On 24.08.2025 19:27, Dmytro Prokopchuk1 wrote:
> MISRA C Rule 11.3 states: "A cast shall not be performed between a pointer
> to object type and a pointer to a different object type."
>
> Violations of this rule arise due to the 'container_of()' macro, which casts
> a member of a structure to its containing structure:
> container_of(ptr, type, member) ({ \
> typeof_field(type, member) *__mptr = (ptr); \
> (type *)( (char *)__mptr - offsetof(type,member) );})
>
> The 'container_of()' macro is safe because it relies on the standardized and
> well-defined 'offsetof()' macro to calculate the memory address of the
> containing structure, while assuming proper alignment and ensuring no
> undefined behavior, provided that the input pointer is valid and points to
> the specified member.
I may have said so before: This all reads okay to me, just that I'm unsure
it would actually be convincing to an assessor. The "provided that ..." is
a pretty strong requirement, which isn't overly hard to get wrong. Stefano,
Nicola - what's your take here?
Jan
