Adding a third option for controlling memory

[stefanos82]

A couple of weeks ago I read this article https://lwn.net/Articles/934679/ and reminded me it can be possible to emulate C++'s RAII behavior using GCC's / clang's extension via cleanup attribute.

@edubart what is your opinion on this kind of mechanism, assuming you are willing to give it a go and let users know this option is available only under GCC and clang?

It's just food for thought, nothing more.

[edubart]

I like this mechanism, and Nelua has official support for something like it. It's the defer statement and the <close> annotation of to-be-closed variables. I added a new section about to-be-closed variables in the overview, please check:

https://nelua.io/overview/#defer
https://nelua.io/overview/#to-be-closed-variables

[stefanos82]

Thank you for letting me know @edubart .

Yes, I know about defer and <close>; my question regarding these two, if I use any of those, does it mean a ## pragmas.nogc = true is being used implicitly behind the scenes?

[stefanos82]

What I really meant was a mechanism to emit such code in C that helps with controlling memory scope.

[edubart]

if I use any of those, does it mean a ## pragmas.nogc = true is being used implicitly behind the scenes?

Both defer statement and to-be-closed variables are orthogonal and unrelated to GC, that is, both work with or without GC, the GC has nothing to do with them.

What I really meant was a mechanism to emit such code in C that helps with controlling memory scope.

The cleanup extension could be used to implement both defer and to-be-closed variables, however Nelua's C code generator is more explicit and explicitly emits the scope ending code. I think this way makes it more compatible with other C compilers.

[stefanos82]

Both defer statement and to-be-closed variables are orthogonal and unrelated to GC, that is, both work with or without GC, the GC has nothing to do with them.

Ah I see.

The cleanup extension could be used to implement both defer and to-be-closed variables, however Nelua's C code generator is more explicit and explicitly emits the scope ending code. I think this way makes it more compatible with other C compilers.

Nice! That's good to know; I learned something new today!

Cheers @edubart 👍