Registering a device interface class

There are two ways to register a device interface class:

• A driver controlling a PnP device can register a device interface in a particular device interface class. As part of registering the device interface, the device interface class will be implicitly created. This topic describes how to use the routines to register a device interface.

• An INF file can contain INF DDInstall.Interfaces sections.

A WDM driver does not name its device objects. Instead, when the driver calls IoCreateDevice to create a device object, it should specify a null string for the device name. For more information, see Creating a device object.

After creating the device object and attaching it to the device stack, one driver calls IoRegisterDeviceInterface to register a device interface class and to create a device interface instance of the class. Typically, the function driver makes this call from its AddDevice routine, but sometimes a filter driver registers the interface.

The routine returns a symbolic link name. A driver passes the link name when it enables or disables the device interface instance. Other system components cannot use a device interface instance until the driver has enabled it. See Enabling and disabling a device interface instance for details.

The driver also uses the symbolic link name to access the registry key, in which it can store information that is specific to the device interface (See IoOpenDeviceInterfaceRegistryKey for more information). Applications use the link name to open the device.

A driver can call IoRegisterDeviceInterface as many times as necessary to register instances of additional device interface classes.

To use device interfaces from a WDF driver, please see Using device interfaces (WDF).