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(*                                                              *)
(*         Gardens Point Modula-2 Library Definition            *)
(*                                                              *)
(*                                                              *)
(*     (c) Copyright 1996 Faculty of Information Technology     *)
(*              Queensland University of Technology             *)
(*                                                              *)
(*     Permission is granted to use, copy and change this       *)
(*     program as long as the copyright message is left intact  *)
(*                                                              *)
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FOREIGN DEFINITION MODULE ShellPipes;
  IMPORT IMPLEMENTATION FROM "shellpipes.o";

  FROM UxFiles IMPORT File;

  PROCEDURE PipeInput(command : ARRAY OF CHAR;
		  VAR stream  : File;
		  VAR opened  : BOOLEAN);
  (* An input stream is returned, or opened is retured false   *)
  (* The standard output of the shell command is piped to the  *)
  (* stream, where it may be read by standard input operations *)

  PROCEDURE PipeOutput(command : ARRAY OF CHAR;
		   VAR stream  : File;
		   VAR opened  : BOOLEAN);
  (* An output stream is returned, or opened is retured false  *)
  (* Output to the stream is piped as standard input to the    *)
  (* specified shell command				       *)

  PROCEDURE ClosePipe(stream : File);
  (* closes the pipe associated with the specified stream      *)

  (* typical usage : 
   *
   *  FROM ShellPipes IMPORT PipeInput, ClosePipe;
   *	...
   *	PipeInput("ls -1 *.def", inFile, ok);
   *	IF ok THEN
   *	  WHILE NOT EndFile(inFile) DO
   *	    ...
   *	  END;
   *	  ClosePipe(inFile);
   *	ELSE ...
   *)
END ShellPipes.
