VCCALLBACK

typedef struct _VCCALLBACK {
    DWORD dwCallback;     
    DWORD dwFlags;     
    HDRVR hDevice;     
    DWORD dwUser;     
} VCCALLBACK, *PVCCALLBACK;

The VCCALLBACK structure contains callback information needed by the VC_StreamInit function. The structure is defined in vcuser.h.

Members

dwCallback

Contains either the address of a callback function, a window handle, or NULL, based on flags set in the dwFlags member. The driver should copy the value of the VIDEO_STREAM_INIT_PARMS structure’s dwCallback member into this member.

dwFlags

Contains flags. Can contain one (or none) of the following flags.

Flag	Definition
CALLBACK_WINDOW	Indicates dwCallback contains a window handle.
CALLBACK_FUNCTION	Indicates dwCallback contains a callback function address.

The driver should copy the value of the VIDEO_STREAM_INIT_PARMS structure’s dwFlags member into this member.

hDevice

Contains a handle to a video channel. The driver should copy the value of the VIDEO_STREAM_INIT_PARMS structure’s hVideo member into this member.

dwUser

Contains client-specified instance data passed to the callback function, if CALLBACK_FUNCTION is set in dwFlags. The driver should copy the value of the VIDEO_STREAM_INIT_PARMS structure’s dwCallbackInst member into this member.

Comments

As indicated by the preceding member descriptions above, the VCCALLBACK structure is used to pass VIDEO_STREAM_INIT_PARMS structure members to VC_StreamInit.