Crossenv: A Virtual Environments for Cross-Compiling Python Extension Modules

Note

This documentation is in the early stages.

Porting a Python app to an embedded device can be complicated. Once you have Python built for your system, you may find yourself needing to include many third-party libraries. Pure-Python libraries usually just work, but many popular libraries rely on compiled C code, which can be challenging to build.

This package is a tool for cross-compiling extension modules. It creates a special virtual environment such that pip or setup.py will cross compile packages for you, often with no further work on your part.

It can be used to:

• Build binary wheels, for installation on target.

• Install packages to a directory for upload or inclusion in a firmware image.

Note

While this tool can cross-compile most Python packages, it can’t solve all the problems of cross-compiling, and it can’t make cross-compiling a completely pain-free process. In some cases manual intervention may still be necessary.

This tool requires Python 3.5 or higher (host and build). Significant work has gone into cross-compiling Python in newer versions, and many of the techniques needed to do the cross compilation properly are not available on older releases.

This tool currently only supports Linux build machines.

Contents:

• Introduction
  • Requirements
  • Vocabulary
  • How it works
  • Installation
• “Quick” Start
  • Build build-python
  • Build or obtain host-python
  • Make the cross environment
  • Use the resulting packages
• Cross-Compiling Environment
  • Environment variables
  • The sys module
  • The os module
  • The platform module