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?
