Douglas Gregor wrote:
On Aug 5, 2005, at 2:07 PM, Michal Kandulski wrote:
Hi!
I'd like to implement a pimpl, pointing to a stack "allocated" buffer by means of palcement new/destroy.
There would be no problem but there are alignment issues.
What really I need is: - a way to check by te means of Boost wheater that an object of class X can be placed (with placement new) in a buffer of given adress and size: - a way of getting a pointer to X (within the buffer) where the object could be paced
boost::optional<T> does this, as does the more-complicated boost::variant.
You'll want to use the type traits alignment_of (to find the alignment of a type) and type_with_alignment (to find a POD type with a given alignment). If you dig around Boost for aligned_storage you'll see the technique we've used.
Doug
Thanks for the answer, but I've already checked both optional and variant. OK. I can get a POD type suitable to store an object of X, but my problem is: how to determine whether the object can be stored in a given stack "allocated" buffer of given size. My input data is: - alignment_of<X>::value, - sizeof(X), - (aligned_storage<alignment_of<X>::value, sizeof(X)>::type) - max_size - m_impl_buffer[max_size] And the question is again: can store an object of X in m_impl_buffer and if I can - where? Michal