Date: Fri, 01 Sep 2000 09:20:48 +0200
From: "Eli Zaretskii" <eliz AT is DOT elta DOT co DOT il>
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In-reply-to: <4j7tqskrvkecn18jfdi9vtpbo5skmm82ke@4ax.com> (message from Jason
	Green on Thu, 31 Aug 2000 19:12:54 +0100)
Subject: Re: Symify fixes
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> From: Jason Green <mail AT jgreen4 DOT fsnet DOT co DOT uk>
> Date: Thu, 31 Aug 2000 19:12:54 +0100
> 
> > The portable way to check for errno is to set it to zero before the
> > call to a function, then see if it is still zero after the function
> > returns.
> 
> Actually no, a system call can legally set errno even if no error
> occured.

I think ANSI specifically disallows this: if no error occured, errno
should be left alone.  In fact, the DJGPP library goes to great
lengths to not set errno to bogus values, for example if you hit the
end of directory during findnext.

In any case, errno should be tested only if you have some other
indication of a failure.  But then `bail' is already called only under
these circumstances.