Path: utzoo!attcan!uunet!husc6!rutgers!rochester!pt.cs.cmu.edu!b.gp.cs.cmu.edu!Ralf.Brown@B.GP.CS.CMU.EDU
From: Ralf.Brown@B.GP.CS.CMU.EDU
Newsgroups: comp.sys.ibm.pc
Subject: Re: How to determine stdin/out redirection
Message-ID: <234377e4@ralf>
Date: 30 Sep 88 13:02:44 GMT
Sender: netnews@pt.cs.cmu.edu
Lines: 17
In-Reply-To: <12265@steinmetz.ge.com>

In article <12265@steinmetz.ge.com>, dixon@control.steinmetz (walt dixon) writes:
}DOS opens the console device in the boot process.  SFN=0 corresponds to
}the console device.  Command.com reopens the console device for StdIn
}and StdOut.  The JFT entries corresponding to StdIn and StdOut (JFT[0]]
}and JFT[1] respectively) will contain a 0 in the absence of redirection.
}By looking within the SFT entry,  one can actually find the name of the
}device/file.  Unfortunately,  any path name information is lost after
}the file is opened.

This must vary from version to version, because for DOS 3.1, SFN[0] is AUX and
SFN[1] is CON.  In the absence of redirection, the first five entries in the
JFT are 1, 1, 1, 0, and 2.
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