A trivial Python SWIG error question

Question

I am trying to get Python running with swig to do C/C++. I am running the tutorial here, 'building a python module'. When I do the call

gcc -c example.c example_wrap.c -I /my_correct_path/python2.5

I get an error:

my_correct_path/python2.5/pyport.h:761:2: error: #error "LONG_BIT definition appears wrong for platform (bad gcc/glibc config?)."
example_wrap.c: In function 'SWIG_Python_ConvertFunctionPtr':
example_wrap.c:2034: warning: initialization discards qualifiers from pointer target type
example_wrap.c: In function 'SWIG_Python_FixMethods':
example_wrap.c:3232: warning: initialization discards qualifiers from pointer target type

It actually does create an example.o file, but it doesn't work. I am using python2.5 not 2.1 as in the example, is this a problem? The error (everything else is just a 'warning') says something about wrong platform. This is a 64bit machine; is this a problem? Is my gcc configured wrong for my machine? How do I get past this?

UPDATE: I am still having problems. How do I actually implement this "fix"?

Answer 1

I found this thread looking for an answer for the same "LONGBIT" error while installing python readline for 32bit python on 64bit centos. The link doesn't have the direct answer, so I had to google further for the answer (which might be straight-forward for seasoned linux users/devs). For future reference, the solution is to force 32-bit by using "-m32" in CFLAGS environment variable.

bash-3.2$ easy_install readline
Searching for readline
Reading http://pypi.python.org/simple/readline/
Reading http://www.python.org/
Best match: readline 2.6.4
Downloading http://pypi.python.org/packages/source/r/readline/readline-2.6.4.tar.gz#md5=7568e8b78f383443ba57c9afec6f4285
Processing readline-2.6.4.tar.gz
Running readline-2.6.4/setup.py -q bdist_egg --dist-dir /tmp/easy_install-mqr9wH/readline-2.6.4/egg-dist-tmp-p3apfF
In file included from /usr/local/python2.6/include/python2.6/Python.h:58,
                 from Modules/readline.c:8:
/usr/local/python2.6/include/python2.6/pyport.h:685:2: error: #error "LONG_BIT definition appears wrong for platform (bad gcc/glibc config?)."
error: Setup script exited with error: command 'gcc' failed with exit status 1

I then tried with CFLAGS=-m32:

bash-3.2$ CFLAGS=-m32 easy_install readline
Searching for readline
Reading http://pypi.python.org/simple/readline/
Reading http://www.python.org/
Best match: readline 2.6.4
Downloading http://pypi.python.org/packages/source/r/readline/readline-2.6.4.tar.gz#md5=7568e8b78f383443ba57c9afec6f4285
Processing readline-2.6.4.tar.gz
Running readline-2.6.4/setup.py -q bdist_egg --dist-dir /tmp/easy_install-uauVci/readline-2.6.4/egg-dist-tmp-YY0tQa
In file included from /usr/include/features.h:352,
                 from /usr/include/limits.h:27,
                 from /usr/lib/gcc/x86_64-redhat-linux/4.1.2/include/limits.h:122,
                 from /usr/lib/gcc/x86_64-redhat-linux/4.1.2/include/syslimits.h:7,
                 from /usr/lib/gcc/x86_64-redhat-linux/4.1.2/include/limits.h:11,
                 from /usr/local/python2.6/include/python2.6/Python.h:19,
                 from Modules/readline.c:8:
/usr/include/gnu/stubs.h:7:27: error: gnu/stubs-32.h: No such file or directory
error: Setup script exited with error: command 'gcc' failed with exit status 1

The latest error is due to not having glibc-devel package for 32bit (thanks to this thread). I also had to install ncurses-devel.i386 and then easy_install went through and ipython recognized it. My life felt ruined until I got this working for the sake of ipython.

bash-3.2$ CFLAGS=-m32 easy_install readline
Searching for readline
Reading http://pypi.python.org/simple/readline/
Reading http://www.python.org/
Best match: readline 2.6.4
Downloading http://pypi.python.org/packages/source/r/readline/readline-2.6.4.tar.gz#md5=7568e8b78f383443ba57c9afec6f4285
Processing readline-2.6.4.tar.gz
Running readline-2.6.4/setup.py -q bdist_egg --dist-dir /tmp/easy_install-dHly4D/readline-2.6.4/egg-dist-tmp-oIEDYl
Adding readline 2.6.4 to easy-install.pth file

Installed /home/hari/bin/python/lib/python2.6/site-packages/readline-2.6.4-py2.6-linux-x86_64.egg
Processing dependencies for readline
Finished processing dependencies for readline

Answer 2

I had the same error when trying to install a Python package, but fixed it.
The "LONG_BIT" error was:

$ easy_install astropy  
/my_path/epd/epd-7.3-2-rh5-x86/include/python2.7/pyport.h:849:2: 
error: #error "LONG_BIT definition appears wrong for platform 
(bad gcc/glibc config?)." error: Setup script exited with error: 
command 'gcc' failed with exit status 1

As you are suggesting, Alex, I had to install the correct version of Python's epd to match the requirement of my machine and that of the package I wanted to install. There were parallel versions of Python running and I think this is where the confusion and error came from. Go to Enthought's Repository (click "Log in to the repository" -> Installers) and install the correct version.

Make sure you clean things up (or ask someone who knows what they are doing to do this for you) by removing the old Python versions. Then of course change your .cshrc path to point to the new version and source the file correctly. I had no problems after I did this.

I realize this questions was asked 4 years ago!

Answer 3

I actually found this thread twice, a couple years apart, both while trying to install libxml2 from source. The library's configure script actually has a --without-python option, which I used instead of trying to fix the error.