This function will create and assign a value to a private named parameter that
can be retrieved using CLEARWIN_STRING@. User defined parameters can be very
useful to communicate information between modules in a program (especially
between DLL's under Win32). This function should not be used to set system
CLEARWIN_STRING@ values except for:
This is the name of the document that is about to be printed. Its default value
is "ClearWin+ Output".