Step-by-step guide to install Pyrex on Windows and compile your first extension

A: Pyrex installation on Windows XP

step A.1

Install [http://www.python.org Python] (we used version 2.4.2)

step A.2

Run the windows installer for [http://www.cosc.canterbury.ac.nz/~greg/python/Pyrex/) Pyrex] (e.g. Pyrex-0.9.3.1.win32.exe)

step A.3

Install [http://www.mingw.org/download.shtml Mingw], the gcc compiler for Windows (download and run MinGW-5.0.2.exe and choose only the "base tools": mingw-runtime 3.9, w32api-3.6, binutils 2.15.91 and gcc-core 3.4.2. Add Mingw path C:\MinGW\bin to the Windows Path environment variable. If you already have cygwin installed, add C:\MinGW\bin before the Cygwin path.

step A.4

Edit the file c:/Python2x/Lib/distutils/distutils.cfg (if it does not exist, create it) and add the following lines: {{{[build] compiler = mingw32}}}

step A.5

MinGW links with msvcrt.dll whereas the main Python distribution links with msvcr71.dll (due to Visual C++ 2003). It is not safe to mix and blend different C runtime libraries (CRT). In order to make minGW link with msvcr71.dll, edit the text file c:\mingw\lib\gcc\mingw32\3.2.4\specs and change -lmsvcrt to -lmsvcr71.

B: Create your first Pyrex module

step B.1

Create a working directory (e.g. D:\pyrex_module\). Write a pyrex module and save it with a pyx extension (e.g. primes.pyx, code available [http://www.cosc.canterbury.ac.nz/~greg/python/Pyrex/) here])

step B.2

Write the following python script and save it as setup.py in your working directory.

{{{from distutils.core import setup from distutils.extension import Extension from Pyrex.Distutils import build_ext setup(

• name = "PyrexGuide", ext_modules=[

  • Extension("primes", ["primes.pyx"]) ],
  cmdclass = {'build_ext': build_ext}

)}}}

If you want to compile several modules, duplicate the line starting with Extension and replace primes by your module names.

step B.3

In your working directory, create a batch file called build_and_install.bat containing the following lines. To run the batch, double-click the file. You will see many "Warning" messages during the building process: do not worry, it is normal.

{{{C:\Python24\python.exe setup.py build_ext install pause}}}

step B.4

Mission completed. The file primes.pyd (a pyd is a Python Extension DLL) is now located in C:\Python24\Lib\site-packages and the primes module is available in Python. In your working directory, you can delete the file primes.c and the build folder created by the building process.

You can now test your new module at the python shell:

{{{>>> import primes >>> primes.primes(10) [2, 3, 5, 7, 11, 13, 17, 19, 23, 29]}}}