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This manual page is for Mac OS X version 10.6If you are running a different version of Mac OS X, view the documentation locally:
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PERLMACOSX(1) Perl Programmers Reference Guide PERLMACOSX(1)
NAME
README.macosx - Perl under Mac OS X
SYNOPSIS
This document briefly describes perl under Mac OS X.
DESCRIPTION
The latest Perl release (5.8.9 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.
Customizations in Apple's Perl
Several custom features have been added to the version of perl in Mac OS X.
Module Search Path (@INC)
Since 10.4 "Tiger", system administrators can easily add paths to perl's module search path. The
file '/Library/Perl/${version}/PrependToPath' contains paths (one per line) that will be added to the
beginning of the search path, while the file '/Library/Perl/${version}/AppendToPath' contains paths
that will be added to the end of the search path.
By default, Mac OS X does not come with a PrependToPath file, but does come with an AppendToPath
file. This file contains the path '/System/Library/Perl/Extras/${version}', where third-party perl
modules that Apple ships on Mac OS X, are installed. In addition, it contains the paths to previous
versions of '/Library/Perl/${version}' (where ${version} are the previous versions of perl that
shipped in Mac OS X), to maintain backwards compatibility.
In 10.5 "Leopard" and beyond, the environment variable NO_PERL_PREPENDTOPATH (set to anything) will
cause perl to not load any PrependToPath file. Likewise, the NO_PERL_APPENDTOPATH environment vari-able variable
able will case perl to not load any AppendToPath file.
In 10.5.7 and beyond, there is a new path, '/Library/Perl/Updates/${version}' that comes before the
system perl directory. Now, when 'INSTALLDIRS=perl' is specified to Makefile.PL, modules that previ-ous previous
ous overwrite those in '/System/Library/Perl/${version}', will now be install in
'/Library/Perl/Updates/${version}'. This allows Apple to update modules in the system perl, but
users will get the versions they installed in '/Library/Perl/Updates/${version}'.
In addition, the Config parameters "installprivlib" and "installarchlib" now corresponds to this new
directory. There are also the new parameters "installupdateslib", "installupdatesarch", "updateslib"
and "updatesarch", which also correspond to this new directory, and are provided for completeness.
Dtrace Support
Dtrace support has been added to perl to allow tracing of perl subroutine calls, both entry and
return. Here is a quick example:
% cat test.pl
#!/usr/bin/perl
sub a {
print "Ah! death. Welcome to thee brother\n";
}
sub b {
print "Where art thou a()?\n";
a();
}
sub c {
print "The band of alphabets\n";
b();
}
sub main {
c();
}
main();
% cat pltest.d
perl$target:::
{
printf("%s\n", copyinstr(arg0));
}
% sudo dtrace -s pltest.d -c 'perl test.pl'
dtrace: description 'perl$target::: ' matched 8 probes
The band of alphabets
Where art thou a()?
Ah! death. Welcome to thee brother
dtrace: pid 50272 has exited
CPU ID FUNCTION:NAME
0 14231 Perl_pp_entersub:sub-entry main
0 14231 Perl_pp_entersub:sub-entry c
0 14231 Perl_pp_entersub:sub-entry b
0 14231 Perl_pp_entersub:sub-entry a
0 15806 Perl_pp_leavesub:sub-return a
0 15806 Perl_pp_leavesub:sub-return b
0 15806 Perl_pp_leavesub:sub-return c
0 15806 Perl_pp_leavesub:sub-return main
64-bit Support
In 10.5 "Leopard", Mac OS X provided both 32 and 64-bit support for libraries and frameworks, allow-ing allowing
ing both 32 and 64-bit applications to be written. While running perl (and all other command-line
programs) remained 32-bit, the 'libperl.dylib' library is 32/64 bits. This allows programs with
embedded perl support to run in both 32 and 64-bit mode as needed.
To support this, changes to the Config module were made to return the correct values for the internal
sizes of perl types. For example, "longsize" return 4 in 32-bits, while it returns 8 in 64-bits.
Related to this support is the new environment variable ARCHFLAGS, which provides a way to build
extensions for different machine and 32/64-bit architectures. The default architecture to build
extensions before 10.5 was the (single) architecture of the building machine. In 10.5, this became
building both 32-bit PowerPC and Intel. With ARCHFLAGS, this can be changed to whatever architec-tures architectures
tures the user wants to build. For example:
% env ARCHFLAGS='-arch i386 -arch ppc -arch x86_64' perl Makefile.PL
% make
% make install
will build 3-way universal.
Multiple Version Support
In 10.6 "SnowLeopard", multiple versions of perl are supported. This means that out of the box, the
default version of perl is 5.10.0. However, to provide backwards compatibility with previous ver-sions versions
sions of perl, especially for systems that have installed (version-specific) perl modules,
'/usr/bin/perl' can be switched to use an older version, on a per-user or system-wide basis. The
previous version of perl that is provided is 5.8.9.
Users can select the older version by simply running the following command:
% defaults write com.apple.versioner.perl Version 5.8.9
Subsequent invocations of '/usr/bin/perl' will then use the 5.8.9 version.
In addition, perl 5.10.0 will ship as a universal binary containing 64-bit support, which will be on
by default. For those cases where 32-bit perl is desired, the following command can be used:
% defaults write com.apple.versioner.perl Prefer-32-Bit -bool yes
(Since perl 5.8.9 will only ship as a 32-bit universal binary, the "Prefer-32-Bit" setting makes no
difference when Version is set to 5.8.9.)
To set defaults systemwide, use the above commands, but replace the third argument with
'/Library/Preferences/com.apple.versioner.perl' (admin privileges will be required).
The environment variables VERSIONER_PERL_VERSION and VERSIONER_PERL_PREFER_32_BIT (set to 'true',
'false', 'yes', 'no', '1' or '0') can also be set, and they have priority over the preference files.
Note: this may changes in future versions of Mac OS X, which may use an improved scheme for making
such settings.
Building Perl
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 mod-ules modules
ules 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
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 userinstalled
installed libraries may need to be re-installed as universal binaries.
64-bit 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 fail-ures. failures.
ures. 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 64-bit support. Similarly, downloads from Fink or Dar-winports Darwinports
winports 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 prebound
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 ques-tion question
tion 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 Con-figure Configure
figure 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 bro-ken broken
ken locale. If you need to use the eu_ES locale, you should contact Apple support.
Other Mac OS X Specific Modules
MacPerl
Quite a bit has been written about MacPerl, the Perl distribution for "Classic MacOS" - that is, ver-sions versions
sions 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 Source-Forge, SourceForge,
Forge, 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 your-self. yourself.
self. 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 -Dpre-fix=/usr -Dprefix=/usr
fix=/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 bina-ries binaries
ries from the OS media, without having to reinstall the entire OS.
AUTHOR
This README was written by Sherm Pendley <[email protected]>, and subsequently updated by Dominic
Dunlop <[email protected]>. The "Starting From Scratch" recipe was contributed by John Montbriand
<[email protected]>.
DATE
Last modified 2009-02-24.
perl v5.8.9 2007-11-17 PERLMACOSX(1)
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