Version 117 (modified by rme, 9 years ago) (diff)


About Clozure CL

Clozure CL is a free Common Lisp implementation that runs on the following platforms:

  • Mac OS X 10.5 and later (ppc32, ppc64, x86, x86-64)
  • Linux (ppc32, ppc64, x86, x86-64, armv7l)
  • FreeBSD 6.x and later (x86, x86-64)
  • Solaris (x86, x86-64)
  • Microsoft Windows XP and later (x86, x86-64)

Some distinguishing features of the implementation include fast compilation speed, native OS threads, a precise, generational, compacting garbage collector, and a convenient foreign-function interface.

Clozure CL used to be called OpenMCL. It is also sometimes called CCL. You will see the three names being used interchangeably.

See SystemRequirements for more details on hardware and software requirements.

Getting Clozure CL

Released Version

The most recent released version of Clozure CL is version 1.6.

Please see for information on how to download it.

After installing CCL, read about getting updates and bug fixes.

Development Version

Some users may wish to run the development version of Clozure CL, which is often called the "trunk".

To get the trunk version of Clozure CL for Darwin/x86, you'd type (where the $ is the shell prompt):

$ svn co

To get a version for a different platform, change the darwinx86 to linuxx86, freebsdx86, solarisx86, windows, darwinppc, linuxppc, or linuxarm.

If you choose to run the trunk, please read about tracking the development version.


The Clozure CL manual is available as a single web page at or as multiple pages at As of Clozure CL 1.2, the DocBook sources for the manual are included with the distribution.

We have started to collect a list of FrequentlyAskedQuestions.


Mailing Lists

There are two CCL-related mailing lists hosted at Click on a list's link to subscribe or to view archived messages.


Everyone interested in Clozure CL is welcome to participate in #ccl on The channel logs are available. We also keep logs for #lisp and logs for #scheme.

Bug Reports

To report a bug or request a feature, please create a ticket. You must first register (thanks, spammers).

Paid Support

Clozure Associates provides commercial support and consulting services for Clozure CL as well as other Common Lisp implementations. These services can range from helping you debug your software to adding extensions to CCL, to providing several full time Lisp programmers to help you build your application. Please contact us at business@… for more information.

Starting Points

CCL Basics

Web Development

Contributing to CCL

In-Depth CCL

Orient Yourself to Clozure CL Culture