Etienne Lorrain wrote: >>> On C structures, for attributes like "const", it is enough to >>> consider that each field inherit the attribute of the structure. >>> But for the volatile attribute, is it valid to treat each field as >>> volatile like GCC does it now? >> "An object that has volatile-qualified type may be >> modified in ways unknown to the implementation or >> have other unknown side effects. Therefore any >> expression referring to such an object shall be >> evaluated strictly according to the rules of the abstract >> machine, as described in 5.1.2.3." >> >> So, any reference to the object must treat the object as >> volatile, and that includes any reference to any part of >> the object. > > If I correctly understand you, GCC is wrong reading a byte when the > byte is part of a volatile structure - GCC needs to read the complete > structure first, and then extract the byte.
I didn't say that. Neither did the standard, by my reckoning. Please read the standard, in particular the part that follows. Andrew.
