Re: Does a template class class built on recursive inheritance
have the same layout as an array?
On 2012-11-22 00:43, Cassio Neri wrote:
Hi all,
I need to know if a template class built on recursive inheritance has the
same layout as an array. More precisely,
template <typename T, size_t N>
class foo;
template <typename T>
class foo<T, 1> {
T value;
};
template <typename T, size_t N>
class foo : private foo<T, 1> {
foo<T, N - 1> value;
};
This is a simplification and so it's important to state that the real foo
has no other non-static data members, it has no virtual methods and it
doesn't derive from anything else (apart from the inheritance from
foo<T, 1> seen above). However, T is unknown in advance. The question is:
can I be sure that foo<T, N> has the same layout as T[N]?
I'm not sure what you actually precisely mean with "same layout". If you
mean whether T[N] and foo<T, N> are /layout-compatible/ according to 3.9
and 9.2: I don't see evidence for that. To the contrary, 9.2 p19
indicates that there might be padding *after* each data member value of
any foo specialization.
HTH & Greetings from Bremen,
Daniel Kr?gler
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