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Interface Identifiers for Printer Drivers

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Important

The modern print platform is Windows' preferred means of communicating with printers. We recommend that you use Microsoft's IPP inbox class driver, along with Print Support Apps (PSA), to customize the print experience in Windows 10 and 11 for printer device development.

For more information, see Modern print platform and the Print support app design guide.

A set of GUIDs is defined in prcomoem.h. Each of these GUIDs is an interface identifier for one of the COM interfaces used for communication between the printer drivers (Unidrv and Pscript5) and plug-ins.

For Windows 2000 and Windows XP, the following GUIDs are defined:

IID_IPrintOemUI IID_IPrintOemUI2 (Pscript5 UI plug-ins on Windows XP and later versions of the Windows operating system) IID_IPrintOemDriverUI IID_IPrintCoreUI2 (Pscript5 UI plug-ins on Windows XP and later versions of the Windows operating system) IID_IPrintOemUni IID_IPrintOemUni2 (Unidrv render plug-ins on Windows XP and later versions of the Windows operating system) IID_IPrintOemUni3 (Unidrv render plug-ins on Windows Vista and later versions of the Windows operating system) IID_IPrintOemDriverUni IID_IPrintOemPS IID_IPrintOemPS2 (Pscript5 render plug-ins on Windows XP and later versions of the Windows operating system) IID_IPrintOemDriverPS IID_IPrintCorePS2 (Pscript5 render plug-ins on Windows XP and later versions of the Windows operating system) Each GUID identifies one version of one interface. If a new version of an interface is defined, a new GUID is added to the list.

User interface plug-ins and rendering plug-ins must identify the interface versions they support. The printer driver (Unidrv or Pscript5) calls a plug-in's IUnknown::QueryInterface method (described in the Windows SDK documentation), specifying an interface identifier as input. If the plug-in supports the specified version, the method must return a pointer to the interface along with a return status of S_OK. Otherwise, it must return E_NOINTERFACE. The driver starts with the interface identifier for the most recent version and continues to call QueryInterface with earlier version identifiers until the method returns S_OK or the driver exhausts the list of version identifiers.

Likewise, Unidrv and Pscript5 provide IUnknown::QueryInterface methods for the IPrintOemDriverUI, IPrintCoreUI2, IPrintOemDriverUni, IPrintOemDriverPS, or IPrintCorePS2 COM interfaces. Plug-ins should call the appropriate interface's QueryInterface method to determine the driver's supported interface version and to receive an interface pointer.