python/cpython
Cpython
CPython is the primary, community-maintained reference implementation of the Python programming language. It functions as a high-level, interpreted execution environment that compiles source code into platform-independent bytecode for processing by a stack-based virtual machine. The runtime manages memory through a combination of reference counting and generational cyclic garbage collection, while dynamic type dispatching determines object behavior at runtime based on metadata stored within object headers.
The project is distinguished by its C-based architecture, which provides a stable foreign function interface for integrating performance-critical native code directly with the interpreter's internal objects. To ensure thread safety within its shared internal state, the runtime utilizes a global interpreter lock that serializes the execution of bytecode instructions. This design supports a comprehensive standard library and enables the development of complex applications across diverse computing environments.
Beyond the core interpreter, the project maintains a robust infrastructure for cross-platform binary distribution, including support for universal binaries and framework-based installations on macOS. It includes extensive built-in tooling for performance benchmarking, testing, and build configuration, all of which are managed through a collaborative open-source workflow.
The repository provides a comprehensive developer’s guide and established coding style standards to support ongoing contributions and language evolution. Detailed instructions for building the interpreter from source on Unix and containerized environments are available within the project documentation.
Features
- Reference Implementations - The primary, community-maintained execution environment that defines the standard behavior and syntax for the entire programming language ecosystem.
- General Purpose Languages - A high-level, interpreted language designed for readability and versatility across web development, data science, and automation tasks.
- Virtual Machines - Executes high-level source code by compiling it into platform-independent bytecode instructions processed by a central evaluation loop.
- Global Interpreter Locks - Serializes execution of bytecode instructions to ensure thread safety and prevent data corruption within the shared internal state of the interpreter.
- Foreign Function Interfaces - Provides a stable binary interface allowing native C code to interact directly with internal interpreter objects and data structures.
- Language Runtimes - Building and maintaining the core interpreter and standard library that powers millions of applications across diverse computing environments.
- Reference Counting - Tracks the number of active references to each object to reclaim memory immediately when an object is no longer needed.
- Garbage Collection Strategies - Identifies and cleans up unreachable object groups that contain circular references by periodically scanning objects across different age-based generations.
- Standard Library Distributions - A comprehensive collection of built-in modules and tools that provide essential functionality for networking, file manipulation, and data processing.
- C-Based Runtimes - A host environment that executes bytecode while providing a stable interface for integrating performance-critical code written in C and C++.
- Dynamic Type Dispatching Systems - Determines object behavior at runtime by inspecting type metadata stored within each object header during every operation.
- Contribution Guides - This guide is a comprehensive resource for contributing to Python – for both new and experienced contributors. It is maintained by the same community that maintains Python. We welcome your contributions! ## Contributing¶
- C Extension Interfaces - Integrating low-level C code with high-level scripts to extend functionality and improve performance for computationally intensive tasks.
- Performance Benchmarks - Benchmarking is useful to test that a change does not degrade performance. The Python Benchmark Suite has a collection of benchmarks for all Python implementations. Documentation about running the benchmarks is in the RE
- Test Runners - The shortest, simplest way of running the test suite is the following command from the root directory of your checkout (after you have built Python): Unix ./python \-m test Copy to clipboard macOS ./python.exe \-m test C
- Contribution Proposals - Improving Python’s code, documentation and tests are ongoing tasks that are never going to be “finished”, as Python operates as part of an ever-evolving system of technology. An even more challenging ongoing task than th
- Contribution Standards - - Coding style guides - **PEP 7** (Style Guide for C Code) - **PEP 8** (Style Guide for Python Code) - Issue tracker - Experts index - Buildbot status - Source code - Browse online - Download a snapshot of the `main` bra
- C API Specifications - ### New features¶ - TODO ### Porting to Python 3.16¶ - TODO ### Deprecated C APIs¶ - TODO ### Removed C APIs¶
- Cross-Platform Installers - Creating executable installers and universal binaries that allow software to run consistently across different operating systems and hardware architectures.
- Build Instructions - These instructions cover how to get a working copy of the source code and a compiled version of the CPython interpreter (CPython is the version of Python available from https://www.python.org/). It also gives an overview
- Compilation Flags - CPython provides several compilation flags which help with debugging various things. While all of the known flags can be found in the `Misc/SpecialBuilds.txt` file, the most critical one is the `Py_DEBUG` flag which crea
- Binary Packaging Scripts - [](#how-do-i-create-a-binary-distribution) Download and unpack the source release from https://www.python.org/download/. Go to the directory `Mac/BuildScript`. There you will find a script `build-installer.py` that does
- Performance Benchmarks - Measuring the execution speed of code changes to ensure that updates improve or maintain the efficiency of the runtime.
- macOS Framework Builds - [](#building-and-using-a-framework-based-python-on-macos) ### 1\. Why would I want a framework Python instead of a normal static Python? [](#1-why-would-i-want-a-framework-python-instead-of-a-normal-static-python) The ma