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From: dave@rlgvax.UUCP (Dave Maxey)
Newsgroups: net.unix-wizards
Subject: Re: Undocumented features
Message-ID: <1952@rlgvax.UUCP>
Date: Sun, 3-Jun-84 01:46:30 EDT
Article-I.D.: rlgvax.1952
Posted: Sun Jun  3 01:46:30 1984
Date-Received: Thu, 31-May-84 23:59:26 EDT
References: <267@pcsbst.UUCP> <1942@rlgvax.UUCP> <518@opus.UUCP> <1948@rlgvax.UUCP>
Organization: CCI Office Systems Group, Reston, VA
Lines: 21

As Guy Harris put it:
> Of course, just because something is a documented feature doesn't guarantee
> that it works either...

Take for instance fseek(3S) in 4.1 (same thing or very similar in system III):
	....
	Rewind(stream) is equivalent to fseek(stream, 0L, 0).

	SEE ALSO
		lseek(2), fopen(3)

	DIAGNOSTICS
		Fseek returns -1 for improper seeks.

System III documentation says that fseek returns non-zero for improper seeks,
zero otherwise. The truth of the matter is: rewind will return negative on
PROPER seeks. If you want to test your rewind status, use fseek(stream, 0L, 0).
This difference hardly makes rewind "equivalent" to fseek(stream, 0L, 0).

			- Dave Maxey (alias tbm)
			{seismo,mcnc,brl-bmd,allegra}!rlgvax!dave