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Re: [Qemu-devel] [PATCH 01/16] net: Add a hub net client
From: |
Stefan Hajnoczi |
Subject: |
Re: [Qemu-devel] [PATCH 01/16] net: Add a hub net client |
Date: |
Mon, 23 Jul 2012 16:23:42 +0100 |
On Mon, Jul 23, 2012 at 4:16 PM, Laszlo Ersek <address@hidden> wrote:
> On 07/23/12 16:52, Stefan Hajnoczi wrote:
>> On Mon, Jul 23, 2012 at 3:05 PM, Laszlo Ersek <address@hidden> wrote:
>
>>> The idea is, rather than
>>>
>>> unsigned int id = hub->num_ports++;
>>>
>>> it should say
>>>
>>> unsigned int id;
>>> /* ... */
>>> id = hub->num_ports++;
>>>
>>> ... Hm, yes, I remember it from
>>> <http://www.manpages.info/freebsd/style.9.html>. But again, I'm not sure
>>> how qemu treats this.
>>
>> "Be careful to not obfuscate the code by initializing variables in the
>> declarations. Use this feature only thoughtfully. DO NOT use
>> function calls in initializers."
>>
>> This?
>>
>> Do you know the rationale? It's not clear to me how this "obfuscates" the
>> code.
>
> I think the rationale is that (a) people tend to reorganize definitions,
> and the expressions in the initializer lists may depend on the original
> order, (b) even worse with removal of variables, (c) many people have a
> "conceptual divide" between the definition block and the logic below it,
> and the first should set constant defaults at most. (Naturally this
> prevents C99/C++ style mixing of definitions and code as well, at least
> without explicit braces.)
>
> I'm one of those people, but again I'm not sure if qemu has any
> guideline on this.
>
>
>> Messing around with side-effects in a series of variable declarations
>> with intializers could be bug-prone. But here there is only one
>> initializer so it's not a problem.
>>
>> Regarding QEMU, there's no coding style rule against initializers.
>> Personally I think that's a good thing because it keeps the code
>> concise - people reading it don't have to keep the declaration in
>> their mind until they hit the initializer later on.
>
> Well I keep the definitions at the top of the block so I can very easily
> return to them visually (and be sure they do nothing else than define
> variables / declare externs), but it's getting philosophical :)
>
> I have nothing against this initializer as-is, I just wanted to voice
> *if* there's such a guideline in qemu *then* it should be followed :)
Yes, I understand - it's a question of style or flamewar fodder :). I
double-checked that there is no guideline in ./CODING_STYLE and
./HACKING.
Stefan
- [Qemu-devel] [PATCH 13/16] net: Make "info network" output more readable info, (continued)
- [Qemu-devel] [PATCH 13/16] net: Make "info network" output more readable info, Stefan Hajnoczi, 2012/07/20
- [Qemu-devel] [PATCH 12/16] net: Rename qemu_del_vlan_client() to qemu_del_net_client(), Stefan Hajnoczi, 2012/07/20
- [Qemu-devel] [PATCH 04/16] hub: Check that hubs are configured correctly, Stefan Hajnoczi, 2012/07/20
- [Qemu-devel] [PATCH 01/16] net: Add a hub net client, Stefan Hajnoczi, 2012/07/20
- Re: [Qemu-devel] [PATCH 01/16] net: Add a hub net client, Laszlo Ersek, 2012/07/23
- Re: [Qemu-devel] [PATCH 01/16] net: Add a hub net client, Stefan Hajnoczi, 2012/07/23
- Re: [Qemu-devel] [PATCH 01/16] net: Add a hub net client, Laszlo Ersek, 2012/07/23
- Re: [Qemu-devel] [PATCH 01/16] net: Add a hub net client, Stefan Hajnoczi, 2012/07/23
- Re: [Qemu-devel] [PATCH 01/16] net: Add a hub net client, Laszlo Ersek, 2012/07/23
- Re: [Qemu-devel] [PATCH 01/16] net: Add a hub net client,
Stefan Hajnoczi <=
- Re: [Qemu-devel] [PATCH 01/16] net: Add a hub net client, Andreas Färber, 2012/07/23
- Re: [Qemu-devel] [PATCH 01/16] net: Add a hub net client, Markus Armbruster, 2012/07/23
- Re: [Qemu-devel] [PATCH 01/16] net: Add a hub net client, Blue Swirl, 2012/07/23
[Qemu-devel] [PATCH 15/16] net: determine if packets can be sent before net queue deliver packets, Stefan Hajnoczi, 2012/07/20
[Qemu-devel] [PATCH 05/16] net: Drop vlan argument to qemu_new_net_client(), Stefan Hajnoczi, 2012/07/20
[Qemu-devel] [PATCH 03/16] net: Look up 'vlan' net clients using hubs, Stefan Hajnoczi, 2012/07/20
[Qemu-devel] [PATCH 10/16] net: Rename VLANClientState to NetClientState, Stefan Hajnoczi, 2012/07/20