X-Git-Url: http://repo.macrolet.net/gitweb/?a=blobdiff_plain;f=doc%2Fsbcl.1;h=216fd6447209d916b65e81124b1504eee243ad4f;hb=44dbdff97fbcc1e5b12e1330da92c5a3dcb94a3b;hp=15b88f985128181bc69c4cebf4ddff96ad005105;hpb=dec94b039e8ec90baf21463df839a6181de606f6;p=sbcl.git diff --git a/doc/sbcl.1 b/doc/sbcl.1 index 15b88f9..216fd64 100644 --- a/doc/sbcl.1 +++ b/doc/sbcl.1 @@ -16,7 +16,7 @@ .TH SBCL 1 "$Date$" .AT 3 .SH NAME -SBCL -- "Steel Bank Common Lisp" +SBCL -- Steel Bank Common Lisp .SH DESCRIPTION @@ -25,6 +25,223 @@ the free CMU CL programming environment. (The name is intended to acknowledge the connection: steel and banking are the industries where Carnegie and Mellon made the big bucks.) +.SH LICENSING + +It is free software, mostly in the public domain, but with some +subsystems under BSD-style licenses which allow modification and +reuse as long as credit is given. It is provided "as is", with no +warranty of any kind. + +For more information about license issues, see the COPYING file in +the distribution. For more information about history, see the +CREDITS file in the distribution. + +.SH RUNNING SBCL + +To run SBCL, type "sbcl" at the command line with no arguments. (SBCL +understands command line arguments, but you probably won't need to use +them unless you're a fairly advanced user. If you are, you should +read the COMMAND LINE SYNTAX section, below.) You should see some +startup messages, then a prompt ("*"). Type a Lisp expression at the +prompt, and SBCL will read it, execute it, print any values returned, +give you another prompt, and wait for your next input. E.g. + + * (+ 1 2 3) + + 6 + * (funcall (lambda (x y) (list x y y)) :toy :choo) + + (:TOY :CHOO :CHOO) + * "Hello World" + + "Hello World" + * + +Many people like to run SBCL, like other Lisp systems, as a subprocess +under Emacs. The Emacs "ilisp" mode provides many convenient features, +like command line editing, tab completion, and various kinds of +coupling between Common Lisp source files and the interactive SBCL +subprocess, but can be somewhat fragile because it tries to be so +clever and intimate in its interactions with the Lisp subprocess. In +case of ilisp problems, running SBCL in the Emacs "shell" mode can a +useful substitute. + +.SH OVERVIEW + +SBCL compiles Common Lisp to native code. (Even today, some 30 years +after the MacLisp compiler, people will tell you that Lisp is an +interpreted language. Ignore them.) + +SBCL aims for but has not completely achieved compliance with the ANSI +standard for Common Lisp. More information about this is available in +the BUGS section below. + +SBCL also includes various non-ANSI extensions, described more fully +in the User Manual. Some of these are in the base system and others +are "contrib" modules loaded on request using REQUIRE. For example, +to load the SB-BSD-SOCKETS module that providces TCP/IP connectivity, + + * (require 'asdf) + * (require 'sb-bsd-sockets) + +Many Lispy extensions have been retained from CMU CL: +.TP 3 +\-- +CMU-CL-style safe implementation of type declarations: +"Declarations are assertions." +.TP 3 +\-- +the source level debugger (very similar to CMU CL's) +.TP 3 +\-- +the profiler (now somewhat different from CMU CL's) +.TP 3 +\-- +saving the state of the running SBCL process, producing a +"core" file which can be restarted later +.TP 3 +\-- +Gray streams (a de-facto standard system of overloadable CLOS classes +whose instances can be used wherever ordinary ANSI streams can be used) +.TP 3 +\-- +weak pointers and finalization (which have unfortunately +suffered from at least some code rot, so that e.g. weak hash +tables don't work) +.PP + +Fundamental system interface extensions are also provided: +.TP 3 +\-- +calling out to C code (a.k.a. FFI, foreign function interface, +with very nearly the same interface as CMU CL) +.TP 3 +\-- +some simple support for operations with a "scripting language" +flavor, e.g. reading POSIX argc and argv, or executing a +subprogram +.PP + +.SH DIFFERENCES FROM CMU CL + +SBCL can be built from scratch using a plain vanilla ANSI Common Lisp +system and a C compiler, and all of its properties are specified by +the version of the source code that it was created from. This clean +bootstrappability was the immediate motivation for forking off of the +CMU CL development tree. A variety of implementation differences are +motivated by this design goal. + +Maintenance work in SBCL since the fork has diverged somewhat from the +maintenance work in CMU CL. Many but not all bug fixes and +improvements have been shared between the two projects, and sometimes +the two projects disagree about what would be an improvement. + +Most extensions supported by CMU CL have been unbundled from SBCL, +including Motif support, the Hemlock editor, search paths, the +low-level Unix interface, the WIRE protocol, various user-level macros +and functions (e.g. LETF, ITERATE, MEMQ, REQUIRED-ARGUMENT), and many +others. + +SBCL inplements multithreading, but in a completely different fashion +from CMU CL: see the User Manual for details. As of 0.8.5 this is +considered beta-quality and must be explicitly enabled at build time. + +SBCL has retained some extensions from its parent CMU CL. Many of the +retained extensions are in these categories: +.TP 3 +\-- +things which might be in the new ANSI spec, e.g. safe type +declarations, weak pointers, finalization, foreign function +interface to C, and Gray streams +.TP 3 +\-- +things which are universally available in Unix scripting languages, +e.g. RUN-PROGRAM and POSIX argv and getenv +.TP 3 +\-- +hooks into the low level workings of the system which can be useful +for debugging, e.g. requesting that a particular function be executed +whenever GC occurs, or tuning compiler diagnostic output +.TP 3 +\-- +unportable performance hacks, e.g. FREEZE-TYPE and PURIFY. For more +information about these, look at the online documentation for symbols +in the SB-EXT package, and look at the user manual. +.PP + +There are also a few retained extensions which don't fall into any +particular category, e.g. the ability to save running Lisp images as +executable files. + +Some of the retained extensions have new names and/or different +options than their CMU CL counterparts. For example, the SBCL function +which saves a Lisp image to disk and kills the running process is +called SAVE-LISP-AND-DIE instead of SAVE-LISP, and SBCL's +SAVE-LISP-AND-DIE supports fewer keyword options than CMU CL's +SAVE-LISP does. + +(Why doesn't SBCL support more extensions natively? Why drop all +those nice extensions from CMU CL when the code already exists? This +is a frequently asked question on the mailing list. There are two +principal reasons. First, it's a design philosophy issue: arguably +SBCL has done its job by supplying a stable FFI, and the right design +decision is to move functionality derived from that, like socket +support, into separate libraries. Some of these are distributed with +SBCL as "contrib" modules, others are distributed as separate software +packages by separate maintainers. Second, it's a practical decision - +focusing on a smaller number of things will, we hope, let us do a +better job on them.) + +.SH THE COMPILER + +SBCL is essentially a compiler-only implementation of Common Lisp. All +nontrivial Lisp code is compiled to native machine code before being +executed, even when the Lisp code is typed interactively at the +"interpreter" prompt. + +SBCL inherits from CMU CL the "Python" native code compiler. (Though +we often avoid that name in order to avoid confusion with the +scripting language also called Python.) This compiler is very clever +about understanding the type system of Common Lisp and using it to +optimize code, and about producing notes to let the user know when the +compiler doesn't have enough type information to produce efficient +code. It also tries (almost always successfully) to follow the unusual +but very useful principle that "declarations are assertions", i.e. +type declarations should be checked at runtime unless the user +explicitly tells the system that speed is more important than safety. + +The compiler reportedly produces pretty good code for modern CPU +architectures which have lots of registers, but its code for the X86 +is marred by many extra loads and stores to stack-based temporary +variables. Because of this, and because of the extra levels of +indirection in Common Lisp relative to C, the performance of SBCL +isn't going to impress people who are impressed by small constant +factors. However, even on the X86 it tends to be faster than byte +interpreted languages (and can be a lot faster). + +The compiled code uses garbage collection to automatically +manage memory. The garbage collector implementation varies considerably +from CPU to CPU. In particular, on some CPUs the GC is nearly exact, +while on others it's more conservative, and on some CPUs the GC +is generational, while on others simpler stop and copy strategies +are used. + +For more information about the compiler, see the user manual. + +.SH DOCUMENTATION + +Currently, the documentation for the system is +.TP 3 +\-- +this man page +.TP 3 +\-- +the user manual +.TP 3 +\-- +doc strings and online help built into the SBCL executable +.PP + .SH COMMAND LINE SYNTAX Command line syntax can be considered an advanced topic; for ordinary @@ -58,14 +275,23 @@ Supported runtime options are .TP 3 .B --core Run the specified Lisp core file instead of the default. (See the FILES -section.) Note that if the Lisp core file is a user-created core file, it may -run a nonstandard toplevel which does not recognize the standard toplevel -options. +section for the standard core, or the system documentation for +SB-INT:SAVE-LISP-AND-DIE for information about how to create a +custom core.) Note that if the Lisp core file is a user-created core +file, it may run a nonstandard toplevel which does not recognize the +standard toplevel options. .TP 3 .B --noinform Suppress the printing of any banner or other informational message at -startup. (This makes it easier to write Lisp programs which work in -Unix pipelines. See also the "--noprogrammer" and "--noprint" options.) +startup. (This makes it easier to write Lisp programs which work +cleanly in Unix pipelines. See also the "--noprint" and +"--disable-debugger" options.) +.TP 3 +.B --help +Print some basic information about SBCL, then exit. +.TP 3 +.B --version +Print SBCL's version information, then exit. .PP In the future, runtime options may be added to control behavior such @@ -75,7 +301,7 @@ Runtime options, including any --end-runtime-options option, are stripped out of the command line before the Lisp toplevel logic gets a chance to see it. -Supported toplevel options for the standard SBCL core are +The toplevel options supported by the standard SBCL core are .TP 3 .B --sysinit Load filename instead of the default system-wide initialization file. @@ -91,34 +317,47 @@ initialization file to be read, but on a Unix system "--userinit .TP 3 .B --eval After executing any initialization file, but before starting the -read-eval-print loop on standard input, evaluate the command given. -More than one --eval option can be used, and all will be executed, in -the order they appear on the command line. +read-eval-print loop on standard input, read and evaluate the command +given. More than one --eval option can be used, and all will be read +and executed, in the order they appear on the command line. +.TP 3 +.B --load +This is equivalent to --eval '(load "")'. The special +syntax is intended to reduce quoting headaches when invoking SBCL +from shell scripts. .TP 3 .B --noprint When ordinarily the toplevel "read-eval-print loop" would be executed, execute a "read-eval loop" instead, i.e. don't print a prompt and don't echo results. Combined with the --noinform runtime option, this -makes it easier to write Lisp "scripts" which work in Unix pipelines. -.TP 3 -.B --noprogrammer -By default, a Common Lisp system tries to ask the programmer for help -when it gets in trouble (by printing a debug prompt on *DEBUG-IO*). -However, this is not useful behavior for a system running with no -programmer available, and this option tries to set up more appropriate -behavior for that situation. Thus we set *DEBUG-IO* to send its -output to *ERROR-OUTPUT*, and to raise an error if any input is -requested from it; and we set *DEBUGGER-HOOK* to output a backtrace, -then exit the process with a failure code. +makes it easier to write Lisp "scripts" which work cleanly in Unix +pipelines. +.TP 3 +.B --disable-debugger +This is equivalent to --eval '(sb-ext:disable-debugger)'. By default, +a Common Lisp system tries to ask the programmer for help when it gets +in trouble (by printing a debug prompt, then listening, on +*DEBUG-IO*). However, this is not useful behavior for a system running +with no programmer available, and this option tries to set up more +appropriate behavior for that situation. This is implemented by +redefining INVOKE-DEBUGGER so that any call exits the process with a +failure code after printing a backtrace, and by redefining *DEBUG-IO* +to send its output to *ERROR-OUTPUT* and to raise an error if any +input is requested from it. (Note that because it is implemented by +modifying special variables and FDEFINITIONs, its effects persist in +.core files created by SB-EXT:SAVE-LISP-AND-DIE. If you want to undo +its effects, e.g. if you build a system unattended and then want to +operate a derived system interactively, see the SB-EXT:ENABLE-DEBUGGER +command.) .PP Regardless of the order in which --sysinit, --userinit, and --eval options appear on the command line, the sysinit file, if it exists, is loaded first; then the userinit file, if it exists, is loaded; then -any --eval commands are executed in sequence; then the read-eval-print -loop is started on standard input. At any step, error conditions or -commands such as SB-EXT:QUIT can cause execution to be terminated -before proceeding to subsequent steps. +any --eval commands are read and executed in sequence; then the +read-eval-print loop is started on standard input. At any step, error +conditions or commands such as SB-EXT:QUIT can cause execution to be +terminated before proceeding to subsequent steps. Note that when running SBCL with the --core option, using a core file created by a user call to the SB-EXT:SAVE-LISP-AND-DIE, the toplevel @@ -132,200 +371,27 @@ involved) toplevel options and any --end-toplevel-options option are stripped out of the command line argument list before user code gets a chance to see it. -.SH OVERVIEW - -SBCL aims for but has not reached ANSI compliance. - -SBCL compiles Lisp to native code, or optionally to more-compact but -much slower byte code. - -SBCL's garbage collector is generational and conservative. - -SBCL includes a source level debugger, as well as the ANSI TRACE -facility and a rudimentary profiler. - -.SH DIFFERENCES FROM CMU CL - -SBCL can be built from scratch using a plain vanilla ANSI Common Lisp -system and a C compiler, and all of its properties are specified by -the version of the source code that it was created from. (This clean -bootstrappability was the immediate motivation for forking off of the -CMU CL development tree.) A variety of internal implementation -differences are motivated by this. - -Maintenance work in SBCL since the fork has diverged in various -details from the maintenance work in CMU CL. E.g. as of 2001-04-12, -SBCL was more ANSI-compliant than CMU CL in various details such as -support for PRINT-OBJECT and DESCRIBE-OBJECT, and SBCL's compiler was -substantially better than CMU CL's at optimizing operations on -non-simple vectors. - -Most extensions supported by CMU CL are not supported in SBCL, -including Motif support, the Hemlock editor, search paths, the -low-level Unix interface, the WIRE protocol, multithreading support, -various user-level macros and functions (e.g. LETF, ITERATE, MEMQ, -REQUIRED-ARGUMENT), and many others. - -SBCL has retained some extensions from parent CMU CL. Many of the -retained extensions are in these categories: -.TP 3 -\-- -things which might be in the new ANSI spec, e.g. weak pointers, -finalization, foreign function interface to C, and Gray streams -.TP 3 -\-- -things which are universally available in Unix scripting languages, -e.g. RUN-PROGRAM and POSIX argv and getenv -.TP 3 -\-- -hooks into the low level workings of the system which can be useful -for debugging, e.g. a list of functions to be run whenever GC occurs, -or parameters to modify compiler diagnostic output -.TP 3 -\-- -unportable performance hacks, e.g. TRULY-THE, FREEZE-TYPE, and PURIFY -.PP - -There are also a few retained extensions which don't fall into -any particular category, e.g. -.TP 3 -\-- -the ability to save running Lisp images as executable files -.PP - -Some of the retained extensions have new names and/or different -options than their CMU CL counterparts. For example, the SBCL function -which saves a Lisp image to disk and kills it is called -SAVE-LISP-AND-DIE instead of SAVE-LISP, and it supports fewer keyword -options than CMU CL's SAVE-LISP. - -(Why doesn't SBCL support more extensions? Why the hell did I (WHN) -drop all those nice extensions from CMU CL when the code already -exists? This is a frequently asked question on the mailing list. The -answer is that they're hard to maintain, and I have enough on my hands -already. Also, in the case of some big and unquestionably useful -extensions, like sockets and Motif, I think that SBCL has done its job -by supplying the FFI, and that people who need, and understand, and -are motivated to maintain the functionality should supply it as a -separate library, which I'd be happy to distribute or link to on the -SBCL home page. Finally, in the case of multithreading, I do think it -belongs in the new ANSI spec, and it'd be a good feature to have, but -I didn't think the CMU CL implementation was sufficiently mature, and -it's such a complicated and far-reaching extension that I thought that -trying to fix it would interfere with the more urgent task of getting -basic ANSI support up to speed.) - -.SH THE COMPILER - -SBCL inherits from CMU CL the "Python" native code compiler. This -compiler is very clever about understanding the type system of Common -Lisp and using it to produce efficient code, and about producing notes -to let the user know when the compiler doesn't have enough type -information to produce efficient code. It also tries (almost always -successfully) to follow the unusual but very useful principle that -type declarations should be checked at runtime unless the user -explicitly tells the system that speed is more important than safety. - -The CMU CL version of this compiler reportedly produces pretty good -code for modern machines which have lots of registers, but its code -for the X86 is marred by a lot of extra loads and stores to -stack-based temporary variables. Because of this, and because of the -extra levels of indirection in Common Lisp relative to C, we find a -typical performance decrease by a factor of perhaps 2 to 5 for small -programs coded in SBCL instead of GCC. - -For more information about the compiler, see the user manual. - -.SH DOCUMENTATION - -Currently, the documentation for the system is -.TP 3 -\-- -the user manual -.TP 3 -\-- -this man page -.TP 3 -\-- -doc strings and online help built into the SBCL executable -.PP - .SH SYSTEM REQUIREMENTS -Unlike its distinguished ancestor CMU CL, SBCL is currently on X86 -(Linux, FreeBSD, and OpenBSD) and Alpha (Linux). It would probably be -straightforward to port the CMU CL support for SPARC, or to port to -NetBSD. - -As of version 0.6.13, SBCL requires on the order of 16Mb RAM to run -on X86 systems. - -.SH ENVIRONMENT - -.TP 10n -.BR SBCL_HOME -If this variable is set, it overrides the default directories for -files like "sbclrc" and "sbcl.core", so that instead of being searched -for in e.g. /etc/, /usr/local/etc/, /usr/lib/, and /usr/local/lib/, they -are searched for only in the directory named by SBCL_HOME. This is -intended to support users who wish to use their own version of SBCL -instead of the version which is currently installed as the system -default. -.PP - -.SH FILES - -/usr/lib/sbcl.core and /usr/local/lib/sbcl.core are the standard -locations for the standard SBCL core, unless overridden by the SBCL_HOME -variable. - -/etc/sbclrc and /usr/local/etc/sbclrc are the standard locations for -system-wide SBCL initialization files, unless overridden by the -SBCL_HOME variable or the --sysinit command line option. - - -$HOME/.sbclrc is the standard location for a user's SBCL -initialization file, unless overridden by the --userinit -command line option. +SBCL currently runs on X86 (Linux, FreeBSD, and OpenBSD), Alpha +(Linux, Tru64), PPC (Linux, Darwin/MacOS X), SPARC (Linux and Solaris +2.x), and MIPS (Linux). For information on other ongoing and possible +ports, see the sbcl-devel mailing list, and/or the web site. -.SH BUGS +SBCL requires on the order of 16Mb RAM to run on X86 systems, though +all but the smallest programs would be happier with 32Mb or more. -To report a bug, please send mail to sbcl-help@lists.sourceforge.net -or sbcl-devel@lists.sourceforge.net. As with any software bug report, -it's most helpful if you remember to describe the environment where -the problem occurs (machine type, O/S name and version, etc.) and if -you can provide enough information to reproduce the problem, -preferably in compact form. +.SH KNOWN BUGS -This section attempts to list the most serious and long-standing bugs -or surprising performance hits. For more detailed and current -information on bugs, see the BUGS file in the distribution. - -It is possible to get in deep trouble by exhausting -memory. To plagiarize a sadly apt description of a language not -renowned for the production of bulletproof software, "[The current -SBCL implementation of] Common Lisp makes it harder for you to shoot -yourself in the foot, but when you do, the entire universe explodes." -.TP 3 -\-- -The system doesn't deal well with stack overflow. (It tends to cause -a segmentation fault instead of being caught cleanly.) -.TP 3 -\-- -Like CMU CL, the SBCL system overcommits memory at startup. On typical -Unix-alikes like Linux and FreeBSD, this means that if the SBCL system -turns out to use more virtual memory than the system has available for -it, other processes tend to be killed randomly (!). -.PP +This section attempts to list the most serious and long-standing bugs. +For more detailed and current information on bugs, see the BUGS file +in the distribution. -The compiler is overaggressive about static typing, assuming that a -function's return type never changes. Thus compiling and loading a -file containing -(DEFUN FOO (X) NIL) -(DEFUN BAR (X) (IF (FOO X) 1 2)) -(DEFUN FOO (X) (PLUSP X)) -then running (FOO 1) gives 2 (because the compiler "knew" -that FOO's return type is NULL). +It is possible to get in deep trouble by exhausting heap memory. The +SBCL system overcommits memory at startup, so, on typical Unix-alikes +like Linux and FreeBSD, this means that if the SBCL system turns out +to use more virtual memory than the system has available for it, other +processes tend to be killed randomly (!). The compiler's handling of function return values unnecessarily violates the "declarations are assertions" principle that it otherwise @@ -335,27 +401,45 @@ compiling a file containing (DECLAIM (FTYPE (FUNCTION (T) NULL) SOMETIMES)) (DEFUN SOMETIMES (X) (ODDP X)) (DEFUN FOO (X) (IF (SOMETIMES X) 'THIS-TIME 'NOT-THIS-TIME)) -then running (FOO 1) gives NOT-THIS-TIME, because the -never compiled code to check the declaration. +then running (FOO 1) gives NOT-THIS-TIME, because the compiler +relied on the truth of the DECLAIM without checking it. -The implementation of multidimensional arrays, especially -multidimensional arrays of floating point numbers, is very -inefficient. - -SYMBOL-FUNCTION is much slower than you might expect, being -implemented not as a slot access but as a search through the -compiler/kernel "globaldb" database. - -CLOS (based on the PCL reference implementation) is somewhat -inefficient. - -There are many nagging pre-ANSIisms, e.g. +Some things are implemented very inefficiently. +.TP 3 +\-- +Multidimensional arrays are inefficient, especially +multidimensional arrays of floating point numbers. +.TP 3 +\-- +The DYNAMIC-EXTENT declaration isn't implemented at all, not even +for &REST lists or upward closures, so such constructs always allocate +their temporary storage from the heap, causing GC overhead. +.TP 3 +\-- +CLOS isn't particularly efficient. (In part, CLOS is so dynamic +that it's slow for fundamental reasons, but beyond that, the +SBCL implementation of CLOS doesn't do some important known +optimizations.) .TP 3 \-- -CLOS (based on the PCL reference implementation) is incompletely -integrated into the system, so that e.g. SB-PCL::FIND-CLASS is a -different function than CL::FIND-CLASS. (This is less of a problem in -practice than the speed, but it's still distasteful.) +SBCL, like most (maybe all?) implementations of Common Lisp on +stock hardware, has trouble +passing floating point numbers around efficiently, because a floating +point number, plus a few extra bits to identify its type, +is larger than a machine word. (Thus, they get "boxed" in +heap-allocated storage, causing GC overhead.) Within +a single compilation unit, +or when doing built-in operations like SQRT and AREF, +or some special operations like structure slot accesses, +this is avoidable: see the user manual for some +efficiency hints. But for general function calls across +the boundaries of compilation units, passing the result of +a floating point calculation +as a function argument (or returning a floating point +result as a function value) is a fundamentally slow operation. +.PP + +There are still some nagging pre-ANSIisms, notably .TP 3 -- The ANSI-recommended idiom for creating a function which is only @@ -367,35 +451,73 @@ doesn't do what you'd expect. (Instead, you have to declare the function as SB-EXT:MAYBE-INLINE to get the desired effect.) .TP 3 \-- -The DYNAMIC-EXTENT declaration is not implemented, and is simply -ignored. (This is allowed by the ANSI spec, but can have a large -efficiency cost in some kinds of code, e.g. code which uses a lot -of upward closures or &REST lists.) -.TP 3 --- -Compiling DEFSTRUCT in strange places (e.g. inside a DEFUN) doesn't -do anything like what it should. -.TP 3 -\-- -The symbol * is the name of a type similar to T. (It's used as part of -the implementation of compound types like (ARRAY * 1) and (CONS * *). -In a strict ANSI implementation, * would not be the name of a type, -but instead just a symbol which is recognized and handled specially by -certain type expanders.) +There are several nonconforming bits of type syntax. E.g. (1) The type +FOO is strictly equivalent to (FOO), so e.g. the type OR is treated as +the type (OR), i.e. the empty type. This is the way that the ancestral +code worked, and even though ANSI specifically forbids it, it hasn't +been fixed yet. (2) The symbol * is the name of a type similar to T. +(It's used as part of the implementation of compound types like (ARRAY +* 1) and (CONS * *). In a strict ANSI implementation, * would not be +the name of a type, but instead just a symbol which is recognized and +handled specially by certain type expanders.) .PP +.SH REPORTING BUGS + +To report a bug, please send mail to the mailing lists sbcl-help or +sbcl-devel. You can find the complete mailing list addresses on the +web pages at . (You may also find fancy +SourceForge bug-tracking machinery there, but don't be fooled. As of +2002-07-25 anyway, we don't actively monitor that machinery, and it +exists only because we haven't been able to figure out how to turn +it off.) + +As with any software bug report, it's most helpful if you can provide +enough information to reproduce the symptoms reliably, and if you say +clearly what the symptoms are. E.g. "There seems to be something wrong +with TAN of very small negative arguments. When I execute +(TAN LEAST-NEGATIVE-SINGLE-FLOAT) interactively on sbcl-1.2.3 on my +Linux 4.5 X86 box, I get an UNBOUND-VARIABLE error." + .SH SUPPORT Various information about SBCL is available at . The mailing lists there are the recommended place to look for support. -.SH DISTRIBUTION +.SH ENVIRONMENT -SBCL is a free implementation of Common Lisp derived from CMU CL. Both -sources and executables are freely available; this software is "as -is", and has no warranty of any kind. CMU and the authors assume no -responsibility for the consequences of any use of this software. See -the CREDITS file in the distribution for more information about -history, contributors and permissions. +.TP 10n +.BR SBCL_HOME +This variable controls where files like "sbclrc", "sbcl.core", and the +add-on "contrib" systems are searched for. If it is not set, then +sbcl sets it from a compile-time default location which is usually +/usr/local/lib/sbcl/ but may have been changed e.g. by a third-party +packager. + +.SH FILES +.TP +.I sbcl +executable program containing some low-level runtime support and +a loader, used to read sbcl.core +.TP +.I sbcl.core +dumped memory image containing most of SBCL, to be loaded by +the 'sbcl' executable. Looked for in $SBCL_HOME, +unless overridden by the --core option. +.TP +.I sbclrc +optional system-wide startup script, looked for in $SBCL_HOME/sbclrc +then /etc/sbclrc, unless overridden by the --sysinit command line +option. +.TP +.I .sbclrc +optional per-user customizable startup script (in user's home +directory, or as specified by --userinit) + +.SH AUTHORS + +Dozens of people have made substantial contributions to SBCL and its +subsystems, and to the CMU CL system on which it was based, over the +years. See the CREDITS file in the distribution for more information.