[Numpy-discussion] Is numpy ignoring CFLAGS?

Dag Sverre Seljebotn dagss@student.matnat.uio...
Mon Jun 28 03:38:21 CDT 2010

Dr. David Kirkby wrote:
> On some 64-bit platforms, which include, but is not limited to:
>   * Some version of OS X (I don't know what versions or processors)
>   * Solaris on SPARC processors.
>   * Solaris on x86 processors.
>   * OpenSolaris on SPARC processors.
>   * OpenSolaris on x86 processors.
>   * HP-UX on PA-RISC processors.
> the default is to build 32-bit objects, but 64-bit objects can be created if 
> needed. This is usually done via adding the -m64 flag when compiling with GCC or 
> SunStudio, though the flag will be different with HP's compiler.
> Numpy is used as part of Sage, but it would appear that adding -m64 to CFLAGS 
> will not work. A comment in the script used to build numpy shows:
First: Is Python built using -m64? If not, is there a reason that NumPy 
in 64 bit and load it into 32 bit Python work? If Python is built with 
-m64 I'd expect NumPy to pick it up automatically as it queries Python 
for the build flags to use...
> # numpy's distutils is buggy and runs a conftest without
> # taking CFLAGS into account. With 64 bit OSX this results
> # in *boom*
> it then goes on to copy a file called gcc_fake, which is basically a script 
> which gets renamed to gcc, but includes the -m64 flag.
> We are using numpy-1.3.0.
> Is this a known bug? If not, can I submit it to a bug database? Better still, 
> does anyone have a patch to resolve it - I hate the idea of making
Until somebody who really knows an answer chimes in;

AFAIK this is a "feature" in distutils itself, so it affects most Python 
software. (Setting CFLAGS overwrites the necesarry CFLAGS settings, like 
-fPIC and -fno-strict-aliasing, that is queried from Python). Try 
setting "OPT" instead?

Dag Sverre

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