Version 109 (modified by pfeilgm, 12 years ago) (diff)


About Clozure CL

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

  • Mac OS X 10.4 and later (PowerPC and x86)
  • Linux (PowerPC and x86)
  • FreeBSD 6.x and later (x86)
  • Solaris (x86)
  • Microsoft Windows XP and later (x86)

There are both 32- and 64-bit versions for all platforms.

Some distinguishing features of the implementation include:

  • fast compilation speed
  • native OS threads
  • precise, generational, compacting garbage collector
  • 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 hardware and software requirements.

Getting Clozure CL

The most recent released version of Clozure CL is version 1.4.

The preferred way to get Clozure CL is via Subversion. For example, to get Clozure CL 1.4 for Darwin/x86, you'd type (where the $ is the shell prompt):

$ svn co

You can get versions for other platforms by changing the darwinx86 to one of linuxx86, freebsdx86, solarisx86, windows, darwinppc, or linuxppc.

Please see Obtaining, Installing, and Running Clozure CL for details on completing the installation.

If there is some reason you cannot use Subversion, you can download an archive listed in the table below. All these archives are available via anonymous ftp at

All packages include both 32- and 64-bit binaries.

x86 PowerPC
Darwin (Mac OS X) .tar.gz (or .dmg) .tar.gz (or .dmg)
FreeBSD .tar.gz
Linux .tar.gz .tar.gz
Solaris .tar.gz
Windows .zip

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


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

Contributing to CCL

In-Depth CCL

Orient Yourself to Clozure CL Culture