Python Subinterpreters Example

An example project of how to use subinterpreters in the lastest version of the Python C API (Python 3.9.7) without threads.

Many examples online use an old, deprecated version where the GIL had to be locked and unlocked manually. These examples no longer work.

How to Run the Code

This example code may be built via the following steps:

1. Update the commented lines of code in CmakeLists.txt to point to your machine's python
2. Run the following command and observe the output

$bash run.sh
Interpreter 0 Initializing val to 0
Interpreter 1 Initializing val to 0
Interpreter 2 Initializing val to 0
Interpreter 0 has been called 1 times
Interpreter 1 has been called 1 times
Interpreter 2 has been called 1 times
Interpreter 0 has been called 2 times
Interpreter 1 has been called 2 times
Interpreter 2 has been called 2 times
Interpreter 0 has been called 3 times
Interpreter 1 has been called 3 times
Interpreter 2 has been called 3 times
Interpreter 0 shutting down now...
Interpreter 1 shutting down now...
Interpreter 2 shutting down now...