[Numpy-discussion] numpy build system questions for use in another project (fwrap)

Kurt Smith kwmsmith@gmail....
Tue Apr 6 21:52:13 CDT 2010

Briefly, I'm encountering difficulties getting things working in numpy
distutils for fwrap's build system.

Here are the steps I want the build system to accomplish:

1) Compile a directory of Fortran 90 source code -- this works.
    - The .mod files generated by this compilation step are put in the
build directory.

2) Fwrap needs to call numpy.distutils.config.try_compile with some
generated fortran source code that depends on the .mod files generated
in 1).

For example:

Suppose a fortran 90 module 'type_params.mod' is generated in step 1).

Fwrap would generate this fortran source code and try to compile it:

subroutine s0(a)
    use, intrinsic :: iso_c_binding
    integer(c_int) :: a
        subroutine s1(a)
            use type_params, only : int_param
            integer(int_param) :: a
        end subroutine s1
    end interface
    call s1(a)
end subroutine s0

If this compiles correctly with no errors about type
incompatibilities, then we know that the int_param in type_params
module corresponds to the C int type.  If it doesn't, then we try the
other C integer types ('c_long', 'c_long_long', 'c_short', 'c_char')
until no error is generated (otherwise fail).  This then ensures that
the type mappings between Fortran and C are correct, and we can then
go on to generate appropriate config files with this information.

So, this generated fortran source code depends on step 1), since the
type_params.mod file must exist first.  Then we call
config.try_compile and see if it works.

My problem is in instantiating numpy.distutils.config such that it is
appropriately configured with command line flags.

I've tried the following with no success:

('self' is a build_ext instance)
cfg = self.distribution.get_command_obj('config')
cfg.finalize_options()  # doesn't do what I hoped it would do.

This creates a config object, but it doesn't use the command line
flags (e.g. --fcompiler=gfortran doesn't affect the fortran compiler

Any pointers?  More generally -- seeing the above, any ideas on how to
go about doing what I'm trying to do better?



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