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From: lm@cottage.WISC.EDU (Larry McVoy)
Newsgroups: comp.unix.questions
Subject: Re: bg process into fg
Message-ID: <3574@spool.WISC.EDU>
Date: Tue, 12-May-87 19:16:05 EDT
Article-I.D.: spool.3574
Posted: Tue May 12 19:16:05 1987
Date-Received: Fri, 15-May-87 03:10:40 EDT
References: <7338@brl-adm.ARPA>
Sender: news@spool.WISC.EDU
Reply-To: lm@cottage.WISC.EDU (Larry McVoy)
Organization: U of Wisconsin CS Dept
Lines: 25

In article <7338@brl-adm.ARPA> kvancamp@ARDEC.arpa (Kenneth Van Camp -FSAC-) writes:
>during the middle of a long run I would like to log back in and 
>interrogate/modify the run.  To do this, I have set up signal interrupts 
>(available via the normal Kill command) to alert the program that I wish to 
>interrogate the model.  Doing normal printf stuff, I never see the output on 
>my terminal because the process is background.  I need a way to bring it 
>into the foreground so I can interact with it.  

Well, how about this?  It's a little coding, but you said that was ok.

Set it up so that upon receipt of the signal, your process opens two
fifo's (I think you might need to be root to create these).  The job
will open one for reading, the other for writing.  But first close
0 and 1 (stdin & stdout) so that the file descriptors returned are 
also 0 and 1 when you do the opens.

Now write a little program that does the same sort of thing - it opens up
the same two fifos.  Copy stdin to the write fifo, and everything read 
comes from the read fifo.   

This may not be clear enough.... Anyone else want to take a crack at
this?  I'm guessing that this will work - I haven't tried it...


Larry McVoy 	        lm@cottage.wisc.edu  or  uwvax!mcvoy