1SBCL(1) General Commands Manual SBCL(1)
2
6 SBCL -- Steel Bank Common Lisp
7
10 SBCL is an implementation of ANSI Common Lisp, featuring a high-perfor‐
11 mance native compiler, native threads on several platforms, a socket
12 interface, a source-level debugger, a statistical profiler, and much
13 more.
14 It is free software, mostly in the public domain, but with some subsys‐
16 tems under BSD-style licenses which allow modification and reuse as
17 long as credit is given. It is provided "as is", with no warranty of
18 any kind.
19 For more information about license issues, see the COPYING file in the
21 distribution. For more information about history, see the CREDITS file
22 in the distribution.
23
26 To run SBCL, type "sbcl". After startup messages a prompt ("*")
27 appears. Enter a Lisp expression, and SBCL will read and execute it,
28 print any values returned, give you another prompt, and wait for your
29 next input.
30 $ sbcl
33 ...[startup messages elided]...
34 * (+ 1 2 3)
35 6
37 * (quit)
38 Most people like to run SBCL as a subprocess under Emacs. The Emacs
40 "Slime" mode provides many convenient features, like command line edit‐
41 ing, tab completion, and various kinds of coupling between Common Lisp
42 source files and the interactive SBCL subprocess.
43 For information on creating "standalone executables" using SBCL, see
45 SB-EXT:SAVE-LISP-AND-DIE in the User Manual.
46
49 For ordinary interactive use, no command line arguments should be nec‐
50 essary.
51 In order to understand the SBCL command line syntax, it is helpful to
53 understand that the system is composed of two parts: a runtime environ‐
54 ment, and the Common Lisp system it supports. Some command line argu‐
55 ments are processed during the initialization of the runtime, and some
56 during the initialization of the Lisp system -- any remaining command
57 line arguments are passed on to user code.
58 The overall command line syntax is:
60 sbcl [runtime options] --end-runtime-options [toplevel options]
62 --end-toplevel-options [user options]
63 Both --end-runtime-options and --end-toplevel-options are optional, and
65 may be omitted. They are intended for use in situations where any com‐
66 mand line options are under user control (eg. in batch files): by using
67 them you can prevent options intended for your program being acciden‐
68 tally processed by SBCL.
69 Supported runtime options are
71 --core <corefilename>
73 Use the specified Lisp core file instead of the default. (See the
74 FILES section for the standard core, or the system documentation for
75 SB-EXT:SAVE-LISP-AND-DIE for information about how to create a cus‐
76 tom core.) Note that if the Lisp core file is a user-created core
77 file, it may run a nonstandard toplevel which does not recognize the
78 standard toplevel options.
79 --dynamic-space-size <megabytes>
81 Size of the dynamic space reserved on startup in megabytes. Default
82 value is platform dependent.
83 --control-stack-size <megabytes>
85 Size of control stack reserved for each thread in megabytes. Default
86 value is 2.
87 --noinform
89 Suppress the printing of any banner or other informational message
90 at startup. (This makes it easier to write Lisp programs which work
91 cleanly in Unix pipelines. See also the "--noprint" and "--dis‐
92 able-debugger" options.)
93 --disable-ldb
95 Disable the low-level debugger. Only effective if SBCL is compiled
96 with LDB.
97 --lose-on-corruption
99 There are some dangerous low level errors (for instance, control
100 stack exhausted, memory fault) that (or whose handlers) can corrupt
101 the image. By default SBCL prints a warning, then tries to continue
102 and handle the error in Lisp, but this will not always work and SBCL
103 may malfunction or even hang. With this option, upon encountering
104 such an error SBCL will invoke ldb (if present and enabled) or else
105 exit.
106 --script <filename>
108 As a runtime option equivalent to --noinform --disable-ldb
109 --lose-on-corruption --end-toplevel-options --script <filename>. See
110 the description of --script as a toplevel option below.
111 --help
113 Print some basic information about SBCL, then exit.
114 --version
116 Print SBCL's version information, then exit.
117 In the future, runtime options may be added to control behavior such as
119 lazy allocation of memory.
120 Runtime options, including any --end-runtime-options option, are
122 stripped out of the command line before the Lisp toplevel logic gets a
123 chance to see it.
124 The toplevel options supported by the standard SBCL core are
126 --sysinit <filename>
128 Load filename instead of the default system-wide initialization
129 file. (See the FILES section.)
130 --no-sysinit
132 Do not load a system-wide initialization file. If this option is
133 given, the --sysinit option is ignored.
134 --userinit <filename>
136 Load filename instead of the default user initialization file. (See
137 the FILES section.)
138 --no-userinit
140 Do not load a user initialization file. If this option is given, the
141 --userinit option is ignored.
142 --eval <command>
144 After executing any initialization file, but before starting the
145 read-eval-print loop on standard input, read and evaluate the com‐
146 mand given. More than one --eval option can be used, and all will be
147 read and executed, in the order they appear on the command line.
148 --load <filename>
150 This is equivalent to --eval '(load "<filename>")'. The special syn‐
151 tax is intended to reduce quoting headaches when invoking SBCL from
152 shell scripts.
153 --noprint
155 When ordinarily the toplevel "read-eval-print loop" would be exe‐
156 cuted, execute a "read-eval loop" instead, i.e. don't print a prompt
157 and don't echo results. Combined with the --noinform runtime option,
158 this makes it easier to write Lisp "scripts" which work cleanly in
159 Unix pipelines.
160 --disable-debugger
162 By default when SBCL encounters an error, it enters the builtin
163 debugger, allowing interactive diagnosis and possible intercession.
164 This option disables the debugger, causing errors to print a back‐
165 trace and exit with status 1 instead -- which is a mode of operation
166 better suited for batch processing. See the User Manual on
167 SB-EXT:DISABLE-DEBUGGER for details.
168 --script <filename>
170 Implies --no-sysinit --no-userinit --disable-debugger
171 --end-toplevel-options.
172 Causes the system to load the specified file and exit immediately
174 afterwards, instead of entering the readl-eval-print loop. If the
175 file begins with a shebang line, it is ignored.
176 Regardless of the order in which toplevel options appear on the command
178 line, the order of actions is:
179 1. Debugger is disabled, if requested.
182 2. Any system initialization file is loaded, unless prohibited.
184 3. Any user initialization file is loaded, unless prohibited.
186 4. --eval and --load options are processed in the order given.
188 Finally, either the read-eval-print loop is entered or the file speci‐
190 fied with --script option is loaded.
191 When running in the read-eval-print loop the system exits on end of
193 file. Similarly, the system exits immediately after processing the file
194 specified with --script.
195 Note that when running SBCL with the --core option, using a core file
197 created by a user call to the SB-EXT:SAVE-LISP-AND-DIE, the toplevel
198 options may be under the control of user code passed as arguments to
199 SB-EXT:SAVE-LISP-AND-DIE. For this purpose, the --end-toplevel-options
200 option itself can be considered a toplevel option, i.e. the user core,
201 at its option, may not support it.
202 In the standard SBCL startup sequence (i.e. with no user core involved)
204 toplevel options and any --end-toplevel-options option are stripped out
205 of the command line argument list before user code gets a chance to see
206 it.
207
210 SBCL is derived from the CMU CL. (The name is intended to acknowledge
211 the connection: steel and banking are the industries where Carnegie and
212 Mellon made the big bucks.)
213 SBCL compiles by default: even functions entered in the read-eval-print
215 loop are compiled to native code, unless the evaluator has been explic‐
216 itly turned on. (Even today, some 30 years after the MacLisp compiler,
217 people will tell you that Lisp is an interpreted language. Ignore
218 them.)
219 SBCL aims for but has not completely achieved compliance with the ANSI
221 standard for Common Lisp. More information about this is available in
222 the BUGS section below.
223 SBCL also includes various non-ANSI extensions, described more fully in
225 the User Manual. Some of these are in the base system and others are
226 "contrib" modules loaded on request using REQUIRE. For example, to
227 load the SB-BSD-SOCKETS module that provides TCP/IP connectivity,
228 * (require 'asdf)
229 * (require 'sb-bsd-sockets)
230 For more information, see the User Manual.
232
234 SBCL inherits from CMU CL the "Python" native code compiler. (Though we
235 often avoid that name in order to avoid confusion with the scripting
236 language also called Python.) This compiler is very clever about under‐
237 standing the type system of Common Lisp and using it to optimize code,
238 and about producing notes to let the user know when the compiler
239 doesn't have enough type information to produce efficient code. It also
240 tries (almost always successfully) to follow the unusual but very use‐
241 ful principle that "declarations are assertions", i.e. type declara‐
242 tions should be checked at runtime unless the user explicitly tells the
243 system that speed is more important than safety.
244 The compiled code uses garbage collection to automatically manage mem‐
246 ory. The garbage collector implementation varies considerably from CPU
247 to CPU. In particular, on some CPUs the GC is nearly exact, while on
248 others it's more conservative, and on some CPUs the GC is generational,
249 while on others simpler stop and copy strategies are used.
250 For more information about the compiler, see the user manual.
252
255 SBCL currently runs on X86 (Linux, FreeBSD, OpenBSD, and NetBSD),
256 X86-64 (Linux), Alpha (Linux, Tru64), PPC (Linux, Darwin/MacOS X),
257 SPARC (Linux and Solaris 2.x), and MIPS (Linux). For information on
258 other ongoing and possible ports, see the sbcl-devel mailing list,
259 and/or the web site.
260 SBCL requires on the order of 16Mb RAM to run on X86 systems, though
262 all but the smallest programs would be happier with 32Mb or more.
263
266 This section attempts to list the most serious and long-standing bugs.
267 For more detailed and current information on bugs, see the BUGS file in
268 the distribution.
269 It is possible to get in deep trouble by exhausting heap memory. The
271 SBCL system overcommits memory at startup, so, on typical Unix-alikes
272 like Linux and FreeBSD, this means that if the SBCL system turns out to
273 use more virtual memory than the system has available for it, other
274 processes tend to be killed randomly (!).
275 The compiler's handling of function return values unnecessarily vio‐
277 lates the "declarations are assertions" principle that it otherwise
278 adheres to. Using PROCLAIM or DECLAIM to specify the return type of a
279 function causes the compiler to believe you without checking. Thus com‐
280 piling a file containing
281 (DECLAIM (FTYPE (FUNCTION (T) NULL) SOMETIMES))
282 (DEFUN SOMETIMES (X) (ODDP X))
283 (DEFUN FOO (X) (IF (SOMETIMES X) 'THIS-TIME 'NOT-THIS-TIME))
284 then running (FOO 1) gives NOT-THIS-TIME, because the compiler relied
285 on the truth of the DECLAIM without checking it.
286 Some things are implemented very inefficiently.
288 -- Multidimensional arrays are inefficient, especially multidimensional
290 arrays of floating point numbers.
291 -- SBCL, like most (maybe all?) implementations of Common Lisp on stock
293 hardware, has trouble passing floating point numbers around effi‐
294 ciently, because a floating point number, plus a few extra bits to
295 identify its type, is larger than a machine word. (Thus, they get
296 "boxed" in heap-allocated storage, causing GC overhead.) Within a
297 single compilation unit, or when doing built-in operations like SQRT
298 and AREF, or some special operations like structure slot accesses,
299 this is avoidable: see the user manual for some efficiency hints.
300 But for general function calls across the boundaries of compilation
301 units, passing the result of a floating point calculation as a func‐
302 tion argument (or returning a floating point result as a function
303 value) is a fundamentally slow operation.
304
306 To report a bug, please send mail to the mailing lists sbcl-help or
307 sbcl-devel. You can find the complete mailing list addresses on the web
308 pages at <http://sbcl.sourceforge.net/>; note that as a spam reduction
309 measure you must subscribe to the lists before you can post. (You may
310 also find fancy SourceForge bug-tracking machinery there, but don't be
311 fooled. As of 2002-07-25 anyway, we don't actively monitor that machin‐
312 ery, and it exists only because we haven't been able to figure out how
313 to turn it off.)
314 As with any software bug report, it's most helpful if you can provide
316 enough information to reproduce the symptoms reliably, and if you say
317 clearly what the symptoms are. For example, "There seems to be some‐
318 thing wrong with TAN of very small negative arguments. When I execute
319 (TAN LEAST-NEGATIVE-SINGLE-FLOAT) interactively on sbcl-1.2.3 on my
320 Linux 4.5 X86 box, I get an UNBOUND-VARIABLE error."
321
324 SBCL can be built from scratch using a plain vanilla ANSI Common Lisp
325 system and a C compiler, and all of its properties are specified by the
326 version of the source code that it was created from. This clean boot‐
327 strappability was the immediate motivation for forking off of the CMU
328 CL development tree. A variety of implementation differences are moti‐
329 vated by this design goal.
330 Maintenance work in SBCL since the fork has diverged somewhat from the
332 maintenance work in CMU CL. Many but not all bug fixes and improvements
333 have been shared between the two projects, and sometimes the two
334 projects disagree about what would be an improvement.
335 Most extensions supported by CMU CL have been unbundled from SBCL,
337 including Motif support, the Hemlock editor, search paths, the WIRE
338 protocol, various user-level macros and functions (e.g. LETF, ITERATE,
339 MEMQ, REQUIRED-ARGUMENT), and many others.
340 (Why doesn't SBCL support more extensions natively? Why drop all those
342 nice extensions from CMU CL when the code already exists? This is a
343 frequently asked question on the mailing list. There are two principal
344 reasons. First, it's a design philosophy issue: arguably SBCL has done
345 its job by supplying a stable FFI, and the right design decision is to
346 move functionality derived from that, like socket support, into sepa‐
347 rate libraries. Some of these are distributed with SBCL as "contrib"
348 modules, others are distributed as separate software packages by sepa‐
349 rate maintainers. Second, it's a practical decision - focusing on a
350 smaller number of things will, we hope, let us do a better job on
351 them.)
352
355 Various information about SBCL is available at <http://www.sbcl.org/>.
356 The mailing lists there are the recommended place to look for support.
357
360 Dozens of people have made substantial contributions to SBCL and its
361 subsystems, and to the CMU CL system on which it was based, over the
362 years. See the CREDITS file in the distribution for more information.
363
366 SBCL_HOME This variable controls where files like "sbclrc",
367 "sbcl.core", and the add-on "contrib" systems are searched
368 for. If it is not set, then sbcl sets it from a compile-time
369 default location which is usually /usr/local/lib/sbcl/ but
370 may have been changed e.g. by a third-party packager.
371
374 sbcl executable program containing some low-level runtime support and
375 a loader, used to read sbcl.core
376 sbcl.core
378 dumped memory image containing most of SBCL, to be loaded by the
379 `sbcl' executable. Looked for in $SBCL_HOME, unless overridden
380 by the --core option.
381 sbclrc optional system-wide startup script, looked for in
383 $SBCL_HOME/sbclrc then /etc/sbclrc, unless overridden by the
384 --sysinit command line option.
385 .sbclrc
387 optional per-user customizable startup script (in user's home
388 directory, or as specified by --userinit)
389
392 Full SBCL documentation is maintained as a Texinfo manual. If is has
393 been installed, the command
394 info sbcl
396 should give you access to the complete manual. Depending on your
398 installation it may also be available in HTML and PDF formats in eg.
399 /usr/local/share/doc/sbcl/
401 See the SBCL homepage
403 <http://www.sbcl.org/>
405 for more information, including directions on how to subscribe to the
407 sbcl-devel and sbcl-help mailing-lists.
4087th Edition $Date: 2009/02/16 21:36:13 $ SBCL(1)