typedef struct{
DWORD dwType;
} DPMSG_GENERIC, *LPDPMSG_GENERIC;
This structure is provided for message processing.
Identifies the system message type.
When a system message is received (that is, the value pointed to by the lpidFrom parameter equals DPID_SYSMSG), first cast the unknown message data to the DPMSG_GENERIC type, and then perform further processing based on the value of dwType. After the message type has been determined, the message can cast to one of the known types of system messages for further processing.