Platform SDK: Hardware |
The FSCTL_REQUEST_BATCH_OPLOCK operation requests a batch opportunistic lock on a file.
To perform this operation, call the DeviceIoControl function using the following parameters.
BOOL DeviceIoControl( (HANDLE) hDevice, // handle to file FSCTL_REQUEST_BATCH_OPLOCK, // dwIoControlCode operation NULL, // lpInBuffer; must be NULL 0, // nInBufferSize; must be zero NULL, // lpOutBuffer; must be NULL 0, // nOutBufferSize; must be zero (LPDWORD) lpBytesReturned, // number of bytes returned (LPOVERLAPPED) lpOverlapped // OVERLAPPED structure );
If lpOverlapped is NULL (nonoverlapped I/O), lpBytesReturned is used internally and cannot be NULL.
If lpOverlapped is not NULL (overlapped I/O), lpBytesReturned can be NULL.
If hDevice was opened with the FILE_FLAG_OVERLAPPED flag, lpOverlapped must point to a valid OVERLAPPED structure. In this case, DeviceIoControl is performed as an overlapped (asynchronous) operation. If the device was opened with the FILE_FLAG_OVERLAPPED flag and lpOverlapped is NULL, the function fails in unpredictable ways.
If hDevice was opened without specifying the FILE_FLAG_OVERLAPPED flag, lpOverlapped is ignored and the DeviceIoControl function does not return until the operation has been completed, or until an error occurs.
If the operation succeeds, DeviceIoControl returns a nonzero value. To determine if the opportunistic lock is granted, call GetLastError. The code ERROR_IO_PENDING indicates that the opportunistic lock was granted. Any other code indicates that the request was denied.
If the operation fails, DeviceIoControl returns zero. To get extended error information, call GetLastError.
For the implications of overlapped I/O on this operation, see the Remarks section of the DeviceIoControl topic.
An FSCTL_REQUEST_BATCH_OPLOCK operation fails if the file is opened in nonoverlapped (synchronous) mode.
Windows NT/2000: Requires Windows 2000.
Windows 95/98: Unsupported.
Header: Declared in Winioctl.h.
Device Input and Output Overview, Device Input and Output Control Codes, CreateFile, DeviceIoControl, Opportunistic Locks, OVERLAPPED