Question

Is the following code safe?

boost::any any_value;

{
    std::string s = "HelloWorld";
    any_value = s;
}

std::string ss = any_cast<std::string>(any_value);

Answer 1

From Boost.Any docs:

template<typename ValueType> any & operator=(const ValueType & rhs);

Makes a copy of rhs, discarding previous content, so that the new
content of is equivalent in both type and value to rhs.

So yes, it’s safe to do that. A copy of the string is stored, not a reference to it.