[Numpy-discussion] Distutils - way to check validity of compiler flag?

[Matthew Brett]

Hi,

On Mon, May 12, 2014 at 12:50 PM, Robert McGibbon <rmcgibbo at gmail.com> wrote:
> In a couple of my projects, we check for flags by compiling little test
> files -- autotools style -- to check for SSE, OpenMP, etc. See e.g.
> https://github.com/rmcgibbo/mdtraj/blob/master/setup.py#L215
>
> If anyone has a better solution, I'm all ears.
>
> -Robert
>
>
> On Mon, May 12, 2014 at 12:24 PM, Matthew Brett <matthew.brett at gmail.com>
> wrote:
>>
>> Hi,
>>
>> I'm sorry to ask this, I guess I should know - but is there any way in
>> disutils or numpy distutils to check whether a compiler flag is valid
>> before doing extension building?
>>
>> I'm thinking of something like this, to check whether the compiler can
>> handle '-fopenmp':
>>
>> have_openmp = check_compiler_flag('-fopenmp')
>> flags = ['-fopenmp'] if have_openmp else []
>>
>> ext = Extension('myext', ['myext.c'],
>>                           extra_compile_args = flags,
>>                           extra_link_args = flags])
>>
>> I guess this would have to go somewhere in the main setup() call in
>> order to pick up custom compilers on the command line and such?

Thanks a lot for the reply.

Your code is nice and clean, but I think that it won't pick up custom
compilers such as python setup.py build --compiler=mingw32 or similar?

I ended up going for an approach suggested by Min RK of IPython fame -
code here:

https://github.com/nipy/dipy/pull/371/files

The basic idea is to wait until the last distutils moment after the
compiler has been configured, and then test with that exact compiler
setup.  It's a little ugly and not too general as it stands, but I'm
posting in case someone runs into the same thing.

Cheers,

Matthew