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From: jjr@ace.ece.arizona.edu (Jeffrey J. Rodriguez)
Newsgroups: comp.unix.questions,comp.unix.programmer
Subject: How do I tell if STDIN is a PIPE?
Message-ID: <1991May26.172328.713@arizona.edu>
Date: 27 May 91 00:23:27 GMT
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How do I tell whether stdin is coming from a pipe?
There must be some system call I can use from a C program.
My problem is that lseek & fseek won't work with a pipe.
Therefore, I need to check stdin to see if it is coming from a pipe.

If stdin is coming from a pipe, then what is the best way to do a seek?
If the input data is not ASCII, then a loop of getchar() won't work.
Therefore, it seems like a loop of fread (one byte at a time)
would be required.
Please let me know if there's a better way to handle this.

		Jeff
		rodriguez@ece.arizona.edu