Pro tip: avoid `int`s as much as possible in your C code. Use defined macros instead.
There is a time and place for int32_t.
So you think you know C? (2016)
111–120 of 344 posts
Re: So you think you know C? (2016)
#112I found it an amusing excrcise, if not terribly relevant, even as someone who spends 90% of his dev time in C. What rubs me about these sorts of articles is they make some presumption about the importance and nessecisity of writing truely portable C, as if the "C Standard" were in and of itself a terribly useful tool. This is in contrast to where I live most of the time which is "GCC as an assembler macro language" (…
It's very much worth reading, Linus Torvalds' opinion of standards that's linked in that article, but I'll link it again here: https://lkml.org/lkml/2018/6/5/769 "So standards are not some kind of holy book that has to be revered. Standards too need to be questioned." The way I see it, a lot of compiler writers are basically taking the standard as gospel and ignoring everything else "because the standard doesn't say…
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Re: So you think you know C? (2016)
#113It is an unsavory set of questions that has no bearing on practical work, also implementation dependent.
The answer is: No, I do not know C or any other language for that matter. I know some implementations of various languages just enough to write sound and readable code. And as I forced to use a bit more languages than I like I rely on local/Internet search to keep my brains concentrated on accomplishing the actual task rather then effing them up trying to figure out some esoteric constructs.
Re: So you think you know C? (2016)
#114There are a few problems with the questionnaire. "I don't know" is pretty generic choice to be given/choosen. Say for example, in question 5, the statement "return i++ + ++i;" is undefined, because the value of i is read and modified twice in a single sequence point (and of course, the order of addition is unspecified), which is not allowed in C. So the answer is "Undefined." (The explanation given in the page not ac…
Omitting the return type is perfectly conforming C89.
Re: So you think you know C? (2016)
#115It is an unsavory set of questions that has no bearing on practical work, also implementation dependent. The answer is: No, I do not know C or any other language for that matter. I know some implementations of various languages just enough to write sound and readable code. And as I forced to use a bit more languages than I like I rely on local/Internet search to keep my brains concentrated on accomplishing the actual…
i didn't do the quiz, but just looking at the first question I have run across structure packing/padding issues so its not entirely useless
Re: So you think you know C? (2016)
#116Earlier quoted context omitted.
I took that to be the point of the article though, that just looking at the code wasn't enough to know and you needed to go further to answer these cases for your exact use case or target platform.
Further: Unless your code is compiled, deployed to a rocket, and fired off the Earth never to return, the question of “what is my platform?” is meaningless in the context of writing good C. So, today, using the compiler installed on your system right now, sizeof(int) = 32. Great. That means nothing, and changes nothing about whether your code is correct. You should not write code relying on it. Just like you should n…
>Unless your code is compiled, deployed to a rocket, and fired off the Earth never to return, the question of “what is my platform?” is meaningless in the context of writing good C.
While I feel the tone of your comparison was intended to be a bit hyberbolic, the reality is a bulk of modern C development occurs in a context similar to the one you describe. Further the thought, utterly foreign to the vast majority of software developers, that the physical machine may not be some utterly abstract and constantly mutating target which there is no hope of understanding is, imo, one of the great dying arts of software engineering - a death perpetuated by the same sort of folks who think CS education should be carried on in Java.
I contend that, these days, most C is written to target a particular compiler, physical machine, and/or device.
Re: So you think you know C? (2016)
#117It is an unsavory set of questions that has no bearing on practical work, also implementation dependent. The answer is: No, I do not know C or any other language for that matter. I know some implementations of various languages just enough to write sound and readable code. And as I forced to use a bit more languages than I like I rely on local/Internet search to keep my brains concentrated on accomplishing the actual…
Of course it has a bearing on practical work, and that it’s implementation-dependent is the whole point. These are mistaken assumptions people make in the real world.
Re: So you think you know C? (2016)
#118Don't we need to know the sizeof int and void* on this machine?
[edit - that seems to be the point sigh]
Re: So you think you know C? (2016)
#119It is an unsavory set of questions that has no bearing on practical work, also implementation dependent. The answer is: No, I do not know C or any other language for that matter. I know some implementations of various languages just enough to write sound and readable code. And as I forced to use a bit more languages than I like I rely on local/Internet search to keep my brains concentrated on accomplishing the actual…
The questions are a bit cute, but they’re not testing obscure corner cases of the language. It’s not like asking if you have the trigraphs memorized. It’s testing fundamental rules about how C works: overflow, integer promotion, order of operations, memory layout, etc.
Re: So you think you know C? (2016)
#120There are a few problems with the questionnaire. "I don't know" is pretty generic choice to be given/choosen. Say for example, in question 5, the statement "return i++ + ++i;" is undefined, because the value of i is read and modified twice in a single sequence point (and of course, the order of addition is unspecified), which is not allowed in C. So the answer is "Undefined." (The explanation given in the page not ac…
It’s not just that stuff. What pissed me off was asking about the return code of a comparator. That’s just bad form. You’re only supposed to check for zero or nonzero. I have never used the value beyond that, and if you are, that’s a problem.
You’re incorrect. The result of a comparison is guaranteed to be zero or one in C. Similarly for the exclamation-point “not” operator, and || and &&.
This isn’t a recent standardization; it’s been an explicitly specified feature of C pretty much since the very beginning of the language. See page 7 of the prehistoric https://www.bell-labs.com/usr/dmr/www/cman.pdf