[SciPy-Dev] build issue on OS X 10.6 - fails on fftpack

[David Cournapeau]

Ralf Gommers wrote:
> 
> 
> On Mon, Mar 1, 2010 at 9:50 AM, David Cournapeau <david@silveregg.co.jp 
> <mailto:david@silveregg.co.jp>> wrote:
> 
>     Ralf Gommers wrote:
> 
>      > $ LDFLAGS="-lgfortran -arch x86_64" FFLAGS="-arch x86_64" python
> 
>     Whenever you redefine one of the CFLAGS/FFLAGS/CXXFLAGS/LDFLAGS, it
>     *overwrites* the default value (contrary to the usual behavior of having
>     its value appended to the default value).
> 
> 
> I followed the instructions under "Obtaining and Building NumPy and 
> SciPy on this page: http://www.scipy.org/Installing_SciPy/Mac_OS_X . 
> There it says that the above command *extends* the build flags. So that 
> info is wrong? Or maybe I'm still not understanding something.

Both are true :) If you build with numscons, then the flags are 
extended. If you build with distutils, the flags are overriden.

The wiki could be made clearer there.

> 
> 
>     here, by overwriting LDFLAGS, you remove all the link options necessary
>     to build a bundle, and the linker believes you want to build an
>     executable (hence the missing main symbol message, and all the
>     unresolved symbols from libpython.dylib).
> 
> 
> To be clear, I'm just trying to build scipy on my own machine

The flag issue is a distutils issue, and happens whenever you call 
setup.py. You should not try to edit flags if you build with distutils, 
really - the overriding support implies that it should be used as last 
resort, and otherwise, everything should be handled within distutils.

cheers,

David