Reader Alexey provided some useful feedback on The Smallest Useful Attribute System. The first point I want to address is the extra copies of strings. When I embedded the strings in the map and the AttributeDescriptor, I had been thinking that if the strings were part of a DLL, and the DLL got unloaded, there would be trouble. On further reflection, it occurred to me that I had over-thought it. If a DLL got unloaded, and then one attempted to fetch attributes on the now dead classes, there are bigger problems going on. So, here’s the fix to the string copies; we go from one static string built into the data and two dynamic copies to just the static string.

class AttributeBinder
{
...snip...
    class AttributeDescriptor
    {
...snip...

        AttributeDescriptor(const char* name, const std::type_info& ti, ptrdiff_t off) :
            name(name), ti(&ti), off(off) { }

        const char* name;
...snip...

    };

    class Predicate
    {
    public:
        bool operator()(char const*const& lhs, char const*const& rhs) const
        {
            return strcmp(lhs, rhs) < 0;
        }
    };

    std::map<const char*, AttributeDescriptor, Predicate> attribs;
};

The std::string has been replaced by const char*, and the map is supplied with an ordering predicate that does the comparisons from the name of the attribute.

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