.. blogpost::
    :title: Build rpy2 on Windows
    :keywords: rpy2
    :date: 2016-08-25
    :categories: module, build

    I started this blog post because I got the following error
    with `rpy2 <http://rpy2.bitbucket.org/>`_:

    ::

        In [2]: %load_ext rpy2.ipython
        ---------------------------------------------------------------------------
        AttributeError                            Traceback (most recent call last)
        <ipython-input-2-a69f80d0128e> in <module>()
        ----> 1 get_ipython().magic('load_ext rpy2.ipython')

        c:\python35_x64\lib\site-packages\IPython\core\interactiveshell.py in magic(sel

        ....

        c:\python35_x64\lib\site-packages\rpy2\ipython\rmagic.py in load_ipython_extension(ip)
            786     # Initialising rpy2 interferes with readline. Since, at this point, we've
            787     # probably just loaded rpy2, we reset the delimiters. See issue gh-2759.
        --> 788     if ip.has_readline:
            789         ip.readline.set_completer_delims(ip.readline_delims)

        AttributeError: 'ZMQInteractiveShell' object has no attribute 'has_readline'

    The first solution just consists in commenting out those two lines:

    ::

        --> 788     # if ip.has_readline:
            789     #     ip.readline.set_completer_delims(ip.readline_delims)

    I then though about compiling rpy2 for Windows. But...
    I'm still figuring out. It does not work but this is
    what I did. You need:

    * Install `R <https://cran.univ-paris1.fr/bin/windows/base/>`_
    * Install `Rtools <https://cran.univ-paris1.fr/bin/windows/Rtools/>`_
    * Install `Cygwin <https://www.cygwin.com/>`_

    Maybe:

    * Install `pexports <https://sourceforge.net/projects/mingw/files/MinGW/Extension/pexports/>`_
      (exports all symbols from a DLL: ``pexports "R.dll" >R.def``,
      `import R <http://www.stats.uwo.ca/faculty/murdoch/software/compilingDLLs/existingDLL.html#import>`_)

    Steps:

    * Get the sources from `rpy2 <https://bitbucket.org/rpy2/rpy2>`_

    **Compilation with Visual Studio 2015 (still failing)**

    Open *_rinterface.c*, comment out the following lines::

        //static PyTypeObject NAInteger_Type;
        //static PyTypeObject NALogical_Type;
        //static PyTypeObject NAReal_Type;
        //static PyTypeObject NAComplex_Type;
        //static PyTypeObject NACharacter_Type;

        //Rp->ResetConsole = EmbeddedR_ResetConsole;

    From a cygwin environment:

    ::

        export PATH=$PATH:'/cygdrive/c/Program Files/R/R-3.3.1/bin/x64'
        export PATH=$PATH:'/cygdrive/c/Program Files/R/R-3.3.1/include'
        export R_HOME=/cygdrive/c/Program\ Files/R/R-3.3.1

    Or from the command line before starting *cygwin*:

        set PATH=%PATH%;c:\Program Files\R\R-3.3.1\bin\x64
        set PATH=%PATH%;c:\Program Files\R\R-3.3.1\include
        set R_HOME=c:\Program Files\R\R-3.3.1
        set PATH=%PATH%;C:\cygwin64\bin

    In file ``distutils/cygwinccompiler.py``, modifies:

    * function *get_msvcr*, replace ::

        else:
            raise ValueError("Unknown MS Compiler version %s " % msc_ver)

      by::

        else:
            return ["msvcr140"]
    * function *Mingw32CCompiler.__init__*, comment out the following lines::

        if is_cygwingcc():
            raise CCompilerError(
                'Cygwin gcc cannot be used with --compiler=mingw32')

    From a Cygwin environment, run:

    ::

        /cygdrive/c/Python35_x64/python setup.py build_ext -I C:\\Program\ Files\\R\\R-3.3.1\\include

    Or from the Windows command line:

    ::

        c:\Python35_x64\python setup.py build_ext -I "C:\Program Files\R\R-3.3.1\include" --compiler=mingw32

    Without the option ``--compiler=mingw32``, I get the following error which
    means I cannot link with *R.dll* symbols.

    ::

        ...

        error LNK2001: unresolved external symbol Rf_allocVector3

        ...

        fatal error LNK1120: 107 unresolved externals

    **Remarks**

    If you get the following error:

    ::

        'sh' is not recognized as an internal or external command

    Just add:

    ::

        set PATH=%PATH%;C:\cygwin64\bin

    https://wanglongqi.github.io/r/2015/04/08/rpy2install/