CcCopyWrite routine

The CcCopyWrite routine copies data from a user buffer to a cached file.


BOOLEAN CcCopyWrite(
  _In_ PFILE_OBJECT   FileObject,
  _In_ PLARGE_INTEGER FileOffset,
  _In_ ULONG          Length,
  _In_ BOOLEAN        Wait,
  _In_ PVOID          Buffer


FileObject [in]

A pointer to a file object for the cached file to which the data is to be written.

FileOffset [in]

A pointer to a variable that specifies the starting byte offset within the cached file.

Length [in]

The length in bytes of the data to be written.

Wait [in]

Set to TRUE if the caller can be put into a wait state until all the data has been copied, FALSE otherwise.

Buffer [in]

A pointer to the buffer from which the data is to be copied.

Return value

The CcCopyWrite routine returns TRUE if the data was copied successfully, FALSE otherwise.


If Wait is TRUE, CcCopyWrite is guaranteed to complete the copy request and return TRUE. If the required pages of the cached file are already resident in memory, the data will be copied immediately and no blocking will occur. If any needed pages are not resident, the caller will be put in a wait state until all required pages have been made resident and the data can be copied.

If Wait is FALSE, CcCopyWrite will refuse to block, and will return FALSE, if the required pages of the cached file are not already resident in memory or if the FO_WRITE_THROUGH flag is set on the file object.

If any failure occurs, CcCopyWrite raises a status exception for that particular failure. For example, if a pool allocation failure occurs, CcCopyWrite raises a STATUS_INSUFFICIENT_RESOURCES exception; if an I/O error occurs, CcCopyWrite raises the status exception of the I/O error. Therefore, to gain control if a failure occurs, the driver should wrap the call to CcCopyWrite in a try-except or try-finally statement.

To cache a file, use CcInitializeCacheMap.


Target platform



Available on Microsoft Windows 2000 and later Windows operating systems.


Ntifs.h (include Ntifs.h or FltKernel.h)







See also




Send comments about this topic to Microsoft