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From: arnold@mathcs.emory.edu (Arnold D. Robbins {EUCC})
Newsgroups: comp.unix.questions,comp.unix.xenix
Subject: Re: How to determine file being redirected to in C
Keywords: redirection
Message-ID: <3763@emory.mathcs.emory.edu>
Date: 1 Mar 89 17:49:03 GMT
References: <10@sherpa.UUCP> <475@ispi.UUCP>
Reply-To: arnold@emory.UUCP (Arnold D. Robbins {EUCC})
Followup-To: comp.unix.questions
Distribution: na
Organization: Emory University
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>In article <10@sherpa.UUCP> rac@sherpa.UUCP (Roger A. Cornelius) writes:
>>  Anyway, can someone tell me how to determine (in C)
>>if output is being redirected, or more precisely, how to determine the
>>file output is being redirected to.  The cat command does this (at

In article <475@ispi.UUCP> jbayer@ispi.UUCP (Jonathan Bayer) writes:
>Use the stat() and fstat() functions, then compare the inode numbers 
>in the structure.  If they are the same then the two files are identical.

Rather, compare the device and inode numbers, and if both are the same
the two files are really the same file.  Two files on two different
filesystems (i.e. devices) can both have the same inode numbers.
-- 
"Unix is a Registered  | Arnold Robbins -- Emory University Computing Center
Bell of AT&T Trademark | DOMAIN: arnold@unix.cc.emory.edu		
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        -- Donn Seeley | BITNET: arnold@emoryu1		FAX:	+1 404 727-2599