[This is preliminary documentation and subject to change.]
The DISPLAY_DEVICE structure receives information about the display device specified by the iDevNum parameter of the EnumDisplayDevices function.
typedef struct _DISPLAY_DEVICE {
    DWORD  cb;
    WCHAR  DeviceName[32];
    WCHAR  DeviceString[128];
    DWORD  StateFlags;
} DISPLAY_DEVICE, *PDISPLAY_DEVICE, *LPDISPLAY_DEVICE;
 
  Windows NT: Requires version 5.0 or later.
  Windows: Unsupported.
  Windows CE: Unsupported.
  Header: Declared in wingdi.h.
  Unicode: Defined as Unicode and ANSI structures.
Device Contexts Overview, Device Context Functions EnumDisplayDevices