[comp.lang.c] How to tell if stdin/stdout is redirected?

jeffs@tsdiag.ccur.com (Jeff Schnell) (03/28/90)

I would like to know if there is a way to tell if stdin/stdout
is redirected.  I would like it in Turbo C and/or Microsoft C
and also in unix.

Thanks
Jeffs
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ralf@b.gp.cs.cmu.edu (Ralf Brown) (03/29/90)

In article <807@tsdiag.ccur.com> jeffs@tsdiag.ccur.com (Jeff Schnell) writes:
}I would like to know if there is a way to tell if stdin/stdout
}is redirected.  I would like it in Turbo C and/or Microsoft C
}and also in unix.

	isatty(fileno(stdin))

works for me under Turbo C (returns nonzero iff stdin points at a character 
device such as CON, PRN, etc) and should work under Unix (since that is where
isatty originated).



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