skip to navigation
skip to content

greenlet 0.4.2

Lightweight in-process concurrent programming

Package Documentation

Latest Version: 0.4.13

The greenlet package is a spin-off of Stackless, a version of CPython that supports micro-threads called “tasklets”. Tasklets run pseudo-concurrently (typically in a single or a few OS-level threads) and are synchronized with data exchanges on “channels”.

A “greenlet”, on the other hand, is a still more primitive notion of micro-thread with no implicit scheduling; coroutines, in other words. This is useful when you want to control exactly when your code runs. You can build custom scheduled micro-threads on top of greenlet; however, it seems that greenlets are useful on their own as a way to make advanced control flow structures. For example, we can recreate generators; the difference with Python’s own generators is that our generators can call nested functions and the nested functions can yield values too. Additionally, you don’t need a “yield” keyword. See the example in tests/

Greenlets are provided as a C extension module for the regular unmodified interpreter.

Greenlets are lightweight coroutines for in-process concurrent programming.

Who is using Greenlet?

There are several libraries that use Greenlet as a more flexible alternative to Python’s built in coroutine support:

Getting Greenlet

The easiest way to get Greenlet is to install it with pip or easy_install:

pip install greenlet
easy_install greenlet

Source code archives and windows installers are available on the python package index at

The source code repository is hosted on github:

The master branch - i.e. the development version - can be installed directly by running one of the following:

pip install greenlet==dev
easy_install greenlet==dev
File Type Py Version Uploaded on Size
greenlet-0.4.2-cp27-none-win32.whl (md5) Python Wheel cp27 2014-01-07 14KB
greenlet-0.4.2-cp27-none-win_amd64.whl (md5) Python Wheel cp27 2014-01-07 15KB
greenlet-0.4.2-cp33-none-win32.whl (md5) Python Wheel cp33 2014-01-07 14KB
greenlet-0.4.2-cp33-none-win_amd64.whl (md5) Python Wheel cp33 2014-01-07 15KB (md5) MS Windows installer 2.7 2014-01-07 234KB (md5) MS Windows installer 3.3 2014-01-07 232KB
greenlet-0.4.2.win32-py2.5.exe (md5) MS Windows installer 2.5 2014-01-07 73KB
greenlet-0.4.2.win32-py2.6.exe (md5) MS Windows installer 2.6 2014-01-07 206KB
greenlet-0.4.2.win32-py2.7.exe (md5) MS Windows installer 2.7 2014-01-07 206KB
greenlet-0.4.2.win32-py3.3.exe (md5) MS Windows installer 3.3 2014-01-07 201KB (md5) Source 2014-01-07 72KB