Fernando Cacciola wrote:
"David Abrahams" <dave@boost-consulting.com> escribió en el mensaje news:uvfee6kpk.fsf@boost-consulting.com...
I'm finding the documentation for in-place factories highly frustrating. There's no formal documentation for TypedInPlaceFactory, and almost no description whatsoever for InPlaceFactory. None of what's there describes how these things interact with optional; it isn't even mentioned in the corresponding section!
That stuff started out almost as an experiment and was intended to be generally usefull for all sorts of container classes. [...]
From the documentation:
"For example, one member of this familiy looks like: template<class T,class A0, class A1> class TypedInPlaceFactory2 { A0 m_a0 ; A1 m_a1 ; public: TypedInPlaceFactory2( A0 const& a0, A1 const& a1 ) : m_a0(a0), m_a1(a1) {} void construct ( void* p ) { new (p) T(m_a0,m_a1) ; } } ; A wrapper class aware of this can use it as: class W { X wrapped_ ; public: W ( X const& x ) : wrapped_(x) {} W ( TypedInPlaceFactory2 const& fac ) { fac.construct(&wrapped_) ; } } ;" This doesn't look correct to me. W::wrapped_ is default constructed and then another X is placement-constructed on top of it.