Question

After successfully compiling a Python/C binding with SIP I wanted to do the same thing with Python/C++. For some reason this doesn’t work.

Here’s the files:

fib.cpp

#include "fib.h"

int fib1(int n)
{
    if (n <= 0) {
        return 0;
    } else if (n <= 2) {
        return 1;
    } else {
        return fib1(n-1) + fib1(n-2);
    }
}

fib.h

int fib1(int n);

fib.sip

%Module fib

%Include fib.h

I run the following command to build the intermediate files:
sip -c . fib.sip

So far everything works.

Now I want to build the .pyd file using distutils.

setup.py

from distutils.core import setup, Extension
import sipdistutils

setup(
  name = 'fib',
  versione = '1.0',
  ext_modules=[
    Extension("fib", ["fib.sip", "fib.cpp"]),
    ],

   cmdclass = {'build_ext': sipdistutils.build_ext}
 )

I run the following command:
python setup.py build

This fails with the following error:

build\temp.win32-2.7\Release\sipfibcmodule.cpp:29:29: error: 'fib1' was not declared in this scope
error: command 'gcc' failed with exit status 1

What could the problem be? Shouldn’t c++ be used as a compiler instead of gcc, by the way?

Any help appreciated!

Kind regards

David

Answer 1

I’ve found a solution that is good enough: namespaces. Next time I’ll read the documentation better. I should also mention that a solution with a Fibonacci class could solve the problem, but I didn’t find that to be satisfying.

Below the content of the files can be found.

fib.cpp

#include "fib.h"

namespace test
{
    int fib1(int n)
    {
        if (n <= 0) {
            return 0;
        } else if (n <= 2) {
            return 1;
        } else {
            return fib1(n-1) + fib1(n-2);
        }
    }
}

fib.h

namespace test
{
    int fib1(int n);
}

fib.sip

%Module fib

namespace test {
    %TypeHeaderCode
    #include "fib.h"
    %End

    int fib1(int n);
};

setup.py – nothing was changed

Exactly the same commands as mentioned before were used.