When should I concern myself with std::iostream::sentry?

Question

Online references have rather brief and vague descriptions on the purpose of std::iostream::sentry. When should I concern myself with this little critter? If it\'s

Answer 1

Formatted input for anything but the basic types (int, double, etc.) doesn't make a lot of sense, and arguably only from them when taken from a non-interactive stream such as an istringstream. So you should probably not be implementing op>> in the first place, and thus not have to worry about sentry objects.