StreamGetPositionFunc

ULONG
StreamGetPositionFunc(
    PDEVICE_INFO pDevInfo
    );

The StreamGetPositionFunc function returns the current position within the capture stream. The function is provided by the kernel-mode driver, and the StreamGetPositionFunc name is a placeholder for a driver-specified function name.

Parameters

pDevInfo

Pointer to the DEVICE_INFO structure returned by VC_Init.

Return Value

Returns the current stream position, in milliseconds. This is the time that has passed since StreamStartFunc was called.

Comments

The VCKernel.lib library calls a kernel-mode driver’s StreamGetPositionFunc function when the driver receives an IOCTL_VIDC_GET_POSITION control code. User-mode drivers using VCUser.lib send this control code by calling VC_GetStreamPos.

Support for a StreamGetPositionFunc function is required, if the device and driver support capture streams. If a driver does support the function, it must place its address in the VC_CALLBACK structure supplied by VCKernel.lib. If a driver that does not support a StreamGetPositionFunc function receives an IOCTL_VIDC_GET_POSITION control code, VCKernel.lib sets the Win32 error code value to STATUS_INVALID_DEVICE_REQUEST.