shell(Command, 0)'. See shell/2 
for details.On Windows, shell/[1,2] 
executes the command using the CreateProcess() API and waits for the 
command to terminate. If the command ends with a
& sign, the command is handed to the WinExec() API, 
which does not wait for the new task to terminate. See also win_exec/2 
and
win_shell/2. 
Please note that the CreateProcess() API does not imply the 
Windows command interpreter (cmd.exe and therefore commands that 
are built in the command interpreter can only be activated using the 
command interpreter. For example, a file can be compied using the 
command below.
?- shell('cmd.exe /C copy file1.txt file2.txt').
Note that many of the operations that can be achieved using the shell 
built-in commands can easily be achieved using Prolog primitives. See
make_directory/1, delete_file/1, rename_file/2, 
etc. The clib package provides library(filesex), 
implementing various high level file operations such as copy_file/2. 
Using Prolog primitives instead of shell commands improves the 
portability of your program.
The library library(process) provides process_create/3 
and several related primitives that support more fine-grained 
interaction with processes, including I/O redirection and management of 
asynchronous processes.
all, collate, ctype, messages,
monetary, numeric or time. For 
details, please consult the C library locale documentation. See also section 
2.18.1. Please note that the locale is shared between all threads 
and thread-safe usage of setlocale/3 
is in general not possible. Do locale operations before starting threads 
or thoroughly study threading aspects of locale support in your 
environment before using in multithreaded environments. Locale settings 
are used by format_time/3, collation_key/2 
and locale_sort/2.~--. Integer 
arguments are passed as Prolog integers, float arguments and Prolog 
floating point numbers and all other arguments as Prolog atoms. New 
applications should use the Prolog flag argv. 
See also the Prolog flag
argv.
A stand-alone program could use the following skeleton to handle command line arguments. See also section 2.10.2.4.
main :-
        current_prolog_flag(argv, Argv),
        append(_PrologArgs, [--|AppArgs], Argv), !,
        main(AppArgs).
The predicates in this section are only available on the Windows version of SWI-Prolog. Their use is discouraged if there are portably alternatives. For example, win_exec/2 and win_shell/2 can often be replaced by the more portable shell/2 or the more powerful process_create/3.
SW_* constants written in lowercase 
without the SW_*:
hide
maximize
minimize
restore
show
showdefault
showmaximized
showminimized
showminnoactive
showna
shownoactive
shownormal. In addition, iconic is a synonym 
for minimize and
normal for shownormal.open,
print or explore or another operation 
registered with the shell for the given document type. On modern systems 
it is also possible to pass a URL as File, 
opening the URL in Windows default browser. This call interfaces to the 
Win32 API ShellExecute(). The Show argument determines the 
initial state of the opened window (if any). See win_exec/2 
for defined values.win_shell(Operation, File, normal)DWORD, 
the value is returned as an integer. If the value is a string, it is 
returned as a Prolog atom. Other types are currently not supported. The 
default `root' is HKEY_CURRENT_USER. Other roots can be 
specified explicitly as
HKEY_CLASSES_ROOT, HKEY_CURRENT_USER,
HKEY_LOCAL_MACHINE or HKEY_USERS. The example 
below fetches the extension to use for Prolog files (see README.TXT 
on the Windows version):
?- win_registry_get_value(
       'HKEY_LOCAL_MACHINE/Software/SWI/Prolog',
       fileExtension,
       Ext).
Ext = pl
CSIDL_ 
and mapping the constant to lowercase. Check the Windows documentation 
for the function SHGetSpecialFolderPath() for a description of the 
defined constants. This example extracts the `My Documents' folder:
?- win_folder(personal, MyDocuments). MyDocuments = 'C:/Documents and Settings/jan/My Documents'
%PATH% is extended with the provided directory.
AbsDir may be specified in the Prolog canonical syntax. See
prolog_to_os_filename/2. 
Note that use_foreign_library/1 
passes an absolute path to the DLL if the destination DLL can be located 
from the specification using absolute_file_name/3.
If open_shared_object/2 
is passed an absolute path to a DLL on a Windows installation 
that supports AddDllDirectory() and friends,124Windows 7 
with up-to-date patches or Windows 8. SWI-Prolog uses 
LoadLibraryEx() with the flags
LOAD_LIBRARY_SEARCH_DLL_LOAD_DIR and
LOAD_LIBRARY_SEARCH_DEFAULT_DIRS. In this scenario, 
directories from %PATH% and not searched. 
Additional directories can be added using win_add_dll_directory/2.
Representing time in a computer system is surprisingly complicated. There are a large number of time representations in use, and the correct choice depends on factors such as compactness, resolution and desired operations. Humans tend to think about time in hours, days, months, years or centuries. Physicists think about time in seconds. But, a month does not have a defined number of seconds. Even a day does not have a defined number of seconds as sometimes a leap-second is introduced to synchronise properly with our earth's rotation. At the same time, resolution demands a range from better than pico-seconds to millions of years. Finally, civilizations have a wide range of calendars. Although there exist libraries dealing with most if this complexity, our desire to keep Prolog clean and lean stops us from fully supporting these.
For human-oriented tasks, time can be broken into years, months, days, hours, minutes, seconds and a timezone. Physicists prefer to have time in an arithmetic type representing seconds or fraction thereof, so basic arithmetic deals with comparison and durations. An additional advantage of the physicist's approach is that it requires much less space. For these reasons, SWI-Prolog uses an arithmetic type as its prime time representation.
Many C libraries deal with time using fixed-point arithmetic, dealing with a large but finite time interval at constant resolution. In our opinion, using a floating point number is a more natural choice as we can use a natural unit and the interface does not need to be changed if a higher resolution is required in the future. Our unit of choice is the second as it is the scientific unit.125Using Julian days is a choice made by the Eclipse team. As conversion to dates is needed for a human readable notation of time and Julian days cannot deal naturally with leap seconds, we decided for the second as our unit. We have placed our origin at 1970-1-1T0:0:0Z for compatibility with the POSIX notion of time as well as with older time support provided by SWI-Prolog.
Where older versions of SWI-Prolog relied on the POSIX conversion functions, the current implementation uses libtai to realise conversion between time-stamps and calendar dates for a period of 10 million years.
We use the following time representations
-true if daylight saving time applies to the current 
time, false if daylight saving time is relevant but not 
effective, and -local 
to extract the local time, 'UTC' to extract a UTC time or 
an integer describing the seconds west of Greenwich.?- date_time_stamp(date(2006,7,214,0,0,0,0,-,-), Stamp), stamp_date_time(Stamp, D, 0), date_time_value(date, D, Date). Date = date(2007, 1, 30)
When computing a time stamp from a local time specification, the UTC offset (arg 7), TZ (arg 8) and DST (arg 9) argument may be left unbound and are unified with the proper information. The example below, executed in Amsterdam, illustrates this behaviour. On the 25th of March at 01:00, DST does not apply. At 02.00, the clock is advanced by one hour and thus both 02:00 and 03:00 represent the same time stamp.
1 ?- date_time_stamp(date(2012,3,25,1,0,0,UTCOff,TZ,DST),
                     Stamp).
UTCOff = -3600,
TZ = 'CET',
DST = false,
Stamp = 1332633600.0.
2 ?- date_time_stamp(date(2012,3,25,2,0,0,UTCOff,TZ,DST),
                     Stamp).
UTCOff = -7200,
TZ = 'CEST',
DST = true,
Stamp = 1332637200.0.
3 ?- date_time_stamp(date(2012,3,25,3,0,0,UTCOff,TZ,DST),
                     Stamp).
UTCOff = -7200,
TZ = 'CEST',
DST = true,
Stamp = 1332637200.0.
Note that DST and offset calculation are based on the POSIX function 
mktime(). If mktime() returns an error, a representation_error
dst is generated.
| key | value | 
| year | Calendar year as an integer | 
| month | Calendar month as an integer 1..12 | 
| day | Calendar day as an integer 1..31 | 
| hour | Clock hour as an integer 0..23 | 
| minute | Clock minute as an integer 0..59 | 
| second | Clock second as a float 0.0..60.0 | 
| utc_offset | Offset to UTC in seconds (positive is west) | 
| time_zone | Name of timezone; fails if unknown | 
| daylight_saving | Bool daylight_savingtrue) 
if dst is in effect | 
| date | Term date(Y,M,D) | 
| time | Term time(H,M,S) | 
date(Y,M,D,H,M,S,O,TZ,DST) or a term date(Y,M,D).
aAbBcCdDeEff can be prefixed by an integer 
to print the desired number of digits. E.g., %3f prints 
milliseconds. This format is not covered by any standard, but available 
with different format specifiers in various incarnations of the 
strftime() function.
FgGVhHIjklmMnOpPrRsStTuUwWxXyYz'%a, %d %b %Y %T %z'). Our 
implementation supports
%:z, which modifies the output to HH:mm as required by 
XML-Schema. Note that both notations are valid in ISO 8601. The sequence %:z 
is compatible to the GNU date(1) command.
Z+%The table below gives some format strings for popular time 
representations. RFC1123 is used by HTTP. The full implementation of
http_timestamp/2 
as available from library(http/http_header) is here.
http_timestamp(Time, Atom) :-
        stamp_date_time(Time, Date, 'UTC'),
        format_time(atom(Atom),
                    '%a, %d %b %Y %T GMT',
                    Date, posix).
| Standard | Format string | 
| xsd | '%FT%T%:z' | 
| ISO8601 | '%FT%T%z' | 
| RFC822 | '%a, %d %b %Y %T %z' | 
| RFC1123 | '%a, %d %b %Y %T GMT' | 
posix, which 
currently only modifies the behaviour of the a, A, b 
and B format specifiers. The predicate is used to be able 
to emit POSIX locale week and month names for emitting standardised 
time-stamps such as RFC1123.parse_time(Text, _Format, Stamp). See parse_time/3.| Name | Example | 
| rfc_1123 | Fri, 08 Dec 2006 15:29:44 
GMT  | 
| Fri, 08 Dec 2006 15:29:44 +0000  | |
| iso_8601 | 2006-12-08T17:29:44+02:00  | 
| 20061208T172944+0200  | |
| 2006-12-08T15:29Z  | |
| 2006-12-08  | |
| 20061208  | |
| 2006-12  | |
| 2006-W49-5  | |
| 2006-342  | 
Date = date(Year,Month,Day). 
Days of the week are numbered from one to seven: Monday = 1, Tuesday = 
2, ... , Sunday = 7.
The Windows executable swipl-win.exe console has a number of predicates to control the appearance of the console. Being totally non-portable, we do not advise using it for your own application, but use XPCE or another portable GUI platform instead. We give the predicates for reference here.
win_window_title for 
consistent naming.bottom, top, topmost and notopmost.
Topmost windows are displayed above all other windows.
true, show the window, if false hide the 
window.
& 
is underlined and defines the associated accelerator key. Before 
is the label before which this one must be inserted. Using -
win_insert_menu('&Application', '&Help')
-