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I’ve always considered “defer” an inelegant kludge in comparison to RAII for automatic cleanup of resources. It’s surprising that the C standards committee is considering adding that to the language. Then again, nearly none of the syntactic C features post-C89 have been very compelling or widely adopted.
I’ve always considered “defer” an inelegant kludge in comparison to RAII for automatic cleanup of resources. It’s surprising that the C standards committee is considering adding that to the language. Then again, nearly none of the syntactic C features post-C89 have been very compelling or widely adopted.
If anything RAII is unfit for C (which doesn't have classes), and in itself, a kludge (it's an idiom, not a language feature).
I’ve always considered “defer” an inelegant kludge in comparison to RAII for automatic cleanup of resources. It’s surprising that the C standards committee is considering adding that to the language. Then again, nearly none of the syntactic C features post-C89 have been very compelling or widely adopted.
defer is great for many use cases, available in Go, Swift and other languages, and nothing like a kludge. If anything RAII is unfit for C (which doesn't have classes), and in itself, a kludge (it's an idiom, not a language feature).
Looking at the article, this specific implementation doesn’t quite go all the way, requiring a special guard {} block instead of working anywhere. A better implementation, working in any context, would be easy but has to be baked into the compiler.
Edit: just saw the proposal for inclusion into the C standard. It is unfortunate that they are considering 1) requiring a guard block and 2) deferring clean up to the end of the function instead of end of the scope. #1 is needless syntax and #2 would make the feature useless within loops by causing explosions and contractions in memory usage.
Isn't this already available as a GCC/LLVM extension? I know several codebases that use it in that form. Good to see it standardized of course...
I’ve always considered “defer” an inelegant kludge in comparison to RAII for automatic cleanup of resources. It’s surprising that the C standards committee is considering adding that to the language. Then again, nearly none of the syntactic C features post-C89 have been very compelling or widely adopted.
Defer is more explicit than RAII, so a better fit for the very explicit C language
A nice alternative is to wrap malloc and give it a context argument. Then free via the context. This is really the same idea but doesn’t need any extra stuff in the language Or you know... free the things you need to free and move on with your life
And leave memory leaks, buffer overflows, and bugs in the process, and we've done for the past 40+ years...
Despite being convenient,I have the feeling that it might be a bad idea. One of the key interest of C compared to more recent languages is that everything is explicit. With a finger you can follow the code as it runs and know exactly what is going on and when exactly. At the opposite, there is c++ that does a lot of things automagically. And it is often hard to understand why you suddenly get a segfault out of blue,…
Destructors are not called randomly.
It's not really random, but it's quite hard to follow.
Earlier quoted context omitted.
defer is great for many use cases, available in Go, Swift and other languages, and nothing like a kludge. If anything RAII is unfit for C (which doesn't have classes), and in itself, a kludge (it's an idiom, not a language feature).
What if you forget to call “defer”? Then your code is incorrect. That’s kludgy in comparison to RAII where it’s impossible to forget to call a destructor.
So it's immediately better compared to the current C situation.
As for compared to RAII? Well, thats one failure mode for defer (forgetting it), whereas there are dozens of ways to mess RAII...