Thank you, both. I'll return to the fold and use NULL, as seems right and proper.
On Thu, Jun 16, 2016 at 7:12 AM David Gibson <da...@gibson.dropbear.id.au> wrote: > On Tue, Jun 14, 2016 at 01:45:10PM +0930, Paul 'Rusty' Russell wrote: > > Dan Good <d...@dancancode.com> writes: > > > Hi David, > > > > > > I'm back home in front of a real keyboard, and want to follow up with > you > > > about your patches. I must admit that my usual practice is to use > NULL, > > > and not 0. Around the time I wrote altstack I had recently read Jen > > > Gustedt's book, Modern C. In it, he makes the point that NULL hides > more > > > than it clarifies (see section 11.7). > > > > (I don't really care: your code, your style). But... > > > > He is so horrifically wrong, it's amazing. > > > > Section 7.17 is loosened from ANSI C which said NULL was 0, presumably > > to *allow* compilers to avoid the varargs issue. A compiler *could* do > > insane shit to make that problem even worse, but you would never use > > such a compiler. There are other legal-but-insane things a compiler can > > do, too, and the answer is the same; real code won't work, nobody else > > cares. > > > > OTOH, using 0 in place of NULL makes for much more potential type order > > confusion. Not to mention confusing every damn C programmer on the > > planet. > > Yeah. I can kind of see the hint of a good idea in those articles, > but on balance they're really not convincing. Basically, as Rusty > says, matching the conventions of the huge bulk of existing C code > outweighs the value of working with a compiler/library that has gone > out of its way to implement this stupidly. > > > Note, I also assume NULL is all zero-bits, > > I try to avoid that one, although I can't be sure I always have - I'm > not sure, but I think one of the s390 variants might break this. > > > that size_t can hold a > > ptrdiff_t, > > Dunno if I've assumed that much. > > > and that a pointer to a function which takes a type * > > argument can be cast and called as a function which takes a void *. > > Yeah, I've used that. > > > If someone ports CCAN to a platform where those are not true, I'd be > > fascinated... > > -- > David Gibson | I'll have my music baroque, and my code > david AT gibson.dropbear.id.au | minimalist, thank you. NOT _the_ > _other_ > | _way_ _around_! > http://www.ozlabs.org/~dgibson >
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