On Tue, Nov 24, 2020 at 04:20:37PM +0100, Markus Armbruster wrote: > Eduardo Habkost <ehabk...@redhat.com> writes: > > > On Tue, Nov 24, 2020 at 09:49:30AM +0100, Markus Armbruster wrote: > >> Eduardo Habkost <ehabk...@redhat.com> writes: > >> > >> > On Mon, Nov 23, 2020 at 08:51:27AM +0100, Markus Armbruster wrote: > >> >> Eduardo Habkost <ehabk...@redhat.com> writes: > >> >> > >> >> > On Fri, Nov 20, 2020 at 06:29:16AM +0100, Markus Armbruster wrote: > >> >> [...] > >> >> >> When the structure of a data type is to be kept away from its users, > >> >> >> I > >> >> >> prefer to keep it out of the public header, so the compiler enforces > >> >> >> the > >> >> >> encapsulation. > >> >> > > >> >> > I prefer that too, except that it is impossible when users of the > >> >> > API need the compiler to know the struct size. > >> >> > >> >> There are cases where the structure of a data type should be > >> >> encapsulated, yet its size must be made known for performance (avoid > >> >> dynamic memory allocation and pointer chasing). > >> >> > >> >> Need for encapsulation correlates with complex algorithms and data > >> >> structures. The cost of dynamic allocation is often in the noise then. > >> > > >> > I don't know what we are talking about anymore. None of this > >> > applies to the QNum API, right? > >> > > >> > QNum/QNumValue are not complex data structures, and the reason we > >> > need the compiler to know the size of QNumValue is not related to > >> > performance at all. > >> > >> We started with the question whether to make QNumValue's members > >> private. We digressed to the question when to make members private. > >> So back to the original question. > >> > >> > We might still want to discourage users of the QNum API from > >> > accessing QNum.u/QNumValue.u directly. Documenting the field as > >> > private is a very easy way to do it. > >> > >> It's a complete non-issue. QNum has been around for years, and we > >> haven't had any issues that could've been plausibly avoided by asking > >> people to refrain from accessing its members. > >> > >> If there was an actual need to keep the members private, I'd move the > >> struct out of the header, so the compiler enforces privacy. > > > > Understood. There's still a question I'd like to answer, to > > decide how the API documentation should look like: > > > > Is QNum.u/QNumValue.u required to be part of the API > > documentation? > > > > If accessing that field directly is not necessary for using the > > API, I don't think it should appear in the documentation (because > > it would be just noise). > > The current patch's comment on QNumValue looks good to me. > > Does this answer your question?
The current patch (v3) doesn't address the question. It doesn't include documentation for the field, but doesn't hide it. kernel-doc will print a warning on that case. -- Eduardo