boost::lexical_cast string to string problem

I'm seeing a problem with lexical_cast. The following code when trying to convert from string to string fails when passed an empty string. The library code that is doing this lexical_cast does not and can not know that the input and output types are the same. I believe that this code should not throw. #include <iostream> #include main() { std::string input(""); try { boost::lexical_caststd::string(input); } catch (boost::bad_lexical_cast& e) { std::cout << "Failed" << std::endl; } }