Declaration :

• Uml : # handles : FileHandle, multiplicity : *
• C++ : protected: list<FileHandle> handles

Declaration :

• Uml : - handles_available : int
• C++ : private: int handles_available

initialized to the maximum number of filehandles the backend may use for mapped files. When no handles are available, the handle which is last in the handles list is closed and (re-)used.
Else this number is decremented for each new filehandle used and incremented for any one explicitly freed.