My understanding is that when an asynchronous operation throws an exception, it will be propagated back to a thread that calls std::future::get().  However, when su         
        
vs2012\vc11\crt\future.cpp
there is an error with the
static const char *const _Future_messages[] =
{   // messages for future errors
"broken promise",
"future already retrieved",
"promise already satisfied",
"no state"
};
this code generated an invalid acceso to "_Future_messages" because _Mycode.value() return 4.
    const char *__CLR_OR_THIS_CALL what() const _THROW0()
    {   // get message string
    return (_Get_future_error_what(_Mycode.value()));
    }
// code example
    std::future empty;
try {
    int n = empty.get();
} catch (const std::future_error& e) {
   const error_code eCode = e.code();
   char *sValue = (char*)e.what();
   std::cout << "Caught a future_error with code " << eCode.message()
              << " - what" << sValue << endl;
}