> This is precisely what I found so confusing about the original text. To > me, "custom" implies that the back end is *customized* to have its own > descriptor implementation to conform to target-specific ABI standards, > not that it uses a generic implementation in common code.
To me, "custom" sounds contradictory with "conform to" in this sentence. And I don't follow your interpretation, back-ends are by definition customized to follow external constraints and not every macro/hook has "custom" in it. > I could make the docs say both things, but from the perspective of a > back end implementor, being explicit that it's a bit mask used to > differentiate descriptors from any valid function pointer (so you can > figure out what an appropriate value to define it to is) is more > critical than describing what target-independent code does with a > descriptor once it has identified that's what it's got. Fair enough. -- Eric Botcazou