Optionally, the PCI may prompt the user to select all entities that are to be used by this operation. This would be done using the %ASKDIG and %ASKDIGINFO directives to select entities and positional information, with the %ADDDIGINFO, %ADDENTNAMEDIG, %ADDENTNODIG, %ADDFINISHDIG directives to build up a suitable buffer of digitised information to use with the %EXECCOMMAND directive.
Alternatively, the PCI may leave this stage to the application itself, by passing an empty buffer (-1) to the %EXECCOMMAND call.