typedef struct tag_dcam* HDCAM

HDCAM is a typedef struct tag_dcam* HDCAM


In DCAM-API , HDCAM is one of the input arguments.

which is declare as...
// declaration of DCAM helper function
HDCAM dcamcon_init_op en();

In main function it can Initialize as...
HDCAM hdcam;

& call as...
// initialize DCAM-API and get HDCAM camera handle....