From: Linus Torvalds <torvalds@osdl.org>
Date: Sun, 25 Jun 2006 18:43:30 GMT
Subject: Re: What's in git.git
Message-ID: <Pine.LNX.4.64.0606251138580.3747@g5.osdl.org>
In-Reply-To: <20060625210724.934617c4.tihirvon@gmail.com>



On Sun, 25 Jun 2006, Timo Hirvonen wrote:
> > 
> > I suspect that both could have been made to use NULL instead to indicate 
> > that no pointer exists.
> 
> I'll look into this.

An alternative is to really mark the char pointer structure members const. 
That is often the preferred thing to do, if usage allows it.

The biggest problem I've traditionally had with structure members that are 
"const char *" has ironically been that the standard C definition of 
"free()" is misdesigned. 

"free()" should take a "const volatile void *", not just a "void *". As it 
is, you often have to cast things to free() just to avoid the warning 
about discarding qualifiers. Which is really sad.

It's perfectly valid to do something like

	struct xyzzy {
		const char *member;
		..
	};

	s->member = strdup(string);
	..
	free(s->member);
	free(s)

but sadly, that member free generates a (bogus) warning.

Of course, we should probably do a "xfree()" anyway, to match our 
"x[c|re]alloc()".

			Linus