Writing a Class Installer
A class installer DLL performs installation operations that apply to devices in a particular device setup class. For example, the system-supplied Ports class installer is responsible for assigning a COM port name to a device in the Ports setup class. If the devices in a particular setup class do not require any special installation operations, a class installer is not required for that setup class.
Microsoft provides class installers for the system-supplied device setup classes that require a class installer. For devices that belong to these setup classes, a vendor can provide a co-installer to perform additional setup operations, if needed.
If you create a new device setup class for your device, you might have to write a class installer. However, you rarely have to create a new device setup class because most devices can be associated with one of the system-supplied device setup classes. For example, the maker of a digital camera might think that digital cameras require a new setup class. However, cameras fall under the image class.
This section contains the following information:
Also, see the section on Writing a Co-installer for general information about processing DIF codes and Using SetupAPI Functions for information about calling the installation functions supplied by SetupAPI.