(inline) "Anthony Williams" <[EMAIL PROTECTED]> wrote in message [EMAIL PROTECTED]">news:[EMAIL PROTECTED]...
[snip] > Gabriel Dos Reis writes: > unsigned char* has _additional_ properties to void* --- you can access the > object representation of _any_ object through an unsigned char* (and for PODs, > you can copy them around using this) > > 3.9p4: > "The object representation of an object of type T is the sequence of N > unsigned char objects taken up by the object of type T, where N equals > sizeof(T)." > > 3.10p15: > "If a program attempts to access the stored value of an object through an > lvalue of other than one of the following types the behavior is undefined: > > - the dynamic type of the object, > > ... > > - a char or unsigned char type." > [snip] > 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. [snip] _______________________________________________ Unsubscribe & other changes: http://lists.boost.org/mailman/listinfo.cgi/boost
