Date: Wed, 07 Aug 2013 02:35:07 +0900 (JST) From: Hiroki Sato <hrs@FreeBSD.org> To: ian@FreeBSD.org Cc: svn-src-head@FreeBSD.org, svn-src-all@FreeBSD.org, src-committers@FreeBSD.org Subject: Re: svn commit: r253995 - in head/usr.sbin: rtadvd rtsold Message-ID: <20130807.023507.62577067127422432.hrs@allbsd.org> In-Reply-To: <1375807689.3320.48.camel@revolution.hippie.lan> References: <201308061549.r76FnImt054058@svn.freebsd.org> <1375807689.3320.48.camel@revolution.hippie.lan>
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Ian Lepore <ian@FreeBSD.org> wrote
in <1375807689.3320.48.camel@revolution.hippie.lan>:
ia> On Tue, 2013-08-06 at 15:49 +0000, Hiroki Sato wrote:
ia> > /* Generate maximum time in timespec. */
ia> > - memset(&tm_max.tv_sec, 0xff, sizeof(tm_max.tv_sec));
ia> > - memset(&tm_max.tv_nsec, 0xff, sizeof(tm_max.tv_nsec));
ia> > - tm_max.tv_sec &= ~(1UL << (sizeof(tm_max.tv_sec) * 8 - 1));
ia> > - tm_max.tv_nsec &= ~(1UL << (sizeof(tm_max.tv_nsec) * 8 - 1));
ia> > + tm_max.tv_sec = (-1) & ~((time_t)1 << ((sizeof(tm_max.tv_sec) * 8) - 1));
ia> > + tm_max.tv_nsec = (-1) & ~((long)1 << ((sizeof(tm_max.tv_nsec) * 8) - 1));
ia> >
ia> > /* set log level */
ia> > if (dflag > 1)
ia>
ia> The maximum number of nsec is 999999999 regardless of the type of
ia> tv_nsec.
ia>
ia> That expression for max time_t sure is ugly, but I can't think of
ia> anything that isn't just differently-ugly. At least the comment makes
ia> the purpose clear.
This was defined as {0x7fffffff, 0x7fffffff} in the original code and
used just as a large enough value to make a conditional (tm_max >
tm_other) be always true, not the exact maximum value. Yes, this is
ugly and can be improved.
-- Hiroki
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