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From: douglas@dcc1.UUCP (Douglas B. Jones)
Newsgroups: net.wanted.sources,net.unix,net.unix-wizards
Subject: new version of popen(3)
Message-ID: <201@dcc1.UUCP>
Date: Fri, 4-Apr-86 20:04:41 EST
Article-I.D.: dcc1.201
Posted: Fri Apr  4 20:04:41 1986
Date-Received: Sat, 5-Apr-86 13:02:59 EST
Distribution: net
Organization: DeKalb Community College, Clarkston GA
Lines: 79
Xref: watmath net.wanted.sources:2107 net.unix:7544 net.unix-wizards:17463


	Hi,

	  In the routine popen(3), a program can open either a read pipe
	or a write pipe to a sub-process (usually a program, like more).
	Does any one have a similar routine that will allow a person to
	have a read/write pipe to a sub-process. The routine might have
	the following format:

	FILE	*wfp,	/* stdin to child */
		*rfp,	/* stdout from child */
		*refp;	/* stderr from child */
	int	p,
		popen2();
	void	pclose2();

	if ((p = popen2("program",wfp,rfp,refp)) < 0) {
		fprintf(stderr,"Can't open pipe to program\n");
		exit(1);
	}

	  At this point :

	p   : index so that pclose2() would know which child to close
	wfp : how I write to the childs' stdin,
	rfp : the stdout from the child to me,
	rwfp: the stderr from the chid to me.

	  The pclose2() routine would be called:

	(void)pclose2(p);	/* p being the return from popen2() */

	  This would be a very helpful program. I imagine it would have
	to deal with sockets(). What would be really nice, is if two version
	of this popen2() could be written. One to allow the calling program
	to work with a child process on the local system, and secondly to
	allow it (the calling program) to work with a child process on
	another system (in the local network).

	   Maybe : popen2() for local (with pclose2()) and  npopen2() for
	remote (withe npclose2()). Npopen2() might have a calling format
	like :

	/* other vars. stated above */
	char	*network = "dcc2";	/* name of our other system */
	int	npopen2();
	void	npclose2();

	if ((p = npopen2("program",wfp,rfp,refp,network)) < 0) {
		fprintf(stderr,"Can't open net pipe to program\n");
		exit(1);
	}

	/* do what ever, ie: write UNIX documentation or crash the system */

	(void)npclose2(p);


	Thanks in advance,
	Douglas
	
	p.s.: Apart from sending this to net.wanted.sources, I am also sending
	      this to net.unix and net.unix-wizards to reach a larger group of
	      people. Response might best go to net.sources. I will be happy
	      to handle responses directly and then post them to net.sources.

-- 

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   Douglas Jones
   TSG, DeKalb College

   douglas@dcc1
   gatech!dcc1!douglas        { calls us each hour }
   akgua!dcc1!douglas         { calls us about twice a day }
   akgua!gatech!dcc1!douglas  { akgua and gatech communicate a lot }

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