On Thu, 2007-07-05 at 17:43 +0100, Al Viro wrote: > On Thu, Jul 05, 2007 at 08:36:35AM -0700, Josh Triplett wrote: > > Wow. Insane. So these all declare the same type: > > __attribute__((foo)) T *v; > > T __attribute__((foo)) *v; > > T *__attribute__((foo)) v; > > ? Specifically, they point to a foo-T, for convenient shooting? > > They all give you foo-pointer-to-T. > T (__attribute__((foo)) *v); > would give pointer-to-foo-T. Doesn't that do exactly what we want, then? If we say T __attribute__((noderef)) *v; , we want a noderef-pointer-to-T, not a pointer-to-noderef-T. noderef should modify a pointer. > > context also represents a qualifier; the position of the qualifier should > > determine things like whether you want to enforce the context when you access > > a pointer or dereference a pointer. > > Since __context__ is (sparse-only) keyword, we are not constrained by > anything anyway. No, I mean __attribute__((context(...))), which means something different. __context__() works as a statement statement changing the context. __attribute__((context(...))) works as an attribute modifying a type to say that it requires a given context, and that accessing/calling it changes the context. Somewhat of an odd distinction, but sparse currently works that way. > > > Frankly, I would rather add a new primitive (__qualifier__) mirroring the > > > __attribute__, but acting like real qualifiers do. And switched the > > > noderef et.al. to it. > > > > Something like that sounds vaguely reasonable. It should allow the same set > > of attributes, and just change what they apply to. To use your example, > > T __qualifier__((foo)) *v; > > and > > T (__attribute__((foo)) *v); > > would mean the same thing. > > Yup, except that it would not accept storage-class-like attributes (e.g. > always_inline). So, to clarify what you mean by storage-class-like: __qualifier__ would accept all attributes that modify a *type* rather than a *declaration*. > And yes, __qualifier__((context(...))) probably might > be a replacement for __context__, to reduce the number of primitives. No, see above. __context__ works as a statement, not as a way to modify a type. That said, "calling this function requires this context or changes the context" and "accessing this variable requires this context or changes the context" may represent different types of attributes. I don't know. - Josh Triplett - To unsubscribe from this list: send the line "unsubscribe linux-sparse" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
