Re: [Qemu-devel] [patch] explicitly initialize tcg_cpu_thread

[Pavel Borzenkov]

On Tue, Nov 1, 2011 at 12:33 PM, Jun Koi <address@hidden> wrote:
> On Tue, Nov 1, 2011 at 3:06 PM, Pavel Borzenkov
> <address@hidden> wrote:
>> On Tue, Nov 1, 2011 at 7:35 AM, Jun Koi <address@hidden> wrote:
>>> This patch explicitly initializes tcg_cpu_thread to NULL in cpus.c
>>> (One code patch in qemu_tcg_init_vcpu() relies on the value of
>>> tcg_cpu_thread to create env->thread and so on )
>>>
>>> Signed-off-by: Jun Koi <address@hidden>
>>
>> You don't need to explicitly initialize objects with static storage
>> duration. They are initialized to NULL/0 implicitly.
>> This is guaranteed by the C standard.
>
> that is good to know, but i think that is better safe than sorry. what
> if we compile Qemu with a compiler that doesnt follow the standard?
>
> also, i remember that we always initialize static vars? or am i wrong?

No, we don't. checkpatch.pl has a check to ensure that static
variables are not explicitly initialized to NULL. Try to check your
patch with this script. It will throw an error:

{{{
ERROR: do not initialise statics to 0 or NULL
#80: FILE: cpus.c:609:
+static QemuThread *tcg_cpu_thread = NULL;

total: 1 errors, 0 warnings, 8 lines checked
}}}

-- 
Pavel

>
> thanks,
> Jun
>
>
>
>
>>> diff --git a/cpus.c b/cpus.c
>>> index f768683..47feb58 100644
>>> --- a/cpus.c
>>> +++ b/cpus.c
>>> @@ -606,7 +606,7 @@ static bool iothread_requesting_mutex;
>>>
>>>  static QemuThread io_thread;
>>>
>>> -static QemuThread *tcg_cpu_thread;
>>> +static QemuThread *tcg_cpu_thread = NULL;
>>>  static QemuCond *tcg_halt_cond;
>>>
>>>  /* cpu creation */
>>>
>>>
>>
>