A memory-mapped file (or file mapping) is the result of associating a file's contents with a portion of the virtual address space of a process. It can be used to share a file or memory between two or more processes.
The GetMappedFileName function receives a process handle and a pointer to an address as input. If the address is within a memory-mapped file in the virtual address space of the process, the function returns the name of the memory-mapped file. The filenames returned by GetMappedFileName use device form, rather than drive letters. For example, the filename c:\winnt\system32\ctype.nls would look like this in device form:
\Device\Harddisk0\Partition1\WINNT\System32\ctype.nls
For more information about memory-mapped files, see File Mapping.