IOCTL_DVD_GET_REGION control code
Returns Region Playback Control (RPC) information for a DVD device, such as whether the player supports the RPC2 standard, the current region code of the player, and the remaining number of times the player's region code can be changed by the user. This IOCTL also indicates the region code of the currently mounted disc. This only works if a DVD is in the drive. The IOCTL_DVD_READ_KEY operation should be used to obtain only the device region code. If the drive region has not been set previously (if it is still at factory default) and if the inserted media has a region, the device region will be set to the current media region.
None. Parameters.DeviceIoControl.OutputBufferLength indicates the size, in bytes, of the buffer at Irp->AssociatedIrp.SystemBuffer, which must be >= sizeof(DVD_REGION).
The driver returns the DVD_REGION data in the buffer at Irp->AssociatedIrp.SystemBuffer.
The Information field is set to the number of bytes transferred. The Status field is set to STATUS_SUCCESS or possibly STATUS_INSUFFICIENT_RESOURCES.