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Boost Exception


#include <boost/exception_ptr.hpp>

    exception_ptr current_exception();


The current_exception function must not be called outside of a catch block.

In addition, to safely copy an exception from one thread to another, if the exception object is copied by current_exception or copy_exception, the two copies must not have shared state. Exceptions that have value-type semantics (as well as the boost::exception type itself) satisfy this requirement.


  • An exception_ptr that refers to the currently handled exception or a copy of the currently handled exception.
  • If the function needs to allocate memory and the attempt fails, it returns an exception_ptr that refers to an instance of std::bad_alloc.




  • It is unspecified whether the return values of two successive calls to current_exception refer to the same exception object.
  • Correct implementation of current_exception may require compiler support, unless enable_current_exception was used at the time the currently handled exception object was passed to throw. Whenever current_exception fails to properly copy the current exception object, it returns an exception_ptr to an object of type that is as close as possible to the original exception type, using unknown_exception as a final fallback. All such types derive from boost::exception, and: