OverlayFunc

BOOLEAN
OverlayFunc(
    PDEVICE_INFO pDevInfo,
    BOOL bOverlay
    );

The OverlayFunc function is provided by kernel-mode video capture drivers to enable and disable the overlay display. The OverlayFunc name is a placeholder for a driver-specified function name.

Parameters

pDevInfo

Pointer to the DEVICE_INFO structure returned by VC_Init.

bOverlay

Set to TRUE if data capture is to be enabled, and FALSE if it is to be disabled.

Return Value

Returns TRUE if the operation succeeds. Otherwise returns FALSE. If FALSE, VCKernel.lib sets the Win32 error code value to STATUS_DEVICE_CONFIGURATION_ERROR.

Comments

The VCKernel.lib library calls a kernel-mode driver’s OverlayFunc function when the driver receives an IOCTL_VIDC_OVERLAY_ON or IOCTL_VIDC_OVERLAY_OFF control code. User-mode drivers using VCUser.lib send this control code by calling VC_Overlay.

Support for an OverlayFunc function is required, if the device provides overlay capabilities. The driver must place the address of its OverlayFunc function in the VC_CALLBACK structure supplied by VCKernel.lib. If a driver that does not support the OverlayFunc function receives an IOCTL_VIDC_OVERLAY_ON or IOCTL_VIDC_OVERLAY_OFF control code, VCKernel.lib sets the Win32 error code value to STATUS_INVALID_DEVICE_REQUEST.