From: Thomas Rast <trast@student.ethz.ch>
Date: Tue, 09 Jun 2009 08:22:30 GMT
Subject: Re: [PATCH v3 1/3] Introduce die_errno() that appends strerror(errno) to die()
Message-ID: <200906091022.31738.trast@student.ethz.ch>
In-Reply-To: <20090608220713.GB29942@sigill.intra.peff.net>

Jeff King wrote:
> On Mon, Jun 08, 2009 at 11:02:18PM +0200, Thomas Rast wrote:
> 
> > +void die_errno(const char *fmt, ...)
> > +{
> > +	va_list params;
> > +	char fmt_with_err[1024];
> > +
> > +	snprintf(fmt_with_err, sizeof(fmt_with_err), "%s: %s", fmt, strerror(errno));
> > +
> > +	va_start(params, fmt);
> > +	die_routine(fmt_with_err, params);
> > +	va_end(params);
> > +}
> 
> Aren't you assuming that strerror(errno) has no '%'-signs here, which is
> what kicked off the whole discussion?

True, of course.  Hrm.

So do we go back to v2 (for 1/3) and ask future callers to never use
custom formats with die_errno, or should I write a version that
doubles the % characters while tacking the error message onto the
format?

[It's a pity that it seems impossible to add an extra argument to the
va_args...]

-- 
Thomas Rast
trast@{inf,student}.ethz.ch