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There's not going to >>>>> be any SONAME change ... >>>> >>>> Is there any ABI change in practice? Both fields will still have a 1bit >>>> size. >>> >>> But what a consumer of the interface reads out of such a field would change >>> in case their compiler settings arrange for signed bitfields when signedness >>> isn't explicit. We don't dictate, after all, what compiler settings to use >>> with our interfaces (which generally is good, but which bites us here). >> >> Hm, I see. I would argue that sign doesn't matter here, as those are >> intended to be booleans, so anything different than 0 would map to >> `true`. But implementation might have hard coded TRUE to -1, and the >> change would then break them? > > That's a possible scenario I'm wary of here, yes. > >> I'm failing to see that, because those implementations would still use >> the old struct declarations they have been built with, and hence would >> still threat it as signed? > > Until they rebuild against the updated header, without any change to > their code. > > Anthony - do you have any thoughts here? Btw in the meantime I'll queue the uncontroversial part of the patch for backport (with a respective not about what was dropped). Jan