Expert Python Programming - Third Edition

The need to use extensions

It's not easy to say when it is a reasonable decision to write extensions in C/C++. The general rule of thumb could be, never, unless you have no other choice. But this is a very subjective statement that leaves a lot of place for the interpretation of what is not doable in Python. In fact, it is hard to find a thing that cannot be done using pure Python code. Still, there are some problems where extensions may be especially useful by adding the following benefits:

• Bypassing GIL in the CPython threading model
• Improving performance in critical code sections
• Integrating third-party dynamic libraries
• Integrating source code written in different languages
• Creating custom datatypes

Of course, for every such problem, ...