On Mon, 2008-03-10 at 18:59 +1300, Amos Jeffries wrote: > Alex Rousskov wrote: > > IMO, at the end of the cleanup, "squid.h" should be the file that all > > sources are guaranteed to include first simply because it is called > > squid.h. Config.h has, by name, a much narrower scope. > > > > I realize that this is subjective and that very few people care about > > things like that in Squid so if, for whatever reason, Amos wants to > > remove squid.h from most files and leave config.h instead, I am not > > going to object since I am not the person doing the cleanup leg work, > > and since the functional effect will be the same. > > > > The little tweaks that are not global in nature should be moved out to > > specific headers and wrappers, of course. The > > guaranteed-to-be-included-first.h file should eventually be almost > > empty. Its primary value is the guarantee itself, which becomes a useful > > tool for [usually temporary] hacks. > > With the testheaders.sh every .h now has > guaranteed-to-be-included-at-earliest-actual-need.
Yes, that is great(*), but to-be-included-first guarantee is a little different (and much easier to support/test). > The hacks should be localized to the object(s) they are hacking anyway > and not affect the entire Squid + sub-programs + linked-programs + > helpers + unit-tests + tools. > > If they do you would be: > - hacking a system include > (which requires config.h for the wrapping!) > - hacking an objects behaviour > (which gets linked/included everywhere its used anyway!) The guaranteed-to-be-included-first.h file is needed for exceptional hacks that defy "normal" rules. For example, it is 3:00 in the morning and you must make Squid to compile on some remote box, but some internal system header is broken and needs a special _BSD_API #define to compile. Many system headers include that header conditionally so you cannot just quickly wrap a system include file to #define that constant. If only you could define it before any system header is included! Such hacks are usually temporary. Again, I am just sharing my experience here. No significant pressure to implement guaranteed-to-be-included-first.h file idea... Thank you, Alex. P.S. Can a script reliably test an included-at-earliest-actual-need guarantee? I think I can write a header that compiles fine without config.h but still needs it to enable an optional API. How would a script detect such a need?
