Re: git on HP NonStop

From: Junio C Hamano <gitster@pobox.com>
Date: Aug 20, 2012, 16:29 UTC
Message-ID: <7vfw7hle6l.fsf@alter.siamese.dyndns.org>
In-Reply-To: <503217F2.5070105@viscovery.net>

Johannes Sixt <j.sixt@viscovery.net> writes:

Show 13 quoted lines

> Am 8/20/2012 12:36, schrieb Joachim Schmitz:
>> int var = var;
>> char *othervar = othervar;
>> 
>> ... 
>>
>> What is the reason for using that self-init stuff? I don't think it is
>> really portable, is it?
>
> It is used to avoid "var may be used uninitialized" warnings for some
> compilers. Officially (according to the C standard), it is undefined
> behavior. But I've observed considerable resistance by Junio to fix this
> properly.

I had resisted

	-	int foo = foo;
        +	int foo = 0;

in the past. If some compiler is not seeing that "foo" is never used uninitialized, such a compiler will generate an unnecessary initialization, so it is not a _proper_ fix anyway (in fact, I do not think a proper fix exists, short of simplifying the code so that less sophisticated compilers can see that "foo" is never used uninitialized).

So, no, I never resisted a "proper" fix. I resisted swapping an unsatisfactory workaround with another.

Between the two unsatisfactory workarounds, the latter (explicit and unnecessary assignment to an innocuous value) is lessor of two evils, so I do not particularly mind it, though. Indeed, I think more recent history shows that we have such changes.