Bug in isatty (all systems!)

[Joel West]

> In article <243 at cuuxb.UUCP> dbaker at cuuxb.UUCP (Darryl Baker) writes:
> 
> The expected value of errno after a mktemp() is 2.
>  ... The problem is that mktemp()
> really should clear errno after the last attempt, or that errno == 2 should
> be a feature (in the BUGS section of mktemp(III)).  

For those keepers of the true faith who savaged my coding practices,
this is exactly my point.  I designed a large software system around
the assumption that errno was always valid and not set as a side-effect.
It took me 6 months (admittedly, I wasn't looking hard) to figure out
why I was always getting "not a typewriter" (because my open routine 
was setting a struct bit to indicate tty/non-tty for every file).

My reason for posting this was to call attention to an error in the
documentation.  All the manuals I've seen are in error, because this
is a known, established, important "SPECIAL CONSIDERATION".

>     As an aside, has anyone noticed that DEC and [name deleted] have removed the
> BUGS entries from the man pages?  I guess that they're afraid that non UN*X
> people will think that BUGS means buggy programs, not unavoidable/historical
> artifacts.

[Name deleted] must refer to my AT&T System V/2.0 manuals.

>     Gould however has done the correct thing, They renamed it 'Special
> Considerations' (rather well named neh?).

The Gould folks tell me they can't call it "Bugs" (Everyone has enough
problems with those anyway) for marketting reasons.  But at least they
left it in.  I don't care what it's called, as long as it's there.

	Joel West	CACI, Inc. - Federal (c/o UC San Diego)
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