The MCI_SYSINFO_PARMS structure contains information for the MCI_SYSINFO command.
typedef struct {
    DWORD dwCallback; 
    LPSTR lpstrReturn; 
    DWORD dwRetSize; 
    DWORD dwNumber; 
    UINT  wDeviceType; 
} MCI_SYSINFO_PARMS;
 When assigning data to the members of this structure, set the corresponding flags in the fdwCommand parameter of the mciSendCommand function to validate the members.
  Windows NT: Requires version 3.1 or later.
  Windows: Requires Windows 95 or later.
  Windows CE: Unsupported.
  Header: Declared in mmsystem.h.
  Unicode: Defined as Unicode and ANSI structures.
MCI Overview, MCI Structures, MCI_SYSINFO, mciSendCommand