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SubjectRe: [PATCH 1/1] kernel/sched.c: Fix array initialization typo
On Sun, 12 Jun 2011 16:09:01 -0700 Andy Isaacson wrote:

> On Sun, Jun 12, 2011 at 04:01:16PM -0600, Jean Sacren wrote:
> > From: Alexey Dobriyan <adobriyan@gmail.com>
> > Date: Mon, 13 Jun 2011 00:35:49 +0300
> > >
> > > On Sun, Jun 12, 2011 at 03:31:07PM -0600, Jean Sacren wrote:
> > > > The fix makes certain so that the size of the initialized arrays doesn't
> > > > go beyond the boundary set by the array size of 40.
> > >
> > > Why would it possibly do that?
> >
> > With that ',' comma, doesn't it imply there might be the 41st element in
> > the array?
>
> No, that's not how C works.
>
> > Despite the fact that that element is bogus.
>
> It's not bogus, it's utterly cromulent. Trailing comma on array
> initializer was mentioned in the original K&R and is explicitly endorsed
> by ISO/IEC 9899:1999 6.7.8 paragraph 1.
>
> > Further, if the comma is there, what's the benefit? I know you're cool,
> > but is it cool in code that way as well?
> > >
> > > And it's not a typo.
> >
> > What is it then?
>
> It is a standard C idiom for defining array contents. If you write

ack. I once worked on on OS where the common idiom for array inits was:

int x[] = {
1
, 2
, 3
};

so that additions only required one line of change.

> int x[] = {
> 1,
> 2,
> 3
> };
>
> then when I add a fourth element to your array, I have to modify two
> lines, and the diff will say
> - 3
> + 3,
> + 4
> };
>
> whereas if you wrote "3," as the last line of the initializer, the diff
> would be one line long.
>
> Furthermore, spot the error in this diff:
>
> @@ -3,4 +3,5 @@ char *x[] = {
> "quick",
> "brown",
> "fox"
> + "jumped"
> };



---
~Randy
*** Remember to use Documentation/SubmitChecklist when testing your code ***

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