DEV_BROADCAST_HDR

The DEV_BROADCAST_HDR structure is a standard header for information related to a device event reported through the WM_DEVICECHANGE message.

The members of the DEV_BROADCAST_HDR structure are contained in each device management structure. To determine which structure you have received through WM_DEVICECHANGE, treat the structure as a DEV_BROADCAST_HDR structure and check its dbch_devicetype member.

typedef struct _DEV_BROADCAST_HDR {
  DWORD dbch_size; 
  DWORD dbch_devicetype; 
  DWORD dbch_reserved; 
} DEV_BROADCAST_HDR;
typedef DEV_BROADCAST_HDR *PDEV_BROADCAST_HDR;

Members

dbch_size

Specifies the size of this structure, in bytes.

If this is a user-defined event, this member must be the size of this header, plus the size of the variable-length data in the _DEV_BROADCAST_USERDEFINED structure.

dbch_devicetype

The device type. Determines the event-specific information that follows the first three members. This member can be one of the following values.

Value	Meaning
DBT_DEVTYP_DEVICEINTERFACE	Windows 98 and Windows 2000: Class of devices. This structure is a DEV_BROADCAST_DEVICEINTERFACE structure.
DBT_DEVTYP_HANDLE	Windows 98 and Windows 2000: File system handle. This structure is a DEV_BROADCAST_HANDLE structure.
DBT_DEVTYP_OEM	OEM- or IHV-defined device type. This structure is a DEV_BROADCAST_OEM structure.
DBT_DEVTYP_PORT	Port device (serial or parallel). This structure is a DEV_BROADCAST_PORT structure.
DBT_DEVTYP_VOLUME	Logical volume. This structure is a DEV_BROADCAST_VOLUME structure.

dbch_reserved

Reserved; do not use.

Requirements

  Windows NT/2000: Requires Windows 2000.
  Windows 95/98: Requires Windows 95 or later.
  Header: Declared in Dbt.h.

See Also

Device Management Overview, Device Management Structures, DEV_BROADCAST_DEVICEINTERFACE, DEV_BROADCAST_HANDLE, DEV_BROADCAST_OEM, DEV_BROADCAST_PORT, DEV_BROADCAST_VOLUME, WM_DEVICECHANGE