The SNiFF+ IDL Parser parses IDL files according to the CORBA 2.0 standard. Symbol information is extracted from the IDL files during parsing. This symbol information is then mapped into C/C++ data types and placed in the Symbol Table.
The symbol information in the Symbol Table is persistent between sessions, meaning that you do not have to reparse IDL source files (and source files of all other languages that SNiFF+ supports, for that matter) whenever you open a project that contains IDL source files.