Comment by uecker
2 hours ago
Two things stick out as un-idiomatic for C. First, the casts before malloc are unnecessary. This you do in C++ but not in C. Second, names with beginning underscore are reserved, and the underscore + capital letter is specifically problematic.
The rest looks fairly nice but there are a couple of things I would do differently: I would not have the tests for NULL, but use signed integers for indices and dimensions, use a flexible array member to integrate the data into the vector type directly, and omit the capacity field (as long as benchmarking does not show it is really needed). I would also use variably modified types for bounds checking, and with C23 the include guards become largely unnecessary.
(edit: minor edit for clarity)
I guess I used function names beginning with underscore as it didn’t occur to me that it might be un-idiomatic. The intention was to make clear to myself that those functions are private and meant to be only used only in that file. But thanks a lot for pointing it out!
About the second paragraph, first of all, thank you for the suggestions. Can I ask you to elaborate a little on the reasons for your proposals? For instance, even if redundant in some cases, I thought to myself it couldn’t be a bad thing to check for null pointers (though I could improve the error handling itself).
In C, you would typically rely much more on tooling to find bugs (but there are different styles and opinions). Checking for null is not bad, but does not usually add anything. If you de-reference a null pointer, you get a segmentation fault (which is safe) and a debugger will give a nice backtrace. So why catch this by writing additional code if the right tool will give you this automatically? A sanitizer could also add such tests automatically.
For a similar reason, it makes sense to use signed integers. A signed overflow sanitizer will find the overflow bugs or safely terminate the program. Finding unsigned wraparound bugs is much harder.
Names beginning with double underbar (or single underbar + capital letter) are reserved. Single underbar + lowercase is not. C23 §6.4.2.1.
Also reserved as identifier with file scope, just not for "any use". In any case, the program used underbar + capital letter.
Ah, I hadn't noticed _SimpleSetNode.
This leaves out part of the clause.
Single underscore followed by non-uppercase is allowed, but not in file scope. This means that you can use them in structs and as local variables, but never as globals.
You're right, and I guess I've been breaking that rule for a while. What's the purpose there? The double-underbar and underbar-capital rules seem to be allowing for non-conflicting introduction of keywords. Is the single-underbar rule to protect standard library headers or something?