Newer Older
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If you read this file _as_is_, just ignore the funny characters you see.
It is written in the POD format (see pod/perlpod.pod) which is specially
designed to be readable as is.

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=head1 NAME

INSTALL - Build and Installation guide for perl 5.

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First, make sure you have an up-to-date version of Perl.  If you
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didn't get your Perl source from CPAN, check the latest version at  Perl uses a version scheme where even-numbered
subreleases (like 5.8.x and 5.10.x) are stable maintenance releases and
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odd-numbered subreleases (like 5.7.x and 5.9.x) are unstable
development releases.  Development releases should not be used in
production environments.  Fixes and new features are first carefully
tested in development releases and only if they prove themselves to be
worthy will they be migrated to the maintenance releases.

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The basic steps to build and install perl 5 on a Unix system with all
the defaults are to run, from a freshly unpacked source tree:
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	sh Configure -de
	make test
	make install

Each of these is explained in further detail below.

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The above commands will install Perl to /usr/local (or some other
platform-specific directory -- see the appropriate file in hints/.)
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If that's not okay with you, you can run Configure interactively, by
just typing "sh Configure" (without the -de args). You can also specify
any prefix location by adding "-Dprefix='/some/dir'" to Configure's args.
To explicitly name the perl binary, use the command
"make install PERLNAME=myperl".

Building perl from source requires an ANSI compliant C compiler.
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A minimum of C89 is required. Some features available in C99 will
be probed for and used when found. The perl build process does not
rely on anything more than C89.

These options, and many more, are explained in further detail below.

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If you're building perl from a git repository, you should also consult
the documentation in pod/perlgit.pod for information on that special

If you have problems, corrections, or questions, please see
L<"Reporting Problems"> below.
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For information on what's new in this release, see the
pod/perldelta.pod file.  For more information about how to find more
specific detail about changes, see the Changes file.
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This document is written in pod format as an easy way to indicate its
structure.  The pod format is described in pod/perlpod.pod, but you can
read it as is with any pager or editor.  Headings and items are marked
by lines beginning with '='.  The other mark-up used is

    B<text>     embolden text, used for switches, programs or commands
    C<code>	literal code
    L<name>     A link (cross reference) to name
    F<file>     A filename
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Although most of the defaults are probably fine for most users,
you should probably at least skim through this document before
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In addition to this file, check if there is a README file specific to
your operating system, since it may provide additional or different
instructions for building Perl.  If there is a hint file for your
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system (in the hints/ directory) you might also want to read it
for even more information.

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For additional information about porting Perl, see the section on
L<"Porting information"> below, and look at the files in the Porting/


=head2 Changes and Incompatibilities

Please see pod/perldelta.pod for a description of the changes and
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potential incompatibilities introduced with this release.  A few of
the most important issues are listed below, but you should refer
to pod/perldelta.pod for more detailed information.

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B<WARNING:> This version is not binary compatible with versions of Perl
earlier than 5.20.0.
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If you have built extensions (i.e. modules that include C code)
using an earlier version of Perl, you will need to rebuild and reinstall
those extensions.
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Pure perl modules without XS or C code should continue to work fine
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without reinstallation.  See the discussion below on
L<"Coexistence with earlier versions of perl 5"> for more details.
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The standard extensions supplied with Perl will be handled automatically.

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On a related issue, old modules may possibly be affected by the changes
in the Perl language in the current release.  Please see
pod/perldelta.pod for a description of what's changed.  See your
installed copy of the perllocal.pod file for a (possibly incomplete)
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list of locally installed modules.  Also see the L<CPAN> module's
C<autobundle> function for one way to make a "bundle" of your currently
installed modules.
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=head1 Run Configure

Configure will figure out various things about your system.  Some
things Configure will figure out for itself, other things it will ask
you about.  To accept the default, just press RETURN.   The default is
almost always okay.  It is normal for some things to be "NOT found",
since Configure often searches for many different ways of performing
the same function.

At any Configure prompt, you can type  &-d  and Configure will use the
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defaults from then on.

After it runs, Configure will perform variable substitution on all the
*.SH files and offer to run make depend.

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The results of a Configure run are stored in the and

=head2 Common Configure options

Configure supports a number of useful options.  Run

	Configure -h

to get a listing.  See the Porting/Glossary file for a complete list of
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Configure variables you can set and their definitions.

=over 4

=item C compiler

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To compile with gcc, if it's not the default compiler on your
system, you should run
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	sh Configure -Dcc=gcc

This is the preferred way to specify gcc (or any another alternative
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compiler) so that the hints files can set appropriate defaults.

=item Installation prefix

By default, for most systems, perl will be installed in
/usr/local/{bin, lib, man}.  (See L<"Installation Directories">
and L<"Coexistence with earlier versions of perl 5"> below for
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further details.)

You can specify a different 'prefix' for the default installation
directory when Configure prompts you, or by using the Configure command
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line option -Dprefix='/some/directory', e.g.

	sh Configure -Dprefix=/opt/perl

If your prefix contains the string "perl", then the suggested
directory structure is simplified.  For example, if you use
prefix=/opt/perl, then Configure will suggest /opt/perl/lib instead of
/opt/perl/lib/perl5/.  Again, see L<"Installation Directories"> below
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for more details.  Do not include a trailing slash, (i.e. /opt/perl/)
or you may experience odd test failures.
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NOTE:  You must not specify an installation directory that is the same
as or below your perl source directory.  If you do, installperl will
attempt infinite recursion.

=item /usr/bin/perl

It may seem obvious, but Perl is useful only when users can easily
find it.  It's often a good idea to have both /usr/bin/perl and
/usr/local/bin/perl be symlinks to the actual binary.  Be especially
careful, however, not to overwrite a version of perl supplied by your
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vendor unless you are sure you know what you are doing.  If you insist
on replacing your vendor's perl, useful information on how it was
configured may be found with

	perl -V:config_args

(Check the output carefully, however, since this doesn't preserve
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spaces in arguments to Configure.  For that, you have to look carefully
at config_arg1, config_arg2, etc.)

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By default, Configure will not try to link /usr/bin/perl to the current
version of perl.  You can turn on that behavior by running

	Configure -Dinstallusrbinperl

or by answering 'yes' to the appropriate Configure prompt.

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In any case, system administrators are strongly encouraged to put
(symlinks to) perl and its accompanying utilities, such as perldoc,
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into a directory typically found along a user's PATH, or in another
obvious and convenient place.

=item Building a development release

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For development releases (odd subreleases, like 5.9.x) if you want to
use Configure -d, you will also need to supply -Dusedevel to Configure,
because the default answer to the question "do you really want to
Configure a development version?" is "no".  The -Dusedevel skips that
sanity check.
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If you are willing to accept all the defaults, and you want terse
output, you can run

	sh Configure -des

=head2 Altering Configure variables for C compiler switches etc.

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For most users, most of the Configure defaults are fine, or can easily
be set on the Configure command line.  However, if Configure doesn't
have an option to do what you want, you can change Configure variables
after the platform hints have been run by using Configure's -A switch.
For example, here's how to add a couple of extra flags to C compiler

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	sh Configure -Accflags="-DPERL_EXTERNAL_GLOB -DNO_HASH_SEED"

To clarify, those ccflags values are not Configure options; if passed to
Configure directly, they won't do anything useful (they will define a
variable in, but without taking any action based upon it).
But when passed to the compiler, those flags will activate #ifdefd code.

For more help on Configure switches, run

	sh Configure -h

=head2 Major Configure-time Build Options

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There are several different ways to Configure and build perl for your
system.  For most users, the defaults are sensible and will work.
Some users, however, may wish to further customize perl.  Here are
some of the main things you can change.

=head3 Threads

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On some platforms, perl can be compiled with support for threads.  To
enable this, run

	sh Configure -Dusethreads

The default is to compile without thread support.

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Perl used to have two different internal threads implementations.  The current
model (available internally since 5.6, and as a user-level module since 5.8) is
called interpreter-based implementation (ithreads), with one interpreter per
thread, and explicit sharing of data.  The (deprecated) 5.005 version
(5005threads) was removed for release 5.10.

The 'threads' module is for use with the ithreads implementation.  The
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'Thread' module emulates the old 5005threads interface on top of the current
ithreads model.

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When using threads, perl uses a dynamically-sized buffer for some of
the thread-safe library calls, such as those in the getpw*() family.
This buffer starts small, but it will keep growing until the result
fits.  To get a fixed upper limit, you should compile Perl with
PERL_REENTRANT_MAXSIZE defined to be the number of bytes you want.  One
way to do this is to run Configure with

=head3 Large file support

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Since Perl 5.6.0, Perl has supported large files (files larger than
2 gigabytes), and in many common platforms like Linux or Solaris this
support is on by default.

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This is both good and bad. It is good in that you can use large files,
seek(), stat(), and -s them.  It is bad in that if you are interfacing Perl
using some extension, the components you are connecting to must also
be large file aware: if Perl thinks files can be large but the other
parts of the software puzzle do not understand the concept, bad things
will happen.

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There's also one known limitation with the current large files
implementation: unless you also have 64-bit integers (see the next
section), you cannot use the printf/sprintf non-decimal integer formats
like C<%x> to print filesizes.  You can use C<%d>, though.

If you want to compile perl without large file support, use

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    sh Configure -Uuselargefiles

=head3 64 bit support

If your platform does not run natively at 64 bits, but can simulate
them with compiler flags and/or C<long long> or C<int64_t>,
you can build a perl that uses 64 bits.

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There are actually two modes of 64-bitness: the first one is achieved
using Configure -Duse64bitint and the second one using Configure
-Duse64bitall.  The difference is that the first one is minimal and
the second one maximal.  The first works in more places than the second.

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The C<use64bitint> option does only as much as is required to get
64-bit integers into Perl (this may mean, for example, using "long
longs") while your memory may still be limited to 2 gigabytes (because
your pointers could still be 32-bit).  Note that the name C<64bitint>
does not imply that your C compiler will be using 64-bit C<int>s (it
might, but it doesn't have to).  The C<use64bitint> simply means that
you will be able to have 64 bit-wide scalar values.

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The C<use64bitall> option goes all the way by attempting to switch
integers (if it can), longs (and pointers) to being 64-bit.  This may
create an even more binary incompatible Perl than -Duse64bitint: the
resulting executable may not run at all in a 32-bit box, or you may
have to reboot/reconfigure/rebuild your operating system to be 64-bit

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Natively 64-bit systems need neither -Duse64bitint nor -Duse64bitall.
On these systems, it might be the default compilation mode, and there
is currently no guarantee that passing no use64bitall option to the
Configure process will build a 32bit perl. Implementing -Duse32bit*
options is planned for a future release of perl.

=head3 Long doubles

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In some systems you may be able to use long doubles to enhance the
range and precision of your double precision floating point numbers
(that is, Perl's numbers).  Use Configure -Duselongdouble to enable
this support (if it is available).

=head3 "more bits"

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You can "Configure -Dusemorebits" to turn on both the 64-bit support
and the long double support.

=head3 Algorithmic Complexity Attacks on Hashes

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Perl 5.18 reworked the measures used to secure its hash function
from algorithmic complexity attacks.  By default it will build with
all of these measures enabled along with support for controlling and
disabling them via environment variables.

You can override various aspects of this feature by defining various
symbols during configure. An example might be:

    Configure -Accflags=-DPERL_HASH_FUNC_SIPHASH

B<Unless stated otherwise these options are considered experimental or
insecure and are not recommended for production use.>

Perl 5.18 includes support for multiple hash functions, and changed
the default (to ONE_AT_A_TIME_HARD), you can choose a different
algorithm by defining one of the following symbols. Note that as of
Perl 5.18 we can only recommend use of the default or SIPHASH. All
the others are known to have security issues and are for research
purposes only.


Perl 5.18 randomizes the order returned by keys(), values(), and each(),
and allows controlling this behavior by using of the PERL_PERTURB_KEYS
option. You can disable this option entirely with the define:


You can disable the environment variable checks and specify the type of
key traversal randomization to be used by defining one of these:


In Perl 5.18 the seed used for the hash function is randomly selected
at process start which can be overridden by specifying a seed by setting
the PERL_HASH_SEED environment variable.

You can change this behavior by building perl with the


define, in which case one has to explicitly set the PERL_HASH_SEED
environment variable to enable the security feature or by adding


to the compilation flags to completely disable the randomisation feature.
Note these modes are poorly tested, insecure and not recommended.
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B<Perl has never guaranteed any ordering of the hash keys>, and the
ordering has already changed several times during the lifetime of Perl
5.  Also, the ordering of hash keys has always been, and continues to
be, affected by the insertion order.  Note that because of this
randomisation for example the Data::Dumper results will be different
between different runs of Perl, since Data::Dumper by default dumps
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hashes "unordered".  The use of the Data::Dumper C<Sortkeys> option is

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See L<perlrun/PERL_HASH_SEED> and L<perlrun/PERL_PERTURB_KEYS> for details on
the environment variables, and L<perlsec/Algorithmic Complexity Attacks> for
further security details.

=head3 SOCKS
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Perl can be configured to be 'socksified', that is, to use the SOCKS
TCP/IP proxy protocol library.  SOCKS is used to give applications
access to transport layer network proxies.  Perl supports only SOCKS
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Version 5.  The corresponding Configure option is -Dusesocks.
You can find more about SOCKS from wikipedia at

=head3 Dynamic Loading

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By default, Configure will compile perl to use dynamic loading.
If you want to force perl to be compiled completely
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statically, you can either choose this when Configure prompts you or
you can use the Configure command line option -Uusedl.
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With this option, you won't be able to use any new extension
(XS) module without recompiling perl itself.

=head3 Building a shared Perl library
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Currently, for most systems, the main perl executable is built by
linking the "perl library" libperl.a with perlmain.o, your static
extensions, and various extra libraries, such as -lm.

On systems that support dynamic loading, it may be possible to
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replace libperl.a with a shared  If you anticipate building
several different perl binaries (e.g. by embedding libperl into
different programs, or by using the optional compiler extension), then
you might wish to build a shared so that all your binaries
can share the same library.

The disadvantages are that there may be a significant performance
penalty associated with the shared, and that the overall
mechanism is still rather fragile with respect to different versions
and upgrades.

In terms of performance, on my test system (Solaris 2.5_x86) the perl
test suite took roughly 15% longer to run with the shared
Your system and typical applications may well give quite different

The default name for the shared library is typically something like
452 (for Perl 5.8.8), or, or simply
453 454 455 456 457 458 459 460 461 462 463  Configure tries to guess a sensible naming convention
based on your C library name.  Since the library gets installed in a
version-specific architecture-dependent directory, the exact name
isn't very important anyway, as long as your linker is happy.

You can elect to build a shared libperl by

	sh Configure -Duseshrplib

To build a shared libperl, the environment variable controlling shared
library search (LD_LIBRARY_PATH in most systems, DYLD_LIBRARY_PATH for
for HP-UX, LIBPATH for AIX, PATH for Cygwin) must be set up to include
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the Perl build directory because that's where the shared libperl will
be created.  Configure arranges makefile to have the correct shared
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library search settings.  You can find the name of the environment
variable Perl thinks works in your your system by

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	grep ldlibpthname

However, there are some special cases where manually setting the
shared library path might be required.  For example, if you want to run
something like the following with the newly-built but not-yet-installed

        ./perl -MTestInit t/misc/failing_test.t


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        ./perl -Ilib ~/my_mission_critical_test

then you need to set up the shared library path explicitly.
You can do this with


for Bourne-style shells, or

   setenv LD_LIBRARY_PATH `pwd`

for Csh-style shells.  (This procedure may also be needed if for some
unexpected reason Configure fails to set up makefile correctly.) (And
again, it may be something other than LD_LIBRARY_PATH for you, see above.)

You can often recognize failures to build/use a shared libperl from error
messages complaining about a missing (or in HP-UX),
for example:
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    18126:./miniperl: /sbin/loader: Fatal Error: cannot map
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There is also an potential problem with the shared perl library if you
want to have more than one "flavor" of the same version of perl (e.g.
with and without -DDEBUGGING).  For example, suppose you build and
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install a standard Perl 5.10.0 with a shared library.  Then, suppose you
try to build Perl 5.10.0 with -DDEBUGGING enabled, but everything else
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the same, including all the installation directories.  How can you
ensure that your newly built perl will link with your newly built rather with the installed  The answer is
that you might not be able to.  The installation directory is encoded
in the perl binary with the LD_RUN_PATH environment variable (or
equivalent ld command-line option).  On Solaris, you can override that
with LD_LIBRARY_PATH; on Linux, you can only override at runtime via
LD_PRELOAD, specifying the exact filename you wish to be used; and on
Digital Unix, you can override LD_LIBRARY_PATH by setting the
_RLD_ROOT environment variable to point to the perl build directory.

In other words, it is generally not a good idea to try to build a perl
with a shared library if $archlib/CORE/$libperl already exists from a
previous build.

A good workaround is to specify a different directory for the
architecture-dependent library for your -DDEBUGGING version of perl.
You can do this by changing all the *archlib* variables in to
point to your new architecture-dependent library.

=head3 Environment access

Perl often needs to write to the program's environment, such as when C<%ENV>
is assigned to. Many implementations of the C library function C<putenv()>
leak memory, so where possible perl will manipulate the environment directly
to avoid these leaks. The default is now to perform direct manipulation
whenever perl is running as a stand alone interpreter, and to call the safe
but potentially leaky C<putenv()> function when the perl interpreter is
embedded in another application. You can force perl to always use C<putenv()>
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by compiling with C<-Accflags="-DPERL_USE_SAFE_PUTENV">, see section
L</"Altering Configure variables for C compiler switches etc.">.
You can force an embedded perl to use direct manipulation by setting
C<PL_use_safe_putenv = 0;> after the C<perl_construct()> call.
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=head2 Installation Directories

The installation directories can all be changed by answering the
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appropriate questions in Configure.  For convenience, all the installation
questions are near the beginning of Configure.  Do not include trailing
slashes on directory names.  At any point during the Configure process,
you can answer a question with  &-d  and Configure will use the defaults
from then on.  Alternatively, you can
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	grep '^install'

after Configure has run to verify the installation paths.

The defaults are intended to be reasonable and sensible for most
people building from sources.  Those who build and distribute binary
distributions or who export perl to a range of systems will probably
need to alter them.  If you are content to just accept the defaults,
you can safely skip the next section.

The directories set up by Configure fall into three broad categories.

=over 4

=item Directories for the perl distribution

By default, Configure will use the following directories for 5.20.2.
$version is the full perl version number, including subversion, e.g.
5.12.3, and $archname is a string like sun4-sunos,
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determined by Configure.  The full definitions of all Configure
variables are in the file Porting/Glossary.

    Configure variable	Default value
    $prefixexp		/usr/local
    $binexp		$prefixexp/bin
    $scriptdirexp	$prefixexp/bin
    $privlibexp		$prefixexp/lib/perl5/$version
    $archlibexp		$prefixexp/lib/perl5/$version/$archname
    $man1direxp		$prefixexp/man/man1
    $man3direxp		$prefixexp/man/man3
    $html1direxp	(none)
    $html3direxp	(none)

$prefixexp is generated from $prefix, with ~ expansion done to convert home
directories into absolute paths. Similarly for the other variables listed. As
file system calls do not do this, you should always reference the ...exp
variables, to support users who build perl in their home directory.

Actually, Configure recognizes the SVR3-style
/usr/local/man/l_man/man1 directories, if present, and uses those
instead.  Also, if $prefix contains the string "perl", the library
directories are simplified as described below.  For simplicity, only
the common style is shown here.

=item Directories for site-specific add-on files

After perl is installed, you may later wish to add modules (e.g. from
CPAN) or scripts.  Configure will set up the following directories to
be used for installing those add-on modules and scripts.

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   Configure        Default
   variable          value
 $siteprefixexp    $prefixexp
 $sitebinexp       $siteprefixexp/bin
 $sitescriptexp    $siteprefixexp/bin
 $sitelibexp       $siteprefixexp/lib/perl5/site_perl/$version
 $siteman1direxp   $siteprefixexp/man/man1
 $siteman3direxp   $siteprefixexp/man/man3
 $sitehtml1direxp  (none)
 $sitehtml3direxp  (none)
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By default, ExtUtils::MakeMaker will install architecture-independent
modules into $sitelib and architecture-dependent modules into $sitearch.

=item Directories for vendor-supplied add-on files

Lastly, if you are building a binary distribution of perl for
distribution, Configure can optionally set up the following directories
for you to use to distribute add-on modules.

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   Configure          Default
   variable            value
 $vendorprefixexp    (none)

 (The next ones are set only if vendorprefix is set.)

 $vendorbinexp       $vendorprefixexp/bin
 $vendorscriptexp    $vendorprefixexp/bin
 $vendorlibexp       $vendorprefixexp/lib/perl5/vendor_perl/$version
 $vendorman1direxp   $vendorprefixexp/man/man1
 $vendorman3direxp   $vendorprefixexp/man/man3
 $vendorhtml1direxp  (none)
 $vendorhtml3direxp  (none)
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These are normally empty, but may be set as needed.  For example,
a vendor might choose the following settings:

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 $prefix           /usr
 $siteprefix       /usr/local
 $vendorprefix     /usr
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This would have the effect of setting the following:

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 $binexp           /usr/bin
 $scriptdirexp     /usr/bin
 $privlibexp       /usr/lib/perl5/$version
 $archlibexp       /usr/lib/perl5/$version/$archname
 $man1direxp       /usr/man/man1
 $man3direxp       /usr/man/man3

 $sitebinexp       /usr/local/bin
 $sitescriptexp    /usr/local/bin
 $sitelibexp       /usr/local/lib/perl5/site_perl/$version
 $sitearchexp      /usr/local/lib/perl5/site_perl/$version/$archname
 $siteman1direxp   /usr/local/man/man1
 $siteman3direxp   /usr/local/man/man3

 $vendorbinexp     /usr/bin
 $vendorscriptexp  /usr/bin
 $vendorlibexp     /usr/lib/perl5/vendor_perl/$version
 $vendorarchexp    /usr/lib/perl5/vendor_perl/$version/$archname
 $vendorman1direxp /usr/man/man1
 $vendorman3direxp /usr/man/man3
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Note how in this example, the vendor-supplied directories are in the
/usr hierarchy, while the directories reserved for the end user are in
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the /usr/local hierarchy.

The entire installed library hierarchy is installed in locations with
version numbers, keeping the installations of different versions distinct.
However, later installations of Perl can still be configured to search the
installed libraries corresponding to compatible earlier versions.
See L<"Coexistence with earlier versions of perl 5"> below for more details
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on how Perl can be made to search older version directories.

Of course you may use these directories however you see fit.  For
example, you may wish to use $siteprefix for site-specific files that
are stored locally on your own disk and use $vendorprefix for
site-specific files that are stored elsewhere on your organization's
network.  One way to do that would be something like

 sh Configure -Dsiteprefix=/usr/local -Dvendorprefix=/usr/share/perl
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=item otherlibdirs

As a final catch-all, Configure also offers an $otherlibdirs
variable.  This variable contains a colon-separated list of additional
directories to add to @INC.  By default, it will be empty.
Perl will search these directories (including architecture and
version-specific subdirectories) for add-on modules and extensions.

For example, if you have a bundle of perl libraries from a previous
installation, perhaps in a strange place:

	Configure -Dotherlibdirs=/usr/lib/perl5/site_perl/5.8.1


There is one other way of adding paths to @INC at perl build time, and
that is by setting the APPLLIB_EXP C pre-processor token to a colon-
separated list of directories, like this

       sh Configure -Accflags='-DAPPLLIB_EXP=\"/usr/libperl\"'

The directories defined by APPLLIB_EXP get added to @INC I<first>,
ahead of any others, and so provide a way to override the standard perl
modules should you, for example, want to distribute fixes without
touching the perl distribution proper.  And, like otherlib dirs,
version and architecture specific subdirectories are also searched, if
present, at run time.  Of course, you can still search other @INC
directories ahead of those in APPLLIB_EXP by using any of the standard
run-time methods: $PERLLIB, $PERL5LIB, -I, use lib, etc.

=item usesitecustomize
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Run-time customization of @INC can be enabled with:

	sh Configure -Dusesitecustomize

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which will define USE_SITECUSTOMIZE and $Config{usesitecustomize}.
When enabled, this makes perl run F<$sitelibexp/> before
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anything else.  This script can then be set up to add additional
entries to @INC.

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=item Man Pages

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By default, man pages will be installed in $man1dir and $man3dir, which
are normally /usr/local/man/man1 and /usr/local/man/man3.  If you
want to use a .3pm suffix for perl man pages, you can do that with
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	sh Configure -Dman3ext=3pm

=item HTML pages

Currently, the standard perl installation does not do anything with
HTML documentation, but that may change in the future.  Further, some
add-on modules may wish to install HTML documents.  The html Configure
variables listed above are provided if you wish to specify where such
documents should be placed.  The default is "none", but will likely
eventually change to something useful based on user feedback.


Some users prefer to append a "/share" to $privlib and $sitelib
to emphasize that those directories can be shared among different

Note that these are just the defaults.  You can actually structure the
directories any way you like.  They don't even have to be on the same

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Further details about the installation directories, maintenance and
development subversions, and about supporting multiple versions are
discussed in L<"Coexistence with earlier versions of perl 5"> below.

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If you specify a prefix that contains the string "perl", then the
library directory structure is slightly simplified.  Instead of
suggesting $prefix/lib/perl5/, Configure will suggest $prefix/lib.

Thus, for example, if you Configure with
-Dprefix=/opt/perl, then the default library directories for 5.9.0 are

    Configure variable	Default value
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	$privlib	/opt/perl/lib/5.9.0
	$archlib	/opt/perl/lib/5.9.0/$archname
	$sitelib	/opt/perl/lib/site_perl/5.9.0
	$sitearch	/opt/perl/lib/site_perl/5.9.0/$archname

=head2 Changing the installation directory

Configure distinguishes between the directory in which perl (and its
associated files) should be installed, and the directory in which it
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will eventually reside.  For most sites, these two are the same; for
sites that use AFS, this distinction is handled automatically.
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However, sites that use package management software such as rpm or
dpkg, or users building binary packages for distribution may also
wish to install perl into a different directory before moving perl
to its final destination.  There are two ways to do that:

=over 4

=item installprefix

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To install perl under the /tmp/perl5 directory, use the following
command line:

    sh Configure -Dinstallprefix=/tmp/perl5

(replace /tmp/perl5 by a directory of your choice).

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Beware, though, that if you go to try to install new add-on
modules, they too will get installed in under '/tmp/perl5' if you
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follow this example.  That's why it's usually better to use DESTDIR,
as shown in the next section.


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If you need to install perl on many identical systems, it is convenient
to compile it once and create an archive that can be installed on
multiple systems.  Suppose, for example, that you want to create an
archive that can be installed in /opt/perl.  One way to do that is by
using the DESTDIR variable during C<make install>.  The DESTDIR is
automatically prepended to all the installation paths.  Thus you
simply do:

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    sh Configure -Dprefix=/opt/perl -des
    make test
    make install DESTDIR=/tmp/perl5
    cd /tmp/perl5/opt/perl
    tar cvf /tmp/perl5-archive.tar .

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=head2 Relocatable @INC

To create a relocatable perl tree, use the following command line:

    sh Configure -Duserelocatableinc

Then the paths in @INC (and everything else in %Config) can be
optionally located via the path of the perl executable.

That means that, if the string ".../" is found at the start of any
path, it's substituted with the directory of $^X. So, the relocation
can be configured on a per-directory basis, although the default with
"-Duserelocatableinc" is that everything is relocated. The initial
install is done to the original configured prefix.

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This option is not compatible with the building of a shared libperl
("-Duseshrplib"), because in that case perl is linked with an hard-coded
rpath that points at the, that cannot be relocated.

=head2 Site-wide Policy settings

After Configure runs, it stores a number of common site-wide "policy"
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answers (such as installation directories) in the file.
If you want to build perl on another system using the same policy
defaults, simply copy the file to the new system's perl build
directory, and Configure will use it. This will work even if was
generated for another version of Perl, or on a system with a
different architecture and/or operating system. However, in such cases,
you should review the contents of the file before using it: for
example, your new target may not keep its man pages in the same place
as the system on which the file was generated.

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Alternatively, if you wish to change some or all of those policy
answers, you should

	rm -f

to ensure that Configure doesn't re-use them.

Further information is in the Policy_sh.SH file itself.

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If the generated file is unsuitable, you may freely edit it
to contain any valid shell commands.  It will be run just after the
platform-specific hints files.

=head2 Disabling older versions of Perl

Configure will search for binary compatible versions of previously
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installed perl binaries in the tree that is specified as target tree,
and these will be used as locations to search for modules by the perl
being built. The list of perl versions found will be put in the Configure
variable inc_version_list.

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To disable this use of older perl modules, even completely valid pure perl
modules, you can specify to not include the paths found:

       sh Configure -Dinc_version_list=none ...

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If you do want to use modules from some previous perl versions, the variable
must contain a space separated list of directories under the site_perl
directory, and has to include architecture-dependent directories separately,

       sh Configure -Dinc_version_list="5.16.0/x86_64-linux 5.16.0" ...

When using the newer perl, you can add these paths again in the
PERL5LIB environment variable or with perl's -I runtime option.

=head2 Building Perl outside of the source directory

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Sometimes it is desirable to build Perl in a directory different from
where the sources are, for example if you want to keep your sources
read-only, or if you want to share the sources between different binary
architectures.  You can do this (if your file system supports symbolic
links) by

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	mkdir /tmp/perl/build/directory
	cd /tmp/perl/build/directory
	sh /path/to/perl/source/Configure -Dmksymlinks ...

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This will create in /tmp/perl/build/directory a tree of symbolic links
pointing to files in /path/to/perl/source.  The original files are left
unaffected.  After Configure has finished you can just say

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	make test
	make install
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as usual, and Perl will be built in /tmp/perl/build/directory.
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=head2 Building a debugging perl

You can run perl scripts under the perl debugger at any time with
B<perl -d your_script>.  If, however, you want to debug perl itself,
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you probably want to have support for perl internal debugging code
(activated by adding -DDEBUGGING to ccflags), and/or support for the
system debugger by adding -g to the optimisation flags. For that,
use the parameter:

	sh Configure -DDEBUGGING


	sh Configure -DDEBUGGING=<mode>

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For a more eye appealing call, -DEBUGGING is defined to be an alias
for -DDEBUGGING. For both, the -U calls are also supported, in order
to be able to overrule the hints or settings.

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Here are the DEBUGGING modes:

=over 4



=item -DEBUGGING=both

Sets both -DDEBUGGING in the ccflags, and adds -g to optimize.

You can actually specify -g and -DDEBUGGING independently (see below),
but usually it's convenient to have both.

=item -DEBUGGING=-g

=item -Doptimize=-g

Adds -g to optimize, but does not set -DDEBUGGING.

(Note:  Your system may actually require something like cc -g2.
Check your man pages for cc(1) and also any hint file for your system.)

=item -DEBUGGING=none


Removes -g from optimize, and -DDEBUGGING from ccflags.

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If you are using a shared libperl, see the warnings about multiple
versions of perl under L<Building a shared Perl library>.

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Note that a perl built with -DDEBUGGING will be much bigger and will run
much, much more slowly than a standard perl.
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=head2 DTrace support

On platforms where DTrace is available, it may be enabled by
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using the -Dusedtrace option to Configure. DTrace probes are available for
subroutine entry (sub-entry) and subroutine exit (sub-exit). Here's a
simple D script that uses them:

  perl$target:::sub-entry, perl$target:::sub-return {
    printf("%s %s (%s:%d)\n", probename == "sub-entry" ? "->" : "<-",
              copyinstr(arg0), copyinstr(arg1), arg2);

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=head2 Extensions

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Perl ships with a number of standard extensions.  These are contained
in the ext/ subdirectory.

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By default, Configure will offer to build every extension which appears
to be supported.  For example, Configure will offer to build GDBM_File
only if it is able to find the gdbm library.
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To disable certain extensions so that they are not built, use the
-Dnoextensions=... and -Donlyextensions=... options.  They both accept
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a space-separated list of extensions, such as C<IPC/SysV>. The extensions
listed in
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C<noextensions> are removed from the list of extensions to build, while
the C<onlyextensions> is rather more severe and builds only the listed
extensions.  The latter should be used with extreme caution since
certain extensions are used by many other extensions and modules:
examples of such modules include Fcntl and IO.  The order of processing
these options is first C<only> (if present), then C<no> (if present).
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Of course, you may always run Configure interactively and select only
the extensions you want.

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If you unpack any additional extensions in the ext/ directory before
running Configure, then Configure will offer to build those additional
extensions as well.  Most users probably shouldn't have to do this --
it is usually easier to build additional extensions later after perl
has been installed.  However, if you wish to have those additional
extensions statically linked into the perl binary, then this offers a
convenient way to do that in one step.  (It is not necessary, however;
you can build and install extensions just fine even if you don't have
dynamic loading.  See lib/ExtUtils/ for more details.)
Another way of specifying extra modules is described in
L<"Adding extra modules to the build"> below.

If you re-use an old but change your system (e.g. by
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adding libgdbm) Configure will still offer your old choices of extensions
for the default answer, but it will also point out the discrepancy to

=head2 Including locally-installed libraries

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Perl comes with interfaces to number of libraries, including threads,
dbm, ndbm, gdbm, and Berkeley db.  For the *db* extension, if
Configure can find the appropriate header files and libraries, it will
automatically include that extension.  The threading extension needs
to be specified explicitly (see L</Threads>).
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Those libraries are not distributed with perl. If your header (.h) files
for those libraries are not in a directory normally searched by your C
compiler, then you will need to include the appropriate -I/your/directory
option when prompted by Configure.  If your libraries are not in a
directory normally searched by your C compiler and linker, then you will
need to include the appropriate -L/your/directory option when prompted
by Configure. See the examples below.

=head3 Examples
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=over 4

=item gdbm in /usr/local

Suppose you have gdbm and want Configure to find it and build the
GDBM_File extension.  This example assumes you have gdbm.h
installed in /usr/local/include/gdbm.h and libgdbm.a installed in
/usr/local/lib/libgdbm.a.  Configure should figure all the
necessary steps out automatically.

Specifically, when Configure prompts you for flags for
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your C compiler, you should include -I/usr/local/include, if it's
not here yet. Similarly, when Configure prompts you for linker flags,
you should include -L/usr/local/lib.
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If you are using dynamic loading, then when Configure prompts you for
linker flags for dynamic loading, you should again include

Again, this should all happen automatically.  This should also work if
you have gdbm installed in any of (/usr/local, /opt/local, /usr/gnu,
/opt/gnu, /usr/GNU, or /opt/GNU).

=item BerkeleyDB in /usr/local/BerkeleyDB

The version of BerkeleyDB distributed by Oracle installs in a
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version-specific directory by default, typically something like
/usr/local/BerkeleyDB.4.7.  To have Configure find that, you need to add
-I/usr/local/BerkeleyDB.4.7/include to cc flags, as in the previous example,
and you will also have to take extra steps to help Configure find -ldb.
Specifically, when Configure prompts you for library directories,
add /usr/local/BerkeleyDB.4.7/lib to the list.  Also, you will need to
add appropriate linker flags to tell the runtime linker where to find the
BerkeleyDB shared libraries.

It is possible to specify this from the command line (all on one
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1075 1076 1077 1078 1079
 sh Configure -de \
    -Dlocincpth='/usr/local/BerkeleyDB.4.7/include             \
                                           /usr/local/include' \
    -Dloclibpth='/usr/local/BerkeleyDB.4.7/lib /usr/local/lib' \
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locincpth is a space-separated list of include directories to search.
Configure will automatically add the appropriate -I directives.

loclibpth is a space-separated list of library directories to search.
Configure will automatically add the appropriate -L directives.

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The addition to ldflags is so that the dynamic linker knows where to find
the BerkeleyDB libraries.  For Linux and Solaris, the -R option does that.
Other systems may use different flags.  Use the appropriate flag for your
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=head2 Specifying a logical root directory

If you are cross-compiling, or are using a compiler which has it's own
headers and libraries in a nonstandard location, and your compiler
understands the C<--sysroot> option, you can use the C<-Dsysroot> option to
specify the logical root directory under which all libraries and headers
are searched for. This patch adjusts Configure to search under $sysroot, instead of /.
--sysroot is added to ccflags and friends so that make in
ExtUtils::MakeMaker, and other extensions, will use it.

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=head2 Overriding an old

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If you want to use an old produced by a previous run of
Configure, but override some of the items with command line options, you
need to use B<Configure -O>.
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=head2 GNU-style configure

If you prefer the GNU-style configure command line interface, you can
use the supplied configure.gnu command, e.g.

	CC=gcc ./configure.gnu

The configure.gnu script emulates a few of the more common configure
options.  Try

	./configure.gnu --help

for a listing.

(The file is called configure.gnu to avoid problems on systems
that would not distinguish the files "Configure" and "configure".)

=head2 Malloc Issues

Perl relies heavily on malloc(3) to grow data structures as needed,
so perl's performance can be noticeably affected by the performance of
the malloc function on your system.  The perl source is shipped with a
version of malloc that has been optimized for the typical requests from
perl, so there's a chance that it may be both faster and use less memory
than your system malloc.

However, if your system already has an excellent malloc, or if you are
experiencing difficulties with extensions that use third-party libraries
that call malloc, then you should probably use your system's malloc.
(Or, you might wish to explore the malloc flags discussed below.)

=over 4

=item Using the system malloc

To build without perl's malloc, you can use the Configure command

	sh Configure -Uusemymalloc

or you can answer 'n' at the appropriate interactive Configure prompt.

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Note that Perl's malloc isn't always used by default; that actually
depends on your system. For example, on Linux and FreeBSD (and many more
systems), Configure chooses to use the system's malloc by default.
See the appropriate file in the F<hints/> directory to see how the
default is set.

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NOTE: This flag is enabled automatically on some platforms if you just
run Configure to accept all the defaults.
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Perl's malloc family of functions are normally called Perl_malloc(),
Perl_realloc(), Perl_calloc() and Perl_mfree().
These names do not clash with the system versions of these functions.

If this flag is enabled, however, Perl's malloc family of functions
will have the same names as the system versions.  This may be required
sometimes if you have libraries that like to free() data that may have
been allocated by Perl_malloc() and vice versa.

Note that enabling this option may sometimes lead to duplicate symbols
from the linker for malloc et al.  In such cases, the system probably
does not allow its malloc functions to be fully replaced with custom


This flag enables debugging mstats, which is required to use the
Devel::Peek::mstat() function. You cannot enable this unless you are
using Perl's malloc, so a typical Configure command would be

       sh Configure -Accflags=-DPERL_DEBUGGING_MSTATS -Dusemymalloc
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to enable this option.


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=head2 What if it doesn't work?

If you run into problems, try some of the following ideas.
If none of them help, then see L<"Reporting Problems"> below.
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=over 4

=item Running Configure Interactively

If Configure runs into trouble, remember that you can always run
Configure interactively so that you can check (and correct) its

All the installation questions have been moved to the top, so you don't
have to wait for them.  Once you've handled them (and your C compiler and
flags) you can type  &-d  at the next Configure prompt and Configure
will use the defaults from then on.

If you find yourself trying obscure command line incantations and
config.over tricks, I recommend you run Configure interactively
instead.  You'll probably save yourself time in the long run.

=item Hint files

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Hint files tell Configure about a number of things:

=over 4

=item o

The peculiarities or conventions of particular platforms -- non-standard
library locations and names, default installation locations for binaries,
and so on.

=item o

The deficiencies of the platform -- for example, library functions that,
although present, are too badly broken to be usable; or limits on
resources that are generously available on most platforms.

=item o

How best to optimize for the platform, both in terms of binary size and/or
speed, and for Perl feature support. Because of wide variations in the
implementation of shared libraries and of threading, for example, Configure
often needs hints in order to be able to use these features.


The perl distribution includes many system-specific hints files
in the hints/ directory. If one of them matches your system, Configure
will offer to use that hint file. Unless you have a very good reason
not to, you should accept its offer.
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Several of the hint files contain additional important information.
If you have any problems, it is a good idea to read the relevant hint file
for further information.  See hints/ for an extensive example.
More information about writing good hints is in the hints/README.hints
file, which also explains hint files known as callback-units.

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Note that any hint file is read before any Policy file, meaning that
Policy overrides hints -- see L</Site-wide Policy settings>.

=item WHOA THERE!!!

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If you are re-using an old, it's possible that Configure detects
different values from the ones specified in this file.  You will almost
always want to keep the previous value, unless you have changed something
on your system.
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For example, suppose you have added libgdbm.a to your system
and you decide to reconfigure perl to use GDBM_File.  When you run
Configure again, you will need to add -lgdbm to the list of libraries.
Now, Configure will find your gdbm include file and library and will
issue a message:

    *** WHOA THERE!!! ***
	The previous value for $i_gdbm on this machine was "undef"!
	Keep the previous value? [y]

In this case, you do not want to keep the previous value, so you
should answer 'n'.  (You'll also have to manually add GDBM_File to
the list of dynamic extensions to build.)

=item Changing Compilers

If you change compilers or make other significant changes, you should
probably not re-use your old  Simply remove it or
rename it, then rerun Configure with the options you want to use.
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=item Propagating your changes to

If you make any changes to, you should propagate
them to all the .SH files by running

	sh Configure -S

You will then have to rebuild by running

	make depend

=item config.over and config.arch

You can also supply a shell script config.over to override
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Configure's guesses.  It will get loaded up at the very end, just
before is created.  You have to be careful with this,
however, as Configure does no checking that your changes make sense.
This file is usually good for site-specific customizations.

There is also another file that, if it exists, is loaded before the
config.over, called config.arch.  This file is intended to be per
architecture, not per site, and usually it's the architecture-specific
hints file that creates the config.arch.
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=item config.h

Many of the system dependencies are contained in config.h.
Configure builds config.h by running the config_h.SH script.
The values for the variables are taken from

If there are any problems, you can edit config.h directly.  Beware,
though, that the next time you run Configure, your changes will be

=item cflags

If you have any additional changes to make to the C compiler command
line, they can be made in cflags.SH.  For instance, to turn off the
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optimizer on toke.c, find the switch structure marked 'or customize here',
and add a line for toke.c ahead of the catch-all *) so that it now reads:

    : or customize here

    case "$file" in
    toke) optimize='-g' ;;
    *) ;;

You should not edit the generated file cflags directly, as your changes will
be lost the next time you run Configure, or if you edit
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To explore various ways of changing ccflags from within a hint file,
see the file hints/README.hints.

To change the C flags for all the files, edit and change either
$ccflags or $optimize, and then re-run

	sh Configure -S
	make depend

=item No sh

If you don't have sh, you'll have to copy the sample file
Porting/ to and edit your to reflect your
system's peculiarities.  See Porting/pumpkin.pod for more information.
You'll probably also have to extensively modify the extension building

=item Porting information

Specific information for the OS/2, Plan 9, VMS and Win32 ports is in the
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corresponding README files and subdirectories.  Additional information,
including a glossary of all those variables, is in the Porting
subdirectory.  Porting/Glossary should especially come in handy.
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Ports for other systems may also be available.  You should check out
1355 for current information on ports to
1356 1357
various other operating systems.

If you plan to port Perl to a new architecture, study carefully the
section titled "Philosophical Issues in Patching and Porting Perl"
in the file Porting/pumpkin.pod and the file pod/perlgit.pod.
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Study also how other non-UNIX ports have solved problems.


=head2 Adding extra modules to the build
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You can specify extra modules or module bundles to be fetched from the
CPAN and installed as part of the Perl build.  Either use the -Dextras=...
command line parameter to Configure, for example like this:

	Configure -Dextras="Bundle::LWP DBI"
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or answer first 'y' to the question 'Install any extra modules?' and
then answer "Bundle::LWP DBI" to the 'Extras?' question.
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The module or the bundle names are as for the CPAN module 'install' command.
This will only work if those modules are to be built as dynamic
extensions.  If you wish to include those extra modules as static
extensions, see L<"Extensions"> above.

Notice that because the CPAN module will be used to fetch the extra
modules, you will need access to the CPAN, either via the Internet,
or via a local copy such as a CD-ROM or a local CPAN mirror.  If you
do not, using the extra modules option will die horribly.

Also notice that you yourself are responsible for satisfying any extra
dependencies such as external headers or libraries BEFORE trying the build.
For example: you will need to have the Foo database specific
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headers and libraries installed for the DBD::Foo module.  The Configure
process or the Perl build process will not help you with these.

=head2 suidperl

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suidperl was an optional component of earlier releases of perl. It is no
longer available.  Instead, use a tool specifically designed to handle
changes in privileges, such as B<sudo>.

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=head1 make depend

This will look for all the includes.  The output is stored in makefile.
The only difference between Makefile and makefile is the dependencies at
the bottom of makefile.  If you have to make any changes, you should edit
makefile, not Makefile, since the Unix make command reads makefile first.
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(On non-Unix systems, the output may be stored in a different file.
Check the value of $firstmakefile in your if in doubt.)

Configure will offer to do this step for you, so it isn't listed
explicitly above.

=head1 make

This will attempt to make perl in the current directory.

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=head2 Expected errors

These error reports are normal, and can be ignored:
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  make: [extra.pods] Error 1 (ignored)
  make: [extras.make] Error 1 (ignored)

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=head2 What if it doesn't work?

If you can't compile successfully, try some of the following ideas.
If none of them help, and careful reading of the error message and
the relevant manual pages on your system doesn't help,
then see L<"Reporting Problems"> below.
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=over 4

=item hints

If you used a hint file, try reading the comments in the hint file
for further tips and information.

=item extensions

If you can successfully build miniperl, but the process crashes
during the building of extensions, run
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	make minitest

to test your version of miniperl.

=item locale

If you have any locale-related environment variables set, try unsetting
them.  I have some reports that some versions of IRIX hang while
running B<./miniperl configpm> with locales other than the C locale.
See the discussion under L<"make test"> below about locales and the
whole L<perllocale/"LOCALE PROBLEMS"> section in the file pod/perllocale.pod.
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The latter is especially useful if you see something like this

	perl: warning: Setting locale failed.
	perl: warning: Please check that your locale settings:
	        LC_ALL = "En_US",
	        LANG = (unset)
	    are supported and installed on your system.
	perl: warning: Falling back to the standard locale ("C").

at Perl startup.

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=item other environment variables

Configure does not check for environment variables that can sometimes
have a major influence on how perl is built or tested. For example,
OBJECT_MODE on AIX determines the way the compiler and linker deal with
their objects, but this is a variable that only influences build-time
behaviour, and should not affect the perl scripts that are eventually
executed by the perl binary. Other variables, like PERL_UNICODE,
PERL5LIB, and PERL5OPT will influence the behaviour of the test suite.
So if you are getting strange test failures, you may want to try
retesting with the various PERL variables unset.

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=item varargs

If you get varargs problems with gcc, be sure that gcc is installed
correctly and that you are not passing -I/usr/include to gcc.  When using
gcc, you should probably have i_stdarg='define' and i_varargs='undef'
in  The problem is usually solved by installing gcc
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correctly.  If you do change, don't forget to propagate
your changes (see L<"Propagating your changes to"> below).
See also the L<"vsprintf"> item below.

=item util.c

If you get error messages such as the following (the exact line
numbers and function name may vary in different versions of perl):

    util.c: In function 'Perl_form':
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    util.c:1107: number of arguments doesn't match prototype
    proto.h:125: prototype declaration

it might well be a symptom of the gcc "varargs problem".  See the
previous L<"varargs"> item.


If you run into dynamic loading problems, check your setting of
the LD_LIBRARY_PATH environment variable.  If you're creating a static
Perl library (libperl.a rather than it should build
fine with LD_LIBRARY_PATH unset, though that may depend on details
of your local setup.
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=item nm extraction

If Configure seems to be having trouble finding library functions,
try not using nm extraction.  You can do this from the command line

	sh Configure -Uusenm

or by answering the nm extraction question interactively.
If you have previously run Configure, you should not reuse your old

=item umask not found

If the build processes encounters errors relating to umask(), the problem
is probably that Configure couldn't find your umask() system call.
Check your  You should have d_umask='define'.  If you don't,
this is probably the L<"nm extraction"> problem discussed above.  Also,
try reading the hints file for your system for further information.

=item vsprintf

If you run into problems with vsprintf in compiling util.c, the
problem is probably that Configure failed to detect your system's
version of vsprintf().  Check whether your system has vprintf().
(Virtually all modern Unix systems do.)  Then, check the variable
d_vprintf in  If your system has vprintf, it should be:


If Configure guessed wrong, it is likely that Configure guessed wrong
on a number of other common functions too.  This is probably
the L<"nm extraction"> problem discussed above.

=item do_aspawn

If you run into problems relating to do_aspawn or do_spawn, the
problem is probably that Configure failed to detect your system's
fork() function.  Follow the procedure in the previous item
on L<"nm extraction">.

=item __inet_* errors

If you receive unresolved symbol errors during Perl build and/or test
referring to __inet_* symbols, check to see whether BIND 8.1 is
installed.  It installs a /usr/local/include/arpa/inet.h that refers to
these symbols.  Versions of BIND later than 8.1 do not install inet.h
in that location and avoid the errors.  You should probably update to a
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newer version of BIND (and remove the files the old one left behind).
If you can't, you can either link with the updated resolver library provided
with BIND 8.1 or rename /usr/local/bin/arpa/inet.h during the Perl build and
test process to avoid the problem.

=item .*_r() prototype NOT found
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On a related note, if you see a bunch of complaints like the above about
reentrant functions -- specifically networking-related ones -- being present
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but without prototypes available, check to see if BIND 8.1 (or possibly
other BIND 8 versions) is (or has been) installed. They install
header files such as netdb.h into places such as /usr/local/include (or into
another directory as specified at build/install time), at least optionally.
Remove them or put them in someplace that isn't in the C preprocessor's
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header file include search path (determined by -I options plus defaults,
normally /usr/include).
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=item #error "No DATAMODEL_NATIVE specified"

This is a common error when trying to build perl on Solaris 2.6 with a
gcc installation from Solaris 2.5 or 2.5.1.  The Solaris header files
changed, so you need to update your gcc installation.  You can either
rerun the fixincludes script from gcc or take the opportunity to
update your gcc installation.

=item Optimizer

If you can't compile successfully, try turning off your compiler's
optimizer.  Edit and change the line



	optimize=' '

then propagate your changes with B<sh Configure -S> and rebuild
with B<make depend; make>.

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=item Missing functions and Undefined symbols

If the build of miniperl fails with a long list of missing functions or
undefined symbols, check the libs variable in the file.  It
should look something like

	libs='-lsocket -lnsl -ldl -lm -lc'

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The exact libraries will vary from system to system, but you typically
need to include at least the math library -lm.  Normally, Configure
will suggest the correct defaults.  If the libs variable is empty, you
need to start all over again.  Run

	make distclean

and start from the very beginning.  This time, unless you are sure of
what you are doing, accept the default list of libraries suggested by

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If the libs variable is missing -lm, there is a chance that
is available, but the required (symbolic) link to is missing.
(same could be the case for other libraries like  You
should check your installation for packages that create that link, and
if no package is installed that supplies that link or you cannot install
them, make the symbolic link yourself e.g.:

 $ rpm -qf /usr/lib64/
 $ ls -lgo /usr/lib64/
 lrwxrwxrwx 1 16 Jan  7  2013 /usr/lib64/ -> /lib64/


 $ sudo ln -s /lib64/ /lib64/

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If the libs variable looks correct, you might have the
L<"nm extraction"> problem discussed above.

If you still have missing routines or undefined symbols, you probably
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need to add some library or other, make a symbolic link like described
above, or you need to undefine some feature that Configure thought was
there but is defective or incomplete.  If you used a hint file, see if
it has any relevant advice.  You can also look through through config.h
for likely suspects.
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