[LexiMax]

A long overdue feature.

Though I do wonder what the chances are that the C subset of C++ will ever add this feature. I use my own homespun "scope exit" which runs a lambda in a destructor quite a bit, but every time I use it I wish I could just "defer" instead.

[pjmlp]

Never, you can already do this with RAII, and naturally it would be yet another thing to complain about C++ adding features.

Then again, if someone is willing to push it through WG21 no matter what, maybe.

[mort96]

C++ implementations of defer are either really ugly thanks to using lambdas and explicitly named variables which only exist to have scoped object, or they depend on macros which need to have either a long manually namespaced name or you risk stepping on the toes of a library. I had to rename my defer macro from DEFER to MYPOROGRAM_DEFER in a project due to a macro collision.

C++ would be a nicer language with native defer. Working directly with C APIs (which is one of the main reasons to use C++ over Rust or Zig these days) would greatly benefit from it.

[anilakar]

Various macro tricks have existed for a long time but nobody has been able to wrap the return statement yet. The lack of RAII-style automatic cleanups was one of the root causes for the legendary goto fail;[1] bug.

[1] https://gotofail.com/

[uecker]

I do not see how defer would have helped in this case.

[surajrmal]

In many cases that's preferred as you want the ability to cancel the deferred lambda.

[mwkaufma]

Just hope those lambdas aren't throwing exceptions ;)