Mapped Memory

Mapped memory allows a process to map part or all of a file's contents into its address space. Once the file has been mapped, direct addressing of the file's contents is done through machine instruction accesses to the mapped memory region. A process can map multiple files, and the same file can be mapped into multiple processes.

Discretionary and mandatory access checks are performed when the file is opened. If a file is opened for read only, it may be mapped for reading only even when the file's attributes permit write access. See the appropriate man page for specific information on security policy and applicable privileges.