How to Force Python to Be 32-Bit on Snow Leopard and Other 32-Bit/64-Bit Questions

How do I force Python to be 32-bit on Snow Leopard and other 32-bit/64-bit questions

1. You can find out a lot about the Python version you're running via the platform module (the sys module also has a few simple helpers)

2. On Mac OS X, you can run a "fat binary" with your chosen architecture with, for example,

   arch -i386 /usr/bin/python

I do not recommend altering /usr/lib/python itself (with the lipo command) -- you could easily make your system unusable by tampering with system files. Maybe installing a separate Python from python.org (for application purposes) while leaving the system Python alone is an acceptable strategy to you -- it's definitely safer than altering system files!-)

As for your third question, hmmm, this one's a stumper to me -- and definitely a question for superuser.com (as well as completely unrelated to Python, it also seems completely unrelated to programming;-).

Force Python to be 32 bit on OS X Lion

You can use the lipo command to create a copy of the Python interpreter with only i386 support.

:; file /usr/bin/python2.7
/usr/bin/python2.7: Mach-O universal binary with 2 architectures
/usr/bin/python2.7 (for architecture i386): Mach-O executable i386
/usr/bin/python2.7 (for architecture x86_64):   Mach-O 64-bit executable x86_64

:; lipo -thin i386 -output python-i386 /usr/bin/python2.7

:; file python-i386 
python-i386: Mach-O executable i386

:; ./python-i386
Python 2.7.2 (default, Jun 20 2012, 16:23:33) 
[GCC 4.2.1 Compatible Apple Clang 4.0 (tags/Apple/clang-418.0.60)] on darwin
Type "help", "copyright", "credits" or "license" for more information.
>>> 

Then arrange for your existing scripts to call python-i386, or (if they use the /usr/bin/env trick) rename it to python and put it in a directory that's in your PATH somewhere before /usr/bin.

Note that looking at platform.architecture() or even platform.machine() doesn't actually tell you if the current process is 32-bit or 64-bit. Those always give 64-bit answers for me. But when I check in Activity Monitor, I can see that my stripped binary is not marked “(64-bit)”, while other processes are.

How do I force my code to use 32-bit Python in a virtual environment?

platform.architecture() is unreliable on OSX, to be sure you're still runing 64 bit and not 32 you should run sys.maxsize > 2**32

https://docs.python.org/2/library/platform.html#platform.architecture

Executing python in 64 bit mode on Mac OS X 10.10

From Jeff's comment, I installed python from brew.

> /usr/local/Cellar/python/2.7.9/bin/python -c 'import sys; print sys.maxint'
9223372036854775807

Now, it works fine at least with brew's python.

Run python as a 32-bit process in Eclipse PyDev on Mac OS X Lion

I think the best approach would be installing a Python that's only 32 bit instead of using the Python installed in the system.

Or if you really want to use the one in the system, you can take a look at: How do I force Python to be 32-bit on Snow Leopard and other 32-bit/64-bit questions on other ways to configure Python to run in 32 bits (VERSIONER_PYTHON_PREFER_32_BIT environment variable seems a good choice).

How to force using 64 bit python on Mac OS X?

Try using arch(1), and supply the specific version of Python:

arch -x86_64 /usr/bin/python2.6

Actually the system should choose the first suitable architecture for you. As

$ file /usr/bin/python2.5
/usr/bin/python2.5: Mach-O universal binary with 2 architectures
/usr/bin/python2.5 (for architecture i386): Mach-O executable i386
/usr/bin/python2.5 (for architecture ppc7400):  Mach-O executable ppc

$ file /usr/bin/python2.6
/usr/bin/python2.6: Mach-O universal binary with 3 architectures
/usr/bin/python2.6 (for architecture x86_64):   Mach-O 64-bit executable x86_64
/usr/bin/python2.6 (for architecture i386): Mach-O executable i386
/usr/bin/python2.6 (for architecture ppc7400):  Mach-O executable ppc

If that python somehow chooses 2.5, then you can't use 64-bit, but if it chooses 2.6 then the x86_64 variant should be automatically selected, as commented below. If it's the former, try to get python_select and change the version to 2.6.

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