IOCTL_VIDEO_SWITCH_DUALVIEW IOCTL (ntddvdeo.h)
Notifies the video miniport that a secondary view is about to be enabled or disabled. A secondary view is enabled by a call to the video port driver's VideoPortCreateSecondaryDisplay.
Windows XP and later send this request to the video miniport driver to notify it of a secondary view change of status. Video miniport drivers can use this notification to make video memory arrangements in advance. For example, when the display driver sets the mode of the primary view, it can reserve video memory for one or more secondary views.
Note This request, which is available in Windows XP and later, can only be used to manage video memory.
Major code
Input buffer
The VRP InputBuffer contains a pointer to a ULONG, which can be one of the two following values:
| Value | Meaning |
|---|---|
| 0 | The device is about to be detached. |
| 1 | The device is about to be attached. |
Output buffer
None
Status block
The miniport driver does not set the Information member of the STATUS_BLOCK structure.
Requirements
| Requirement | Value |
|---|---|
| Header | ntddvdeo.h |