"David B. Held" <[EMAIL PROTECTED]> wrote in message aslftb$cr2$[EMAIL PROTECTED]">news:aslftb$cr2$[EMAIL PROTECTED]... > "Eric Woodruff" <[EMAIL PROTECTED]> wrote in message > aslbsn$nt3$[EMAIL PROTECTED]">news:aslbsn$nt3$[EMAIL PROTECTED]... > > [snip] > > > > > holder<Foo> h; > > > new (h.storage) Foo; > > > > What is the meaning of that syntax? > > This is placement new syntax. It means construct a Foo at the address > h.storage, without allocating any memory. >
So the type really is of Foo, which has to mean that casting h.storage back to a Foo* using reinterpret_cast is covered by the standard. > > > ... > > > T* u = dangerous_cast<T*>(h.storage); // can't do this with > > > reinterpret_cast > > > > Why would you want to do that in the first place. > > Because you want to get at the T in h in a portable way. Which brings > me to my next point. Since it seems this is the only context in which this > cast is guaranteed to give a meaningful result, maybe it should be called > placement_cast<>? > > Dave > > > > > _______________________________________________ > Unsubscribe & other changes: http://lists.boost.org/mailman/listinfo.cgi/boost > _______________________________________________ Unsubscribe & other changes: http://lists.boost.org/mailman/listinfo.cgi/boost
