FSCTL_OPLOCK_BREAK_ACK_NO_2 IOCTL (winioctl.h)

Responds to notification that an opportunistic lock on a file is about to be broken. Use this operation to unlock all opportunistic locks on the file but keep the file open.

To perform this operation, call the DeviceIoControl function using the following parameters.

BOOL DeviceIoControl(
  (HANDLE) hDevice,                 // handle to file
  FSCTL_OPLOCK_BREAK_ACK_NO_2,      // dwIoControlCode
  NULL,                             // lpInBuffer
  0,                                // nInBufferSize
  NULL,                             // lpOutBuffer
  0,                                // nOutBufferSize
  (LPDWORD) lpBytesReturned,        // number of bytes returned
  (LPOVERLAPPED) lpOverlapped       // OVERLAPPED structure
);

Remarks

This operation is used only by client applications that have requested an opportunistic lock from a local server. Client applications requesting opportunistic locks from remote servers must not request them directly—the network redirector transparently requests opportunistic locks for the application.

For the implications of overlapped I/O on this operation, see the Remarks section of the DeviceIoControl topic.

When you receive notification that an opportunistic lock on a file is about to be broken, use the FSCTL_OPLOCK_BREAK_ACK_NO_2 control code to indicate to the server that you want to relinquish any opportunistic locks but plan to keep the file open. If the operation returns the error code ERROR_IO_PENDING, the server has granted a level 2 lock on the file.

One alternative to using FSCTL_OPLOCK_BREAK_ACK_NO_2 is to indicate that the application is about to close the file anyway. Use the FSCTL_OPBATCH_ACK_CLOSE_PENDING control code for this response.

Another alternative, used if the lock being broken is an exclusive opportunistic lock, is to indicate the file should receive a level 2 opportunistic lock instead. Use the FSCTL_OPLOCK_BREAK_ACKNOWLEDGE control code for this response.

Applications are notified that an opportunistic lock is broken by using the hEvent member of the OVERLAPPED structure associated with the file on which the opportunistic lock is broken. Applications may also use functions such as GetOverlappedResult and HasOverlappedIoCompleted.

In Windows 8 and Windows Server 2012, this code is supported by the following technologies.

Requirements

See also

• CreateFile
• DeviceIoControl
• FSCTL_OPBATCH_ACK_CLOSE_PENDING
• FSCTL_OPLOCK_BREAK_ACKNOWLEDGE
• GetOverlappedResult
• HasOverlappedIoCompleted
• OVERLAPPED
• Oplock Semantics
• Opportunistic Locks