3 ms·

Back when I independently invented this due to being self-taught, I didn't know about offsetof(), and I just put the collection at the start and cast the pointe

• DSMan195276 7y ago
  Yeah, even just 'upcasting' is surprisingly effective as well, it's really just inheritance. The lack of being able to embed more than one 'thing' is painful though. And if you're not careful you can run into ugly strict aliasing issues like `struct sockaddr` has (Though a quick `-fno-strict-aliasing` can make all your problems go away...) And I would agree, I find a surprising number of people think C is 'easy' because it doesn't contain that many built-in constructs, and then get completely stuck when they try to use it. To get really good at C, you need a very solid understanding of common and effective patterns you can use. You can still write C without such things, but it quickly becomes a mess of random patterns and inconsistencies. And unfortunately, I can't really think of one source you can really point to for learning them (though admittedly I haven't really looked into it tons).
  • juped 7y ago
    Casting around between the type of the first struct member and the type of the overall struct is okay under strict aliasing, but unfortunately sockaddr violates it because sockaddr isn't a member of sockaddr_in. Not that I knew this at the time, it was just a mysterious rule.
• codr7 7y ago
  Yeah, I used to spend a lot of time reinventing OOP in C back in the days. Part of the problem is I learned C++ long before I took a serious look at C. These days I definitely prefer embedding/baseof since it's more explicit. When I need polymorphism, stuffing some function pointers in a struct usually works well enough.