Adam Badura:
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.
The authoritative reference for exception_ptr is now the C++0x standard draft http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2009/n2857.pdf which states in 18.8.5/7: "The referenced object shall remain valid at least as long as there is an exception_ptr object that refers to it."