FlushViewOfFile

The FlushViewOfFile function writes to the disk a byte range within a mapped view of a file.

BOOL FlushViewOfFile(
  LPCVOID lpBaseAddress,         // starting address
  SIZE_T dwNumberOfBytesToFlush  // number of bytes in range
);

Parameters

lpBaseAddress

[in] Pointer to the base address of the byte range to be flushed to the disk representation of the mapped file.

dwNumberOfBytesToFlush

[in] Specifies the number of bytes to flush. If dwNumberOfBytesToFlush is zero, the file is flushed from the base address to the end of the mapping.

Return Values

If the function succeeds, the return value is nonzero.

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

Remarks

Flushing a range of a mapped view causes any dirty pages within that range to be written to the disk. Dirty pages are those whose contents have changed since the file view was mapped.

When flushing a memory-mapped file over a network, FlushViewOfFile guarantees that the data has been written from the local computer, but not that the data resides on the remote computer. The server can cache the data on the remote side. Therefore, FlushViewOfFile can return before the data has been physically written to disk. However, you can cause FlushViewOfFile to return only when the physical write is complete by specifying the FILE_FLAG_WRITE_THROUGH flag when you open the file with the CreateFile function.

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, CreateFile, MapViewOfFile, UnmapViewOfFile