Re: [TUHS] C question for the historians

On Wed, Nov 8, 2017 at 9:17 AM, Arthur Krewat <krewat(a)kilonet.net> wrote: No it wouldn't. That would be a bug. s/==/!=/ there and you might be right. Except code reviews that make such 'crazy' suggestions often do more to introduce bugs than prevent future bugs. But even then, there's a time and place for testing against zero, especially in code that has complicated bit testing, where you only want to proceed if a subset of bits are set and others are clear. Or if you are mixing boolean and flags, it can be clearer. Or do the Linux-school and go with if (!!(flags & DLADM_OPT_PERSIST)) { to really confuse things... Seriously? What do (or would) "original C" programmers think of this? To Acceptable to the compiler sure. But if you use the different forms to convey information to the reader, then you might choose something slightly different. For pointers, say, you have the choice of the following forms: if (foo) if (!foo) if (foo == NULL) if (foo != NULL) if (foo == 0) if (foo != 0) The middle two remind the reader that foo is a pointer, while the first two might slightly suggest that from other context near by. The last one, though technically correct, suggest the original author may be confusing pointers and ints, even though its 100% legal C in every single properly implemented C compiler (even if the native representation of a null-pointer has bits set). It also spurs even more bogus comments that it is wrong on exotic architectures because someone wants to appear to be smart, but is actually being wrong, or reporting a situation where a compiler that purports to be a C compiler is actually implementing a different language that is only superficially similar to C. Wow! That's grade a crazy they are smoking. That's not a rule in C, and not even a widely followed 'kool-aide kult kode" practice, but there's so many different cults, it's hard to keep up. Warner