On Thu, Oct 18, 2018 at 05:48:16PM +0200, Duy Nguyen wrote: > > - conditional compilation, where we may or may not need a > > static helper. These generally fall into one of two > > categories: > > > > - the call should not be conditional, but rather the > > function body itself should be (and may just be a > > no-op on one side of the #if). That keeps the > > conditional pollution out of the main code. > > > > - call-chains of static helpers should all be in the > > same #if block, so they are all-or-nothing > > Grouping is not always desired because it could break better function > layout. Have a look at read-cache.c where _ieot_extension functions > are #if'd because the only call sites are from pthread code (#if'd far > away). True, though as long as they are triggered by the same set of #if conditions, that is fine. Putting them in the same block is just an easy way to make sure that is the case. ;) > In this particular case though I think we should be able to avoid so > much #if if we make a wrapper for pthread api that would return an > error or something when pthread is not available. But similar > situation may happen elsewhere too. Yeah, I think that is generally the preferred method anyway, just because of readability and simplicity. > Having said that, if people do consider MAYBE_UNUSED before #if'ing > everywhere (and opening up more conditional build problems in future), > I think this change is fine. I'd like to use it as a last resort, certainly. Mostly the fact that we compile cleanly _now_ makes me think that it probably won't be that hard to keep it going. I think the biggest potential problem with this is going to be obscure configurations where some functions are used or not used. So somebody silencing a compiler warning may inadvertently break another case if they're not careful. But that's already a problem to some degree (and part of why we try to push the conditionality out to the whole-function level). -Peff
