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From: yang@nff.ncl.omron.co.jp (YANG Liqun)
Newsgroups: comp.unix.programmer
Subject: Re:How to determine the destination of standard output?
Message-ID: <YANG.91Feb8143638@newyork.nff.ncl.omron.co.jp>
Date: 8 Feb 91 05:36:38 GMT
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Organization: OMRON Corp., Kyoto, Japan
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<ping@cubmol.bio.columbia.edu(Shiping Zhang)> writes:

>I'm not sure if this subject has be discussed before. I want to know
>if there is a way to tell within a program where its standard output
>goes. More specifically, if the output goes to the terminal screen, or
>goes to a pipe, or is redirected into a disk file. Thanks for any info.

If you want to if the standard output is terminal, use ttyname() or isatty.
Otherwise, use
     #include <sys/types.h>
     #include <sys/stat.h>

     fstat(fd, buf)
     int fd;
     struct stat *buf;

check buf->st_mode. 
--
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|		Yang Li-qun                                                   |
|		OE, OMRON Corporation                                         |
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