Eric Woodruff writes: > "Anthony Williams" <[EMAIL PROTECTED]> wrote in > message [EMAIL PROTECTED]">news:[EMAIL PROTECTED]... > > Thus, given that h.storage is properly aligned, (which is the purpose of > the > > other union member), after "new(h.storage) Foo", h.storage contains a Foo > > object. Thus accessing it through a pointer-to-Foo is legal, as Foo is the > > dynamic type of the object. > > > > This is precisely my reasoning why reinterpret_cast<> is _not_ > implementation defined. > > It must be the case that it is equal to the situation of having > > Foo* -> char */void* -> Foo* if Foo is the dynamic type of the object.
Nowhere do I see a requirement that supports your deductions. Indeed there are very few requirements on reinterpret_cast<>, other than the fact that what it does must be defined by the implementation. For pointers to objects, these amount to: * T1* can be converted to T2* and back again unchanged (unless T2 has stricter alignment requirements). * You can convert a pointer to the first member of a POD struct to a pointer to the struct, and vice-versa. * A Null pointer of any type can be cast to a null pointer of any other type. Anthony -- Anthony Williams Senior Software Engineer, Beran Instruments Ltd. Remove NOSPAM when replying, for timely response. _______________________________________________ Unsubscribe & other changes: http://lists.boost.org/mailman/listinfo.cgi/boost
