Compiling 64 bit python on a mac - cannot compute sizeof (int)

Mark Dickinson dickinsm at
Fri Jul 3 22:18:09 CEST 2009

On Jul 3, 5:30 pm, Keflavich <keflav... at> wrote:
> I'm trying to compile a 64 bit version of python 2.6.2 on my mac (OS X
> 10.5.7), and am running into a problem during the configure stage.
> I configure with:
> ./configure --enable-framework=/Library/Frameworks --enable-
> universalsdk MACOSX_DEPLOYMENT_TARGET=10.5 --with-universal-archs=all -
> with-readline-dir=/usr/local
> because I want 64 and 32 bit, and I needed to install a 64 bit
> readline as a prerequisite.
> configure fails at:
> checking size of int... configure: error: cannot compute sizeof (int)

I confess that I don't fully understand the intricacies of the various
OS X autoconf options, but I think the problem is that the --enable-
universalsdk option takes a directory.  If that directory isn't
given, it appears to default to /Developer/SDKs/MacOSX10.4u.sdk (at
least on my OS X 10.5.7 machine), which would likely conflict with

Try either changing MACOSX_DEPLOYMENT_TARGET to 10.4, or using --
enable-universalsdk=/Developer/SDKs/MacOSX10.5.sdk  (or whatever the
appropriate directory is on your system).  For some reason, I think
using --enable-universalsdk=/ also works on my system.  If none of
that helps, you might try asking this question over on the pythonmac-
sig mailing list. (


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