- Reference manual
- Getting started quickly
- The user's initialisation file
- Initialisation files and goals
- Command line options
- UI Themes
- GNU Emacs Interface
- Online Help
- Command line history
- Reuse of top-level bindings
- Overview of the Debugger
- Environment Control (Prolog flags)
- An overview of hook predicates
- Automatic loading of libraries
- Packs: community add-ons
- The SWI-Prolog syntax
- Rational trees (cyclic terms)
- Just-in-time clause indexing
- Wide character support
- System limits
- SWI-Prolog and 64-bit machines
- Binary compatibility
- Reference manual
SWI-Prolog can be executed in one of the following modes:
- These options must appear as only option. They cause Prolog to print an informational message and exit. See section 2.4.1.
swipl[option ...] script-file [arg ...]
- These arguments are passed on Unix systems if file that starts with
#!/path/to/executable[option ...] is executed. Arguments after the script file are made available in the Prolog flag argv.
swipl[option ...] prolog-file ... [[
--] arg ...]
- This is the normal way to start Prolog. The options are described in
section 2.4.2, section
2.4.3 and section 2.4.4.
The Prolog flag argv
provides access to arg ... If the options are
followed by one or more Prolog file names (i.e., names with extension
.prologor (on Windows) the user preferred extension registered during installation), these files are loaded. The first file is registered in the Prolog flag associated_file. In addition, pl-win[.exe] switches to the directory in which this primary source file is located using working_directory/2.
swipl-o output -c prolog-file ...
- The -c option is used to compile a set of Prolog files into an executable. See section 2.4.5.
swipl-o output -b bootfile prolog-file ...
- Bootstrap compilation. See section 2.4.6.
- When given as the only option, it prints the architecture identifier (see Prolog flag arch) and exits. See also --dump-runtime-variables.
- --dump-runtime-variables [=format]
- When given as the only option, it prints a sequence of variable settings
that can be used in shell scripts to deal with Prolog parameters. This
feature is also used by swipl-ld (see section
12.5). Below is a typical example of using this feature.
eval `swipl --dump-runtime-variables` cc -I$PLBASE/include -L$PLBASE/lib/$PLARCH ...
The option can be followed by
=shto dump in POSIX shell format (default) or
=cmdto dump in MS-Windows cmd.exe compatible format.
- When given as the only option, it summarises the most important options.
- When given as the only option, it summarises the version and the architecture identifier.
- Print a key (string) that represents the binary compatibility on a number of aspects. See section 2.22.
Note that boolean options may be written as
--no-name (false). They
are written as
--no-name below as the default is‘true'.
- Enable debugging on an interrupt signal (Control-C,
SIGINT) immediately. Normally debugging on interrupt is enabled when entering the interactive toplevel. This flag can be used to start the debugger on an interrupt while executing goals from -g or initialization/[1,2]. See also the Prolog flag debug_on_interrupt.
- Use DIR as home directory. See section 12.6 for details.
- Set the Prolog flag verbose
silent, suppressing informational and banner messages. Also available as -q.
- Disable debugging. See the current_prolog_flag/2 flag generate_debug_info for details.
- Inhibit any signal handling by Prolog, a property that is sometimes
desirable for embedded applications. This option sets the flag
false. See section 220.127.116.11 for details. Note that the handler to unblock system calls is still installed. This can be prevented using
--sigalert=0additionally. See --sigalert.
- Disable threading for the multi-threaded version at runtime. See also the flags threads and gc_thread.
- Do not attach extension packages (add-ons). See also attach_packs/0 and the Prolog flag packs.
- Enable/disable the xpce GUI subsystem. The default is to make it
available as autoload component if it is installed and the system can
access the graphics. Using
--pceload the xpce system in user space and
--no-pcemakes it unavailable in the session.
- --pldoc [=port]
- Start the PlDoc documentation system on a free network port and launch
the user's browser on
http://localhost:port. If port is specified, the server is started at the given port and the browser is not launched.
- Use signal NUM (1 ... 31) for alerting a thread. This is
needed to make thread_signal/2,
and derived Prolog signal handling act immediately when the target
thread is blocked on an interruptible system call (e.g., sleep/1,
read/write to most devices). The default is to use
SIGUSR2. If NUM is 0 (zero), this handler is not installed. See prolog_alert_signal/2 to query or modify this value at runtime.
- Unix only. Switches controlling the terminal for allowing single-character commands to the tracer and get_single_char/1. By default, manipulating the terminal is enabled unless the system detects it is not connected to a terminal or it is running as a GNU-Emacs inferior process. See also tty_control.
- This option is available only in swipl-win.exe and is used for
the start-menu item. If causes plwin to start in the folder
...\My Documents\Prologor local equivalent thereof (see win_folder/2). The
Prologsubdirectory is created if it does not exist.
- Optimised compilation. See current_prolog_flag/2 flag optimise for details.
- -l file
- Load file. This flag provides compatibility with some other Prolog systems.10YAP, SICStus It is used in SWI-Prolog to skip the program initialization specified using initialization/2 directives. See also section 18.104.22.168, and initialize/0.
- -s file
- Use file as a script file. The script file is loaded after the initialisation file specified with the -f file option. Unlike -f file, using -s does not stop Prolog from loading the personal initialisation file.
- -f file
- Use file as initialisation file instead of the default
init.pl.‘-f none’stops SWI-Prolog from searching for a startup file. This option can be used as an alternative to -s file that stops Prolog from loading the personal initialisation file. See also section 2.2.
- -F script
- Select a startup script from the SWI-Prolog home directory. The script
file is named
<script>.rc. The default script name is deduced from the executable, taking the leading alphanumerical characters (letters, digits and underscore) from the program name. -F none stops looking for a script. Intended for simple management of slightly different versions. One could, for example, write a script
iso.rcand then select ISO compatibility mode using
pl -F isoor make a link from iso-pl to pl.
- -x bootfile
- Boot from bootfile instead of the system's default boot file. A boot file is a file resulting from a Prolog compilation using the -b or -c option or a program saved using qsave_program/[1,2].
- -p alias=path1[:path2 ... ]
- Define a path alias for file_search_path. alias is the name
of the alias, and arg path1 ... is a list of values for the alias. On
Windows the list separator is
. On other systems it is
. A value is either a term of the form alias(value) or pathname. The computed aliases are added to file_search_path/2 using asserta/1, so they precede predefined values for the alias. See file_search_path/2 for details on using this file location mechanism.
- This flag disables the most important extensions of SWI-Prolog version 7 (see section 5) that introduce incompatibilities with earlier versions. In particular, lists are represented in the traditional way, double quoted text is represented by a list of character codes and the functional notation on dicts is not supported. Dicts as a syntactic entity, and the predicates that act on them, are still supported if this flag is present.
- Stops scanning for more arguments, so you can pass arguments for your application after this one. See current_prolog_flag/2 using the flag argv for obtaining the command line arguments.
As of version 7.7.14 the stacks are no longer limited individually. Instead, only the combined size is limited. Note that 32 bit systems still pose a 128Mb limit. See section 2.20.1. The combined limit is by default 1Gb on 64 bit machines and 512Mb on 32 bit machines.
For example, to limit the stacks to 32Gb use the command below. Note
that the stack limits apply per thread. Individual threads may
be controlled using the
stack_limit(+Bytes) option of
thread_create. Any thread can call
adjust the stack limit. This limit is inherited by threads created from
$ swipl --stack-limit=32g
- Limit the combined size of the Prolog stacks to the indicated size. The suffix specifies the value as bytes, Kbytes, Mbytes or Gbytes.
- Limit for the table space. This is where tries holding memoized11The letter M is used because the T was already in use. It is a memnonic for Memoizing. answers for tabling are stored. The default is 1Gb on 64 bit machines and 512Mb on 32 bit machines. See the Prolog flag table_space.
- Limit for the table space for shared tables. See section 7.9.
- -g goal
- Goal is executed just before entering the top level. This
option may appear multiple times. See section
2.3 for details. If no initialization goal is present the system
to print the welcome message. The welcome message can be suppressed with
--quiet, but also with -g true. goal
can be a complex term. In this case quotes are normally needed to
protect it from being expanded by the shell. A safe way to run a goal
non-interactively is below. If go/0 succeeds
-g halt causes the process to stop with exit
code 0. If it fails, the exit code is 1; and if it raises an exception,
the exit code is 2.
% swipl <options> -g go -g halt
- -t goal
- Use goal as interactive top level instead of the default goal prolog/0. The goal can be a complex term. If the top-level goal succeeds SWI-Prolog exits with status 0. If it fails the exit status is 1. If the top level raises an exception, this is printed as an uncaught error and the top level is restarted. This flag also determines the goal started by break/0 and abort/0. If you want to prevent the user from entering interactive mode, start the application with‘-g goal -t halt’.
- -c file ...
- Compile files into an‘intermediate code file'. See section 2.11.
- -o output
- Used in combination with -c or -b to determine output file for compilation.
The following options are for system maintenance. They are given for reference only.
- -b initfile ...-c file ...
- Boot compilation. initfile ... are compiled by the C-written bootstrap compiler, file ... by the normal Prolog compiler. System maintenance only.
- -d token1,token2,...
- Print debug messages for DEBUG statements tagged with one of the
indicated tokens. Only has effect if the system is compiled with the
-DO_DEBUGflag. System maintenance only.