From: Jeff King <peff@peff.net>
Date: Thu, 10 Aug 2017 21:02:46 GMT
Subject: Re: [PATCH] strbuf: clear errno before calling getdelim(3)
Message-ID: <20170810210246.p4vp2ibahgsii7fc@sigill.intra.peff.net>
In-Reply-To: <cd49ce13-db87-89c1-77e7-998fdb9442c3@web.de>

On Thu, Aug 10, 2017 at 10:56:40PM +0200, René Scharfe wrote:

> getdelim(3) returns -1 at the end of the file and if it encounters an
> error, but sets errno only in the latter case.  Set errno to zero before
> calling it to avoid misdiagnosing an out-of-memory condition due to a
> left-over value from some other function call.

Looks good to me.

> Do we need to save and restore the original value of errno?  I doubt it,
> but didn't think deeply about it, yet.

I'd say no. Anybody depending on strbuf_getwholeline() is clearly
already wrong in the error case. And in general I think we assume that
syscalls can clear errno on success if they choose to (this isn't a
syscall, but obviously it is calling some).

-Peff