cpython/Mac

============
MacOSX Notes
============

This document provides a quick overview of some Mac OS X specific features in
the Python distribution.


Building and using a universal binary of Python on Mac OS X
===========================================================

1. What is a universal binary
-----------------------------

A universal binary build of Python contains object code for both PPC and i386
and can therefore run at native speed on both classic powerpc based macs and
the newer intel based macs.

2. How do I build a universal binary
------------------------------------

You can enable universal binaries by specifying the "--enable-universalsdk"
flag to configure::

  $ ./configure --enable-universalsdk
  $ make
  $ make install

This flag can be used a framework build of python, but also with a classic
unix build. Either way you will have to build python on Mac OS X 10.4 (or later)
with Xcode 2.1 (or later). You also have to install the 10.4u SDK when 
installing Xcode.


Building and using a framework-based Python on Mac OS X.
========================================================


1. Why would I want a framework Python instead of a normal static Python?
--------------------------------------------------------------------------

The main reason is because you want to create GUI programs in Python. With the
exception of X11/XDarwin-based GUI toolkits all GUI programs need to be run 
from a fullblown MacOSX application (a ".app" bundle).

While it is technically possible to create a .app without using frameworks you
will have to do the work yourself if you really want this.

A second reason for using frameworks is that they put Python-related items in
only two places: "/Library/Framework/Python.framework" and 
"/Applications/MacPython 2.6".  This simplifies matters for users installing 
Python from a binary distribution if they want to get rid of it again. Moreover,
due to the way frameworks work a user without admin privileges can install a 
binary distribution in his or her home directory without recompilation.

2. How does a framework Python differ from a normal static Python?
------------------------------------------------------------------

In everyday use there is no difference, except that things are stored in
a different place. If you look in /Library/Frameworks/Python.framework
you will see lots of relative symlinks, see the Apple documentation for
details. If you are used to a normal unix Python file layout go down to
Versions/Current and you will see the familiar bin and lib directories.

3. Do I need extra packages?
----------------------------

Yes, probably.  If you want Tkinter support you need to get the OSX AquaTk 
distribution, this is installed by default on Mac OS X 10.4 or later. If
you want wxPython you need to get that. If you want Cocoa you need to get
PyObjC. 

4. How do I build a framework Python?
-------------------------------------

This directory contains a Makefile that will create a couple of python-related
applications (fullblown OSX .app applications, that is) in
"/Applications/MacPython 2.6", and a hidden helper application Python.app 
inside the Python.framework, and unix tools "python" and "pythonw" into 
/usr/local/bin.  In addition it has a target "installmacsubtree" that installs 
the relevant portions of the Mac subtree into the Python.framework.

It is normally invoked indirectly through the main Makefile, as the last step
in the sequence

 1. ./configure --enable-framework

 2. make
 
 3. make install

This sequence will put the framework in /Library/Framework/Python.framework,
the applications in "/Applications/MacPython 2.6" and the unix tools in 
/usr/local/bin.

Installing in another place, for instance $HOME/Library/Frameworks if you have
no admin privileges on your machine, has only been tested very lightly. This
can be done by configuring with --enable-framework=$HOME/Library/Frameworks.
The other two directories, "/Applications/MacPython-2.6" and /usr/local/bin, 
will then also be deposited in $HOME. This is sub-optimal for the unix tools, 
which you would want in $HOME/bin, but there is no easy way to fix this right 
now.

If you want to install some part, but not all, read the main Makefile. The
frameworkinstall is composed of a couple of sub-targets that install the
framework itself, the Mac subtree, the applications and the unix tools.

There is an extra target frameworkinstallextras that is not part of the
normal frameworkinstall which installs the Demo and Tools directories
into "/Applications/MacPython 2.6", this is useful for binary distributions.

What do all these programs do?
===============================

"IDLE.app" is an integrated development environment for Python: editor,
debugger, etc.

"PythonLauncher.app" is a helper application that will handle things when you
double-click a .py, .pyc or .pyw file. For the first two it creates a Terminal
window and runs the scripts with the normal command-line Python. For the
latter it runs the script in the Python.app interpreter so the script can do
GUI-things. Keep the "alt" key depressed while dragging or double-clicking a
script to set runtime options. These options can be set once and for all
through PythonLauncher's preferences dialog.

The commandline scripts /usr/local/bin/python and pythonw can be used to run
non-GUI and GUI python scripts from the command line, respectively.

How do I create a binary distribution?
======================================

Go to the directory "Mac/OSX/BuildScript". There you'll find a script 
"build-installer.py" that does all the work. This will download and build
a number of 3th-party libaries, configures and builds a framework Python,
installs it, creates the installer pacakge files and then packs this in a 
DMG image.

The script will build a universal binary, you'll therefore have to run this
script on Mac OS X 10.4 or later and with Xcode 2.1 or later installed.

All of this is normally done completely isolated in /tmp/_py, so it does not
use your normal build directory nor does it install into /.

Because of the way the script locates the files it needs you have to run it
from within the BuildScript directory. The script accepts a number of 
command-line arguments, run it with --help for more information.

Configure warnings
==================

The configure script sometimes emits warnings like the one below::

   configure: WARNING: libintl.h: present but cannot be compiled
   configure: WARNING: libintl.h:     check for missing prerequisite headers?
   configure: WARNING: libintl.h: see the Autoconf documentation
   configure: WARNING: libintl.h:     section "Present But Cannot Be Compiled"
   configure: WARNING: libintl.h: proceeding with the preprocessor's result   
   configure: WARNING: libintl.h: in the future, the compiler will take precedence
   configure: WARNING:     ## -------------------------------------- ##
   configure: WARNING:     ## Report this to http://bugs.python.org/ ##
   configure: WARNING:     ## -------------------------------------- ##

This almost always means you are trying to build a universal binary for
Python and have libaries in ``/usr/local`` that don't contain the required
architectures. Temporarily move ``/usr/local`` aside to finish the build.

Odds and ends
=============

Something to take note of is that the ".rsrc" files in the distribution are
not actually resource files, they're AppleSingle encoded resource files. The
macresource module and the Mac/OSX/Makefile cater for this, and create
".rsrc.df.rsrc" files on the fly that are normal datafork-based resource
files.

	Jack Jansen, Jack.Jansen@cwi.nl, 15-Jul-2004.
	Ronald Oussoren, RonaldOussoren@mac.com, 26-May-2006