NAME
README.macosx - Perl under Mac OS X
SYNOPSIS
This document briefly describes perl under Mac OS X.
DESCRIPTION
The latest Perl release (5.8.8 as of this writing) builds without
changes under Mac OS X. Under 10.3 "Panther" and newer OS versions, all
self-tests pass, and all standard features are supported.
Earlier Mac OS X releases (10.2 "Jaguar" and older) did not include a
completely thread-safe libc, so threading is not fully supported. Also,
earlier releases included a buggy libdb, so some of the DB_File tests
are known to fail on those releases.
Installation Prefix
The default installation location for this release uses the traditional
UNIX directory layout under /usr/local. This is the recommended
location for most users, and will leave the Apple-supplied Perl and its
modules undisturbed.
Using an installation prefix of ’/usr’ will result in a directory
layout that mirrors that of Apple’s default Perl, with core modules
stored in ’/System/Library/Perl/${version}’, CPAN modules stored in
’/Library/Perl/${version}’, and the addition of
’/Network/Library/Perl/${version}’ to @INC for modules that are stored
on a file server and used by many Macs.
SDK support
First, export the path to the SDK into the build environment:
export SDK=/Developer/SDKs/MacOSX10.3.9.sdk
Use an SDK by exporting some additions to Perl’s ’ccflags’ and
’..flags’ config variables:
./Configure -Accflags="-nostdinc -B$SDK/usr/include/gcc \
-B$SDK/usr/lib/gcc -isystem$SDK/usr/include \
-F$SDK/System/Library/Frameworks" \
-Aldflags="-Wl,-syslibroot,$SDK" \
-de
Universal Binary support
To compile perl as a universal binary (built for both ppc and intel),
export the SDK variable as above, selecting the 10.4u SDK:
export SDK=/Developer/SDKs/MacOSX10.4u.sdk
In addition to the compiler flags used to select the SDK, also add the
flags for creating a universal binary:
./Configure -Accflags="-arch i686 -arch ppc -nostdinc -B$SDK/usr/include/gcc \
-B$SDK/usr/lib/gcc -isystem$SDK/usr/include \
-F$SDK/System/Library/Frameworks" \
-Aldflags="-arch i686 -arch ppc -Wl,-syslibroot,$SDK" \
-de
In Leopard (MacOSX 10.5.6 at the time of this writing) you must use the
10.5 SDK:
export SDK=/Developer/SDKs/MacOSX10.5.sdk
You can use the same compiler flags you would use with the 10.4u SDK.
Keep in mind that these compiler and linker settings will also be used
when building CPAN modules. For XS modules to be compiled as a
universal binary, any libraries it links to must also be universal
binaries. The system libraries that Apple includes with the 10.4u SDK
are all universal, but user-installed libraries may need to be re-
installed as universal binaries.
64-bit PPC support
Follow the instructions in INSTALL to build perl with support for
64-bit integers ("use64bitint") or both 64-bit integers and 64-bit
addressing ("use64bitall"). In the latter case, the resulting binary
will run only on G5-based hosts.
Support for 64-bit addressing is experimental: some aspects of Perl may
be omitted or buggy. Note the messages output by Configure for further
information. Please use "perlbug" to submit a problem report in the
event that you encounter difficulties.
When building 64-bit modules, it is your responsiblity to ensure that
linked external libraries and frameworks provide 64-bit support: if
they do not, module building may appear to succeed, but attempts to use
the module will result in run-time dynamic linking errors, and
subsequent test failures. You can use "file" to discover the
architectures supported by a library:
$ file libgdbm.3.0.0.dylib
libgdbm.3.0.0.dylib: Mach-O fat file with 2 architectures
libgdbm.3.0.0.dylib (for architecture ppc): Mach-O dynamically linked shared library ppc
libgdbm.3.0.0.dylib (for architecture ppc64): Mach-O 64-bit dynamically linked shared library ppc64
Note that this issue precludes the building of many Macintosh-specific
CPAN modules ("Mac::*"), as the required Apple frameworks do not
provide PPC64 support. Similarly, downloads from Fink or Darwinports
are unlikely to provide 64-bit support; the libraries must be rebuilt
from source with the appropriate compiler and linker flags. For further
information, see Apple’s 64-Bit Transition Guide at
<http://developer.apple.com/documentation/Darwin/Conceptual/64bitPorting/index.html>.
libperl and Prebinding
Mac OS X ships with a dynamically-loaded libperl, but the default for
this release is to compile a static libperl. The reason for this is
pre-binding. Dynamic libraries can be pre-bound to a specific address
in memory in order to decrease load time. To do this, one needs to be
aware of the location and size of all previously-loaded libraries.
Apple collects this information as part of their overall OS build
process, and thus has easy access to it when building Perl, but
ordinary users would need to go to a great deal of effort to obtain the
information needed for pre-binding.
You can override the default and build a shared libperl if you wish
(Configure ... -Duseshrlib), but the load time on pre-10.4 OS releases
will be greater than either the static library, or Apple’s pre-bound
dynamic library.
With 10.4 "Tiger" and newer, Apple has all but eliminated the
performance penalty for non-prebound libraries.
Updating Apple’s Perl
In a word - don’t, at least without a *very* good reason. Your scripts
can just as easily begin with "#!/usr/local/bin/perl" as with
"#!/usr/bin/perl". Scripts supplied by Apple and other third parties as
part of installation packages and such have generally only been tested
with the /usr/bin/perl that’s installed by Apple.
If you find that you do need to update the system Perl, one issue worth
keeping in mind is the question of static vs. dynamic libraries. If you
upgrade using the default static libperl, you will find that the
dynamic libperl supplied by Apple will not be deleted. If both
libraries are present when an application that links against libperl is
built, ld will link against the dynamic library by default. So, if you
need to replace Apple’s dynamic libperl with a static libperl, you need
to be sure to delete the older dynamic library after you’ve installed
the update.
Known problems
If you have installed extra libraries such as GDBM through Fink (in
other words, you have libraries under /sw/lib), or libdlcompat to
/usr/local/lib, you may need to be extra careful when running Configure
to not to confuse Configure and Perl about which libraries to use.
Being confused will show up for example as "dyld" errors about symbol
problems, for example during "make test". The safest bet is to run
Configure as
Configure ... -Uloclibpth -Dlibpth=/usr/lib
to make Configure look only into the system libraries. If you have
some extra library directories that you really want to use (such as
newer Berkeley DB libraries in pre-Panther systems), add those to the
libpth:
Configure ... -Uloclibpth -Dlibpth='/usr/lib /opt/lib'
The default of building Perl statically may cause problems with complex
applications like Tk: in that case consider building shared Perl
Configure ... -Duseshrplib
but remember that there’s a startup cost to pay in that case (see above
"libperl and Prebinding").
Starting with Tiger (Mac OS X 10.4), Apple shipped broken locale files
for the eu_ES locale (Basque-Spain). In previous releases of Perl,
this resulted in failures in the "lib/locale" test. These failures have
been supressed in the current release of Perl by making the test ignore
the broken locale. If you need to use the eu_ES locale, you should
contact Apple support.
MacPerl
Quite a bit has been written about MacPerl, the Perl distribution for
"Classic MacOS" - that is, versions 9 and earlier of MacOS. Because it
runs in environment that’s very different from that of UNIX, many
things are done differently in MacPerl. Modules are installed using a
different procedure, Perl itself is built differently, path names are
different, etc.
From the perspective of a Perl programmer, Mac OS X is more like a
traditional UNIX than Classic MacOS. If you find documentation that
refers to a special procedure that’s needed for MacOS that’s
drastically different from the instructions provided for UNIX, the
MacOS instructions are quite often intended for MacPerl on Classic
MacOS. In that case, the correct procedure on Mac OS X is usually to
follow the UNIX instructions, rather than the MacPerl instructions.
Carbon
MacPerl ships with a number of modules that are used to access the
classic MacOS toolbox. Many of these modules have been updated to use
Mac OS X’s newer "Carbon" toolbox, and are available from CPAN in the
"Mac::Carbon" module.
Cocoa
There are two ways to use Cocoa from Perl. Apple’s PerlObjCBridge
module, included with Mac OS X, can be used by standalone scripts to
access Foundation (i.e. non-GUI) classes and objects.
An alternative is CamelBones, a framework that allows access to both
Foundation and AppKit classes and objects, so that full GUI
applications can be built in Perl. CamelBones can be found on
SourceForge, at <http://www.sourceforge.net/projects/camelbones/>.
Starting From Scratch
Unfortunately it is not that difficult somehow manage to break one’s
Mac OS X Perl rather severely. If all else fails and you want to
really, REALLY, start from scratch and remove even your Apple Perl
installation (which has become corrupted somehow), the following
instructions should do it. Please think twice before following these
instructions: they are much like conducting brain surgery to yourself.
Without anesthesia. We will not come to fix your system if you do
this.
First, get rid of the libperl.dylib:
# cd /System/Library/Perl/darwin/CORE
# rm libperl.dylib
Then delete every .bundle file found anywhere in the folders:
/System/Library/Perl
/Library/Perl
You can find them for example by
# find /System/Library/Perl /Library/Perl -name '*.bundle' -print
After this you can either copy Perl from your operating system media
(you will need at least the /System/Library/Perl and /usr/bin/perl), or
rebuild Perl from the source code with "Configure -Dprefix=/usr
-Dusershrplib" NOTE: the "-Dprefix=/usr" to replace the system Perl
works much better with Perl 5.8.1 and later, in Perl 5.8.0 the settings
were not quite right.
"Pacifist" from CharlesSoft (<http://www.charlessoft.com/>) is a nice
way to extract the Perl binaries from the OS media, without having to
reinstall the entire OS.
AUTHOR
This README was written by Sherm Pendley <sherm@dot-app.org>, and
subsequently updated by Dominic Dunlop <domo@computer.org>. The
"Starting From Scratch" recipe was contributed by John Montbriand
<montbriand@apple.com>.
DATE
Last modified 2006-02-24.