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From: Urs Thuermann <urs@isnogud.escape.de>
To: linux-kernel@vger.kernel.org
Subject: Re: [BUG] settimeofday(2) succeeds for microsecond value more than USEC_PER_SEC and for negative value
Date: 02 May 2003 20:06:13 +0200	[thread overview]
Message-ID: <m265otw7e2.fsf@isnogud.escape.de> (raw)
In-Reply-To: <3E973546.70809@mvista.com>; from george anzinger on Fri, 11 Apr 2003 14:36:06 -0700

george anzinger <george@mvista.com> writes:

> Uh, sure.  This is the test I prefer:
> 
> 	if( (unsigned long)tv->usec > USEC_PER_SEC)
> 		return EINVAL;
> 
> Note that the unsigned picks up the negative value as well as the >
> (and it does it in only one machine code test/jmp :)

No, don't do the compilers job.  Just write

        if (tv->usec < 0 || tv->usec >= USEC_PER_SEC) { ... }

This is easier to read, portable, and generates the same machine code
as your C code, at least in all gcc versions since gcc-2.7.2.3 (I
don't have older gcc versions here on my machine to test).


urs

  reply	other threads:[~2003-05-02 17:57 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2003-04-11 13:07 [BUG] settimeofday(2) succeeds for microsecond value more than USEC_PER_SEC and for negative value Aniruddha M Marathe
2003-04-11 21:36 ` george anzinger
2003-05-02 18:06   ` Urs Thuermann [this message]
  -- strict thread matches above, loose matches on Subject: below --
2003-04-12 10:43 Aniruddha M Marathe
2003-04-12 19:25 ` george anzinger
2003-04-11  5:12 Aniruddha M Marathe
2003-04-11  6:26 ` george anzinger

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