Geoff Chappell - Software Analyst
The IPrinterFolder interface has just the one method (after the IUnknown methods):
BOOL IsPrinter (LPCITEMIDLIST);
The IPrinterFolder interface is implemented in the NT builds of SHELL32.DLL 5.00 and higher.
Though this interface dates from 1999, it was still not documented by Microsoft as late as the January 2007 edition of the Windows Vista Software Development Kit (SDK).