Re: [RFC PATCH] cleanup: make scoped_guard() to be return-friendly

From: Markus Elfring
Date: Mon Sep 30 2024 - 07:33:12 EST



> Current scoped_guard() implementation does not support that,
> due to compiler complaining:

> +++ b/include/linux/cleanup.h
> @@ -168,9 +168,16 @@ static inline class_##_name##_t class_##_name##ext##_constructor(_init_args) \
>
> #define __guard_ptr(_name) class_##_name##_lock_ptr
>
> -#define scoped_guard(_name, args...) \
> - for (CLASS(_name, scope)(args), \
> - *done = NULL; __guard_ptr(_name)(&scope) && !done; done = (void *)1)
> +#define scoped_guard(_name, args...) \
> + __scoped_guard_labeled(__UNIQUE_ID(label), _name, args)
> +
> +#define __scoped_guard_labeled(_label, _name, args...) \
> + if (0) \
> + _label: ; \
> + else \
> + for (CLASS(_name, scope)(args); \
> + __guard_ptr(_name)(&scope), 1; \
> + ({ goto _label; }))
>
> #define scoped_cond_guard(_name, _fail, args...) \
> for (CLASS(_name, scope)(args), \

* How do you think about to define such macros before their use?

* Would you ever like to avoid reserved identifiers in such source code?
https://wiki.sei.cmu.edu/confluence/display/c/DCL37-C.+Do+not+declare+or+define+a+reserved+identifier


Regards,
Markus