Steel Bank Common Lisp is an open source / free software Common Lisp implementation. It provides an integrated native compiler, interpreter, and debugger.

SBCL is a fork off of the main branch of CMUCL. SBCL is distinguished from CMUCL by a greater emphasis on maintainability. In particular, the SBCL system can be built directly from its source code, so that the output corresponds to the source code in a controlled, verifiable way, and arbitrary changes can be made to the system without causing bootstrapping problems. SBCL also places less emphasis than CMU CL does on new non-ANSI extensions, or on backward compatibility with old non-ANSI features.

More information at the project page at, and on the SBCL Internals CLiki

Common-Lisp-Controller-compatible SBCL Debian (.deb) packages are part of Debian GNU/Linux 3.0/Woody and Debian GNU/Linux 3.1/Sarge for Alpha, x86, PPC, and SPARC. Later releases will include more architectures.

Local pages

Building 0.8.4 on SPARC

The Sun's assembler doesn't like the GNU syntax used in the SBCL assembler sources, so something like the following is required:

$ ln -s `which gcc` ~/bin/gcc
$ ln -s `which gas` ~/bin/as
$ export COMPILER_PATH=~/bin

Also, when building from CMUCL you need to add the following stanza to src/cold/ansify.lisp:

#+(and cmu sparc) 
(ext:set-floating-point-modes :traps '(:overflow :invalid :divide-by-zero))

SBCL Advocacy Haiku

(unless (equalp
         "SBCL") (quit))



As of SBCL 1.0.22, shebang-scripts are supported via the --script option (add #!/usr/bin/sbcl --script as the first line). However, --script option changes the way initialization is performed (no sysinit (/etc/sbclrc) and no userinit (~/.sbclrc)).

Older versions of SBCL don't tolerate shebang lines (CLISP does). To create an SBCL script, manual/Shebang-Scripts.html suggests using an external trampoline or init hair. That's silly. An executable file without a shebang line defaults to sh. So an SBCL script is simply

$ cat foo
exec sbcl --noinform --load $0 --end-toplevel-options "$@"
(format t "hi~%")
$ chmod a+x foo
$ ./foo
To compile, simply
fasl=`dirname $0`/`basename $0 .lisp`.fasl
[ $fasl -ot $0 ] && sbcl --noinform --eval "(compile-file \"$0\")" --eval "(quit)" > /dev/null
exec sbcl --noinform --load $fasl --end-toplevel-options "$@"

Installing SBCL from source not in /usr/local

Unpack the source tarball.

Set INSTALL_ROOT to where you want it to go.


Now use this hack so it will look for the core file in the right place

  export CC="cc '-DSBCL_HOME=\"$INSTALL_ROOT/lib/sbcl/\"'"

Using Common Lisp Controller with a self installed SBCL

Put this in your .sbclrc

(require 'sb-bsd-sockets) ; needed now because it does not gel well with the path munging by the common-lisp-controller

(load "/usr/share/common-lisp/source/common-lisp-controller/common-lisp-controller.lisp")
(common-lisp-controller:init-common-lisp-controller-v4 "sbcl")

Adding GNU Readline support

Evgeniy Zhemchugov has written a GNU readline loader to get uparrow history and tab completion like in CLISP. Download or clone and load it from your ~/.sbclrc