34 lines
996 B
Perl
34 lines
996 B
Perl
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/* $Id$
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Part of SWI-Prolog
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Author: Jan Wielemaker
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E-mail: jan@swi.psy.uva.nl
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WWW: http://www.swi.psy.uva.nl/projects/SWI-Prolog/
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Copying: GPL-2. See the file COPYING or http://www.gnu.org
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Copyright (C) 1990-2001 SWI, University of Amsterdam. All rights reserved.
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*/
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:- use_module(library(unix)).
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/* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
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Simple demo illustrating the combination of fork/1 and pipe/2 to make
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Prolog fork a child to do some work and get back when done. Using
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wait_for_input/3 you can make the main Prolog task wait for multiple
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childs to return results.
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- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */
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fork_demo(Result) :-
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pipe(Read, Write),
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fork(Pid),
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( Pid == child
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-> close(Read),
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format(Write, '~q.~n', [hello(world)]),
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flush_output(Write), % stream is fully buffered!
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halt
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; close(Write),
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read(Read, Result),
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close(Read)
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).
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