On Tuesday 2018-10-09 17:41, David Howells wrote: >Jan Engelhardt <jengelh@xxxxxxx> wrote: > >> """it [the array size expression] shall be a converted constant expression of >> type std::size_t and its value shall be greater than zero.""" >> —http://eel.is/c++draft/dcl.array > >Interesting. You're not actually quoting the full sentence: > > If the constant-expression is present, it shall be a converted > constant expression of type std::size_t and its value shall be > greater than zero. > >This suggests that: > > __u64 ptr[] > >is actually valid I think that kind of validity only goes for this kind of standalone decl: extern int myints[]; but not for []-inside-struct.