On Wed, Dec 12, 2012 at 10:49 AM, Rob Stewart <robertstewart@comcast.net>wrote:
std::string does not have a 'null' state.
It's the state represented by empty().
I am not sure it is so certainly accepted by all.
It is the logical interpretation. It indicates whether the string is non-empty. I don't see any other generally useful interpretation, do you?
Qt's QString has both empty() and isNull() and they are not always the same. Basically empty() is a zero-byte string, but null is a never-been-set-or-allocated string. ie QString name = database.get("Name"); name.empty() == true means the Name field was empty name.isNull() == true means the Name field doesn't exist in the database. Somewhat like optional<string>. I am NOT saying whether this is a good thing. Just a widely known example of interpretation. Tony