Date: Fri, 7 Oct 2005 09:28:46 -0700 From: Brooks Davis <brooks@one-eyed-alien.net> To: Andreas Kohn <andreas.kohn@gmx.net> Cc: freebsd-hackers@freebsd.org Subject: Re: struct timeval: why is tv_sec long? Message-ID: <20051007162846.GB12691@odin.ac.hmc.edu> In-Reply-To: <1128644542.1273.36.camel@klamath.syndrom23.de> References: <1128644542.1273.36.camel@klamath.syndrom23.de>
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On Fri, Oct 07, 2005 at 02:22:22AM +0200, Andreas Kohn wrote:
> Hi,
>=20
> is there any special reason for timeval.tv_sec being long?
tv_sec is presumably long becuase that way 64-bit platforms end up with
timevals that don't suffer from the 2038 bug. time_t is also long (or
rather synonimous with it) on all but alpha platforms.
> --- sys/_timeval.h
> /*
> * Structure returned by gettimeofday(2) system call, and used in other
> calls.
> */
> struct timeval {
> long tv_sec; /* seconds (XXX should be
> time_t) */
> suseconds_t tv_usec; /* and microseconds */
> };
> ---
>=20
> I just stumbled across this code in an application,
> ---
> timeval tv;
> gettimeofday(&tv, 0);
>=20
> char tbuf[64];
> struct tm tmp;
> strftime(tbuf, sizeof(tbuf), "%b %d %H:%M:%S", localtime_r(&tv.tv_sec,
> &tmp));
> ---
>=20
> and this fails to compile on FreeBSD. I fixed the application code now,
> but I do wonder why that XXX in sys/_timeval.h is there.
> _timeval.h came into existence on 31-Dec-2002, before that timeval was
> defined in sys/time.h with both tv_sec and tv_usec as long.
>=20
> Could anyone offer any pointers?
You probably can just cast the tv.tv_sec to a time_t. Alternativly, you
could allocate a time_t and assing tv_sec to it since that will work on
alpha where the other won't.
-- Brooks
--=20
Any statement of the form "X is the one, true Y" is FALSE.
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