[boost] [exception] Lifetime of exception refered to by exception_ptr

I failed to find in Boost.Exception documentation any note on how long is the lifetime of an exception object referred to by an exception_ptr. Also I failed to find it in the referred N2179 (http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2007/n2179.html). It seems logical to assume that the lifetime is not shorter then the lifetime of any exception_ptr object referring to the exception object. N2179 suggests possibility of use of smart pointer as implementation of exception_ptr which makes that assumption even more justified. However I think that documentation should be explicit with this. Adam Badura