Re: [PATCH v2] devtools: allow variable declaration inside for loop

[Thomas Monjalon <thomas@monjalon.net>]

03/05/2023 14:19, Morten Brørup:
> > From: Bruce Richardson [mailto:bruce.richardson@intel.com]
> > Sent: Wednesday, 3 May 2023 12.57
> > 
> > On Wed, May 03, 2023 at 11:30:53AM +0100, Ferruh Yigit wrote:
> > > Declaring variable inside for loop is not supported via C89 and it was
> > > checked in checkpatch.sh via commit [1].
> > > But as DPDK supported C standard is becoming C99/C11 [2], declaring
> > > variable inside loop can be allowed.
> > >
> > > [1]
> > > Commit 43e73483a4b8 ("devtools: forbid variable declaration inside
> > for")
> > >
> > > [2]
> > > https://dpdk.org/patch/121912
> > >
> > > Signed-off-by: Ferruh Yigit <ferruh.yigit@amd.com>
> > > ---
> > > Cc: Bruce Richardson <bruce.richardson@intel.com>
> > > Cc: David Marchand <david.marchand@redhat.com>
> > >
> > > v2:
> > >  * Update coding convention too
> > > ---
> > 
> > Acked-by: Bruce Richardson <bruce.richardson@intel.com>
> 
> Acked-by: Morten Brørup <mb@smartsharesystems.com>
> 
> [...]
> 
> > > @@ -558,6 +558,7 @@ Local Variables
> > >
> > >  * Variables should be declared at the start of a block of code rather
> > than in the middle.
> > 
> > I'd love to see this restriction removed in future too. Having a
> > variable
> > declared on first use in the middle of block I find a far easier way of
> > working as a) it saves scrolling to look for variable definitions and b)
> > it
> > makes it far easier when adding/removing blocks of code e.g. commenting
> > out
> > for testing,  to have all the code together rather than having variables
> > at
> > the top to add/remove also.
> 
> And c) Initializing the variables close to where they are used the first time reduces the risk of initializing them incorrectly. Especially when modifying a block of code, initialization of its variables might be missed if out of sight. (Although this is probably a consequence of "a)".)
> 
> I consider it old style to only declare variables at the start of a block of code, and this style of coding should be considered obsolete.
> 
> If you are really old (like me?), you might remember when function parameters were provided like this:
> 
> int main(argc, argv)
> int argc;
> char *argv[];
> {
> 	return(0);
> }
> 
> We have moved on from that to a more modern coding style a long time ago. We should also move on to a more modern coding style regarding variable declarations.

Old men are used to look for variable types at the beginning of functions.
Having only new code adopting a different style may be confusing a little.
Note I'm not against it, just asking for more feedbacks.