Cross compiling (i386 from amd64) with distutils

[bobicanprogram]

On Nov 7, 7:19 pm, Jason <jason.hee... at gmail.com> wrote:
> My situation is this: I have a Diamond Systems single-board computer
> with a
> matching GPIO board. DS have a library for controlling the GPIO
> board... but
> it's a static library (libdscud-6.02.a) with an accompanying header
> (dscud.h).
> I'd like to create a Python extension to use the device.
>
> The architecture of the SBC is 486, and it runs Debian Squeeze/Grip.
> While it
> is possible to develop on it directly, I'd rather use my desktop
> machine
> (Debian Squeeze, amd64).
>
> If I write a simple C program to control the device, I'd include the
> header
> file and cross-compile it like so:
>
>     gcc -m32 -march=i386 -lpthread -I/usr/local/dscud-6.02 -o dio
> dio.c \
>         /usr/local/dscud-6.02/libdscud-6.02.a
>
> To get myself started with the Python extension, I've basically taken
> the
> "noddy" demo[1] and thrown in a function call from the DSC library
> just to see
> if I can get something to build.
>
> My distutils setup.py looks like:
>
> ----
> from distutils.core import setup, Extension
>
> module1 = Extension('noddy',
>             sources = ['src/noddy.c'],
>             libraries = ['pthread'],
>             include_dirs = ['/usr/local/dscud-6.02'],
>             extra_objects = ['/usr/local/dscud-6.02/libdscud-6.02.a'],
>             extra_compile_args = ['-m32', '-march=i386'])
>
> setup(name = 'Noddy', version = '1.0', description = 'This is a demo
> package',
>       ext_modules = [module1])
> ----
>
> This works fine on the target machine with "python setup.py build",
> but when I
> try it on my desktop machine, I get:
>
> ----
> $ python setup.py build
> running build
> running build_ext
> building 'noddy' extension
> creating build
> creating build/temp.linux-x86_64-2.6
> creating build/temp.linux-x86_64-2.6/src
> gcc -pthread -fno-strict-aliasing -DNDEBUG -g -fwrapv -O2 -Wall
> -Wstrict-prototypes -fPIC -I/usr/local/dscud-6.02 -I/usr/include/
> python2.6 -c
> src/noddy.c -o build/temp.linux-x86_64-2.6/src/noddy.o -m32 -
> march=i386
> In file included from /usr/include/python2.6/Python.h:58,
>                  from src/noddy.c:1:
> /usr/include/python2.6/pyport.h:694:2: error: #error "LONG_BIT
> definition
> appears wrong for platform (bad gcc/glibc config?)."
> error: command 'gcc' failed with exit status 1
>
> ----
>
> So is it possible to get distutils to cross compile something like
> this, and
> if so, what am I missing? Or am I using the wrong tool for the job?
>
> Target python ver. is 2.6. GCC is 4.4.5.
>
> Cheers,
> Jason
>
> [1]http://docs.python.org/extending/newtypes.html


Cross compilation might be one solution to Python access.   The SIMPL
toolkit (http://www.icanprogram.com/simpl; http://www.icanprogram.com/06py/lesson1/lesson1.html)
might be easier.   If you ultimately want to communicate from a 64bit
to a 32bit system,  you'll probably want to use a text based tokenized
messaging strategy as opposed to the binary one in these examples.

bob