From: Scott Wood <scottwood@freescale.com>
To: u-boot@lists.denx.de
Subject: [U-Boot] use of C99
Date: Wed, 08 Apr 2009 17:26:10 -0500 [thread overview]
Message-ID: <49DD2482.7040909@freescale.com> (raw)
In-Reply-To: <49DD10BF.80002@freescale.com>
Timur Tabi wrote:
> Scott Wood wrote:
>
>> It frees the variable up for later such blocks to use. As does
>> declaring iterators inside a for loop, but I guess that's forbidden as
>> well. :-)
>
> I'm not sure whether we want to allow the same variable to be defined
> more than once, even with the same type, inside a function.
What's wrong with this:?
for (i = 0; i < n; i++) {
int j;
...
}
for (i = 0; i < m; i++) {
int j;
...
}
>> Chances are it will allocate all stack space for all variables up front,
>> regardless of where they're declared.
>
> Yes, but it many cases it won't allocate any stack space at all because
> it will just keep the variable in a register. My point was that if a
> variable is defined later in a function, then it's more likely to have
> limited scope, so the compiler will be more likely to use a register
> instead of stack to store it.
I don't think it will make a difference. The compiler knows what the
lifetime of the variable is, regardless of where you declare it.
-Scott
next prev parent reply other threads:[~2009-04-08 22:26 UTC|newest]
Thread overview: 29+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-04-08 18:51 [U-Boot] use of C99 Kumar Gala
2009-04-08 19:28 ` Wolfgang Denk
2009-04-08 19:46 ` Jerry Van Baren
2009-04-08 20:25 ` Timur Tabi
2009-04-08 20:46 ` Premi, Sanjeev
2009-04-08 20:57 ` Timur Tabi
2009-04-08 21:26 ` Premi, Sanjeev
2009-04-08 21:34 ` Timur Tabi
2009-04-08 21:03 ` Ben Warren
2009-04-08 21:23 ` Premi, Sanjeev
2009-04-08 20:52 ` Scott Wood
2009-04-08 21:01 ` Timur Tabi
2009-04-08 22:26 ` Scott Wood [this message]
2009-04-08 21:34 ` Wolfgang Denk
2009-04-08 21:38 ` Timur Tabi
2009-04-08 22:39 ` Graeme Russ
2009-04-08 22:45 ` Timur Tabi
2009-04-08 22:59 ` Wolfgang Denk
2009-04-08 23:09 ` Scott Wood
2009-04-08 22:28 ` Scott Wood
2009-04-08 21:27 ` Wolfgang Denk
2009-04-08 23:22 ` Larry Johnson
2009-04-08 23:40 ` Scott Wood
2009-04-09 4:27 ` Kumar Gala
2009-04-09 11:38 ` Jerry Van Baren
-- strict thread matches above, loose matches on Subject: below --
2009-04-09 1:53 Pink Boy
2009-04-09 2:12 ` Jerry Van Baren
2009-04-09 5:50 ` Wolfgang Denk
2009-04-09 13:27 ` Larry Johnson
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