Python: how to determine if running in 32 or 64bit mode?

BrianK · 06-23-2011, 03:10 PM

I know I've done this before, but my googling is failing, so I'll ask here.

How can I programmatically determine if my python script is being run with a 32 or 64 bit interpreter? Better yet, is there a one-liner I can run that will print out the word size of the current python session?

dugan · 06-23-2011, 03:28 PM

sys.maxint?

audriusk · 06-23-2011, 03:54 PM

Code:

import platform
print platform.architecture()[0]

Be sure to read the docstring for details:

Code:

$ pydoc platform.architecture

BrianK · 06-23-2011, 05:56 PM

Thanks to both of you. I think I have my answer now.

I appears that platform.architecture() may only return the architecture of the python on which it is being run as opposed to the 64 or 32-bittedness of the actual instance. Under OSX, you can run in 32bit mode by prefacing the command with a given architecture. For example:

Code:

$ arch -x86_64 /usr/bin/python2.6 -c "import sys;print '%x' % sys.maxint"
7fffffffffffffff

$ arch -i386 /usr/bin/python2.6 -c "import sys;print '%x' % sys.maxint"
7fffffff

$ arch -x86_64 /usr/bin/python2.6 -c "import platform; print platform.architecture()"
('64bit', '')

$ arch -i386 /usr/bin/python2.6 -c "import platform; print platform.architecture()"
('64bit', '')

so platform.architecture may not be as reliable, but it seems like a good way to check if a given python is 32 or 64bit capable.

bgeddy · 06-23-2011, 06:40 PM

Just to elaborate on what you now have - how about the following :

Code:

arch -x86_64 /usr/bin/python2.6 -c "import math,sys;print '%dbit' % (round(math.log(sys.maxint,2)+1))"
arch -i386 /usr/bin/python2.6 -c "import math,sys;print '%dbit' % (round(math.log(sys.maxint,2)+1))"

To report the actual bittedness of the running version of python rather than a long hex number.

BrianK · 06-23-2011, 06:51 PM

Ahh, very cool, bgeddy. Thanks for that addition.

audriusk · 06-24-2011, 08:34 AM

Quote:

Originally Posted by BrianK

I appears that platform.architecture() may only return the architecture of the python on which it is being run as opposed to the 64 or 32-bittedness of the actual instance.

Yes, just checked the docs and it's noted there: http://docs.python.org/library/platf...m.architecture