/usr/lib/swi-prolog/library/time.pl is in swi-prolog-nox 5.10.4-3ubuntu1.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 | /* $Id$
Part of SWI-Prolog
Author: Jan Wielemaker
E-mail: J.Wielemaker@cs.vu.nl
WWW: http://www.swi-prolog.org
Copyright (C): 1985-2009, University of Amsterdam
This program is free software; you can redistribute it and/or
modify it under the terms of the GNU General Public License
as published by the Free Software Foundation; either version 2
of the License, or (at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with this library; if not, write to the Free Software
Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
As a special exception, if you link this library with other files,
compiled with a Free Software compiler, to produce an executable, this
library does not by itself cause the resulting executable to be covered
by the GNU General Public License. This exception does not however
invalidate any other reasons why the executable file might be covered by
the GNU General Public License.
*/
:- module(time,
[ alarm/3, % +Time, :Callable, -Id
alarm/4, % +Time, :Callable, -Id, +Options
alarm_at/4, % +Time, :Callable, -Id, +Options
remove_alarm/1, % +Id
install_alarm/1, % +Id
install_alarm/2, % +Id, +Time
uninstall_alarm/1, % +Id
current_alarm/4, % ?At, ?:Goal, ?Id, ?Status
call_with_time_limit/2 % +Time, :Callable
]).
:- use_module(library(lists)).
:- set_prolog_flag(generate_debug_info, false).
:- meta_predicate
call_with_time_limit(+, 0),
alarm(+, 0, -),
alarm(+, 0, -, +),
alarm_at(+, 0, -, +).
%% alarm(+Time, :Callable, -Id) is det.
%% alarm(+Time, :Callable, -Id, +Options) is det.
%
% Set up an alarm to be signaled Time seconds from now. If the
% alarm expires, Callable is called asynchronously. Callable can
% be used to raise an exception using throw/1 to abort some
% execution.
%
% Options is a list of Name(Value) options. Currently defined
% options are:
%
% * remove(Bool)
% If =true= (default =false=), remove the alarm-event (as
% remove_alarm/1) after it has been fired.
% * install(Bool)
% If =false= (default =true=) do not install the alarm.
% It must be installed separately using install_alarm/1.
%% alarm_at(+Time, :Callable, -Id, +Options) is det
%
% As alarm/4, but schedule the alarm at an absolute point in time.
%
% @see date_time_stamp/2.
%% install_alarm(+Id) is det.
%
% Install an alarm allocated using alarm/4 with the install(false)
% option.
%
% @deprecated With the introduction of setup_call_cleanup/3,
% this predicate is probably no longer needed.
%% remove_alarm(+Id) is det.
%
% Remove an alarm. If it has not yet been fired, it never will.
%% current_alarm(?Time, :Goal, ?Id, ?Status) is nondet.
%
% Enumerate the alarms in the schedule. Time is the absolute time
% the event is scheduled for (see also get_time/1). Goal is the
% goal to execute, Id is the identifier and Status is the
% scheduling status. It takes the value =done= if the alarm has
% been fired, =next= if the event is the next to be executed and
% =scheduled= otherwise.
:- use_foreign_library(foreign(time)).
%% call_with_time_limit(+Time, :Goal) is semidet.
%
% Call Goal, while watching out for a (wall-time) limit. If this
% limit is exceeded, the exception =time_limit_exceeded= is
% raised. Goal is called as in once/1.
%
% @throws =time_limit_exceeded=
call_with_time_limit(Time, Goal) :-
Time > 0, !,
setup_call_cleanup(alarm(Time, time_limit_exceeded(Time),
Id, [install(false)]),
run_alarm_goal(Id, Goal),
remove_alarm_notrace(Id)).
call_with_time_limit(_Time, _Goal) :-
throw(time_limit_exceeded).
run_alarm_goal(AlarmID, Goal) :-
install_alarm(AlarmID),
Goal, !.
time_limit_exceeded(_Time) :-
throw(time_limit_exceeded).
current_alarm(Time, Goal, Id, Status) :-
current_alarms(Time, Goal, Id, Status, List),
member(alarm(Time, Goal, Id, Status), List).
/*******************************
* HANDLE MESSAGES *
*******************************/
:- multifile
prolog:message/3.
prolog:message(time_limit_exceeded) -->
[ 'Time limit exceeded' ].
|