notice that you yourself are responsible for satisfying any extra
 1449 dependencies such as external headers or libraries BEFORE trying the
 1450 build.  For example: you will need to have the Foo database specific
 1451 headers and libraries installed for the DBD::Foo module.  The Configure
 1452 process or the Perl build process will not help you with these.
 1454 =head2 suidperl
 1456 suidperl was an optional component of earlier releases of perl. It is no
 1457 longer available.  Instead, use a tool specifically designed to handle
 1458 changes in privileges, such as B<sudo>.
 1460 =head1 make depend
 1462 This will look for all the includes.  The output is stored in makefile.
 1463 The only difference between Makefile and makefile is the dependencies at
 1464 the bottom of makefile.  If you have to make any changes, you should edit
 1465 makefile, not Makefile, since the Unix make command reads makefile first.
 1466 (On non-Unix systems, the output may be stored in a different file.
 1467 Check the value of $firstmakefile in your config.sh if in doubt.)
 1469 Configure will offer to do this step for you, so it isn't listed
 1470 explicitly above.
 1472 =head1 make
 1474 This will attempt to make perl in the current directory.
 1476 =head2 Expected errors
 1478 These error reports are normal, and can be ignored:
 1480   ...
 1481   make: [extra.pods] Error 1 (ignored)
 1482   ...
 1483   make: [extras.make] Error 1 (ignored)
 1485 =head2 What if it doesn't work?
 1487 If you can't compile successfully, try some of the following ideas.
 1488 If none of them help, and careful reading of the error message and
 1489 the relevant manual pages on your system doesn't help,
 1490 then see L<"Reporting Problems"> below.
 1492 =over 4
 1494 =item hints
 1496 If you used a hint file, try reading the comments in the hint file
 1497 for further tips and information.
 1499 =item extensions
 1501 If you can successfully build miniperl, but the process crashes
 1502 during the building of extensions, run
 1504 	make minitest
 1506 to test your version of miniperl.
 1508 =item locale
 1510 If you have any locale-related environment variables set, try unsetting
 1511 them.  I have some reports that some versions of IRIX hang while
 1512 running B<./miniperl configpm> with locales other than the C locale.
 1513 See the discussion under L<"make test"> below about locales and the
 1514 whole L<perllocale/"LOCALE PROBLEMS"> section in the file
 1515 pod/perllocale.pod.  The latter is especially useful if you see something
 1516 like this
 1518 	perl: warning: Setting locale failed.
 1519 	perl: warning: Please check that your locale settings:
 1520 	        LC_ALL = "En_US",
 1521 	        LANG = (unset)
 1522 	    are supported and installed on your system.
 1523 	perl: warning: Falling back to the standard locale ("C").
 1525 at Perl startup.
 1527 =item other environment variables
 1529 Configure does not check for environment variables that can sometimes
 1530 have a major influence on how perl is built or tested. For example,
 1531 OBJECT_MODE on AIX determines the way the compiler and linker deal with
 1532 their objects, but this is a variable that only influences build-time
 1533 behaviour, and should not affect the perl scripts that are eventually
 1534 executed by the perl binary. Other variables, like PERL_UNICODE,
 1535 PERL5LIB, and PERL5OPT will influence the behaviour of the test suite.
 1536 So if you are getting strange test failures, you may want to try
 1537 retesting with the various PERL variables unset.
 1539 =item LD_LIBRARY_PATH
 1541 If you run into dynamic loading problems, check your setting of
 1542 the LD_LIBRARY_PATH environment variable.  If you're creating a static
 1543 Perl library (libperl.a rather than libperl.so) it should build
 1544 fine with LD_LIBRARY_PATH unset, though that may depend on details
 1545 of your local setup.
 1547 =item nm extraction
 1549 If Configure seems to be having trouble finding library functions,
 1550 try not using nm extraction.  You can do this from the command line
 1551 with
 1553 	sh Configure -Uusenm
 1555 or by answering the nm extraction question interactively.
 1556 If you have previously run Configure, you should not reuse your old
 1557 config.sh.
 1559 =item umask not found
 1561 If the build processes encounters errors relating to umask(), the problem
 1562 is probably that Configure couldn't find your umask() system call.
 1563 Check your config.sh.  You should have d_umask='define'.  If you don't,
 1564 this is probably the L<"nm extraction"> problem discussed above.  Also,
 1565 try reading the hints file for your system for further information.
 1567 =item do_aspawn
 1569 If you run into problems relating to do_aspawn or do_spawn, the
 1570 problem is probably that Configure failed to detect your system's
 1571 fork() function.  Follow the procedure in the previous item
 1572 on L<"nm extraction">.
 1574 =item __inet_* errors
 1576 If you receive unresolved symbol errors during Perl build and/or test
 1577 referring to __inet_* symbols, check to see whether BIND 8.1 is
 1578 installed.  It installs a /usr/local/include/arpa/inet.h that refers to
 1579 these symbols.  Versions of BIND later than 8.1 do not install inet.h
 1580 in that location and avoid the errors.  You should probably update to a
 1581 newer version of BIND (and remove the files the old one left behind).
 1582 If you can't, you can either link with the updated resolver library
 1583 provided with BIND 8.1 or rename /usr/local/bin/arpa/inet.h during the
 1584 Perl build and test process to avoid the problem.
 1586 =item .*_r() prototype NOT found
 1588 On a related note, if you see a bunch of complaints like the above about
 1589 reentrant functions -- specifically networking-related ones -- being
 1590 present but without prototypes available, check to see if BIND 8.1 (or
 1591 possibly other BIND 8 versions) is (or has been) installed. They install
 1592 header files such as netdb.h into places such as /usr/local/include (or
 1593 into another directory as specified at build/install time), at least
 1594 optionally.  Remove them or put them in someplace that isn't in the C
 1595 preprocessor's header file include search path (determined by -I options
 1596 plus defaults, normally /usr/include).
 1598 =item #error "No DATAMODEL_NATIVE specified"
 1600 This is a common error when trying to build perl on Solaris 2.6 with a
 1601 gcc installation from Solaris 2.5 or 2.5.1.  The Solaris header files
 1602 changed, so you need to update your gcc installation.  You can either
 1603 rerun the fixincludes script from gcc or take the opportunity to
 1604 update your gcc installation.
 1606 =item Optimizer
 1608 If you can't compile successfully, try turning off your compiler's
 1609 optimizer.  Edit config.sh and change the line
 1611 	optimize='-O'
 1613 to
 1615 	optimize=' '
 1617 then propagate your changes with B<sh Configure -S> and rebuild
 1618 with B<make depend; make>.
 1620 =item Missing functions and Undefined symbols
 1622 If the build of miniperl fails with a long list of missing functions or
 1623 undefined symbols, check the libs variable in the config.sh file.  It
 1624 should look something like
 1626 	libs='-lsocket -lnsl -ldl -lm -lc'
 1628 The exact libraries will vary from system to system, but you typically
 1629 need to include at least the math library -lm.  Normally, Configure
 1630 will suggest the correct defaults.  If the libs variable is empty, you
 1631 need to start all over again.  Run
 1633 	make distclean
 1635 and start from the very beginning.  This time, unless you are sure of
 1636 what you are doing, accept the default list of libraries suggested by
 1637 Configure.
 1639 If the libs variable is missing -lm, there is a chance that libm.so.1
 1640 is available, but the required (symbolic) link to libm.so is missing.
 1641 (same could be the case for other libraries like libcrypt.so).  You
 1642 should check your installation for packages that create that link, and
 1643 if no package is installed that supplies that link or you cannot install
 1644 them, make the symbolic link yourself e.g.:
 1646  $ rpm -qf /usr/lib64/libm.so
 1647  glibc-devel-2.15-22.17.1.x86_64
 1648  $ ls -lgo /usr/lib64/libm.so
 1649  lrwxrwxrwx 1 16 Jan  7  2013 /usr/lib64/libm.so -> /lib64/libm.so.6
 1651  or
 1653  $ sudo ln -s /lib64/libm.so.6 /lib64/libm.so
 1655 If the libs variable looks correct, you might have the
 1656 L<"nm extraction"> problem discussed above.
 1658 If you still have missing routines or undefined symbols, you probably
 1659 need to add some library or other, make a symbolic link like described
 1660 above, or you need to undefine some feature that Configure thought was
 1661 there but is defective or incomplete.  If you used a hint file, see if
 1662 it has any relevant advice.  You can also look through through config.h
 1663 for likely suspects.
 1665 =item toke.c
 1667 Some compilers will not compile or optimize the larger files (such as
 1668 toke.c) without some extra switches to use larger jump offsets or
 1669 allocate larger internal tables.  You can customize the switches for
 1670 each file in cflags.SH.  It's okay to insert rules for specific files
 1671 into makefile since a default rule only takes effect in the absence of a
 1672 specific rule.
 1674 =item Missing dbmclose
 1676 SCO prior to 3.2.4 may be missing dbmclose().  An upgrade to 3.2.4
 1677 that includes libdbm.nfs (which includes dbmclose()) may be available.
 1679 =item error: too few arguments to function 'dbmclose'
 1681 Building ODBM_File on some (Open)SUSE distributions might run into this
 1682 error, as the header file is broken. There are two ways to deal with this
 1684  1. Disable the use of ODBM_FILE
 1686     sh Configure ... -Dnoextensions=ODBM_File
 1688  2. Fix the header file, somewhat like this:
 1690     --- a/usr/include/dbm.h  2010-03-24 08:54:59.000000000 +0100
 1691     +++ b/usr/include/dbm.h  2010-03-24 08:55:15.000000000 +0100
 1692     @@ -59,4 +59,4 @@ extern datum  firstkey __P((void));
 1694      extern datum   nextkey __P((datum key));
 1696     -extern int     dbmclose __P((DBM *));
 1697     +extern int     dbmclose __P((void));
 1699 =item Warning (mostly harmless): No library found for -lsomething
 1701 If you see such a message during the building of an extension, but
 1702 the extension passes its tests anyway (see L<"make test"> below),
 1703 then don't worry about the warning message.  The extension
 1704 Makefile.PL goes looking for various libraries needed on various
 1705 systems; few systems will need all the possible libraries listed.
 1706 Most users will see warnings for the ones they don't have.  The
 1707 phrase 'mostly harmless' is intended to reassure you that nothing
 1708 unusual is happening, and the build process is continuing.
 1710 On the other hand, if you are building GDBM_File and you get the
 1711 message
 1713     Warning (mostly harmless): No library found for -lgdbm
 1715 then it's likely you're going to run into trouble somewhere along
 1716 the line, since it's hard to see how you can use the GDBM_File
 1717 extension without the -lgdbm library.
 1719 It is true that, in principle, Configure could have figured all of
 1720 this out, but Configure and the extension building process are not
 1721 quite that tightly coordinated.
 1723 =item sh: ar: not found
 1725 This is a message from your shell telling you that the command 'ar'
 1726 was not found.  You need to check your PATH environment variable to
 1727 make sure that it includes the directory with the 'ar' command.  This
 1728 is a common problem on Solaris, where 'ar' is in the /usr/ccs/bin
 1729 directory.
 1731 =item db-recno failure on tests 51, 53 and 55
 1733 Old versions of the DB library (including the DB library which comes
 1734 with FreeBSD 2.1) had broken handling of recno databases with modified
 1735 bval settings.  Upgrade your DB library or OS.
 1737 =item Bad arg length for semctl, is XX, should be ZZZ
 1739 If you get this error message from the F<cpan/IPC-SysV/t/sem.t> test, your
 1740 System V IPC may be broken.  The XX typically is 20, and that is what ZZZ
 1741 also should be.  Consider upgrading your OS, or reconfiguring your OS
 1742 to include the System V semaphores.
 1744 =item cpan/IPC-SysV/t/sem........semget: No space left on device
 1746 Either your account or the whole system has run out of semaphores.  Or
 1747 both.  Either list the semaphores with "ipcs" and remove the unneeded
 1748 ones (which ones these are depends on your system and applications)
 1749 with "ipcrm -s SEMAPHORE_ID_HERE" or configure more semaphores to your
 1750 system.
 1752 =item GNU binutils
 1754 If you mix GNU binutils (nm, ld, ar) with equivalent vendor-supplied
 1755 tools you may be in for some trouble.  For example creating archives
 1756 with an old GNU 'ar' and then using a new current vendor-supplied 'ld'
 1757 may lead into linking problems.  Either recompile your GNU binutils
 1758 under your current operating system release, or modify your PATH not
 1759 to include the GNU utils before running Configure, or specify the
 1760 vendor-supplied utilities explicitly to Configure, for example by
 1761 Configure -Dar=/bin/ar.
 1765 The F<Configure> program has not been able to find all the files which
 1766 make up the complete Perl distribution.  You may have a damaged source
 1767 archive file (in which case you may also have seen messages such as
 1768 C<gzip: stdin: unexpected end of file> and C<tar: Unexpected EOF on
 1769 archive file>), or you may have obtained a structurally-sound but
 1770 incomplete archive.  In either case, try downloading again from the
 1771 official site named at the start of this document.  If you do find
 1772 that any site is carrying a corrupted or incomplete source code
 1773 archive, please report it to the site's maintainer.
 1775 =item invalid token: ##
 1777 You are using a non-ANSI-compliant C compiler.  To compile Perl, you
 1778 need to use a compiler that supports ANSI C.  If there is a README
 1779 file for your system, it may have further details on your compiler
 1780 options.
 1782 =item Miscellaneous
 1784 Some additional things that have been reported:
 1786 Genix may need to use libc rather than libc_s, or #undef VARARGS.
 1788 NCR Tower 32 (OS 2.01.01) may need -W2,-Sl,2000 and #undef MKDIR.
 1790 UTS may need one or more of -K or -g, and #undef LSTAT.
 1792 FreeBSD can fail the F<cpan/IPC-SysV/t/sem.t> test if SysV IPC has not been
 1793 configured in the kernel.  Perl tries to detect this, though, and
 1794 you will get a message telling you what to do.
 1796 Building Perl on a system that has also BIND (headers and libraries)
 1797 installed may run into troubles because BIND installs its own netdb.h
 1798 and socket.h, which may not agree with the operating system's ideas of
 1799 the same files.  Similarly, including -lbind may conflict with libc's
 1800 view of the world.  You may have to tweak -Dlocincpth and -Dloclibpth
 1801 to avoid the BIND.
 1803 =back
 1805 =head2 Cross-compilation
 1807 Perl can be cross-compiled.  It is just not trivial, cross-compilation
 1808 rarely is.  Perl is routinely cross-compiled for several platforms: as of
 1809 January 2014, these include Android, Blackberry 10, PocketPC aka
 1810 WinCE, ARM Linux, and Solaris.  Previous versions of
 1811 Perl also provided support for Open Zaurus, Symbian, and
 1812 the IBM OS/400, but it's unknown if those ports are still functional.
 1813 These platforms are known as the B<target> platforms, while the systems
 1814 where the compilation takes place are the B<host> platforms.
 1816 What makes the situation difficult is that first of all,
 1817 cross-compilation environments vary significantly in how they are set
 1818 up and used, and secondly because the primary way of configuring Perl
 1819 (using the rather large Unix-tool-dependent Configure script) is not
 1820 awfully well suited for cross-compilation.  However, starting from
 1821 version 5.18.0, the Configure script also knows two ways of supporting
 1822 cross-compilation, so please keep reading.
 1824 See the following files for more information about compiling Perl for
 1825 the particular platforms:
 1827 =over 4
 1829 =item WinCE/PocketPC
 1831 L<README.ce or perlce|perlce>
 1833 =item Android
 1835 L<"Cross-compilation" in README.android or
 1836 perlandroid|perlandroid/Cross-compilation>
 1838 =item Blackberry
 1840 L<"Cross-compilation" in README.qnx or perlqnx|perlqnx/Cross-compilation>
 1842 =item Solaris
 1844 L<"CROSS-COMPILATION" in README.solaris or
 1845 perlsolaris|perlsolaris/CROSS-COMPILATION>
 1847 =item Linux
 1849 This document; See below.
 1851 =back
 1853 Packaging and transferring either the core Perl modules or CPAN
 1854 modules to the target platform is also left up to the each
 1855 cross-compilation environment.  Often the cross-compilation target
 1856 platforms are somewhat limited in diskspace: see the section
 1857 L<Minimizing the Perl installation> to learn more of the minimal set
 1858 of files required for a functional Perl installation.
 1860 For some cross-compilation environments the Configure option
 1861 C<-Dinstallprefix=...> might be handy, see L<Changing the installation
 1862 directory>.
 1864 About the cross-compilation support of Configure: There's two forms.
 1865 The more common one requires some way of transferring and running
 1866 executables in the target system, such as an ssh connection; this is the
 1867 C<./Configure -Dusecrosscompile -Dtargethost=...> route.  The second
 1868 method doesn't need access to the target system, but requires you to
 1869 provide a config.sh, and and a canned Makefile; the rest of this section
 1870 describes the former.
 1872 This cross-compilation setup of Configure has successfully been used in
 1873 a wide variety of setups, such as a 64-bit OS X host for an Android ARM
 1874 target, or an amd64 Linux host targeting x86 Solaris, or even Windows.
 1876 To run Configure in cross-compilation mode the basic switch that
 1877 has to be used is C<-Dusecrosscompile>:
 1879    sh ./Configure -des -Dusecrosscompile -D...
 1881 This will make the cpp symbol USE_CROSS_COMPILE and the %Config
 1882 symbol C<usecrosscompile> available.
 1884 During the Configure and build, certain helper scripts will be created
 1885 into the Cross/ subdirectory.  The scripts are used to execute a
 1886 cross-compiled executable, and to transfer files to and from the
 1887 target host.  The execution scripts are named F<run-*> and the
 1888 transfer scripts F<to-*> and F<from-*>.  The part after the dash is
 1889 the method to use for remote execution and transfer: by default the
 1890 methods are B<ssh> and B<scp>, thus making the scripts F<run-ssh>,
 1891 F<to-scp>, and F<from-scp>.
 1893 To configure the scripts for a target host and a directory (in which
 1894 the execution will happen and which is to and from where the transfer
 1895 happens), supply Configure with
 1897     -Dtargethost=so.me.ho.st -Dtargetdir=/tar/get/dir
 1899 The targethost is what e.g. ssh will use as the hostname, the targetdir
 1900 must exist (the scripts won't create it), the targetdir defaults to /tmp.
 1901 You can also specify a username to use for ssh/rsh logins
 1903     -Dtargetuser=luser
 1905 but in case you don't, "root" will be used.  Similarly, you can specify
 1906 a non-standard (i.e. not 22) port for the connection, if applicable,
 1907 through
 1909     -Dtargetport=2222
 1911 If the name of C<cc> has the usual GNU C semantics for cross
 1912 compilers, that is, CPU-OS-gcc, the target architecture (C<targetarch>),
 1913 plus names of the C<ar>, C<nm>, and C<ranlib> will also be automatically
 1914 chosen to be CPU-OS-ar and so on.
 1915 (The C<ld> requires more thought and will be chosen later by Configure
 1916 as appropriate).  This will also aid in guessing the proper
 1917 operating system name for the target, which has other repercussions, like
 1918 better defaults and possibly critical fixes for the platform.  If
 1919 Configure isn't guessing the OS name properly, you may need to either add
 1920 a hint file redirecting Configure's guess, or modify Configure to make
 1921 the correct choice.
 1923 If your compiler doesn't follow that convention, you will also need to
 1924 specify which target environment to use, as well as C<ar> and friends:
 1926     -Dtargetarch=arm-linux
 1927     -Dcc=mycrossgcc
 1928     -Dar=...
 1930 Additionally, a cross-compilation toolchain will usually install it's own
 1931 logical system root somewhere -- that is, it'll create a directory
 1932 somewhere which includes subdirectories like C<'include'> or C<'lib'>.  For
 1933 example, you may end up with F</skiff/local/arm-linux>, where
 1934 F</skiff/local/arm-linux/bin> holds the binaries for cross-compilation,
 1935 F</skiff/local/arm-linux/include> has the headers, and
 1936 F</skiff/local/arm-linux/lib> has the library files.
 1937 If this is the case, and you are using a compiler that understands
 1938 C<--sysroot>, like gcc or clang, you'll want to specify the
 1939 C<-Dsysroot> option for Configure:
 1941     -Dsysroot=/skiff/local/arm-linux
 1943 However, if your don't have a suitable directory to pass to C<-Dsysroot>,
 1944 you will also need to specify which target environment to use:
 1946     -Dusrinc=/skiff/local/arm-linux/include
 1947     -Dincpth=/skiff/local/arm-linux/include
 1948     -Dlibpth=/skiff/local/arm-linux/lib
 1950 In addition to the default execution/transfer methods you can also
 1951 choose B<rsh> for execution, and B<rcp> or B<cp> for transfer,
 1952 for example:
 1954     -Dtargetrun=rsh -Dtargetto=rcp -Dtargetfrom=cp
 1956 Putting it all together:
 1958     sh ./Configure -des -Dusecrosscompile \
 1959         -Dtargethost=so.me.ho.st \
 1960         -Dtargetdir=/tar/get/dir \
 1961         -Dtargetuser=root \
 1962         -Dtargetarch=arm-linux \
 1963         -Dcc=arm-linux-gcc \
 1964         -Dsysroot=/skiff/local/arm-linux \
 1965         -D...
 1967 or if you are happy with the defaults:
 1969     sh ./Configure -des -Dusecrosscompile \
 1970         -Dtargethost=so.me.ho.st \
 1971         -Dcc=arm-linux-gcc \
 1972         -D...
 1974 Another example where the cross-compiler has been installed under
 1975 F</usr/local/arm/2.95.5>:
 1977     sh ./Configure -des -Dusecrosscompile \
 1978         -Dtargethost=so.me.ho.st \
 1979         -Dcc=/usr/local/arm/2.95.5/bin/arm-linux-gcc \
 1980         -Dsysroot=/usr/local/arm/2.95.5
 1982 There is also a C<targetenv> option for Configure which can be used
 1983 to modify the environment of the target just before testing begins
 1984 during 'make test'.  For example, if the target system has a nonstandard
 1985 /tmp location, you could do this:
 1987     -Dtargetenv="export TMPDIR=/other/tmp;"
 1989 If you are planning on cross-compiling to several platforms, or some
 1990 other thing that would involve running Configure several times, there are
 1991 two options that can be used to speed things up considerably.
 1992 As a bit of background, when you
 1993 call Configure with C<-Dusecrosscompile>, it begins by actually partially
 1994 building a miniperl on the host machine, as well as the generate_uudmap
 1995 binary, and we end up using that during the build.
 1996 So instead of building that new perl every single time, you can build it
 1997 just once in a separate directory, and then pass the resulting binaries
 1998 to Configure like this:
 2000     -Dhostperl=/path/to/second/build/dir/miniperl
 2001     -Dhostgenerate=/path/to/second/build/dir/generate_uudmap
 2003 Much less commonly, if you are cross-compiling from an ASCII host to an
 2004 EBCDIC target, or vise versa, you'll have to pass C<-Uhostgenerate> to
 2005 Configure, to signify that you want to build a generate_uudmap binary
 2006 that, during make, will be run on the target system.
 2008 =head1 make test
 2010 This will run the regression tests on the perl you just made.  If
 2011 'make test' doesn't say "All tests successful" then something went
 2012 wrong.
 2014 Note that you can't run the tests in background if this disables
 2015 opening of /dev/tty. You can use 'make test-notty' in that case but
 2016 a few tty tests will be skipped.
 2018 =head2 What if make test doesn't work?
 2020 If make test bombs out, just cd to the t directory and run ./TEST
 2021 by hand to see if it makes any difference.
 2023 One way to get more detailed information about failed tests and
 2024 individual subtests is to run the harness from the t directory:
 2026 	cd t ; ./perl harness <list of tests>
 2028 (this assumes that most basic tests succeed, since harness uses
 2029 complicated constructs). If no list of tests is provided, harness
 2030 will run all tests.
 2032 If individual tests fail, you can often run them by hand (from the main
 2033 perl directory), e.g.,
 2035 	./perl -I. -MTestInit t/op/groups.t
 2037 You should also read the individual tests to see if there are any helpful
 2038 comments that apply to your system.  You may also need to setup your
 2039 shared library path if you get errors like:
 2041 	/sbin/loader: Fatal Error: cannot map libperl.so
 2043 The file t/README in the t subdirectory contains more information about
 2044 running and modifying tests.
 2046 See L</"Building a shared Perl library"> earlier in this document.
 2048 =over 4
 2050 =item locale
 2052 Note:  One possible reason for errors is that some external programs
 2053 may be broken due to the combination of your environment and the way
 2054 'make test' exercises them.  For example, this may happen if you have
 2055 one or more of these environment variables set:  LC_ALL LC_CTYPE
 2056 LC_COLLATE LANG.  In some versions of UNIX, the non-English locales
 2057 are known to cause programs to exhibit mysterious errors.
 2059 If you have any of the above environment variables set, please try
 2061 	setenv LC_ALL C
 2063 (for C shell) or
 2065 	LC_ALL=C;export LC_ALL
 2067 for Bourne or Korn shell) from the command line and then retry
 2068 make test.  If the tests then succeed, you may have a broken program that
 2069 is confusing the testing.  Please run the troublesome test by hand as
 2070 shown above and see whether you can locate the program.  Look for
 2071 things like:  exec, `backquoted command`, system, open("|...") or
 2072 open("...|").  All these mean that Perl is trying to run some
 2073 external program.
 2075 =item Timing problems
 2077 Several tests in the test suite check timing functions, such as
 2078 sleep(), and see if they return in a reasonable amount of time.
 2079 If your system is quite busy and doesn't respond quickly enough,
 2080 these tests might fail.  If possible, try running the tests again
 2081 with the system under a lighter load.  These timing-sensitive
 2082 and load-sensitive tests include F<t/op/alarm.t>,
 2083 F<dist/Time-HiRes/t/alarm.t>, F<dist/Time-HiRes/t/clock.t>,
 2084 F<dist/Time-HiRes/t/itimer.t>, F<dist/Time-HiRes/t/usleep.t>,
 2085 F<dist/threads-shared/t/waithires.t>,
 2086 F<dist/threads-shared/t/stress.t>, F<lib/Benchmark.t>,
 2087 F<lib/Memoize/t/expmod_t.t>, and F<lib/Memoize/t/speed.t>.
 2089 You might also experience some failures in F<t/op/stat.t> if you build
 2090 perl on an NFS filesystem, if the remote clock and the system clock are
 2091 different.
 2093 =item Out of memory
 2095 On some systems, particularly those with smaller amounts of RAM, some
 2096 of the tests in t/op/pat.t may fail with an "Out of memory" message.
 2097 For example, on my SparcStation IPC with 12 MB of RAM, in perl5.5.670,
 2098 test 85 will fail if run under either t/TEST or t/harness.
 2100 Try stopping other jobs on the system and then running the test by itself:
 2102 	./perl -I. -MTestInit t/op/pat.t
 2104 to see if you have any better luck.  If your perl still fails this
 2105 test, it does not necessarily mean you have a broken perl.  This test
 2106 tries to exercise the regular expression subsystem quite thoroughly,
 2107 and may well be far more demanding than your normal usage.
 2109 =item libgcc_s.so.1: cannot open shared object file
 2111 This message has been reported on gcc-3.2.3 and earlier installed with
 2112 a non-standard prefix.  Setting the LD_LIBRARY_PATH environment variable
 2113 (or equivalent) to include gcc's lib/ directory with the libgcc_s.so.1
 2114 shared library should fix the problem.
 2116 =item Failures from lib/File/Temp/t/security saying "system possibly insecure"
 2118 First, such warnings are not necessarily serious or indicative of a
 2119 real security threat.  That being said, they bear investigating.
 2121 Note that each of the tests is run twice.  The first time is in the
 2122 directory returned by File::Spec->tmpdir() (often /tmp on Unix
 2123 systems), and the second time in the directory from which the test was
 2124 run (usually the 't' directory, if the test was run as part of 'make
 2125 test').
 2127 The tests may fail for the following reasons:
 2129 (1) If the directory the tests are being run in is owned by somebody
 2130 other than the user running the tests, or by root (uid 0).
 2132 This failure can happen if the Perl source code distribution is
 2133 unpacked in such a way that the user IDs in the distribution package
 2134 are used as-is.  Some tar programs do this.
 2136 (2) If the directory the tests are being run in is writable by group or
 2137 by others, and there is no sticky bit set for the directory.  (With
 2138 UNIX/POSIX semantics, write access to a directory means the right to
 2139 add or remove files in that directory.  The 'sticky bit' is a feature
 2140 used in some UNIXes to give extra protection to files: if the bit is
 2141 set for a directory, no one but the owner (or root) can remove that
 2142 file even if the permissions would otherwise allow file removal by
 2143 others.)
 2145 This failure may or may not be a real problem: it depends on the
 2146 permissions policy used on this particular system.  This failure can
 2147 also happen if the system either doesn't support the sticky bit (this
 2148 is the case with many non-UNIX platforms: in principle File::Temp
 2149 should know about these platforms and skip the tests), or if the system
 2150 supports the sticky bit but for some reason or reasons it is not being
 2151 used.  This is, for example, the case with HP-UX: as of HP-UX release
 2152 11.00, the sticky bit is very much supported, but HP-UX doesn't use it
 2153 on its /tmp directory as shipped.  Also, as with the permissions, some
 2154 local policy might dictate that the stickiness is not used.
 2156 (3) If the system supports the POSIX 'chown giveaway' feature and if
 2157 any of the parent directories of the temporary file back to the root
 2158 directory are 'unsafe', using the definitions given above in (1) and
 2159 (2).  For Unix systems, this is usually not an issue if you are
 2160 building on a local disk.  See the documentation for the File::Temp
 2161 module for more information about 'chown giveaway'.
 2163 See the documentation for the File::Temp module for more information
 2164 about the various security aspects of temporary files.
 2166 =back
 2168 The core distribution can now run its regression tests in parallel on
 2169 Unix-like platforms. Instead of running C<make test>, set C<TEST_JOBS>
 2170 in your environment to the number of tests to run in parallel, and run
 2171 C<make test_harness>. On a Bourne-like shell, this can be done as
 2173     TEST_JOBS=3 make test_harness  # Run 3 tests in parallel
 2175 An environment variable is used, rather than parallel make itself,
 2176 because L<TAP::Harness> needs to be able to schedule individual
 2177 non-conflicting test scripts itself, and there is no standard interface
 2178 to C<make> utilities to interact with their job schedulers.
 2180 =head1 make install
 2182 This will put perl into the public directory you specified to
 2183 Configure; by default this is /usr/local/bin.  It will also try to put
 2184 the man pages in a reasonable place.  It will not nroff the man pages,
 2185 however.  You may need to be root to run B<make install>.  If you are not
 2186 root, you must still have permission to install into the directories
 2187 in question and you should ignore any messages about chown not working.
 2189 If "make install" just says "'install' is up to date" or something
 2190 similar, you may be on a case-insensitive filesystems such as Mac's HFS+,
 2191 and you should say "make install-all".  (This confusion is brought to you
 2192 by the Perl distribution having a file called INSTALL.)
 2194 =head2 Installing perl under different names
 2196 If you want to install perl under a name other than "perl" (for example,
 2197 when installing perl with special features enabled, such as debugging),
 2198 indicate the alternate name on the "make install" line, such as:
 2200     make install PERLNAME=myperl
 2202 You can separately change the base used for versioned names (like
 2203 "perl5.8.9") by setting PERLNAME_VERBASE, like
 2205     make install PERLNAME=perl5 PERLNAME_VERBASE=perl
 2207 This can be useful if you have to install perl as "perl5" (e.g. to avoid
 2208 conflicts with an ancient version in /usr/bin supplied by your vendor).
 2209 Without this the versioned binary would be called "perl55.8.8".
 2211 =head2 Installing perl under a different directory
 2213 You can install perl under a different destination directory by using
 2214 the DESTDIR variable during C<make install>, with a command like
 2216 	make install DESTDIR=/tmp/perl5
 2218 DESTDIR is automatically prepended to all the installation paths.  See
 2219 the example in L<"DESTDIR"> above.
 2221 =head2 Installed files
 2223 If you want to see exactly what will happen without installing
 2224 anything, you can run
 2226 	./perl installperl -n
 2227 	./perl installman -n
 2229 make install will install the following:
 2231     binaries
 2233 	perl,
 2234 	    perl5.n.n	where 5.n.n is the current release number.  This
 2235 			will be a link to perl.
 2237     scripts
 2239 	cppstdin	This is used by the deprecated switch perl -P,
 2240 			if your cc -E can't read from stdin.
 2241 	corelist	Shows versions of modules that come with
 2242                         different
 2243 			versions of perl.
 2244 	cpan		The CPAN shell.
 2245 	enc2xs		Encoding module generator.
 2246 	h2ph		Extract constants and simple macros from C
 2247                         headers.
 2248 	h2xs		Converts C .h header files to Perl extensions.
 2249 	instmodsh	A shell to examine installed modules.
 2250 	libnetcfg	Configure libnet.
 2251 	perlbug		Tool to report bugs in Perl.
 2252 	perldoc		Tool to read perl's pod documentation.
 2253 	perlivp		Perl Installation Verification Procedure.
 2254 	piconv		A Perl implementation of the encoding conversion
 2255 			utility iconv.
 2256 	pl2pm		Convert Perl 4 .pl files to Perl 5 .pm modules.
 2257 	pod2html,	Converters from perl's pod documentation format
 2258 	pod2man,
 2259 	pod2text,
 2260 	pod2usage
 2261 	podchecker	POD syntax checker.
 2262 	podselect	Prints sections of POD documentation.
 2263 	prove		A command-line tool for running tests.
 2264 	psed		A Perl implementation of sed.
 2265 	ptar		A Perl implementation of tar.
 2266 	ptardiff	A diff for tar archives.
 2267 	ptargrep	A grep for tar archives.
 2268 	shasum		A tool to print or check SHA checksums.
 2269 	splain		Describe Perl warnings and errors.
 2270 	xsubpp		Compiler to convert Perl XS code into C code.
 2271 	zipdetails	display the internal structure of zip files
 2273     library files
 2275 			in $privlib and $archlib specified to
 2276 			Configure, usually under /usr/local/lib/perl5/.
 2278     documentation
 2280 	man pages	in $man1dir, usually /usr/local/man/man1.
 2281 	module man
 2282 	pages		in $man3dir, usually /usr/local/man/man3.
 2283 	pod/*.pod	in $privlib/pod/.
 2285 installperl will also create the directories listed above
 2286 in L<"Installation Directories">.
 2288 Perl's *.h header files and the libperl library are also installed
 2289 under $archlib so that any user may later build new modules, run the
 2290 optional Perl compiler, or embed the perl interpreter into another
 2291 program even if the Perl source is no longer available.
 2293 =head2 Installing with a version-specific suffix
 2295 Sometimes you only want to install the perl distribution with a
 2296 version-specific suffix.  For example, you may wish to install a newer
 2297 version of perl alongside an already installed production version.
 2298 To only install the version-specific parts of the perl installation, run
 2300 	Configure -Dversiononly
 2302 or answer 'y' to the appropriate Configure prompt.  Alternatively,
 2303 you can just manually run
 2305 	./perl installperl -v
 2307 and skip installman altogether.
 2309 See also L<"Maintaining completely separate versions"> for another
 2310 approach.
 2312 =head1 cd /usr/include; h2ph *.h sys/*.h
 2314 Some perl scripts need to be able to obtain information from the
 2315 system header files.  This command will convert the most commonly used
 2316 header files in /usr/include into files that can be easily interpreted
 2317 by perl.  These files will be placed in the architecture-dependent
 2318 library ($archlib) directory you specified to Configure.
 2320 Note: Due to differences in the C and perl languages, the conversion
 2321 of the header files is not perfect.  You will probably have to
 2322 hand-edit some of the converted files to get them to parse correctly.
 2323 For example, h2ph breaks spectacularly on type casting and certain
 2324 structures.
 2326 =head1 installhtml --help
 2328 Some sites may wish to make perl documentation available in HTML
 2329 format.  The installhtml utility can be used to convert pod
 2330 documentation into linked HTML files and install them.
 2332 Currently, the supplied ./installhtml script does not make use of the
 2333 html Configure variables.  This should be fixed in a future release.
 2335 The following command-line is an example of one used to convert
 2336 perl documentation:
 2338   ./installhtml                   \
 2339       --podroot=.                 \
 2340       --podpath=lib:ext:pod:vms   \
 2341       --recurse                   \
 2342       --htmldir=/perl/nmanual     \
 2343       --htmlroot=/perl/nmanual    \
 2344       --splithead=pod/perlipc     \
 2345       --splititem=pod/perlfunc    \
 2346       --verbose
 2348 See the documentation in installhtml for more details.  It can take
 2349 many minutes to execute a large installation and you should expect to
 2350 see warnings like "no title", "unexpected directive" and "cannot
 2351 resolve" as the files are processed. We are aware of these problems
 2352 (and would welcome patches for them).
 2354 You may find it helpful to run installhtml twice. That should reduce
 2355 the number of "cannot resolve" warnings.
 2357 =head1 cd pod && make tex && (process the latex files)
 2359 Some sites may also wish to make the documentation in the pod/ directory
 2360 available in TeX format.  Type
 2362 	(cd pod && make tex && <process the latex files>)
 2364 =head1 Starting all over again
 2366 If you wish to rebuild perl from the same build directory, you should
 2367 clean it out with the command
 2369 	make distclean
 2371 or
 2373 	make realclean
 2375 The only difference between the two is that make distclean also removes
 2376 your old config.sh and Policy.sh files.  (A plain 'make clean' is now
 2377 equivalent to 'make realclean'.)
 2379 If you are upgrading from a previous version of perl, or if you
 2380 change systems or compilers or make other significant changes, or if
 2381 you are experiencing difficulties building perl, you should not reuse
 2382 your old config.sh.
 2384 If your reason to reuse your old config.sh is to save your particular
 2385 installation choices, then you can probably achieve the same effect by
 2386 using the Policy.sh file.  See the section on L<"Site-wide Policy
 2387 settings"> above.
 2389 =head1 Reporting Problems
 2391 Please report problems to the GitHub issue tracker at
 2392 https://github.com/Perl/perl5/issues, which will ask for the
 2393 appropriate summary configuration information about your perl, which
 2394 may help us track down problems far more quickly.  But first you should
 2395 read the advice in this file, carefully re-read the error message and
 2396 check the relevant manual pages on your system, as these may help you
 2397 find an immediate solution.  Once you've exhausted the documentation,
 2398 please report bugs to us using the GitHub tracker.
 2400 The summary configuration information can be printed with C<perl -V>.
 2401 If the install fails, or you want to report problems with C<make test>
 2402 without installing perl, then you can run it by hand from this source
 2403 directory with C<./perl -V>.
 2405 If the build fails too early to run perl, then please
 2406 B<run> the C<./myconfig> shell script, and include its output along
 2407 with an accurate description of your problem.
 2409 If Configure itself fails, and does not generate a config.sh file
 2410 (needed to run C<./myconfig>), then please open an issue with the
 2411 description of how Configure fails along with details of your system
 2412 -- for example the output from running C<uname -a>.
 2414 Please try to make your message brief but clear.  Brief, clear bug
 2415 reports tend to get answered more quickly.  Please don't worry if your
 2416 written English is not great -- what matters is how well you describe
 2417 the important technical details of the problem you have encountered,
 2418 not whether your grammar and spelling is flawless.
 2420 Trim out unnecessary information.  Do not include large files (such as
 2421 config.sh or a complete Configure or make log) unless absolutely
 2422 necessary.  Do not include a complete transcript of your build
 2423 session.  Just include the failing commands, the relevant error
 2424 messages, and whatever preceding commands are necessary to give the
 2425 appropriate context.
 2427 If the bug you are reporting has security implications which make it
 2428 inappropriate to send to a public issue tracker, then see
 2430 for details of how to report the issue.
 2432 If you are unsure what makes a good bug report please read "How to
 2433 report Bugs Effectively" by Simon Tatham:
 2434 http://www.chiark.greenend.org.uk/~sgtatham/bugs.html
 2436 =head1 Coexistence with earlier versions of perl 5
 2438 Perl 5.30.3 is not binary compatible with versions of Perl earlier than
 2439 5.30.0.
 2440 In other words, you will have to recompile your XS modules.
 2442 In general, you can usually safely upgrade from one version of Perl
 2443 (e.g.  5.X.Y) to another similar minor version (e.g. 5.X.(Y+1))) without
 2444 re-compiling all of your extensions.  You can also safely leave the old
 2445 version around in case the new version causes you problems for some
 2446 reason.
 2448 Usually, most extensions will probably not need to be recompiled to be
 2449 used with a newer version of Perl.  Here is how it is supposed to work.
 2450 (These examples assume you accept all the Configure defaults.)
 2452 Suppose you already have version 5.8.7 installed.  The directories
 2453 searched by 5.8.7 are typically like:
 2455 	/usr/local/lib/perl5/5.8.7/$archname
 2456 	/usr/local/lib/perl5/5.8.7
 2457 	/usr/local/lib/perl5/site_perl/5.8.7/$archname
 2458 	/usr/local/lib/perl5/site_perl/5.8.7
 2460 Now, suppose you install version 5.8.8.  The directories
 2461 searched by version 5.8.8 will be:
 2463 	/usr/local/lib/perl5/5.8.8/$archname
 2464 	/usr/local/lib/perl5/5.8.8
 2465 	/usr/local/lib/perl5/site_perl/5.8.8/$archname
 2466 	/usr/local/lib/perl5/site_perl/5.8.8
 2468 	/usr/local/lib/perl5/site_perl/5.8.7/$archname
 2469 	/usr/local/lib/perl5/site_perl/5.8.7
 2470 	/usr/local/lib/perl5/site_perl/
 2472 Notice the last three entries -- Perl understands the default structure
 2473 of the $sitelib directories and will look back in older, compatible
 2474 directories.  This way, modules installed under 5.8.7 will continue
 2475 to be usable by 5.8.7 but will also accessible to 5.8.8.  Further,
 2476 suppose that you upgrade a module to one which requires features
 2477 present only in 5.8.8.  That new module will get installed into
 2478 /usr/local/lib/perl5/site_perl/5.8.8 and will be available to 5.8.8,
 2479 but will not interfere with the 5.8.7 version.
 2481 The last entry, /usr/local/lib/perl5/site_perl/, is there so that
 2482 5.6.0 and above will look for 5.004-era pure perl modules.
 2484 Lastly, suppose you now install 5.10.0, which is not binary compatible
 2485 with 5.8.x.  The directories searched by 5.10.0 (if you don't change the
 2486 Configure defaults) will be:
 2488 	/usr/local/lib/perl5/5.10.0/$archname
 2489 	/usr/local/lib/perl5/5.10.0
 2490 	/usr/local/lib/perl5/site_perl/5.10.0/$archname
 2491 	/usr/local/lib/perl5/site_perl/5.10.0
 2493 	/usr/local/lib/perl5/site_perl/5.8.8
 2495 	/usr/local/lib/perl5/site_perl/5.8.7
 2497 	/usr/local/lib/perl5/site_perl/
 2499 Note that the earlier $archname entries are now gone, but pure perl
 2500 modules from earlier versions will still be found.
 2502 This way, you can choose to share compatible extensions, but also upgrade
 2503 to a newer version of an extension that may be incompatible with earlier
 2504 versions, without breaking the earlier versions' installations.
 2506 =head2 Maintaining completely separate versions
 2508 Many users prefer to keep all versions of perl in completely
 2509 separate directories.  This guarantees that an update to one version
 2510 won't interfere with another version.  (The defaults guarantee this for
 2511 libraries after 5.6.0, but not for executables. TODO?)  One convenient
 2512 way to do this is by using a separate prefix for each version, such as
 2514 	sh Configure -Dprefix=/opt/perl5.30.3
 2516 and adding /opt/perl5.30.3/bin to the shell PATH variable.  Such users
 2517 may also wish to add a symbolic link /usr/local/bin/perl so that
 2518 scripts can still start with #!/usr/local/bin/perl.
 2520 Others might share a common directory for maintenance sub-versions
 2521 (e.g. 5.10 for all 5.10.x versions), but change directory with
 2522 each major version.
 2524 If you are installing a development subversion, you probably ought to
 2525 seriously consider using a separate directory, since development
 2526 subversions may not have all the compatibility wrinkles ironed out
 2527 yet.
 2529 =head2 Upgrading from 5.29.10 or earlier
 2531 B<Perl 5.30.3 may not be binary compatible with Perl 5.29.10 or
 2532 earlier Perl releases.>  Perl modules having binary parts
 2533 (meaning that a C compiler is used) will have to be recompiled to be
 2534 used with 5.30.3.  If you find you do need to rebuild an extension with
 2535 5.30.3, you may safely do so without disturbing the older
 2536 installations.  (See L<"Coexistence with earlier versions of perl 5">
 2537 above.)
 2539 See your installed copy of the perllocal.pod file for a (possibly
 2540 incomplete) list of locally installed modules.  Note that you want
 2541 perllocal.pod, not perllocale.pod, for installed module information.
 2543 =head1 Minimizing the Perl installation
 2545 The following section is meant for people worrying about squeezing the
 2546 Perl installation into minimal systems (for example when installing
 2547 operating systems, or in really small filesystems).
 2549 Leaving out as many extensions as possible is an obvious way:
 2550 Encode, with its big conversion tables, consumes a lot of
 2551 space.  On the other hand, you cannot throw away everything.  The
 2552 Fcntl module is pretty essential.  If you need to do network
 2553 programming, you'll appreciate the Socket module, and so forth: it all
 2554 depends on what do you need to do.
 2556 In the following we offer two different slimmed down installation
 2557 recipes.  They are informative, not normative: the choice of files
 2558 depends on what you need.
 2560 Firstly, the bare minimum to run this script
 2562   use strict;
 2563   use warnings;
 2564   foreach my $f (</*>) {
 2565      print("$f\n");
 2566   }
 2568 in Linux with perl-5.30.3 is as follows (under $Config{prefix}):
 2570   ./bin/perl
 2571   ./lib/perl5/5.30.3/strict.pm
 2572   ./lib/perl5/5.30.3/warnings.pm
 2573   ./lib/perl5/5.30.3/i686-linux/File/Glob.pm
 2574   ./lib/perl5/5.30.3/feature.pm
 2575   ./lib/perl5/5.30.3/XSLoader.pm
 2576   ./lib/perl5/5.30.3/i686-linux/auto/File/Glob/Glob.so
 2578 Secondly, for perl-5.10.1, the Debian perl-base package contains 591
 2579 files, (of which 510 are for lib/unicore) totaling about 3.5MB in its
 2580 i386 version.  Omitting the lib/unicore/* files for brevity, the
 2581 remaining files are:
 2583   /usr/bin/perl
 2584   /usr/bin/perl5.10.1
 2585   /usr/lib/perl/5.10.1/Config.pm
 2586   /usr/lib/perl/5.10.1/Config_git.pl
 2587   /usr/lib/perl/5.10.1/Config_heavy.pl
 2588   /usr/lib/perl/5.10.1/Cwd.pm
 2589   /usr/lib/perl/5.10.1/DynaLoader.pm
 2590   /usr/lib/perl/5.10.1/Errno.pm
 2591   /usr/lib/perl/5.10.1/Fcntl.pm
 2592   /usr/lib/perl/5.10.1/File/Glob.pm
 2593   /usr/lib/perl/5.10.1/Hash/Util.pm
 2594   /usr/lib/perl/5.10.1/IO.pm
 2595   /usr/lib/perl/5.10.1/IO/File.pm
 2596   /usr/lib/perl/5.10.1/IO/Handle.pm
 2597   /usr/lib/perl/5.10.1/IO/Pipe.pm
 2598   /usr/lib/perl/5.10.1/IO/Seekable.pm
 2599   /usr/lib/perl/5.10.1/IO/Select.pm
 2600   /usr/lib/perl/5.10.1/IO/Socket.pm
 2601   /usr/lib/perl/5.10.1/IO/Socket/INET.pm
 2602   /usr/lib/perl/5.10.1/IO/Socket/UNIX.pm
 2603   /usr/lib/perl/5.10.1/List/Util.pm
 2604   /usr/lib/perl/5.10.1/POSIX.pm
 2605   /usr/lib/perl/5.10.1/Scalar/Util.pm
 2606   /usr/lib/perl/5.10.1/Socket.pm
 2607   /usr/lib/perl/5.10.1/XSLoader.pm
 2608   /usr/lib/perl/5.10.1/auto/Cwd/Cwd.so
 2609   /usr/lib/perl/5.10.1/auto/DynaLoader/autosplit.ix
 2610   /usr/lib/perl/5.10.1/auto/DynaLoader/dl_expandspec.al
 2611   /usr/lib/perl/5.10.1/auto/DynaLoader/dl_find_symbol_anywhere.al
 2612   /usr/lib/perl/5.10.1/auto/DynaLoader/dl_findfile.al
 2613   /usr/lib/perl/5.10.1/auto/Fcntl/Fcntl.so
 2614   /usr/lib/perl/5.10.1/auto/File/Glob/Glob.so
 2615   /usr/lib/perl/5.10.1/auto/Hash/Util/Util.so
 2616   /usr/lib/perl/5.10.1/auto/IO/IO.so
 2617   /usr/lib/perl/5.10.1/auto/List/Util/Util.so
 2618   /usr/lib/perl/5.10.1/auto/POSIX/POSIX.so
 2619   /usr/lib/perl/5.10.1/auto/POSIX/autosplit.ix
 2620   /usr/lib/perl/5.10.1/auto/POSIX/load_imports.al
 2621   /usr/lib/perl/5.10.1/auto/Socket/Socket.so
 2622   /usr/lib/perl/5.10.1/lib.pm
 2623   /usr/lib/perl/5.10.1/re.pm
 2624   /usr/share/doc/perl/AUTHORS.gz
 2625   /usr/share/doc/perl/Documentation
 2626   /usr/share/doc/perl/README.Debian
 2627   /usr/share/doc/perl/changelog.Debian.gz
 2628   /usr/share/doc/perl/copyright
 2629   /usr/share/lintian/overrides/perl-base
 2630   /usr/share/man/man1/perl.1.gz
 2631   /usr/share/man/man1/perl5.10.1.1.gz
 2632   /usr/share/perl/5.10.1/AutoLoader.pm
 2633   /usr/share/perl/5.10.1/Carp.pm
 2634   /usr/share/perl/5.10.1/Carp/Heavy.pm
 2635   /usr/share/perl/5.10.1/Exporter.pm
 2636   /usr/share/perl/5.10.1/Exporter/Heavy.pm
 2637   /usr/share/perl/5.10.1/File/Spec.pm
 2638   /usr/share/perl/5.10.1/File/Spec/Unix.pm
 2639   /usr/share/perl/5.10.1/FileHandle.pm
 2640   /usr/share/perl/5.10.1/Getopt/Long.pm
 2641   /usr/share/perl/5.10.1/IPC/Open2.pm
 2642   /usr/share/perl/5.10.1/IPC/Open3.pm
 2643   /usr/share/perl/5.10.1/SelectSaver.pm
 2644   /usr/share/perl/5.10.1/Symbol.pm
 2645   /usr/share/perl/5.10.1/Text/ParseWords.pm
 2646   /usr/share/perl/5.10.1/Text/Tabs.pm
 2647   /usr/share/perl/5.10.1/Text/Wrap.pm
 2648   /usr/share/perl/5.10.1/Tie/Hash.pm
 2649   /usr/share/perl/5.10.1/attributes.pm
 2650   /usr/share/perl/5.10.1/base.pm
 2651   /usr/share/perl/5.10.1/bytes.pm
 2652   /usr/share/perl/5.10.1/bytes_heavy.pl
 2653   /usr/share/perl/5.10.1/constant.pm
 2654   /usr/share/perl/5.10.1/fields.pm
 2655   /usr/share/perl/5.10.1/integer.pm
 2656   /usr/share/perl/5.10.1/locale.pm
 2657   /usr/share/perl/5.10.1/overload.pm
 2658   /usr/share/perl/5.10.1/strict.pm
 2659   /usr/share/perl/5.10.1/unicore/*
 2660   /usr/share/perl/5.10.1/utf8.pm
 2661   /usr/share/perl/5.10.1/utf8_heavy.pl
 2662   /usr/share/perl/5.10.1/vars.pm
 2663   /usr/share/perl/5.10.1/warnings.pm
 2664   /usr/share/perl/5.10.1/warnings/register.pm
 2666 A nice trick to find out the minimal set of Perl library files you will
 2667 need to run a Perl program is
 2669    perl -e 'do "prog.pl"; END { print "$_\n" for sort keys %INC }'
 2671 (this will not find libraries required in runtime, unfortunately, but
 2672 it's a minimal set) and if you want to find out all the files you can
 2673 use something like the below
 2675  strace perl -le 'do "x.pl"' 2>&1 \
 2676                              | perl -nle '/^open\(\"(.+?)"/ && print $1'
 2678 (The 'strace' is Linux-specific, other similar utilities include 'truss'
 2679 and 'ktrace'.)
 2681 =head2 C<-DNO_MATHOMS>
 2683 If you configure perl with C<-Accflags=-DNO_MATHOMS>, the functions from
 2684 F<mathoms.c> will not be compiled in. Those functions are no longer used
 2685 by perl itself; for source compatibility reasons, though, they weren't
 2686 completely removed.
 2691 If you configure perl with C<-Accflags=-DNO_PERL_INTERNAL_RAND_SEED>,
 2692 perl will ignore the C<PERL_INTERNAL_RAND_SEED> environment variable.
 2694 =head1 DOCUMENTATION
 2696 Read the manual entries before running perl.  The main documentation
 2697 is in the pod/ subdirectory and should have been installed during the
 2698 build process.  Type B<man perl> to get started.  Alternatively, you
 2699 can type B<perldoc perl> to use the supplied perldoc script.  This is
 2700 sometimes useful for finding things in the library modules.
 2702 =head1 AUTHOR
 2704 Original author:  Andy Dougherty doughera@lafayette.edu , borrowing very
 2705 heavily from the original README by Larry Wall, with lots of helpful
 2706 feedback and additions from the perl5-porters@perl.org folks.
 2708 If you have problems, corrections, or questions, please see
 2709 L<"Reporting Problems"> above.
 2713 This document is part of the Perl package and may be distributed under
 2714 the same terms as perl itself, with the following additional request:
 2715 If you are distributing a modified version of perl (perhaps as part of
 2716 a larger package) please B<do> modify these installation instructions
 2717 and the contact information to match your distribution. Additional
 2718 information for packagers is in F<PACKAGING>.