[Numpy-discussion] Should we drop support for "one file" compilation mode?

Nathaniel Smith njs at pobox.com
Tue Oct 6 13:14:19 EDT 2015

On Tue, Oct 6, 2015 at 10:10 AM, David Cournapeau <cournape at gmail.com> wrote:
> On Tue, Oct 6, 2015 at 6:07 PM, Nathaniel Smith <njs at pobox.com> wrote:
>> On Tue, Oct 6, 2015 at 10:00 AM, Antoine Pitrou <solipsis at pitrou.net>
>> wrote:
>> > On Tue, 6 Oct 2015 09:40:43 -0700
>> > Nathaniel Smith <njs at pobox.com> wrote:
>> >>
>> >> If you need some npy_* function it'd be much better to let us know
>> >> what it is and let us export it in an intentional way, instead of just
>> >> relying on whatever stuff we accidentally exposed?
>> >
>> > Ok, we seem to be using only the complex math functions (npy_cpow and
>> > friends, I could make a complete list if required).
>> And how are you getting at them? Are you just relying the way that on
>> ELF systems, if two libraries are loaded into the same address space
>> then they automatically get access to each other's symbols, even if
>> they aren't linked to each other? What do you do on Windows?
> It is possible (and documented) to use any of the npy_ symbols from npymath
> from outside numpy:
> http://docs.scipy.org/doc/numpy-dev/reference/c-api.coremath.html#linking-against-the-core-math-library-in-an-extension
> The design is not perfect (I was young and foolish :) ), but it has worked
> fairly well and has been used in at least scipy since the 1.4/1.5 days IIRC
> (including windows).

Okay, so just to confirm, it looks like this does indeed implement the
static linking thing I just suggested (so perhaps I am also young and
foolish ;-)) -- from looking at the output of get_info("npymath"), it
seems to add -I.../numpy/core/include to the compiler flags, add
-lnpymath -L.../numpy/core/lib to the linker flags, and then
.../numpy/core/lib contains only libnpymath.a, so it's static linking.


Nathaniel J. Smith -- http://vorpus.org

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