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Lightweight in-process concurrent programming
C Python C++ Assembly Batchfile
Latest commit 602204b @snaury snaury Update
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benchmarks Remove unuseful while loop in benchmarks
doc Update greenlet.txt
platform Add suuport for ppc64 in LE mode running ABIv2
tests Try to fix spurious thread test failures
.gitignore ignore MANIFEST and .ropeproject
.travis.yml Try to use travis containers
AUTHORS Add Tony Breeds and Ulrich Weigand to AUTHORS
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LICENSE.PSF Attempt to clarify greenlet license Update
NEWS Bump version to 0.4.9
README.rst get rid of development version install instructions Don't symlink libraries unless inplace build is requested
greenlet.c Fix stack switching on sparc
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make-win-release Build 3.5 binaries on Windows Don't symlink libraries unless inplace build is requested Catch unit-test errors in
setup.cfg Add gztar to sdist formats Test greenlet on Python 3.5
slp_platformselect.h arm32: Make it work on iOS
tox.ini add testenv:docs, which tests "make html" in doc directory


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:

Documentation is available on

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