Tag Archives: Wrapper

Building Boost.Python with a custom Python3

I’ve started working on porting some Python libraries to Python3, but I required using an old Visual Studio (2012) for which there is no Python3 version. In the end, I tried following this tutorial. The issue with the tutorial is that you are downloading the externals by hand. It is actually simpler to call get_externals.bat from the PCBuild folder.

Be aware that the solution is a little bit flawed. pylauncher is built in win32 mode in Release instead of x64. This has an impact on deployment.

Once this is done, I had to deploy the build to a proper location so that it is self contained. I inspired myself heavily from another tutorial by the same author, only adding 64 bits support in this gist.

Once this was done, time to build Boost.Python! To start, just compile bjam the usual way, don’t add Python options on the command line, this will utterly fail in Boost.Build. Then add in user-config.jam the following lines (with the proper folders):

using python : 3.4 : D:/Tools/Python-3.4.5/_INSTALL/python.exe : D:/Tools/Python-3.4.5/_INSTALL/include : D:/Tools/Python-3.4.5/_INSTALL/libs ;

This should build the debug and release mode with this line:

.\b2 --with-python --layout=versioned toolset=msvc-11.0 link=shared stage address-model=64
.\b2 --with-python --layout=versioned toolset=msvc-11.0 link=shared stage address-model=64 python-debugging=on
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Wrapping a C++ container in Python

When moving to Python, the real big problem that arises is the transformation of a Python array into the C++ container the team used for years.

Let’s set some hypothesis :

  • there is a separation between the class containing the data and the class that uses the data (iterators, …)
  • the containing class can be changed (policy or strategy pattern)

The first hypothesis is derived from the responsibility principle, the two classes have two distinct responsibilities, the first allocates the data space and allows simple access to it, the second allows usual operations (assignation, comparison tests or iterations for instance).

The second one will be the heart of the wrapper. It allows to change the way data is stored and accessed in a simple way.
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