Boost C++ Libraries of the most highly regarded and expertly designed C++ library projects in the world. Herb Sutter and Andrei Alexandrescu, C++ Coding Standards

Boost Exception


#include <boost/exception_ptr.hpp>

    typedef error_info<struct tag_original_exception_type,std::type_info const *> original_exception_type;

This error_info typedef is used by current_exception if it defaults to returning an exception_ptr that refers to an object of type unknown_exception, to record in it the std::type_info of the original exception object.