PERLMACOSX(1) Perl Programmers Reference Guide PERLMACOSX(1)
NAME
perlmacosx - Perl under Mac OS X
SYNOPSIS
This document briefly describes Perl under Mac OS X.
curl http://www.cpan.org/src/perl-5.16.2.tar.gz > perl-5.16.2.tar.gz
tar -xzf perl-5.16.2.tar.gz
cd perl-5.16.2
./Configure -des -Dprefix=/usr/local/
make
make test
sudo make install
DESCRIPTION
The latest Perl release (5.16.2 as of this writing) builds without changes under all versions of Mac OS X from 10.3 "Panther" onwards.
In order to build your own version of Perl you will need 'make' this is part of the Apples developer tools (you only need the 'unix
tools'), usually supplied with Mac OS install DVDs. You do not need the latest version of Xcode (which is now charged for) in order to
install make.
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 ${version} are the previous versions of perl that shipped in
Mac OS X), to maintain backwards compatibility.
In 10.5 "Leopard" and beyond, the environment variable NO_PERL_PREPENDTOPATH (set to anything) will cause perl to not load any
PrependToPath file. Likewise, the NO_PERL_APPENDTOPATH environment variable will case perl to not load any AppendToPath file.
In 10.5.7 for versions of perl before 5.16.2, there is a new path, '/Library/Perl/Updates/${version}' that comes before the system perl
directory. When 'INSTALLDIRS=perl' is specified to Makefile.PL, modules that previous 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/${version}'.
In addition, the Config parameters "installprivlib" and "installarchlib" now corresponds to this new directory. There are also the new
parameters "installupdateslib", "installupdatesarch", "updateslib" and "updatesarch", which also correspond to this new directory, and are
provided for completeness.
However, for perl 5.16.2 in Mac OS X 10.7, the order of the include paths was changed so that '/Library/Perl/5.16.2' came before
'/System/Library/Perl/5.16.2', so '/Library/Perl/Updates' is no longer needed. The Config parameters "installprivlib" and "installarchlib"
have returned to their original values, and "installupdateslib", "installupdatesarch", "updateslib" and "updatesarch" have been removed.
Dtrace Support
Dtrace support has been added to perl to allow tracing of perl subroutine calls, both entry and return. Here is a quick example:
% cat test.pl
#!/usr/bin/perl
sub a {
print "Ah! death. Welcome to thee brother
";
}
sub b {
print "Where art thou a()?
";
a();
}
sub c {
print "The band of alphabets
";
b();
}
sub main {
c();
}
main();
% cat pltest.d
perl$target:::
{
printf("%s
", 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
Since 10.5 "Leopard", Mac OS X provided both 32 and 64-bit support for libraries and frameworks, allowing 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. In 10.6 and beyond, the default architectures were changed to building 32-bit
for both PowerPC and Intel, and 64-bit only for Intel. With ARCHFLAGS, this can be changed to whatever architectures the user wants to
build. For example:
% env ARCHFLAGS='-arch i386 -arch x86_64' perl Makefile.PL
% make
% make install
will build only 2-way universal.
Multiple Version Support
Since 10.6 "SnowLeopard", more than one version of perl are supported. So out of the box, the default version of perl is 5.16. However,
to provide backwards compatibility with previous versions of perl, especially for systems that have installed (version-specific) perl
modules, or to provide newer versions of perl that we aren't ready to make the default, '/usr/bin/perl' can be switched to use an alternate
version, on a per-user or system-wide basis. The alternate version of perl that is provided is .
Users can select the alternate version by simply running the following command:
% defaults write com.apple.versioner.perl Version
Subsequent invocations of '/usr/bin/perl' will then use the version.
In addition, both perl versions 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
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 (set to one of the supported versions) and VERSIONER_PERL_PREFER_32_BIT (set to 'true',
'false', 'yes', 'no', '1' or '0') can also be set, and they override the settings in any 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 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 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 responsibility 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 64-bit 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 ... -Duseshrplib), 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 suppressed 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.
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 -Duseshrplib" 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 2011-10-31.
perl v5.16.2 2013-08-25 PERLMACOSX(1)