UnmapViewOfFile

The UnmapViewOfFile function unmaps a mapped view of a file from the calling process's address space.

BOOL UnmapViewOfFile(
  LPCVOID lpBaseAddress   // starting address
);

Parameters

lpBaseAddress

[in] Pointer to the base address of the mapped view of a file that is to be unmapped. This value must be identical to the value returned by a previous call to the MapViewOfFile or MapViewOfFileEx function.

Return Values

If the function succeeds, the return value is nonzero, and all dirty pages within the specified range are written "lazily" to disk.

If the function fails, the return value is zero. To get extended error information, call GetLastError.

Remarks

Although an application may close the file handle used to create a file-mapping object, the system holds the corresponding file open until the last view of the file is unmapped:

• Windows 95: Files for which the last view has not yet been unmapped are held open with the same sharing restrictions as the original file handle.
• Windows NT/2000: Files for which the last view has not yet been unmapped are held open with no sharing restrictions.

Requirements

  Windows NT/2000: Requires Windows NT 3.1 or later.
  Windows 95/98: Requires Windows 95 or later.
  Header: Declared in Winbase.h; include Windows.h.
  Library: Use Kernel32.lib.

See Also

File Mapping Overview, File Mapping Functions, MapViewOfFile, MapViewOfFileEx