Re: [PATCH 0/3] Add offsetofp() and offsetofendp() for pointer arithmetic

[Bence Csókás]

Hi,

On 2026. 11. 06. 9:04, Christoph Hellwig wrote:
> On Thu, Nov 05, 2026 at 06:16:15PM +0100, Bence Csokas wrote:
> > A common usage pattern for offsetof() is the following:
> >
> >    offsetof(typeof(*ptr), member)
> >
> > Condense this operation to one macro for a more maintainable code base.
>
> What exactly makes non-standard macros with no obvious safety benefit
> more maintainable?

It is written out in more detail in the msg of 1/3: it helps keep lines 
short, and as typeof(*ptr) may not come naturally to many, some may be 
compelled to write out the typename twice::

  struct my_struct_type *p;
  off = offsetof(struct my_struct_type, member);
  // pointer arithmetic with p and off

which induces additional work if *p's type changes.

However, as Sashiko pointed out (don't know why it didn't write this 
earlier), struct_offset() already exists, so we should just use that 
one, and probably add a struct_offset_end() variant.

Sorry for the noise, everyone.

Bence