Eukaryotes. Eukaryotes are organisms made up of cells that possess a membrane-bound nucleus (that holds genetic material) as well as membrane-bound organelles. Genetic material in eukaryotes is contained within a nucleus within the cell and DNA is organized into chromosomes. Eukaryotic organisms may be multicellular or single-celled organisms. All animals are eukaryotes. Other eukaryotes include plants, fungi, and protists. A typical eukaryotic cell might contain the following parts: plasma membrane; nucleolus
A unique_lock can be created without immediately locking, can unlock at any point in its existence, and can transfer ownership of the lock from one instance to another. So you always use lock_guard, unless you need the capabilities of unique_lock. A condition_variable needs a unique_lock.
This is because the variable is marked as 'protected', in the absence of which, the same error as depicted above, would have been displayed. Also, creating an instance of the class xxx, does not allow access to the protected variables. The keyword DIM is optional, when used in consonance with access modifiers.