Re: [PATCH 1/5] progress.c: replace signal() with sigaction()

From: Junio C Hamano <gitster@pobox.com>
Date: May 28, 2014, 17:35 UTC
Message-ID: <xmqqvbspdcwl.fsf@gitster.dls.corp.google.com>
In-Reply-To: <87sinuiad2.fsf@fencepost.gnu.org>

David Kastrup <dak@gnu.org> writes:

Show 21 quoted lines

>>> diff --git a/progress.c b/progress.c
>>> index 261314e..24df263 100644
>>> --- a/progress.c
>>> +++ b/progress.c
>>> @@ -66,8 +66,12 @@ static void set_progress_signal(void)
>>>  static void clear_progress_signal(void)
>>>  {
>>>  	struct itimerval v = {{0,},};
>>> +	struct sigaction sa;
>>> +
>>> +	memset(&sa, 0, sizeof(sa));
>>> +	sa.sa_handler = SIG_IGN;
>>
>> A C99 initialiser here would save the call to memset. Unfortunately
>> Documentation/CodingGuidelines is fairly clear on not using C99
>> initialisers, given the fact we're now at git 2.0 maybe it's time to
>> revisit this policy?
>
> If I look at the initialization of v in the context immediately above
> the new code, it would appear that somebody already revisited this
> policy.

The existing structure initialization that says "the first field of the structure is set to 0" implying "everything else will also be set to 0" is not what we avoid. That is straight C89.

What we avoid is an initializer with a designator, e.g.

	struct sigaction sa = {
        	.sa_handler = NULL,
                .sa_flags = 0,
	};