Here's a cross compile patch I prepared a while ago but
never got around to submitting.  I've been using it
happily for months to cross compile python for embedded
systems.

Below is a descriptive excerpt from the patch.  Also
note that the patch modifies configure.in, but not
configure.  You will need to regenerate configure with
something like 

autoconf configure.in >configure

This patch is inpsired from work by Klaus Reimer at
http://www.ailis.de/~k/docs/crosscompiling/python.php

+ Cross Compiling
+ ---------------
+ 
+ Python can be cross compiled by supplying different
--host and --build
+ parameters to configure.  (Python is compiled on the
"build" system
+ and executed on the "host" system, in case you forgot
:).  Python is
+ tricky to cross compile because it needs to execute
parts of itself
+ during construction.  To work around this, make's
VPATH feature is
+ used to compile a native python in the subdirectory
"buildpython".
+ When parts of python need to be executed during
construction, the
+ "buildpython" versions are used.
+ 
+ A consequence of using the VPATH feature is that you
may not do a
+ cross compile build in the source directory.  In
other words, do this:
+ 
+ mkdir mydir
+ cd mydir
+ ../Python/configure --host=powerpc-405-linux-gnu
--build=i686-pc-linux-gnu
+ make
+ 
+ Cross compiling works well under linux, mileage may
vary for other
+ platforms.
+ 
+ A few reminders on using configure to cross compile:
+ - Cross compile tools must be in the PATH.
+ - Cross compile tools must be prefixed with the host type
+ (ie powerpc-405-linux-gnu-cc,
powerpc-405-linux-gnu-ranlib, ...)
+ - CC, CXX, AR, and RANLIB must be undefined when
running configure and
+ make.  Configure will detect them.
+ 
+ If you need a cross compiler, check out Dan Kegel's
crosstool:
+ http://www.kegel.com/crosstool
+ 
+ 

Logged In: YES 
user_id=2772

This patch applies cleanly to today's CVS head.

If building in the source directory while cross compiling
fails, please make configure complain about it.

This patch makes the build process invoke make recursively,
which is a big minus.  I'd rather see pgen built with a
HOSTCC and just assume python is available on $PATH for the
setup.py step.  There's no reason to build all the shared
modules in buildpython, either, which would speed things up
a fair bit.

On to how it worked for me:
Not cross-compiling, this produces no unexpected test
failures in "make test". (redhat9)

Cross compiling for i386-pc-bsdi2.1 everything goes fine
until it tries to run buildpython and make shared modules,
but shared modules don't work in the first place on bsdi2. 
I did not test the resulting Python binary.

Cross compiling for i386-redhat-linux (libc6) some
extensions fail to build, but this could be because my
header files for the cross-development environment are not
complete.  Running "make test" tries to invoke the
"buildpython/python" and doesn't work.  Running it manually
I get some skips due to modules that did not build, but
everything that did build seems to pass. (OK, so I wrote
this before the tests completed, but they're off to a good
start)

I currently cross-compile python 2.3 for win32 (mingw), and
until recently cross-compiled it for bsdi2 and redhat6. 
However, I did not use configure or the included makefiles
to do this (in order to integrate in a non-recursive build
procedure that builds several packages), so this patch is
unlikely to benefit me directly.

I don't think this patch is ready to be applied.

Logged In: YES 
user_id=114429

we've been using this with uClibc for a while now and it
works great ...

ive personally built (on amd64) & deployed (on
x86/ppc/arm/mips/sh4) python ... would great if this finally
made it into the official sources :)

Logged In: YES 
user_id=148412

Any progress with this on? 
python and perl are two of the last major things to overcome
in the x-compile world.

Logged In: YES 
user_id=843814

It still works for me, so I've had limited interest in
working on it further.

I think a "real" cross compile patch will involve
significant refactoring of distutils and the main setup.py
script.  Should this start with a PEP?

Logged In: YES 
user_id=1277505

Just thought I'd let you know that this patch works against
Python 2.4.2. I had Python running on my custom AT91RM9200
board (ARM920T core) in about 20 minutes.

*snaps* for Daniel!!

Logged In: YES 
user_id=845425

Hmm. not so much luck here. I get the following error after
patching then autoconf. I am running on Fedora Core 4.

Any suggestions?

[dlambert@lambsys Python-2.4.2]$ autoconf configure.in
>configure
[dlambert@lambsys Python-2.4.2]$ ./configure
configure: error: cannot run /bin/sh ./config.sub
[dlambert@lambsys Python-2.4.2]$

Logged In: YES 
user_id=843814

You can't configure in the source directory with the cross
compile patch.  This is explained in the directions.

Logged In: YES 
user_id=845425

Thanks for the quick reply, and sorry for the confusion.

I DID try the cross compile in a sub directory. That failed
with the same error. I then tried a non-cross build in the
main directory, that also failed (which was my previous
post). Here is my complete transcript after untarring Python:

[dlambert@lambsys Python-2.4.2]$ patch -p0 < ../python-patch
can't find file to patch at input line 3
Perhaps you used the wrong -p or --strip option?
The text leading up to this was:
--------------------------
|*** python-cvs-pristine/dist/src/README        Fri Mar  5
08:33:21 2004
|--- python/dist/src/README     Mon Apr  5 14:30:23 2004
--------------------------
File to patch: README
patching file README
Hunk #1 succeeded at 1130 (offset 30 lines).
can't find file to patch at input line 48
Perhaps you used the wrong -p or --strip option?
The text leading up to this was:
--------------------------
|*** python-cvs-pristine/dist/src/configure.in  Sun Mar 21
17:45:41 2004
|--- python/dist/src/configure.in       Mon Apr  5 16:15:07 2004
--------------------------
File to patch: configure.in
patching file configure.in
Hunk #2 succeeded at 609 (offset 58 lines).
Hunk #3 succeeded at 3072 (offset 112 lines).
can't find file to patch at input line 113
Perhaps you used the wrong -p or --strip option?
The text leading up to this was:
--------------------------
|*** python-cvs-pristine/dist/src/Makefile.pre.in       Thu
Mar 18 01:51:27 2004
|--- python/dist/src/Makefile.pre.in    Mon Apr  5 15:56:00 2004
--------------------------
File to patch: Makefile.pre.in
patching file Makefile.pre.in
Hunk #2 succeeded at 163 (offset 3 lines).
Hunk #4 succeeded at 309 (offset 5 lines).
Hunk #6 succeeded at 470 (offset 5 lines).
Hunk #7 succeeded at 624 (offset 1 line).
Hunk #8 succeeded at 839 (offset 7 lines).
Hunk #9 succeeded at 923 (offset 1 line).
Hunk #10 succeeded at 969 (offset 7 lines).
can't find file to patch at input line 309
Perhaps you used the wrong -p or --strip option?
The text leading up to this was:
--------------------------
|*** python-cvs-pristine/dist/src/setup.py      Sun Mar 21
12:59:46 2004
|--- python/dist/src/setup.py   Mon Apr  5 15:20:55 2004
--------------------------
File to patch: setup.py
patching file setup.py
Hunk #1 succeeded at 198 (offset -2 lines).
patching file python/dist/src/config.guess
patching file python/dist/src/config.sub
[dlambert@lambsys Python-2.4.2]$
[dlambert@lambsys Python-2.4.2]$
[dlambert@lambsys Python-2.4.2]$ autoconf configure.in >
configure
[dlambert@lambsys Python-2.4.2]$ mkdir cross-build
[dlambert@lambsys Python-2.4.2]$ cd cross-build
[dlambert@lambsys cross-build]$ ../configure
--host=arm-linux --build=i686-pc-li nux-gnu
configure: error: cannot run /bin/sh ../config.sub
[dlambert@lambsys cross-build]$

Logged In: YES 
user_id=843814

patch isn't lying about wrong -p options.  Use -p3 instead
of -p0.

Cheers,
Dan.

Logged In: YES 
user_id=845425

Oops! All works fine now. Thanks :-)

Logged In: YES 
user_id=1420135

I am a Chinese and my English is very poor.I'm sorry if 
what I said is wrong.My question is What should I do 
after './configure'.Before this I have done patch and 
autoconf.

Thanks :-)

Logged In: YES 
user_id=843814

After configure you run "make".

But did you use configure as the instructions say?  You
cannot just use "./configure".

Good luck,
Dan.

Logged In: YES 
user_id=1420135

Thank you for your rapid answer.But I still can't solve my 
question.I can't find the whole instructions. Can you give 
me the whole instructions by EMAIL,my email is 
xudong888@163.com,thanks.
My "host" system is mips embbed_linux,the release of the 
linux kernel is 2.4.xx and the CPU type is MIPS 4Kc.There 
are no python installed on this system.My "build" system is 
i86 and operate system is RedHat9.0,and has installed 
python2.4.1 and cross-compiling Tools mipsel-linux-gcc.I 
can cross compile C program for the "host" system.I have 
writed some program with python language.I can get the 
binary from python script by use freeze.py on the "build" 
system. Now I want to run the binary on the "host" 
system.Can you tell me how should I do.
in addition,I don't know what parameter I should input to 
use this patch.
finally,I'm sorry for my poor English.I like python very 
much,but I can't get help in chinese.

Logged In: YES 
user_id=1420135

If you have accounts of MSN,please add me.My accounts is 
xudong_888@hotmail.com. I am very impatient.I hope I can 
get some help from you.Thanks.

Logged In: YES 
user_id=1420135

I have resolved my question,now I can run python on the 
mips machine,and can run some binary build by python.Can I 
also cross compile pygame for python?But the pygame source 
does't has 'configure' and 'Makefiel' files,setup.py 
instead in source package.How should I do?
Thanks :-)

Logged In: YES 
user_id=1081828

Hi,

I try to cross compile Python-2.4.2 for an etrax processor.
I have successfully applied the patch to Python sources.
I then cd to a "MyPython" directory.
I call ../Python-2.4.2/configure --build cris --host i386-linux
It works ok (did not see an error)
I all make
I get the following error after a while :
make : *** No rule to make target '@BUILDPGEN@', needed by
'../Python-2.4.2/Include/graminit.h'. Stop.

Any Idea ?
Nicolas

Logged In: YES 
user_id=843814

Did you run autoconf after patching as instructed?

Also, your --build and --host options seem backwards.  host
is the arch you want python to run on, build is the arch you
build python on.

Cheers,
Dan.

Logged In: YES 
user_id=1081828

You are right, I have misunderstood --build and --host
signification.

And I also forgotten to run autoconf partialy because I
don't have autoconf installed on my system. So I didn't pay
attention it didn't run.

Thanks for your help.
I'll let you know if this works in a few days.

Nicolas

Logged In: YES 
user_id=1330285

Hi again,

I finaly dad enought time to work on my project.
So, I compiled autoconf tools for my system.
Then, I rerun all the steps successfully.

Thanks again for your help.

Nicolas

Logged In: YES 
user_id=1330285

Me again, sorry...


What Should I get after compilation has finished ?
Where are the files for my target ?

Nicolas

Logged In: YES 
user_id=843814

> I then cd to a "MyPython" directory.
> I call ../Python-2.4.2/configure ...

Then your files should be in your "MyPython" directory.

Logged In: YES 
user_id=1330285

Yes I guess.

But it seems that all I get is for the build system.
If I try to execute on the build system ./python it runs.
Also, there is no hostbuild subdirectory. Is it ok ?

Nicolas

Logged In: YES 
user_id=843814

The build system python should be in "MyPython/buildpython",
and the host python should just be in "MyPython"

Are you sure you applied the patch right?  What you're
getting is what would happen if you didn't apply the patch
at all.

Logged In: YES 
user_id=1330285

If I try to aplly the patch again, I get messages saying a
patch has allready been applied.
To apply the patch I executed the following :

cd Python-2.4.2
patch <../python-patch.txt

Logged In: YES 
user_id=843814

You didn't apply the patch properly.  See the other messages
about the use of the -p option.  Start with a fresh source
tree and use:

cd Python-2.4.2
patch -p3 <../python-patch.txt

Logged In: YES 
user_id=1229536

Hi there,
I am trying to cross compile python on the fox board
(etrax). now everything seemed to go well but when running
the python binary is says:
./python: error while loading shared libraries:
libstdc++.so.5: cannot load shared object file: No such file
or directory

I only ftp-ed the python bin not the (much bigger)
libpython2.4a ....
seems this is a library archive of some kind ?
do i need it?
how do i use it then?

thanx a million if you can help me out.

hugo

Logged In: YES 
user_id=843814

Hi hugo.

The problems you are having are less python related and more
system-building/cross-development issues, and this is the
wrong forum for hashing out this stuff out.

I recommend building a linux-from-scratch system
(http://www.linuxfromscratch.org/) on an ordinary PC to
learn how the insides of linux machine works and how to fix
things when they go wrong.

Good luck,
Dan.

Logged In: YES 
user_id=1330285

Hi again,

It seems I'm successfull in cross-compiling python.
But I'm not sure of what I have to save on the host platform.
There is python executable of course. But there is no lib
directory with .so files and .py files in the directory
where python is built.
Can you tell me what files/directories you save on your host
platform ?
Thanks again for your support.
Nicolas

Logged In: YES 
user_id=843814

I use this command:

make install prefix=/my/temp/dir

Logged In: YES 
user_id=1543599

Hello, Wondering if your still offering some support.   
   
As people have reported success with 2.4.2 I decided to use  
that version. I have been carefull to follow the steps as  
described but still having some difficulty.  
  
The steps I take are:  
  
patch -p3 < ../python-patch  
autoconf configure.in >configure  
mkdir cross-build  
cd cross-build  
../configure --host=cris-axis-linux-gnu 
--build=i486-slackware-linux  
  
I also edit the LINKCC line in the makefile and include  
-static (as I want to run on devboard with limited memory  
and not to worry about shared libraries)  
  
make throws lots of errors like:  
  
*** WARNING: renaming "struct" since importing it failed:  
build/lib.linux-i686-2.4/struct.so: cannot open shared  
object file: No such file or directory  
building 'regex' extension  
cris-axis-linux-gnu-gcc -DNDEBUG -g -O3 -Wall  
-Wstrict-prototypes -fPIC -fno-strict-aliasing -I.  
-I/root/Python-2.4.2/./Include -I/usr/local/include  
-I/root/Python-2.4.2/cross-build/Include  
-I/root/Python-2.4.2/cross-build/buildpython  
-c /root/Python-2.4.2/Modules/regexmodule.c -o  
build/temp.linux-i686-2.4/regexmodule.o  
cris-axis-linux-gnu-gcc -DNDEBUG -g -O3 -Wall  
-Wstrict-prototypes -fPIC -fno-strict-aliasing -I.  
-I/root/Python-2.4.2/./Include -I/usr/local/include  
-I/root/Python-2.4.2/cross-build/Include  
-I/root/Python-2.4.2/cross-build/buildpython  
-c /root/Python-2.4.2/Modules/regexpr.c -o  
build/temp.linux-i686-2.4/regexpr.o  
cris-axis-linux-gnu-gcc -shared  
build/temp.linux-i686-2.4/regexmodule.o  
build/temp.linux-i686-2.4/regexpr.o -L/usr/local/lib -o  
build/lib.linux-i686-2.4/regex.so  
  
and  
  
cris-axis-linux-gnu-gcc -DNDEBUG -g -O3 -Wall  
-Wstrict-prototypes -fPIC -fno-strict-aliasing -I.  
-I/root/Python-2.4.2/./Include -I/usr/local/include  
-I/root/Python-2.4.2/cross-build/Include  
-I/root/Python-2.4.2/cross-build/buildpython  
-c /root/Python-2.4.2/Modules/_ssl.c -o  
build/temp.linux-i686-2.4/_ssl.o  
/root/Python-2.4.2/Modules/_ssl.c:30:25: openssl/rsa.h: No  
such file or directory  
  
make install prefix=/root/Python-2.4.2/cross-build  
  
throws the same errors but finishes.  
  
I then mount cross-build via nfs and run python  
  
Python 2.4.2 (#2, Jun 28 2006, 18:35:28)  
[GCC 3.2.1 Axis release R61/1.61] on linux2  
Type "help", "copyright", "credits" or "license" for more  
information.  
>>> import time  
import time  
Traceback (most recent call last):  
  File "<stdin>", line 1, in ?  
ImportError: /mnt/flash/Python/lib/python2.4/lib-dynload/time.so:  
undefined symbol: PyExc_IOError  
>>>  
  
>>> import socket  
import socket  
Traceback (most recent call last):  
  File "<stdin>", line 1, in ?  
  File "/mnt/flash/Python/lib/python2.4/socket.py", line  
45, in ?  
    import _socket  
ImportError: /mnt/flash/Python/lib/python2.4/lib-dynload/_socket.so:  
undefined symbol: PyObject_GenericGetAttr  
  
Any hint as to what might be causing these  errors would be  
most appreciated.  
  
Cheers  
  
Matthew  

Logged In: YES 
user_id=843814

This stuff is becoming hazy for me, but I'll try to offer
some ideas:

- Does it help if you put your build directory outside of
the source directory?

- Why is the system looking for struct.so when you told it
to be static?  I suspect static support is broken for a lot
of modules.  Does it go better when you take the static
switch out?  Assuming you have a few other apps in your
system besides python (a shell, busybox maybe), I question
wether static would actually save any memory.  It perhaps is
a little more complex to get all the libraries in their
correct location, but I'll bet coaxing a python system to be
static is way harder.

- It is normal for some things to bomb out while compiling
because the python build scripts always check the build
system for library availability.  In many cases you don't
need those broken libraries.  It is also often possible to
hack up the install scripts to work properly for a cross
compiled system.  That said, simple things like struct
should be working properly without hackery.

Cheers,
Dan.

I can definitely chime in on this issue.

A (proper) testcase would be to do something like the following:

# Example item -- this isn't what you'll be using...
CROSS_COMPILE_PREFIX=binos_c3.4.3-p1.mips64-octeon-linux-

AS="${CROSS_COMPILE}as" \
CC="${CROSS_COMPILE}gcc" \
CC="${CROSS_COMPILE}c++" \
LD="${CROSS_COMPILE}ld" \
NM="${CROSS_COMPILE}nm" \
./configure --prefix=/usr/local \
BUILD_PYTHON=/path/to/native/python \
DESTDIR=/where/i/want/to/install/python \
--build=`"${CROSS_COMPILE}gcc" -dumpmachine` \
--host=`arch`

NOTES:
- arch(1) is a GNU specific utility, so it won't work outside of Linux!
- I'll leave it as an exercise to the reader to specify the correct
CFLAGS, CPPFLAGS, LDFLAGS, and LDLIBS.

Some testcases during the compile that fail if cross-compiling are (with
2.6.1):
- chflags
- lchflags
- printf with %zd format support.

Thanks!

Am I correct in this understanding, or is Pgen unneeded after the
grammar file is generated?

Garrett: your configure method is overly complicated.  all you need to
do is set --build=binos_c3.4.3-p1.mips64-octeon-linux.  autoconf will
figure out all the other toolchain settings.

Mike, the python configure script fail to detect some of toolchain tools.

Coming back to this issue, I really want to resolve it on TRUNK and for
it to make its way into 2.6.3 and 2.x trunk, as well as 3.0.2 and 3.x
trunk. I am more than happy to sign a contributor agreement if this will
push things along quicker.

Thanks,
-Garrett

I'm trying to resolve this issue on:

2.6-releasemaint
trunk
3.1-releasemaint
py3k

first by resolving issues configure.in, but there are a TON of
AC_TRY_RUN's, which means that this code cannot be cross-compiled as-is
(25 on 2.x -- 27 on 3.x).

Is requiring the end-user to define the autoconf variables appropriately
to their platform when running configure (when provided an error message
telling them so), a longterm sustainable requirement? I know it isn't as
user friendly, but this is a definite problem that either needs to be
fixed in the autoconf tests (if possible) or the C code itself.

I wouldn't mind updating the INSTALL or README files to reflect this
change either, if needed.

Documenting the parameters needed to avoid all AC_TRY_RUNs is a good first  
step for any that are not obvious how to convert from AC_TRY_RUN into 
something else.

AC_TRY_RUN is already documented:
http://www.gnu.org/software/autoconf/manual/html_node/Obsolete-Macros.html#index-AC_005fTRY_005fRUN-1992

there are a bunch of distros out there (like OE and Gentoo) that have
been maintaining cross-compile patches for python.  i'm pretty sure the
stuff in Gentoo works for 2.6.x, but i havent tried 3.1.x yet.

ive given up on pushing to upstream as this bug (among others)) shows
that such attempts go nowhere

Removing a toxic person from the cc list.  Mike, please go harm some other 
all volunteer project.

On Sun, Nov 1, 2009 at 5:50 AM, Mike Frysinger <report@bugs.python.org> wrote:
>
> Mike Frysinger <vapier@users.sourceforge.net> added the comment:
>
> AC_TRY_RUN is already documented:
> http://www.gnu.org/software/autoconf/manual/html_node/Obsolete-Macros.html#index-AC_005fTRY_005fRUN-1992
>
> there are a bunch of distros out there (like OE and Gentoo) that have
> been maintaining cross-compile patches for python.  i'm pretty sure the
> stuff in Gentoo works for 2.6.x, but i havent tried 3.1.x yet.
>
> ive given up on pushing to upstream as this bug (among others)) shows
> that such attempts go nowhere

Actually what Mike showed was helpful for me. I didn't realize that
the 3rd argument to AC_TRY_RUN was for Canadian cross, aka
cross-compiling.

My personal opinion on why past attempts have failed (and it's just my
opinion) is probably because:

1. The change set wasn't incremental, thus the diff was large, and the
checkin was rejected.
2. The patch was based on previous versions of python, which doesn't
help the current trunk, release-maint* branches, etc.

I'm more than happy to steal existing code (if possible :)..), but it
should be well designed so longterm maintenance can be eased, and the
cross-compile issue can be resolved in a correct manner.

It took me 2 months to rewrite the Makefile infrastructure for LTP --
this should be a lot simpler and less painful to resolve (in terms of
autotools input files, Makefile, etc). setup.py and distutils is
something that I need to defer to someone more seasoned in the python
internals (at least for mentoring) s.t. it can be resolved on all
branches.

First comes first, I'll propose some changes for cross-compilation
dealing with some of the AC_TRY_RUN tests -- there are some tests that
can be turned into preprocessor defines and/or AC_TRY_COMPILES [the
sizeof(pthread_t), etc], then I'll look at the other tests and propose
appropriate action for them.

If needed individuals in the python org. aren't aware of this work, it
probably should be brought to their attention sometime in the next
couple of weeks, because I need to make sure core team members are
aware of these changes so that they can get reviewed and checked into
the project in a timely manner (my group needs to upgrade from 2.4.2
to python 2.6.x in the next couple months; this is a stopgap item for
us because we use a cross-compilation environment).

All the best,
-Garrett

Gregory: there's no need to be a dick.  i'm pointing out the obvious --
bugs have been open literally for *years* with zero assistance/feedback
from anyone who can actually get things merged.  people have posted
patches, but no one has said "xxx needs to be done in order to get
merged".  you havent posted anything here either (assuming you're
someone who can actually get things merged and not just comment in a
tracker).  if you can at least do something with trackers, you should
start by marking 1597850 as a dupe of this one.  or you can simply prove
my point by continuing to contribute nothing.

the basic required changes are simple -- fix the few autoconf tests. 
getting automatic cross-detection (building a host python/pygen
automatically) isnt nearly as important as long as people have a way to
tell the build system to use a different python/pgen for build purposes.
 last i looked, these simple changes were pretty trivial to move across
major versions of python.

i fixed the chflags specific check a long time ago (as i imagine others
have as well):
http://sources.gentoo.org/dev-lang/python/files/python-2.6-chflags-cross.patch

same goes for the printf %zd test:
http://sources.gentoo.org/dev-lang/python/files/python-2.5-cross-printf.patch

however, unless these trivial baby steps can be made, worrying about the
next step (properly cross-compiling modules and such) is a complete
waste of time as these require diving into the python-specific build
system which does see a lot of churn over versions.

Ok. Taking a look at trunk...

The following could be converted to AC_TRY_COMPILE statements for the
3rd AC_TRY_RUN tuple:

1. $ac_enable_profiling : 697
2. $ac_cv_no_strict_aliasing_ok : 921
3. $ac_cv_opt_olimit_ok : 1070
4. $ac_cv_olimit_ok : 1092
5. $ac_cv_pthread_is_default : 1126
6. $ac_cv_kpthread : 1163
7. $ac_cv_pthread : 1225
8. $ac_osx_32bit : 1569
9. $ac_cv_pthread_system_supported : 2229
10. $ac_cv_have_size_t_format : 3959

The following can just be converted to AC_TRY_COMPILE:
1. $ipv6 : 2278
2. $ac_cv_have_chflags : 2663
3. $ac_cv_have_lchflags : 2693

The following will need to be sorted out, as to what needs to be done
here, as they are legitimate runtime only tests:
1. $ac_cv_little_endian_double : 3249
2. $ac_cv_big_endian_double : 3271
3. $ac_cv_mixed_endian_double : 3299
4. $ac_cv_x87_double_rounding : 3354
5. $ac_cv_broken_sem_getvalue : 3395
6. $ac_cv_tanh_preserves_zero_sign : 3430
7. $ac_cv_wchar_t_signed : 3510
8. $ac_cv_rshift_extends_sign : 3597
9. $ac_cv_broken_nice : 3714
10. $ac_cv_broken_poll : 3735
11. $ac_cv_working_tzset : 3772

Taking a look at py3k, most of the offsets are the same -- some have
changed, but the only the test which doesn't exist in trunk is the
following:

1. $ac_cv_broken_mbstowcs : 3872

Again, this is a valid runtime test, so it needs to be sorted out what
should be done here with cross-compilation.

these two have been merged and applied to trunk.

"""
i fixed the chflags specific check a long time ago (as i imagine others
have as well):
http://sources.gentoo.org/dev-lang/python/files/python-2.6-chflags-
cross.patch

same goes for the printf %zd test:
http://sources.gentoo.org/dev-lang/python/files/python-2.5-cross-
printf.patch
"""

the chflags is specifically documented as needing a runtime test:
# On Tru64, chflags seems to be present, but calling it will
# exit Python

which is why i left the default of AC_TRY_RUN but cross-compile falls
back to a simple link test.  btw, a compile test is not valid when
trying to see if a function exists.  you'll get a successful compile
(and warning about implicit function), but no error because you didnt
finally link the object with the undefined reference.

somewhat similar are the compiler checks (profile/pthread/alias/etc...).
 some compilers do different things when linking and compiling (like gcc
and -pthread), so sticking to a LINK in the fallback of the RUN is
better, although not always perfect.  some flags are accepted/ignored by
compilers and issue only warnings about the unknown flags, not errors. 
but this issue probably isnt worth worrying about considering the code
in there today suffers from this edge case (and if no one is
complaining, then forget about it).

in terms of making sure all AC_TRY_RUN's have cross-compile fallbacks, i
only worried about the ones that actually get exercised.  the two i
posted fixes for are the only ones ive seen people (and myself) actively
hit.

the ipv6 should def have a LINK fallback, and it should try using
in6addr_any as that is often an exported symbol (which is missing when
ipv6 doesnt exist).

the double endian checks could easily be made into a compile test with a
creative grep.  pick a double value that expands into a funky ascii
string and then grep the object file for a match.  otherwise, a char
swapped ascii string indicates it's big endian.

the wchar/rshift signed tests can be made into a compile-only test by
creative use of arrays (like autoconf does now with compile sizeof() tests).
  main() { char foo[(((wchar_t) -1) < ((wchar_t) 0)) ? 1 : -1]; }
compilers will portably abort when array size is negative, and this
expression should be a constant.

i dont think any of the "broken" ones need to be sorted out as they
already have cross-compile fall backs and there isnt much to be done in
figuring out if the run time env is broken.

thanks Greg for the commits !

This bug affects me as well. Adding myself to CC.

The stage of this bug could be changed to "patch review", since a patch is available.

As a cross compile patch and being a feature request this must target 3.2.

See also #3754.

Please remember that the bug tracker is meant to develop Python, not offer support about autoconf or patch(1).

I have two questions:

Will a new developer be assigned to this bug?
And, why are we wasting comments and grave-digging five-year-old discussions?

> Will a new developer be assigned to this bug?
If someone is willing to take charge, yes.  We’re all volunteers, with varying free time and skill sets.  For example, I’m not an expert about compilation, so I try to learn thanks to those issues.

> why are we wasting comments and grave-digging five-year-old discussions?
Comments are not a scarce resource, it’s okay.  An unclosed bug, even that old, is still something to act upon: declare it superseded, outdated, rejected or fix it.  This happens all the time.

i really dont understand your point.  python uses autoconf and therefore any questions about python's usage of autoconf to accomplish cross-compiles is completely valid here.

no one was asking for general autoconf help.

It seemed to me that there were quite a number of messages asking about how to apply the patch and what to do after the configure step.

What is the current status of this patch? What is missing to apply it upstream?

hello wrobell , I see that issue3754 has patches for more recent line of code and issue 1597850 is related too.  Would you like to test the patches in there? If successful, this feature can be pushed further (and considered) for inclusion.

Senthil,

I would be more than happy to do that but for Python 3.2 (or there is no chance to backport it?). Python 3.3 is too far in time at the moment.

Code compatibility wise there is not much difference between Python3.2
and Python3.3. So you can do it for Python3.2 (in a bitbucket cpython
branch) and it is found stable, there are good chances that it will be
can be made in Python3.3 and future. I don't think, this would be
backported.

Hi wrobell.  As a new feature, this could not be backported to stable versions.  Regarding status, there are currently a number of duplicate or overlapping reports and patches, it’s rather difficult to find out which one should be reviewed.

Hi Eric,

Good point. I was just about ask, which bug and patch are the primary ones? :)

closing this issue. please continue in issue 3754.