2.4.2 Command line options for running Prolog

Note that boolean options may be written as --name (true), --noname or --no-name (false). They are written as --no-name below as the default is‘true’.

-D name[=value]

Set the Prolog flag name to value. The flags are set immediately after loading the initial saved state. If the flag is already defined, value is converted to the type of the flag. If the flag is undefined it is set to a number of value represents a number and an atom otherwise. If no =value is given, a Boolean value is used. If name is no-flag, flag is set to false. Otherwise, the flag name is set to true. The name[=value] may follow the -D immediately or appear as the next commandline argument.

Note that many of the commandline options are reflected by a Prolog flag. We intend to handle these as synonyms. Currently, some of the commandline flags affect the Prolog initilization before loading the saved state has completed, while other may not be changed after Prolog initialization. For example, future versions will support -Dhome=dir to change the notion of the Prolog installation directory.

--debug-on-interrupt

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.

--home[=DIR]

Use DIR as home directory. See section 12.6 for details. If DIR is omitted, the found location is printed and the process exits. If the location cannot be found an error is printed and the process exits with status 1.

--quiet

Set the Prolog flag verbose to silent, suppressing informational and banner messages. Also available as -q.

--no-debug

Disable debugging. See the current_prolog_flag/2 flag generate_debug_info for details.

--no-signals

Inhibit any signal handling by Prolog, a property that is sometimes desirable for embedded applications. This option sets the flag signals to false. See section 12.4.25.1 for details. Note that the handler to unblock system calls is still installed. This can be prevented using --sigalert=0 additionally. See --sigalert.

--no-threads

Disable threading for the multi-threaded version at runtime. See also the flags threads and gc_thread.

--no-packs

Do not attach extension packages (add-ons). See also attach_packs/0 and the Prolog flag packs.

--no-pce

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 --pce load the xpce system in user space and --no-pce makes it unavailable in the session.

--on-error =style

How to handle on errors. See the Prolog flag on_error for details.

--on-warning =style

How to handle on warnings. See the Prolog flag on_warning for details.

--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.

--sigalert=NUM

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.

--no-tty

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.

--win-app

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\Prolog or local equivalent thereof (see win_folder/2). The Prolog subdirectory is created if it does not exist.

-O

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 2.11.1.1, 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.rc and then select ISO compatibility mode using pl -F iso or 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.

--traditional

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.